89 S10 4.3 Need help troubleshooting TBI/IAC Idle issue - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ChevyTech · 08-27-2014, 10:39 PM

Bleed Passage:
Some TBI units have a hole (Bleed passage) to release the fuel pressure when the pump stops and some TBI units hold the pressure after the engine is shut off. I have tried to find the criteria for which units have the bleed hole and which don’t but have never been able to find GM information on this.

I will see if I have photos of this, but not today. I have more projects then time.

76C10Stepside · 08-28-2014, 05:02 PM

Quote:

Originally Posted by ChevyTech

Bleed Passage:
Some TBI units have a hole (Bleed passage) to release the fuel pressure when the pump stops and some TBI units hold the pressure after the engine is shut off. I have tried to find the criteria for which units have the bleed hole and which don’t but have never been able to find GM information on this.

I will see if I have photos of this, but not today. I have more projects then time.

Thanks!

76C10Stepside · 04-05-2015, 05:02 PM

I'm back from a long vacation from the S10. The driver side injector went from not spraying to a constant dribble, which flooded the crankcase with gas for the second time. A new injector got it back up and running. Runs pretty well, drove it around yesterday. But there was a slight smell of gas. The first time I looked for leaks, I didn't see any.

New Problems!

1. The coolant temp guage does not register at all.
Cleaned up the ground connections at the front of the intake manifold as suggested, then started engine to see if that fixed, only to find...

2. BOTH of the fuel line fittings in/out of the throttle body were leaking. After tightening both very snug, it is still leaking slightly. I noticed that the line fittings have plastic seals on the ends. Will I have to replace entire lines with new ones?

Thanks

08-27-2014, 10:39 PM	#1
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	Re: 89 S10 4.3 Need help troubleshooting TBI/IAC Idle issue Bleed Passage: Some TBI units have a hole (Bleed passage) to release the fuel pressure when the pump stops and some TBI units hold the pressure after the engine is shut off. I have tried to find the criteria for which units have the bleed hole and which don’t but have never been able to find GM information on this. I will see if I have photos of this, but not today. I have more projects then time. __________________ For those of you that are wondering why you are not getting replies to your thread: Did you give the model, year, engine, fuel system type, and transmission information? If it is modified from what came stock from the factory, let us know that too.

04-05-2015, 05:02 PM	#3
76C10Stepside Registered User Join Date: Feb 2012 Location: Olympia, WA Posts: 300	Re: 89 S10 4.3 Need help troubleshooting TBI/IAC Idle issue I'm back from a long vacation from the S10. The driver side injector went from not spraying to a constant dribble, which flooded the crankcase with gas for the second time. A new injector got it back up and running. Runs pretty well, drove it around yesterday. But there was a slight smell of gas. The first time I looked for leaks, I didn't see any. New Problems! 1. The coolant temp guage does not register at all. Cleaned up the ground connections at the front of the intake manifold as suggested, then started engine to see if that fixed, only to find... 2. BOTH of the fuel line fittings in/out of the throttle body were leaking. After tightening both very snug, it is still leaking slightly. I noticed that the line fittings have plastic seals on the ends. Will I have to replace entire lines with new ones? Thanks



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