FCSFrank

Ignition control question??

Car running rough (lots of threads on this subject). Car was running okay but sometimes had a hard time starting with lots of black stuff out the tail pipe and rough running but would clear up within a few seconds and 1500-200 RPM. Today IO washed the car and now its running like its on 4,5,6 cylinders. It has done this before that resulted in the conditions prior to the wash. When I was washing I didn’t open the hood and was careful not to spray water in the engine area. But now the car is hard to start, I need to floor it to get it going, and when it does start it has No (0) power and barely rums in gear.

When the car is running and I disconnect the Left plug to the ignition control unit nothing happens, but when I unplug the right on the car dies???? Does that mean the ignition control unit is bad?? because only 1/2 of the ignition control unit is working?

What else could be wrong (there's an endless question)

Thanks in Advance

Frank
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91 S4 Auto

Tommy928

Either that and/or the coil(s) are bad.

FCSFrank

There was some moisture around the ignition control unit - I blew it out with compressed air???

Tommy928

I would soak it up with paper towels and let it air dry. Forced air may push moisture into the unit causing malfunction.

FCSFrank

good thought !....

Alan

Yes you are running on 4 cylinders - could be the final stage ignition unit, the coil for that bank or the distributor or it could be the ignition (injector) control circuit for that bank (the transparent relay on the ECU frame down by the CE panel) - check it for illuminated LED's while running.

Alan

Mrmerlin

pull off both of the coil wires and check for corrosion also make sure the hot post is dry and the hot post cover is fitted. Make sure that you have a thick black wire going from each coil mount to each cylinder head this is the ground. .When its dark spray some water with a spray bottle on the wires check and see if you find any arcing (engine running)

worf928

Swap a connection on the final stage amps shown in your picture. Take the plug that when pulled makes the engine die and put that plug in the other amp. If the car will not run then its that amp. If it does run then it's downstream of the amp: coil, wires, etc.

FCSFrank

I'll try the suggestions thur. any more thoughts??

Thanks for all of the thoughts


Frank

TheoJ

Frank,
just start by verifying that all spark plus do make a spark. Easy if you have some spare plugs and someone operating the starter, or if you have one of those inductive lights. If all sparks are there you can rule out quite a bit.

FCSFrank

Car seems to work fine today. it was 98 deg. today so all is dry. the only issue I have is that I still have to floor it the get it started. In the future I plan to replace all ignition stuff from the ignition control unit onward.. I'm sure it due anyway. I just need to figure out why I need to floor it to start it. when driving the "check engine" light comes on and then its hard to start. if it doesn't come on it usually starts normal.. I'm thinking a sensor of MAF.????

Thank all

Frank
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91S4 auto