Jonnybegood

Hello everyone, I have a 1989 Iroc 5.7.(Bad starter) one day it started and the next day did not. And when it did start it was very lumpy misfiring. Anyway the car needed a MOT. I took it to my local garage when it started. The car went through its MOT. I went to pick up the car and guess what the car has now been at the garage for about 4 months now. It did not start. Anyway I/My mechanics cannot work it out. I have bought a new distributer, leads, spark plugs still no spark.
I even had an auto electrics guy look at the car, he touched the ECU unplugged and plugged back in, then we had a spark but not a very good one. I also had the ECU tested all fine. This is where I am at this moment in time, ECU will be put back in the car and see what happens, could it be the timmings?. I really think its very odd why would the car end up not starting it has always been a good starter. The car has only 85000 miles from new and has always started straight away in the past. Ps could it be injectors? But my mechanics think not.
This is bugging me does anyone know what the problem is?

Injuneer

Have you scanned it for codes? Have you checked the fuel pressure? Have you verified the injectors are getting the ground signal from the PCM to fire them, by using a 'noid light? Have you verified you have 12V on the positive wire at each injector with the key on?

How did you determine the spark was "not a very good one"? Do you have spark at the coil? .... at the individual plugs?

I'm assuming "MOT" is some sort of periodic vehicle inspection... not a term used here in the State.

ws6transam

Any news yet, JohnnyBGood?
I too, doubt it is the injectors. A single bad injector won't cause the other seven to up and quit. It sounds like an ignition, ground or ECM issue. I would try getting up under the passenger footwell and pull down the ECM, unplug it, remove the access panel, and re-seat the PROM chip. Re-plug the ECM in and see if it starts.

After that, I would re-check to make sure the distributor is plugged in properly and that it is aligned properly. If it's been replaced, it could have been installed 180 degrees out of phase; That'll do it. So will having the spark plug posts in the wrong position relative to the rotor. As will having the oil pump shaft slot mis-clocked when installing, causing the rotor to be in the wrong position relative to # 1 cylinder top-dead-center. To check this, remove the #1 cylinder's spark plug, and rotate the engine with a torque wrench on the harmonic balancer bolt until # 1 comes up to top-dead-center on it's compression stroke. Then, look to see if the rotor is facing the #1 cylinder post on the distributor. If it's pointed at #6 post (the one facing the fiewall/air conditioning unit), you are out by 180 degrees. If it's facing somewhere else, such as straight at the intake plenum, then your distributor rotor is mis-clocked by one spline on the cam gear. This is usually because the oil pump shaft rotates during installation as the distributor and cam gears engage.

Check that distributor installation carefully before diagnosing anything else.

Injuneer

As happens all too often, this individual signed off immediately after his first post, and never came back.

ws6transam

I guess I'll stick to answering posts that are less than a week old.

Jonnybegood

Sorry that i have not got back to you kind guys offering me help.
I have now got to the bottom of the problem. The car needed a new ECU which worked...Now I need a new chip or at least a working one...Can anyone help. I promise i will answer back I have been a little busy. Regards Jon