Stalling on start 92 TPI no cannister
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Stalling on start 92 TPI no cannister
So .... I have been ASE master since 1976 and was Olds master from 1983 to 97 when I took a government OBD II regulatory job. Retired now and helping a friend who purchased a finished (no idea by whom) street rod powered by a 1992 Camaro TPI .... In my previous world this would be a "cob job" ... anyway the thing has (Problem 1) a severe hunting condition / with a couple stalls when first started and less severe but still present condition on hot re-start. Once it is drivable it idles pretty well / no stalling.
Whoever did this did not install a charcoal cannister or purge / tank psi valve. It has a 4x line fuel sender .... Supply & Return / one with a check valve allowing psi into the tank only and a fourth open at just inside the tank / no restriction. (Problem 2) he is having trouble getting a full tank and the vent line with the check valve fills with fuel. The unrestricted vent line is ported into the filler neck up by the cap. (It seems to me that the unrestricted one should go to a cannister allowing fuel vapor or overfilling the tank to migrate into the cannister?)
So far I set the TPS to .5
Rerouted the PCV
Adjusted the min throttle opening (several times) too much opening resulted in excessive RPM coming to a stop.
The IAC counts properly reflect what the engine is doing (too much throttle plate opening and its requesting 0 counts and while surging the numbers are trying to keep up but can't.)
It is in closed loop and the O2 sensor (cross counts and block learn show pretty good overall fuel control.)
Added... 2 orange hot (keep alive) wires at the PCM plug stayed hot with the key off and one pink/black trace (wake up) received 12.5 when the key was turned on / went to 0 at key off.
There was another orange that did not get / have power but the schematic I had did not show it.
I was also pondering where the grounds were located on the engine ("back in the day" I had a weird running 3.8 PFI that someone put all the grounds on the same bolt. Apparently the O2 ground on the same location as the PCM ground caused issues?
Then I looked at the tank lines and lack of a cannister and determined help is needed.
My nickname on this site is DrOlds and my name is Bob.
Whoever did this did not install a charcoal cannister or purge / tank psi valve. It has a 4x line fuel sender .... Supply & Return / one with a check valve allowing psi into the tank only and a fourth open at just inside the tank / no restriction. (Problem 2) he is having trouble getting a full tank and the vent line with the check valve fills with fuel. The unrestricted vent line is ported into the filler neck up by the cap. (It seems to me that the unrestricted one should go to a cannister allowing fuel vapor or overfilling the tank to migrate into the cannister?)
So far I set the TPS to .5
Rerouted the PCV
Adjusted the min throttle opening (several times) too much opening resulted in excessive RPM coming to a stop.
The IAC counts properly reflect what the engine is doing (too much throttle plate opening and its requesting 0 counts and while surging the numbers are trying to keep up but can't.)
It is in closed loop and the O2 sensor (cross counts and block learn show pretty good overall fuel control.)
Added... 2 orange hot (keep alive) wires at the PCM plug stayed hot with the key off and one pink/black trace (wake up) received 12.5 when the key was turned on / went to 0 at key off.
There was another orange that did not get / have power but the schematic I had did not show it.
I was also pondering where the grounds were located on the engine ("back in the day" I had a weird running 3.8 PFI that someone put all the grounds on the same bolt. Apparently the O2 ground on the same location as the PCM ground caused issues?
Then I looked at the tank lines and lack of a cannister and determined help is needed.
My nickname on this site is DrOlds and my name is Bob.
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