Townsend
01-01-2004, 04:13 PM
Ok, I've got one that's stumped me... How about you?
'94 D90, 3.9, 90K
This is a new "feature" that has been happening for about two weeks now. When the vehicle is cold - now I don't mean really really cold I mean that all heat is dissipated as in it sat in the garage overnight (outside temp ~ 30F). I let the pre-oiler run and build oil pressure and then crank - it starts and idles perfectly for a cold engine, about 1000 rpm. I can drive slowly with no hesitation but if I reach around (it is not 100% consistent) 1800-2000rpm the engine will surge/stall as if either NO fuel or spark. If I continue to slow and coast in gear and let off the gas or press in the clutch it will (re)continue to run and idle perfectly normal. Occasionally if I press in the clutch it will stall but restart immediately.
Once it has warmed up the problem disappears completely. I can shut it off for quite some time but as long as there is some heat it will start and run normal.
It really seems to me as though it is a fuel delivery issue as it
runs great at all other times. The fuel pump primes as expected
during the initial key turn. No codes are thrown to the ECU. New
coil. New fuel filter. I have not messed with the fuel pump relays
as they are hidden behind the AC unit (by the way, anyone have the relay part # to add to the Parts Substitution Table on D-90.com - it's a $7 part that I would like to have a spare of...)
I know there is a bulletin about a cold start chip but the symptoms
occur when it's not really all that cold and it's never done this
before when its been really cold. Its been happening for a couple
of weeks now.
Is there such a thing as a temp sensor that tells the ECU that the
engine is cold/hot that could be failing?
All help and thoughts are appreciated. I apologize for the cross
post to the D90 list...
Thanks! -Townsend.
'94 D90, 3.9, 90K
This is a new "feature" that has been happening for about two weeks now. When the vehicle is cold - now I don't mean really really cold I mean that all heat is dissipated as in it sat in the garage overnight (outside temp ~ 30F). I let the pre-oiler run and build oil pressure and then crank - it starts and idles perfectly for a cold engine, about 1000 rpm. I can drive slowly with no hesitation but if I reach around (it is not 100% consistent) 1800-2000rpm the engine will surge/stall as if either NO fuel or spark. If I continue to slow and coast in gear and let off the gas or press in the clutch it will (re)continue to run and idle perfectly normal. Occasionally if I press in the clutch it will stall but restart immediately.
Once it has warmed up the problem disappears completely. I can shut it off for quite some time but as long as there is some heat it will start and run normal.
It really seems to me as though it is a fuel delivery issue as it
runs great at all other times. The fuel pump primes as expected
during the initial key turn. No codes are thrown to the ECU. New
coil. New fuel filter. I have not messed with the fuel pump relays
as they are hidden behind the AC unit (by the way, anyone have the relay part # to add to the Parts Substitution Table on D-90.com - it's a $7 part that I would like to have a spare of...)
I know there is a bulletin about a cold start chip but the symptoms
occur when it's not really all that cold and it's never done this
before when its been really cold. Its been happening for a couple
of weeks now.
Is there such a thing as a temp sensor that tells the ECU that the
engine is cold/hot that could be failing?
All help and thoughts are appreciated. I apologize for the cross
post to the D90 list...
Thanks! -Townsend.