I'm currently putting my '89 1.7 GL back on the road. Mainly doing bodywork at the moment but the engine's not been running to well at times. Sounds like a missfire or rough running. Car has not been on the road for 6 years but has been started and moved regularly, esp. this year. It was OK when taken off the road. I've already done the in line fuel filter, all ignition leads, dizzy cap, rotor arm, checked plugs. Two days ago it got so bad I could hardly start it. I thought I'd damaged the renix ECU by welding with the battery connected (I do disconect, but forgot the other day). Tonight I decided to check the flywheel sensor as I'd been grinding a lot and wondered if lots of metal fillings could have stuck to the magnet (It was very windy here the other day!). Found it in a filthy oily mess:
On cleaning, refitting and starting the car, a smoother missfire! tried removing the ignition leads one at a time, no change when i took number 4 off and engine ran better with 1 off In fact it ran better when I just left the two leads touching but not fixed on the plugs. Very odd. Ran the engine a bit faster like this for a few seconds and sounded almost normal but a bit rough, then put the leads back on the plugs. Engine now smooth and perfect though the revs (but idle a bit low). Anyone got any ideas what could be going on as I've had it running fine, but then the next day it's back to missfire again. Cold engine problem, intermittent ignition fault or could it be a carb problem? My next test will be to see if the renix unit is ok, there's a good explanation of it on the V.O.C forum with ways to test it.
Check the disty for oil in the cap, although sounds more serious. Could be tracking at the plugs or faulty plugs. When you remove the lead the voltage can go higher and clear some obstacles or something like that. I used to do alot of wet motorway driving in my 360 and once or twice it refused to start due to a dirty coil at going home time I removed a plug lead and cranked the engine until a spark was seen against the block, then put it back on and the engine started fine. Cleaning the coil usually made it more reliable.
Thanks for that, the distributor cap is new and should be oil free as I've hardly run the car since changed it a few months ago. I'll check and clean the coil contacts on the renix unit and other contacts as it does look very dirty. Damp may get in as the car is not being run up to full running temperature very often at the moment while I move it in and out the garage and it does stand outside sometimes. I went to start the car this morning and it was running fine! If the problem returns I'll try new plugs, then at least that's one less thing it could be.
I'm not convinced as to what it could be, but the one thing you don't mention you've checked is the coil on the renix. The 2 torx screws on the front will let the coil drop off, which you'll need to do during mac's Renix check anyway. Just check those contacts arn't oxidised.
Tried starting it this morning again and it's still running fine (Thats the first time I've had consistent good running since I've been working on it). I'm letting the engine warm properly from now on when moving it around to work on the body. No I've not tried the coil contacts yet, I will check/clean them when I get chance. TBH I'm new to messing about electronic ignition and just finding my way around all the bits and bobs, it seams fairly straight forward once you get down to it though.
tried removing the ignition leads one at a time, no change when i took number 4 off and engine ran better with 1 off 
In fact it ran better when I just left the two leads touching but not fixed on the plugs. Very odd. Ran the engine a bit faster like this for a few seconds and sounded almost normal but a bit rough, then put the leads back on the plugs. Engine now smooth and perfect though the revs (but idle a bit low). Anyone got any ideas what could be going on as I've had it running fine, but then the next day it's back to missfire again. Cold engine problem, intermittent ignition fault or could it be a carb problem? My next test will be to see if the renix unit is ok, there's a good explanation of it on the V.O.C forum with ways to test it.
