g5nad

I have a 86 944 turbo that will not start once warmed up.
If I let it cool to were the temp guage shows 1/4 it cranks right up again. (45min later)
First thing I changed, DME relay - Still no start.
Next check for fuel pressure - Ok so we had a problem, lost pressure right upon shutdown.
I changed the check valve on the fuel pump - Still no start, but holds fuel pressure now.
Next on the list - Check ignition coil - I have power to black lead when ignition on. I have a pulsing power to green lead, when cranking. So I am unsure if this is correct ?
Changed out coil anyway just to be sure $60 - Still no start
Changed out ignition cables full set also.
New plugs, cap and rotor.
How do I check the speed sensors ?
DME ?

Thanks for the help !

mikl1976

does it shut off if it runs for awhile? or just not start if it is to hot?

g5nad

It has shut off once while running.

mikl1976

how does the dme board look? i had a problem with mine once.. looked like someone tried to repair it.. but the sodder kept comming apart due to the excessive heat..

g5nad

I have never checked that. Is the DME computer located under the passanger floor board ?
What do I look at once I have it out ?
Any particular section of the board ?

Thanks.

mikl1976

i believe it is... think you have to pull the carpet back and there is a board covering it... and under that is the dme computer...
look for any burnt spots, soder comming off, any damage whatsoever.

g5nad

Ok, have the DME computer out. Upon inspection I notice three connection pins connecting to the harness have corrosion on them. Most of the corrosion is on point 15 and it has spread to 14 and 13. Should that cause the hot start condition ? I can clean off the points on the computer and harness connection. What should I use as a cleaner ?
The Board on both sides looks as though there is alot of yellowish golden residue randomly all over the place. There does not seem to be any burnt or black spots anywhere. What else should I look for.

Thanks for all your help.

mikl1976

it is very posible that could be the problem.. im not sure about best way to clean it.. the corrosion might be causing it not to work correctly... might have someone who knows what to look for take a look at it

eclou

Just heat the corroded points with a solder just until the solder "flashes".

Eugene

Kevin Baker

How hot is the car getting? Shouldn't go past the 2nd white line. FWIW you may want to look at the DME engine temp sender. It's a $35 part at BAP/Geon (ask for Tony at Richmond store, nice guy). I'd also replace the coil. I had a warm drivability, stalling problem that "cleared up" after I replaced MOST of the FI system, and ignition system. If you have time today and want to drive to Spring, I'd be happy to have a look/meet a new "Greaselinger"

g5nad

Well tested all the points on the computer board, even flashed a couple. Cleaned up all corrosion on DME pins and harness connection point. Made a HUGE diffrence in how the car idled and ran. Felt as though the boost felt alot cleaner and stronger, idle was almost perfect with none of those small minor light hessitations that he hear normally. Everyone should clean out those connections points ! That was the good news. Bad news is, the hot start problem is still there.
MAN THIS IS DRIVING ME CRAZY ! Car runs great, but I cant talk it anywhere fearing if it stallls I am stuck ! It has only stalled on me once, just died for some reason. Is that an indication of anything ?

mikl1976

damn... glad you got it working better... but it is still there huh..... i am at a loss right now... im sure someone here can help out though

mikl1976

just a quick stupid question.. is the air filter old? it might not be getting enough air

Chris_924s

I will always resolder every component lead on the DME. A cold solder or intermittent may not be visible.

I suggest this to rule out any other issues. Since I have resoldered my DME I havent had a problem with it in 6 years of daily driving.. how's that for proof.

Also check the FPR- well known hot-start problem child.

g5nad

I confirmed that I have no spark to the distributor when car is hot.
I replaced the coil already, so that is not it.
What else can I check .... ? Grounds ?