Clicking sound under dash, engine dies

[delneroni]

A couple of weeks ago I started hearing a rapid clicking sound from under the dash of my 1990 Plymouth Laser 2.0L Turbo. I thought the radio/disc player was malfunctioning. But soon the engine started to cut out when this happened. Within a couple of days, everytime I started the engine the clicking would start and the engine would shut down after a few seconds. So the car is completely down now.

My mechanic replaced the MPI relay but the problem still occurred, so he said it was the computer (ECU). I sent the control unit to an Foreign Auto Computer in Florida and they said there was a problem with it and supposedly fixed it and sent it back - but when we reinstalled it we experienced the same problem (no change). Engine starts, revs up, then dies.

We also replaced the air intake unit with all the air flow sensors in it, but no luck, same result. So at this point I am out a few hundred dollars with no progress being made.

I spoke to the guy that fixed the computer and he said they tested it in their car before shipping it back to me, and it worked ok. So it would seem that the computer is not the problem, but I am still not 100% convinced of this..

We are out of ideas. Every other case of this kind I have read about was fixed by replacing or rebuilding the ECU or the MPI relay. If it is not the computer or the relay, what else could be causing the engine to shut down shortly after startup? What other possibilities should we look for?

Thanks for any help you can offer.

Del

 

[Lionel Hutz]

The capacitors in your ECU are probably leaking.

http://www.tmo.com/howto/ecu1g/caps.htm

 

[huafist]

Your capacitors have leaked and the electrolyte has eaten away the fuel pump control traces. Whomever you sent it to probably just replaced the caps and said it's good because the ECU will pass a heartbeat test and doesn't throw any error codes in this state.

This is a common failure when dealing with leaky capacitors. Send it to steve, he'll fix it for you.

 

[oldman]

This is a common failure when dealing with leaky capacitors. Send it to steve, he'll fix it for you.

Wiseman steve has fixed 2 90 ECUs for me already, pm him if he doesn't see this one. Have you check for fuel, spark and compression after fixing of the ECU?

 

[steve]

Whenever people have the problem where the car starts up and run for a a few seconds after they release the starter I suggest they try manually running the fuel pump to see if car stays running. By pulling pin 7 of the MPI relay low (to Ground) your simulating what the ECU does to power the pump. That pin is connected to both pins 63 and 66 on the ECU. You can pull one and jumper it to ground and the pump should start running when the ignition is on.

Steve

 

[Spoolin4Ever]

I know this is 2 months late but.........Yeah the Capacitors leaking may have damaged the board: get a known good ECU to swap it out with (and/or buy a uused one off of dsmtrader.com).

 

[delneroni]

Everybody who said the problem was the ECU was right. Thing is, we sent it out to be rebuilt by Foreign Auto Computer in Florida, and they said they fixed it (charged me $200), but all the problems were the same - so we assumed the ECU was ok and we had some other problem.

But then I switched to a different service shop in Rhode Island, and they told me the computer was still bad. So we yanked the computer again and sent it back to Foreign Auto Computer. This time they sent back a replacement unit (no extra charge), and when we put it back into the car, everything worked - car started correctly, idled fine, even with the air conditioning on, and even the popup headlight that would not close started closing (don't ask me why, since I was told the computer does not control that).

So if you have idling problems, starting problems, etc., the ECU is suspect number one. Replace that thing, but make sure your replacement works right. If they had rebuilt it correctly the first time, it would have saved a lot of time and money searching for other causes.

Case closed!

 

[steve]

So we yanked the computer again and sent it back to Foreign Auto Computer. This time they sent back a replacement unit (no extra charge), and when we put it back into the car, everything worked - car started correctly, idled fine, even with the air conditioning on, and even the popup headlight that would not close started closing (don't ask me why, since I was told the computer does not control that).

I should hope they would send you a replacement. Let's just cross out fingers that this one lasts, I haven't been impressed by what I've seen come out of them. From the ones that show up here I'm don't think they spend much time cleaning leakage.

Steve

 

[SlowChild3]

When I get around 4500 RPM I hear a solid tone beeping noise untill I shift. Kind of like a annoying ring. Could this be my ECU? Ran idles and runs fine but when I hear the noise it seems to misfire a bit. Maybe a boost leak?
Sorry for Hijack