Wikkid911

I'd try the DME fix as suggested earlier. Pennies in comparison to what you are spending.

Rouxzy

A good suggenstion was made to me a while back to keep a spare DME relay in the glove compartment. They are about $30. It is not a question of if the relay will go but when. When I had issues I put the spare in and was able to eliminate that as a problem.
Tom

amr89c4

Make the simple jumper and just try it. You aren't going to hurt anything (provided you hook it up as directed) and .30 worth of diagnostic parts is hard to beat.

psiegel

I am like a broken record with this but clean the ISV. A very dirty ISV can do this and the cost is about nothing.
Good Luck
Peter

Solitude

1)Try DME relay first. 2)fuel pump. 3)Ignition coil.
I had the same problem. My car will start with other EUC but ran rough. I don't think it is your ECU. Steve from Rennsports system recommended me to http://www.systemsc.com/ . It was my Ignition coil.
Thanks Steve.

toffi

Hey Folks,

The second rebuilt unit arrived and after my mechanic installed it on the car (he also changed to new DME relay and a couple of sensors), here is the situation:

1. When I picked up the car, the engine started fine without hesitation
2. I then drove around for about 15 minutes and everything was just fine until ....
3. I stopped at a traffic light and the engine suddenly stalled (the car was in "D" gear and foot on brake). It simply just stalled/shut down without even struggled to stay on.
4. I restarted the car (once again no hesitation) again and drove for another 15 minutes and reached home
5. I then put the car on "P" gear for a short while for around 1 minute and the engine stalled again.

Not sure if it is the ECU again (if so it makes it 2 faulty ECUs in a row) or something else that might have gone wrong so I need to check with my mechanics again. Fuel pump seems to be fine as I was able to drive for 15 minutes without noticing any problem there. I will try to clean the ISV and check the ignition coil (and this was replaced few month ago) ...

Regards,
Ken

Frank 993 C4S

Ken,

you are getting some good advice here. My only input would be to check out the cheap (DME, fuel pressure and contamination, ISV clean, etc.) stuff first before embarking on things like ECA swaps. Good luck! Frank.

Streetfighter

When was the last time the spark plugs were replaced? I to am having the same problem, car starts up cold and runs well on idle and drives well. Once hot, it dies at idle when I am at a stop light. Christmas tree effect, car fires up again, but won't idle without me keeping my foot on the gas. I replaced the fuel pump, DME relay, and I am thinking about replacing the ignition coils. Car has 101k miles on it and no receipt of it being replaced. I am interested to hear what you come up with.

boxsey911

As some have already said you seem to have proved (at great expense) that the ECU is not the cause. Another thing to add to the list is to go round all the hose clamps on the inlet manifold and tighten them up to remove any air leaks. They are more likely to start leaking when the engine is warm which seems to be one of your symptoms.

david@st ives

Mine was stalling,

I know it isnt a permanent solution but there is a tiny red cap near the idle control valve on a vaccuum pipe, pull it off and see if the stalling stops.

I know there must be an underlying cause ie faulty control valve, but it cured my hunting and stalling problem immediately.

Another possible cause of difficult starting could be the flywheel sensor

RichieRoo

Just had a thought... What about the idle position microswitch? If it isn't fully depressed the idle
stabilizer doesn't function.

Mine gave me a few problems with stalling because the throttle return spring would only be strong
enough to depress it intermittently. It has two adjusting screws, but I found them hard to get onto,
so for a quick test I wrapped a wire-tie around the throttle arm, to make it thicker to ensure it touched.
(can post a picture if it would help).

74threeliter

I followed Bazar01's advice on pelican and it cured it for me. Car would turn over but just driving down the street it would buck and restart-go then buck and restart-go. I replaced dme relay, then I read, " ignition switch supplying the switched power to various electrical components, loose connectors to AFM, loose or dirty ground points,". My issue was an old ignition switch wire that had built up resistance(hardened wire feel) and was not supplying power correctly/consistently. I still use a 1974 ignition switch.... soon to change completely. good luck toffi et al.

chris951

I always keep a spare dme relay in the glove box for those occasions

klr10

Clean the ISV with carb cleaner and check the idle microswitch, prime suspects.