Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 29 July 2002 at 17:15:16 UK time | |
Hi guys, I'm hoping one or more of you may be able to help me with the challenge I currently face with my Elan. History... I hadn't driven the car for maybe 2 weeks. Came to use it and the battery was discharged and would not start the engine. Jumped the car and then drove approx 40+ miles to charge the battery. Stopped for 4 hours, then started the car with no probs and drove back. Later that day, I can to use it again and it was misfiring badly and upon trying to drive it, was cangarooing like a mad thing. Tried again the next day and it would not start. The battery was not holding charge so I first disconnected the boot light (knowing it to be a problem) and when the charger was not doing any good, purchased a replacement. Tries to start her again and although the engine is turning over it is not firing up. I have checked several things: Spark plugs - These are less than six months old and have doe no more than 1000 miles but appeared to have quite a heavy carbon deposit on them. Re-gapped them checked for cracks, even bought new ones, to no avail. HT leads are fine - 6 month old Magnecors. There is a fine spark on both the plugs and HT leads when grounded on the engine. Petrol appears to be getting through as there is quite a strong petrol odour from the exhaust and one the plugs. I am getting no "Check Engine Light" and there are no fault codes stored. Following the Engine Management section of the Workshop Manual, I feel the closest description would be the Cut Out, Misses section of EMK.6. I therefore went through the process of checking for misfiring / crossfiring by startnig the engine, disconnectng the Idle Air Control and then, one by one, grounding the HT leads to observe drops in RPM. Each cylinder dropped by approx 50 RPM except number 1. I've now exhauseted my basics of ideas and am hunting for help in whatever form it may take. I am sure I can solve the problem myself if only I can diagnose it in the first place. Look forward to any and all replies. Matt
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Robert Collins
West Yorkshire
United Kingdom
robert@moorways.freeserve.co.uk
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| Posted 29 July 2002 at 19:32:47 UK time | |
Matt.
Just a thought.
Apparently a duff connection on (or a failed) coolant temperature sensor can cause the engine to run at maximum enrichment. May be buggering up your spark plugs??
See
http://www.lotuselancentral.com/cts.htm
for a write-up.
Rob.
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S D ENGLISH
South Yorkshire
United Kingdom
s.english@hannahreed.co.uk
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| Posted 29 July 2002 at 20:39:28 UK time | |
Hi Matt
Firstly I expect that you've checked that you've not been sold some duff petrol. I had similar problem once and after checking with petrol station found that the petrol was contaminated with water.
About three years ago I put a brand new engine in my M100 and it wouldn't start - tried everything. Good spark, smell of petrol, engine turned over, timing spot on. After a month of no success - I, to my shame, called the RAC stating my car wouldn't start on the drive. The RAC guy was a gem - I confessed all - he had a sense of humour too and over the next hour he got the car going. The problem was all 4 injectors were sticking to varying degrees. The fuel in the fuel rail had evaporated due to time and the hot weather leaving a residue which was stopping the injectors functioning correctly. By gently tapping each injector in turn with the wooden handle of a screwdiver each was coaxed into life and the engine fired hesitently at first but then perfectly. I was wondering with the recent hot weather?
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M Evans
West Yorkshire
United Kingdom
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| Posted 29 July 2002 at 21:46:01 UK time | |
Its quite likely that your battery was just dry (Especially this time of year)
How many rpm did you drop on cylinder 1 more or less than 50?
When the engine has been running a bit and you take the plugs out are any of them colder than the others?
Have you got the old HT leads available?
When you start have you tried using the hot start failed procedure? (basically full throttle during the crank and initial start) Then try to keep it at high rpm while the plugs clear
Top suspect is the coolant temperature sensor (more usually just the connector) as Robert said or maybe a sticking IAC valve.
Another possibility is a dodgy coil. Can you get access to a voltage tester? (an adjustable spark gap thing)
When you test the spark plugs have you been doing it with all the plugs out and all the plugs still connected but earthed to the engine?
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 29 July 2002 at 22:48:11 UK time | |
Thanks for your support guys. That CTS sounds like the likely cause. As regards the RPM drop... Cylinders 2, 3 & 4 dropped approx 50 and 1 did not even twitch. One of the problems I'm having is an intermittent ability to start one time and then not the next, so making a consistent symptom analysis is difficult. Don't think I still have the old HT leads... they were well old (probably the originals) The new ones have been working great for the last several months as a daily driver so i don't think its them. I've noticed in the past that if the car has been standing for a few days / week without a run, it is a bit lumpy when you first start up and the smooths out after 20 - 30 secs. I initially thought this was the same this time, but the symptoms did not clear. As regards testing the coil... give me a few pointers. I have an ajustable voltmeter that a friend just bought me for this very problem but, having never used one before and not being the most conversant with electrics, how would i go about testing the coil(s) without leaping backwards across the garage? I have been testing the plugs one at a time, taking one out, testing it, then replacing it before checking the next. I'm a complete rank amateur at this mechanics lark, butfigue its better (and cheaper) to learn and maintain it myself. Thanks again. Matt
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S D ENGLISH
South Yorkshire
United Kingdom
s.english@hannahreed.co.uk
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| Posted 29 July 2002 at 23:38:43 UK time | |
Matt
With respect to CTS - as earlier e-mail I installed a new engine in my M100 - purchased it from Peter Smith Sportscars in Derby. Daniel (Spares Manager) called me approx 6 months later and asked if I had a CTS on my old engine as they had a problem M100 which would not run correctly - Lotus could not supply this part (back order!). My 2nd hand CTS cured the problem and I know they subsequently obtained a number direct from Isuzu - costs I recall were circa £38. If you can't source a replacement - may be worth contacting them. Good luck.
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 05 August 2002 at 19:35:14 UK time | |
Still having no joy with this bugger getting started. I've removed the CTS and it has no corrosion on the contacts or visible signs of failure. I've checked the timing belt and that is spot on. I've checked the compression of all cylinders and they are all spot on. I've flushed and changed the coolant.I've cleaned and re-gapped all the spark plugs and I've given all the injectors a good tap to aleviate any potential stickyness. It started and ran very poorly yesterday and today it will not start at all! Any more ideas?
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 05 August 2002 at 20:18:39 UK time | |
Matt,
Fumbling in the dark here, but a few ideas...
Bad engine earth.
Simple test for a major intake system blockage - try starting with the big fat rubber hose removed from the throttle body.
Have you checked the basic engine timing is OK?
http://www.lotuselancentral.com/timing.htm
has a write-up but of course you need to be able to start the bloody thing first... :-(
If you have a multimeter (they're only about £15 to buy a cheap one) you can go around all the engine sensors, checking voltage, resistance etc. All the values are posted in the workshop manuals on lotuselancentral.com
If your timing's OK, spark looks strong, fuel seems to be getting through, then the next thing I can think of is the MAP sensor might be reading wrong, which again would bugger up the fuel mixture.
To check the MAP sensor (it's mounted about centrally on the bulkhead, behind the windscreen wiper linkage), get a 6" bit of wire and strip about 3/4 of an inch of insulation off the end.
BTW this is the technique I used to test my poor man's fuel cut preventer....
Disconnect the plug off the sensor. With the plug disconnected and the ignition on, check that the left hand pin on the plug (viewed from the front of the car) has +5 volts. This is the power supply to the sensor.
Switch the ignition off again and make a loop in the stripped end of your bit of wire.
If you look at the plug, you'll see it's possible to wrap the loop of wire round the centre pin on the plug and still be able to jam the plug back on the sensor. This will allow you to test the voltage at the centre pin, with everything connected up and the ignition on.
Be VERY careful not to short between the pins or to earth with your bit of bodgit wire!!!
With your multimeter connected to the wire and the ignition on, you should see something in the region of 2.3 - 2.5v on the centre pin of the sensor. This is the voltage you'd expect from a healthy MAP sensor with the engine stopped. No voltage, or wose still +5v suggests a duff MAP sensor.
HTH
Rob.
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Sooty
Lancs
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| Posted 05 August 2002 at 20:26:12 UK time | |
I'd really love to understand what the hell you guys are talking about .... someday.
But for now I'll keep driving it till it breaks !!
SOOTY
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M Evans
West Yorkshire
United Kingdom
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| Posted 05 August 2002 at 20:40:03 UK time | |
Matt,
Is your car an SE or an S2?
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 05 August 2002 at 21:17:18 UK time | |
1990 SE (and pink!)
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M Evans
West Yorkshire
United Kingdom
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| Posted 05 August 2002 at 21:40:36 UK time | |
Personally i'd try another coil on it before too long (A100E6084F - somewhere about 80 pounds from Lotus) Then maybe go for a CAS rebuild.
Another possibility first though - The CO pot has gone faulty and your mixture is way too rich.
Assuming non A/C car then this should be at the top right of the ECU (sort of behind the connector, you'll only see it from
underneath with your head in the footwell)
Pin B12 on the ECU (Slate/Blue) to ground should be somewhere between 0.6 and 4.2v with the ignition on. If its at the extremes then its probably wrong.
Disconnect the battery and then reconnect after about 30 secs to wipe the ECU non volatile memory.
Tweak the pot with a screwdriver to midpoint. Look for somwhere around 2.5v and it should start.
Remember to start using the hotstart procedure and then keep a wide throttle opening (2500rpm say). Don't let it slow or fast idle for the first 5 mins.
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 05 August 2002 at 21:45:22 UK time | |
Thanks for your ideas Rob. A 'bad engine earth' was one of the first things I was recommended to check by a mate, but to be honest I haven't got a clue where I should be looking. I presume it is the braded style cables that I can see running via the bonnet hinges down either side of the engine. I think one goes into the ignition coils, but after that I haven't got a clue. Where does it end up grounding on the chassis?
I'll try venturing into the world of the multimeter, but i haven't had cause to use one before so bare with me!
Checking back over archive posts on Lotus Elan Central I noted thatthere have been a couple of incidents of a similar nature. Heavy carbon deposits on the plugs and exhaust, so I'm still thinking it could be the CTS. Saying that, I don't fancy splashing out £35 to ind out t still doesn't work. And as I can't get it to a Lotus garage I'm kinda stuck.
Could any of these sensors fail suddenly, i.e. working and then 2 hours later not working at all, and if so, which is the most likely to fail in this way?
Matt
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M Evans
West Yorkshire
United Kingdom
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| Posted 05 August 2002 at 23:43:49 UK time | |
The engine earth you seem to be worried about connects on the right hand side (looking from the drivers seat) of the plenum chamber (this is the thing with DOHC 16v written on the top)
The earth braid itself is sort of right next to the pipes on the bottom of the power steering reservoir and goes from the chassis longeron behind the engine mount on the rhs of the engine to a bolted connection that goes into a tapped hole in the horizontal plane on the RH end of the plenum chamber. It might actually be into the end of the secondary throttle body, but i'm reasonably sure its not onto the engine itself as when I saw where it was connected from the factory it suprised me, gaskets and things like that getting in the way of a low resistance connection.
The main thing this does is provide the earth return for the alternator and starter motor, which if its not done right goes right through your ecu <vbg>
If you follow the wires from the end of the fuel injector rectangular plastic harness support and you'll see the engine management earth (3 or 4 black wires) The engine earth braid should go to the same point.
The CTS should set a code 14 or 15 if it were faulty, but not necessarily set a check engine light. If you get it going and it still faulty check for fault codes again.
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S D ENGLISH
South Yorkshire
United Kingdom
s.english@hannahreed.co.uk
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| Posted 06 August 2002 at 23:26:11 UK time | |
Matt
Sorry to harp on - put I am as you will have discerned a petrolhead - have you had the fuel pressure checked at the fuel rail? - see manual - not a problem with fuel filter? - easy to change and replacement obtainable from Halfords.
Simon
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Matt Pritchard
Swindon
UK
matt.p@newyoultd.co.uk
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| Posted 07 August 2002 at 01:07:54 UK time | |
Thanks Simon, I'll check the fuel pressure out. The petrol filter is under 15,000 miles old so should be ok. From what I remember from changing it last time, it wasn't 'that' easy!!
Cheers
Matt
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S D ENGLISH
South Yorkshire
United Kingdom
s.english@hannahreed.co.uk
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| Posted 07 August 2002 at 23:00:00 UK time | |
Matt
You're right - it was a bugger to remove I now remember! -lost skin on three knuckles. Hang in there.
Good luck
Simon
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 08 August 2002 at 01:30:31 UK time | |
I managed to get the thing started after a bit more tinkering, by doing the 'hot start' method. Fired up and ran at a slightly high idle, lots of fumes from the exhaust, which may or may not be due to the many attempts at starting clearing out. Still sounded lumpy and 'not right' to me, although better than it had been, and there seemed to be an excessive 'tappet style' noise from the engine bay. (I know there aren't any tappets on the thing, but you know what I mean.) The exhaust note was also off from how I remember (it's been nearly a month since I last heard it run sweetly). Then, to top things off, I noticed a slight smoke rising from the front of the engine! On inspection, it appears to be the gasket between the exhaust manifold and head which, although a bitch to access, I should be able to sort out.
I've now decided to get a well experienced mobile tuning and diagnostics guy round to check it out. Don't know what he'll come up with, but it can't make things worse - can it?
If any one has any additional feedback or ideas based on the new info, they are still welcome!
Thanks all
Matt
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peter bentley
United Kingdom
peter@bentleywood.demon.co.uk
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| Posted 08 August 2002 at 15:59:08 UK time | |
forgive me but whats a CTS ?
my guess for what its worth is fuel pressure, but as i say its a guess.
peter
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robert collins
hebden bridge
robert@moorways.freeserve.co.uk
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| Posted 08 August 2002 at 17:18:37 UK time | |
CTS = Coolant temperature sensor (? or sender).
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Matt Pritchard
Swindon
mattt.p@newyoultd.co.uk
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| Posted 08 August 2002 at 17:54:11 UK time | |
In this case it was the Coolant Temperature Sensor that I was referring to. Helps control the fuel air mixture, ignition timing etc.
Just had a mobile tuning guy around, and now wish I'd done it 3 weeks earlier... the guy's a bloody genius (helped by a shed-load of diagnostic kit). Managed to get the tappetty sound virtually silenced with new some engine additive mixture. I was actually the hydraulic lifters that were making the noise and as the additive takes a couple of thousand miles to work properly it should get even better.
From all his checks he determined that the Manifold Air Pressure Sensor (MAP) is on the way out, or is not function at top notch. Has anyone got any sources they are prepared to share where I can get one cheaper than Lotus and Co will charge. Any American importers or UK Isuzu dealers. My local Isuzu dealer hadn't even heard of the Impulse.
Thanx again
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 08 August 2002 at 21:17:30 UK time | |
Matt,
The MAP sensor is a standard GM part.
It's the 2-bar sensor you need. If your local vauxhall garage look blankly at you, try
http://www.aquamist.co.uk/sl/plist/frm.html
Look for part no 806 666 - (click on the little tick symbol in the rightmost column on the page).
Price £66
HTH Rob.
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 09 August 2002 at 00:13:26 UK time | |
Your a star Rob. One of their distributors is 5-6 miles from home. I owe you a drink for saving me the extra sixty odd quid!
Matt
P.S. - any idea where I might get a Coolant Temp Sensor cheaper? (thought i might as well change it if I can get one) I've seen them on US sites for the Isuzu Impulse for as little as $7.99, but they don't appear to deliver this side of the pond.
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peter bentley
United Kingdom
peter@bentleywood.demon.co.uk
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| Posted 09 August 2002 at 10:31:21 UK time | |
whats this additive then ??
peter
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Laurence
Hampshire
UK
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| Posted 12 August 2002 at 09:10:50 UK time | |
Matt, was the additive Slick 50 ?
Laurence
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 12 August 2002 at 09:49:40 UK time | |
I forgot to check the name of it before he went, but I think the additive was from the STP range and was specifically for hydraulic lifters. I've seen the Wynn's version on the shelves, but so far haven't seen this one.
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 12 August 2002 at 13:15:21 UK time | |
Matt,
Any chance I can have your knackered MAP sensor off you, to make it into a plug-and-play fuel cut preventer?
Rob.
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 12 August 2002 at 15:56:35 UK time | |
Rob
Still got to get the replacement yet. I got one from Vauxhall that looks identical but does not work at all! So I now have one on order from the distributors of that weblink you posted.
I was gonna butcher the faulty one to see what the workings are like. I don't see how too much can go wrong with the damn thing. I managed to get the CAS up and running again thanks to the link on Elan Central. But as you helped out with that link I'll send it to you as and when I get the new one installed and running. Email me your postal address off board.
Would the CTS be the same as in the Isusu Impulse? I ask as I've found an American site that does international orders and stocks all the bits for the Impulse. Check it out and let me know what you think.
http://webepc.com/cgi-bin/sewse?/u/www/webepc.com/cmm/scripts/epc10.cmm
Matt
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Matt Pritchard
Swindon
matt.p@newyoultd.co.uk
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| Posted 12 August 2002 at 15:59:50 UK time | |
If that link doesn't work, try this one!
http://www.discountautoparts.com/index.htm
Then just follow the links and add the details of the Isuzu Impulse, year and part etc.
Anyone got experience of importing and the potential cost involved? Shipping, Duty etc.
Matt
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robert collins
At the Calderdale MENCAP 50th birthday party
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| Posted 17 August 2002 at 16:11:48 UK time | |
Matt,
I spotted a note in the Elan engine management manual re faulty MAP sensors. Apparently the system is designed to cope with a failed MAP sensor, by using other readings (throttle position, revs etc.) to infer values and keep you running.
If that's the case, you should be able to completely unplug the MAP sensor and run (not very smoothly I guess) without it.
Rob.
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 19 August 2002 at 09:43:19 UK time | |
Can confirm on my car the engine starts, revs and idles ok with the map sensor unplugged.
Rob.
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Matt Pritchard
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| Posted 19 August 2002 at 17:31:45 UK time | |
Thanks rob. I'll check it straight away... If it don't work then I'll start looking elsewhere.
Matt
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Matt Pritchard
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| Posted 19 August 2002 at 17:55:31 UK time | |
Tell me Rob... Was it just the electrical connector that you had disconnected, or did you take off the hose connection as well?
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 19 August 2002 at 19:38:33 UK time | |
I just unplugged the electrical connection - if you undo the hose, then you'll need to plug the end, or it'll suck air in at idle. Had no problem at all starting from virtually cold (had just moved car out of garage first). The "check engine" light did come on though, with the MAP sensor unplugged.
Rob.
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Matt Pritchard
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| Posted 19 August 2002 at 20:06:05 UK time | |
Doh!... That'll explain the pop then!... Don't tell me I've buggered anything or I may have to resort to leaping off bridges. I'll plug the hose back on and try again. Just look the other way and pretend you don't know me.
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 19 August 2002 at 20:34:31 UK time | |
Pop?!?!?
No Idea what that might be. I wouldn't have expected anything significantly bad to happen just from leaving that little hose disconnected, just that it'd idle a bit lean, or a bit fast or something.
Any idea where the pop came from??
Rob.
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Matt Pritchard
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| Posted 19 August 2002 at 20:43:06 UK time | |
Nope! As I was in the car with the door closed, I could't make out whether it was from the engine bay or the exhaust. I was turning the engine over in an attempt to start it, expecting to either have the same none starter or for it to jump to life with the aid of the other sensors. It was trying to start after the first couple of seconds then there was the popping incident which kinda scred me into leaving it alone until I'd checked again with you.
The sensor was neither plug or plumbed in, so I was hoping it was either the lack of manifold sucking in air and generating the pop or it was a build up of pressure in the system from several failed start attempts last week.
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 19 August 2002 at 20:57:15 UK time | |
Are we talking LOUD pop or quiet pop? I get pops from the exhaust quite often. Unburned fuel builds up in the exhaust then ignites with a pop or a crackle. I get it a lot on overrun, eg downhill using engine braking. Nothing earth shaking, just a bit of a pop which is loud enough to be a bit embarassing at times.
If you were cranking the motor with the throttle wide open, then the disconnected MAP sensor pipe would make bugger all difference anyway.
Just a thought - before you reconnect the MAP sensor, see if you can blow through the pipe (hold the throttle linkage open at the same time). It'd be a bit of a pi$$er if a blockage in the pipe was the cause of all your troubles.
Rob.
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 19 August 2002 at 21:04:45 UK time | |
Just trying to think how the pop sounded. I get the overun pop myself but, from memory of the last time I drove the thing properly (6+ weeks now) i remember it being a little more basey.
I was initially trying to determine whether it was a pop or a 'crack'. I can't actually think of the appropriate word to describe it, suffice to say it was poppy with a slightly higher note than the normal bass I get from the SS exhaust system.
I'll do the pipe check, replumb the MAP sensor in and try it again in the light of tomorrow.
Thanks again Rob
Matt
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 20 August 2002 at 14:51:51 UK time | |
Rob,
Having checked the pipe for blockages (none evident) and re-plumbed in the MAP sensor I managed to get her started after a couple of attempts. Still very lumpy when trying to increase revs at all and searching at idle.
I've checked again with the MAP sensor supplier and they are still out of stock.
Matt
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Philbo
upstairs
phil@informatica.uk.com
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| Posted 20 August 2002 at 16:32:03 UK time | |
Matt, have you tried here: http://www.aquamist.co.uk/sl/plist/frm.html for a replacement GM 2bar sensor? I ordered the 3bar one for my Unichip upgrade (now delayed by a few weeks), and it arrived the next day.
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robert collins
hebden bridge
robert@moorways.freeserve.co.uk
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| Posted 20 August 2002 at 16:52:12 UK time | |
Matt,
From the way you describe it, it sounds like unplugging the MAP sensor has made no difference, which would tend to suggest something else is at fault (as well as the MAP?)
Has the CAS gone again??
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 20 August 2002 at 17:39:24 UK time | |
Philbo,
Thats where I'm waiting on. The local supplier to me is only 6 miles away and contacted both them and his other contact who are waiting on the 2 Bar sensor. He's chasing them up at the end of the week.
Cheers for the thought tho.
Matt
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 20 August 2002 at 17:50:22 UK time | |
rob,
You're right, it does sound pretty mush the same as when I had the MAP installed, but with that in mind, the last time I had the MAP plugged in, it would not run at all.
I don't think the CAS has gone again. I did check the basic physical state of it when I was conducting my visual diagnostics and although there was some surface corrosion (which I cleared up) it otherwise seemed OK. I did the DIY resoldering about 8+ months ago and it has worked fine since then. Again no check light to indicate that may be the problem.
From what I remember, the ECU uses a combination of the Throttle Position Sensor and the Idle Air Control to compensate for problems with the MAP. Should I be looking to these 2, and if so, how would I do a home diagnostic with little more than a Multimeter?
I still have a tendancy to think back to the CTS as well.
Any thoughts?
Matt
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 20 August 2002 at 18:42:02 UK time | |
Anyone have any insider knowledge or thoughts as to whether the MAP sensor, Trottle Position sensor and CTS are the same on the Isuzu Impulse. The guys at Aquamist.co.uk are awaiting an order for parts from GM, including the 2 Bar MAP sensor, which they placed over a month ago. So it could be with them tomorrow or it could be another 3 months away!
I've found a US parts place with an online facility that ship worldwide daily and they list all three of the above. I am pretty sure the CTS is for the same as it lists it as "[COOLANT TEMPERATURE SENSOR]; TURBOCHARGER; DOHC", but the others are not so obvious.
Cheers
Matt
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Philbo
Upstairs
phil@informatica.uk.com
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| Posted 20 August 2002 at 19:58:30 UK time | |
Matt, you are welcome to "borrow" my 2bar MAP sensor when I install my 3bar one...this would have been tomorrow but I'm now waiting on the next generation of Unichip to be released "in a few weeks".
If you're still stuck when mine gets liberated from my car, you can have it until your supplies come through - I'd like to hang on to my one long term in case I sell the Elan (not likely, but you never know) and want to hang on to the Unichip.
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 20 August 2002 at 21:09:17 UK time | |
Matt,
You can check the CTS with a multimeter, by measuring its resistance. The manuals on Lotuselancentral contain a table showing resistance (in ohms) versus temperature. It's in Section EMK-4 but I can't tell you the exact file to look for as I'm reading from a hard copy.
Likewise, you can unplug the MAP sensor and TPS to check their power supply. With the ignition on, you should get a +5volts supply at one of the pins on each connector. Then to test the output from each, you can use my bodgit-with-a-bit-of-wire technique to test the signal outputs from them.
NB I found that you have to be careful to make sure that the ground lead of your multimeter is WELL grounded! I ended up jamming the test probe firmly under part of the turbo heat shield to get a good connection.
The other thing I thought of was the procedure for timing adjustment from Lotuselancentral, where you put the ECU in "field service" mode, which forces it to run without reference to any of the engine sensors except the CAS. I guess that'd be a way of narrowing down the search slightly.
Not sure what you can do to test the IAC valve, but there's a procedure to re-set it back to a "base" position. From Lotuselancentral,
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Slowly raise engine speed over 2,000 rpm, and return to idle slowly to reset the IAC valve at the 20 count position.
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Other than that I'm about run out of ideas DIY-wise. Testing fuel pressure and checking individual injectors needs gear that I personally haven't got access to.
Hope you get it sorted soon,
Rob.
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 21 August 2002 at 01:47:18 UK time | |
Philbo,
You're an absolute star. I'll obviously keep you posted as to the delivery situation. But as and when you have your unichip and 3 bar sensor sorted I would be most grateful if i could borrow your existing one. Post a message up here or drop me an email when your new 'go-faster' bits come through.
Cheers
Matt
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 21 August 2002 at 01:51:45 UK time | |
Rob,
Thanks again for your suggestions and your patience with me and the challenge. I'll run through each of those points tomorrow / today and let you know the results.
Matt
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 22 August 2002 at 15:51:36 UK time | |
Tell me Rob / Phil
Would the 3 bar MAP sensor work on the Elan as standard? Just thinking it may be easier to get hold of the 3 bar than the 2 bar. Or is there some ECU programming that will confuse the hell out of it?
Started through the diagnostics that you've suggested and basic results are as follows:
Started the engine and placed it into diagnostic mode with the paper clip. The engine revs dropped significantly at idle to nearly stalling, then raised slightly. The revs then regained slightly before pulsing (i.e - dropping and increasing evenly) every 1-1.5 secs)
From checking the voltage supply to the MAP sensor, I get a steady 5V with ignition on.
Making my loopy wire now to check the rest, but feedback on the above would be great.
Matt
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Philbo
Upstairs
phil@informatica.uk.com
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| Posted 22 August 2002 at 16:07:33 UK time | |
Matt
No, you can't use the 3bar MAP sensor as it produces different output voltages for the same pressure - 0V at 1bar vacuum and 5V at max (+1Bar for the 2bar sensor and +2bar for the 3bar sensor).
When you had a real +1bar the ECU would think you only had about +.3bar and would run lean, damaging the engine.
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 22 August 2002 at 21:12:36 UK time | |
Matt,
Will have a read of the manual re the unstable idle in diagnostic mode.
Rob.
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 22 August 2002 at 22:55:44 UK time | |
Just done voltage tests for the MAP sensor, and TPS.
Both are returning a 5 V supply.
The MAP is showing an output of 2.35V, which by my reckoning is within normal parameters and correct me if I'm wrong, but implies that there is not a problem with it!
The TPS has an output of .4V at Idle and 4V at full open throttle. Again, within the normal parameters.
I'm having trouble getting a resistance reading from the CTS - any tips?
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 22 August 2002 at 23:25:46 UK time | |
Is it showing zero resistance or infinite resistance?
I'd first guess the temperature, then look up in the table roughly what the resistance should be, then set the multimeter scale accordingly.
Maybe you've just discovered the problem?
Rob.
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 22 August 2002 at 23:30:32 UK time | |
Another test I did with the MAP sensor was to pressurise it with a bike pump and see how its output responds - the voltage should change almost instantly as the pressure changes.
Sluggish response would indicate a dodgy sensor, but shouldn't cause idling problems as the pressure doesn't change much at idle.
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 23 August 2002 at 16:09:09 UK time | |
Rob,
I'm getting absolutely no reading off the CTS at all. I.e. I set it to either 2000 or 20,000 ohms and get a digital default of '1', this does not change when connecting it to the terminals on the CTS. Outside air temp is approx 70 F and should therefore return a reading of 3,400 ohms, but I can't get a reading on the multimeter.
Would this indicate to you that the CTS has gone (as we suspected all along)? From what I understand, reading the elan central writeup, the CTS would return a reading of -70C if the sensor was faulty. Would that mean that the 'infinite resistance' is outside of the multimeters capable range?
The Auto Tune guy that I had out concluded that the MAP sensor was on the way out. I cannot remember the exact readings of his equipment but, when the engine was running, it was essentially peaking momentarilty when the throttle was opened, but then returned to the base reading with the throttle still open. Not knowing how the damn thing works, would that mean the MAP is faulty too? I'll do the bike pump test to check it again.
Matt
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 23 August 2002 at 18:05:56 UK time | |
Just tested the MAP sensor with the pump attached and the voltage increase is instantaneusfrom the idle 2.35v up to about 5v.
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 23 August 2002 at 19:24:20 UK time | |
Matt the "1" indicated on the multimeter is what I meant by infinite resistance, IE resistance so high it's off the scale.
That kind of suggests to me that the CTS is buggered.
Regarding the MAP sensor, it sounds OK to me, but it's difficult to test it under vacuum conditions (as when idling) unless you've got the special hand-pump tool for testing vacuum systems.
Thinking logically about the MAP sensor response when running, I'd expect it to show a pretty low voltage at idle (ie under quite a bit of vacuum) then the voltage would go up as you opened the throttle (as air rushes into the plenum, the pressure increases, but is still under a bit of vacuum) maximum vacuum/lowest voltage would occur on overrun, when engine revs are high but the throttle is closed. Not sure how this squares up with the tests the auto-tune guy did tho'
I'll just pop out and see if I can get an ohmmeter reading of my CTS...
Rob.
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 23 August 2002 at 19:46:45 UK time | |
:-( too dark to see what I'm doing. Will try another time.
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Lou Screw
Home
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| Posted 24 August 2002 at 13:41:16 UK time | |
Matt,
Just how many wires are on the connector to the CTS you are checking?
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 24 August 2002 at 21:08:07 UK time | |
Without looking I'd say 2!
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Matt Pritchard
Swindon
United Kingdom
matt.p@newyoultd.co.uk
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| Posted 30 August 2002 at 20:13:54 UK time | |
Wooo Hoooo!
Got my baby back on the road again.
The CTS was the culprit all along. Ordered one in from the states, via the internet last Saturday and it came through this morning. Now she's humming sweetly again.
FWIW - the CTS from america (for the Isuzu Impulse) is £12.00 and even with shipping etc came in at under £30.00 which is about £15 cheaper than the lotus part (without postage)
Matt
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Robert Collins
Hebden Bridge
robert@moorways.freeserve.co.uk
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| Posted 01 September 2002 at 16:25:00 UK time | |
Great Stuff Matt. At Last!
I reckon a multimeter should be on every Elan owner's Xmas present list.
Rob.
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