I purchased an 89 Blazer that had been sitting for 2-3 years. I trailered it to my mechanic. He replaced fuel tank, sending unit, pump, fuel lines before ever starting it. Had a bad injector that was replaced once attempting to start. Now it cold starts and sounds fine, but after it warms up, it sputters and chokes itself out. They have replaced the MAP sensor, distributor and ignition module, EGR valve,plugs, wires, and cut the Cat off. Still doing the same. O2 sensor getting replaced tomorrow. Any other ideas?
CK5
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Fuel issue?
- Thread starter utmb_pa
- Start date
No codes.
Not just codes
And not trying to be rude, but that is a list of parts already
Seems like a lot of guessing and shooting the parts cannon at it
The O2 numbers, as with all of the sensors, have both out voltages or mV readings, as well as BLM and Integrator numbers
It could be fuel delivery, ignition, or the ECM giving/receiving bad data
Did the fuel filter get changed? I figured it got fresh fuel at the pump change
Unless that work was done wrong or had a bad part, we’re leaning towards believing it’s not one of those areas. But was this problem occurring before all this work?
The issue starting at warm up suggests it could be the engine temp sensor or even starting due to the onset of closed loop operation
All guessing of course without data
And not trying to be rude, but that is a list of parts already
Seems like a lot of guessing and shooting the parts cannon at it
The O2 numbers, as with all of the sensors, have both out voltages or mV readings, as well as BLM and Integrator numbers
It could be fuel delivery, ignition, or the ECM giving/receiving bad data
Did the fuel filter get changed? I figured it got fresh fuel at the pump change
Unless that work was done wrong or had a bad part, we’re leaning towards believing it’s not one of those areas. But was this problem occurring before all this work?
The issue starting at warm up suggests it could be the engine temp sensor or even starting due to the onset of closed loop operation
All guessing of course without data
Check the IAC valve, they can get gummed up and stick. You can clean them, but might as well replace it being cheap enough
Not rude at all. My mechanic is younger. He is great on Hondas, Toyotas, even LS stuff. He doesn’t do older stuff very often. But he is knee deep in it now. I’m not sure he knows how to do a deeper dive. Doesn’t give him the same feedback that a LS engine does with scanner. The fuel filter is new as well.
need to clear up "chokes itself out" does this mean it is run so rich at warm up it dies? Or could it be the other way around and not enough fuel at warm up ?
This is why we need blm and int numbers
I don't need BLM, block learn would be handy though
starts up fine, but then rough idle and dies after engine warms up some.
Still unclear whether fat or lean.
Gonna start with it going lean after warm up.
Need to look for vacuum leaks. Intake mating surface and TBI base.
The injector replacement, new or rebuilt? One or two replaced?
Has anyone messed with the idle screw on the tbi? Should yellow temper paint on the screw. Don't mess with it, w/o going minium air relearn after.
Engine coolant temp sensor wiring, especially the grounds at the thermostat, those get abused when being serviced.
Gonna start with it going lean after warm up.
Need to look for vacuum leaks. Intake mating surface and TBI base.
The injector replacement, new or rebuilt? One or two replaced?
Has anyone messed with the idle screw on the tbi? Should yellow temper paint on the screw. Don't mess with it, w/o going minium air relearn after.
Engine coolant temp sensor wiring, especially the grounds at the thermostat, those get abused when being serviced.
Block learn multipler
BLM
I know, the acronym has been appropriated.
Yeah the bureau of land management pisses me off too
The other thing that pulls back when warm is timing
If the timing was set with the disconnect connected it will do this also
Very true.
