Background: Car was randomly stalling while driving and sometimes while at idle, all dash lights would go off. Car would sometimes magically come back to life straight away if I was cruising - other times it would stay dead for a few minutes with all dash lights off, even with key in on position. Then the dash lights would come back on and I could start the car again. I changed the PTU for a series 2 and this seemed to fix the problem, but now it's back. I do need to get the adaptor for the PTU soldered to the existing connectors, as the join isn't great due to their age, so this could be the cause of the problem but I just wanted to list the other symptoms here to see if it could also be something else or if all symptoms could be caused by PTU issues. Also, I have just done both a ECU and Transmission diagnosis (auto trans) and both came back clear with no stored codes. I'd need a cable to check further. Car has stage 3 transmission valve body upgrade installed. Symptoms - Squealing belt - I think P/Steering belt, though it squeals even when wheel straight. Could a belt issue cause any of these problems? - Car randomly stalling as above. - When car has recovered from these hissy fits, afterward when the car is idling in Park it idles at about 1500 RPM. Putting the car back into drive slams it back into gear (as you'd expect). - When car has overdrive turned off and you cruise around the speed it would normally engage, the car will attempt to shift gears then go back to it's original gear every few seconds. Keeping the revs higher stops this, letting them back down to normal and it will start trying to shift again. With overdrive on this problem doesn't exist. - Old coilpack connections caused problems a while ago (one was loose and causing an occasional miss), though I don't think it is doing it anymore and even if it were, it probably wouldn't be causing this issue would it? So, apart from getting the PTU connections fixed, any other ideas? Especially revolving around the transmission and it's possible connection. Does the air regulator cause anything like this?
I had a similar problem after adjusting my tps. Only at night though, when there was the most load on my electrical system. Fine while driving but come to a stop at the lights and revs dipped down a bit too much and the car stalls. Mind you I had my thermo fan, stereo, lights, fuel pump etc all going at 12v so quite a drain. Got home and adjusted the idle screw to cope > no problems since. Is your alternator belt slightly loose causing the squeal?
Loose earth, battery or alternator terminals. The fact that all your dash lights go out points away from any sensor or PTU related problem. The bad earth could have triggered a failure in the S1 PTU though. Check battery and alternator connections, clean and tighten. Also check the earth on the chassis above the battery, the plenum and the block. Lastly while the car is idling jiggle the harness near the fuse box's, both drivers side firewall and passenger side arch to make sure you don't have a dodgy connection there as well. While a PTU can cause the intermittant drop outs, it won't shut down the dash lights, only a power failure will do that, and commonly a dirty earth somewhere along the line.
seconded bad main engine earth or battery connection. though bad positive will stop car from starting, bad earth causes mysterious electrical gremlins as you get a voltage difference between battery earth and engine and your guages will read high and eratic follow the earth cable and make sure shes bolted well to back of engine and gearbox
Thirded. i've seen a a similar problem a while ago with similar symptoms and it was due to poor power supply. Can't remember if it was bad earth or main 12v+ feed that was the issue, but definately mains power related
Thanks all. Taking it to auto sparkies tomorrow to get some other work done, will get them to check earths while they are at it.
Ok, can anyone tell me what to start checking for bad earths? I'm sure the battery if fine, as it's not only got the stock earth in the negative wire, I've also installed a grounding kit I made up a couple of years back and that' got solid connections all round. Where else do i look for earths? Cause all those wires give me a head spin and I don't know where to start A friend of mine said it might be a relay somewhere overheating, any of those I could check and/or replace? Or better off checking for more earths that might be dodgy? I still need to check through the fuses properly, but would they go bad? I though fuses were either on or busted? Obviously my electrical knowledge is not PhD level. I know how to work a multi-meter and read circuit diagrams etc. but don't be afraid to dumb it down for me.
Pull each fuse to check blades do not have arc marks on them and are nice and clean. Did the auto electrician check all the earth points for you?
mine did similar It turned out to be cas, check the plug to the cas, clean and reinstall. might work, did with mine. Hope this helps, Andy
