spicyguy2005

I have 1989 420sel that had transmission work on about a year ago. Everything went fine until this winter. It happened on one of the coldest day. I drove on highway and noticed that when I set cruise on the engine was a little rough for a while. After driving for about half an hour, the engine suddenly stop when I took off from the highway and going to stop at the stop sign. After that it would not start. The engine cranked but would not start. After about 10-15 minutes, I tried again and after really long start I start hearing the engine firing. It came back to work normally. The mechanic that I took to found that one of the fuel pumps was bad, so he replaced with the used unit that he had and also replaced fuel pump relay to used OEM one. The car was doing fine until the weather got cold again. The same problem happened. I and my mechanic kind of thinking that it is not very likely that it's going to be fuel problem. One other thing that he think might be is the ignition system. The problem is when he has the car, the problem doesn't occur.

Does anyone have any idea? I am thinking it sounds like electronic problem and may be I should replacing ignition control unit with some of the used one that I can find on ebay. Is there anyway to test what is really wrong with the car, which part is really bad?

Thanks for all your help.

spicyguy2005

I have to add a little more. The second time that it happened the engine was a little rough before it stopped running. I have to wait about 5-10 minutes again to get it to start again. It happened 3-4 times, almost every stop sign that I used a brake. After that the weather was a little warmer and nothing happened again. The car is at the garage right now and my mechanic put some of his tester on waiting for the problem to happen, but it just not happen.

onizika

see the fuel filter near the engine

spicyguy2005

Fuel filter was replaced with fuel pump.

jhodg5kc

Sounds like a fuel pump relay to me...

Can you hear the pumps running when the car dies/fails to start?

Jonathan

spicyguy2005

Just an update on the issue. My mechanic did 2 wiring with small light bulbs, one from the fuel pump and another one from one of the spark plugs. So, in case the car doesn't start again, I can tell whether the pump is not working or whether the spark plug is not firing. Yesterday, it was quite cold in the morning, close to 0 degree F. I had trouble getting the car to start again and it appeared that the spark plug was not firing. Today I just got a used Ignition control unit from ebay. While I was driving to my mechanic to have the unit swabbed, car was running fine until I put cruise on, then car was running bumpy.

After part replaced, I drove out from the garage with no problem. Putting cruise on, the car was running very smooth as it should be. Tonight at about 11 pm, 10 degree F, my car started with no difficulty at all. It sounds like the problem might be solved. The Ignition unit that was on the car has no label on it. It might be some of the after market one that previous owner had put in some time before.

Hope that the problem is solved and thanks everybody for giving some comments. I will update the situation again next week.