Need Help With a 93 4.3L TBI
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Joined: Jun 2011
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Need Help With a 93 4.3L TBI
93 GMC Sierra with a 4.3L V6 and TBI, 140,000 miles. It don't like to idle and is low on power.
It has a new:
Ignition module
Coil tested good
Rotor and cap
Plug wires and plugs gapped to .045, old plugs where tan in color
Fuel filter
Intake manifold gasket
TBI base gasket
Rebuilt fuel pressure regulator, and all new gaskets and seals in TBI unit
Idle air valve
Coolant temp sensor
Have tried a new map sensor, but used one is on there now. I have also checked for vacuum leaks.
The throttle position sensor appears to work although I have no specs for it.
Fuel pump is quiet, have checked it's relay and fuse and all look good.
I have checked for codes and found none. Have unhooked battery trying to reset ECU.
Could it need a new timing chain, I have not checked the timing recently.
All comments welcome.
It has a new:
Ignition module
Coil tested good
Rotor and cap
Plug wires and plugs gapped to .045, old plugs where tan in color
Fuel filter
Intake manifold gasket
TBI base gasket
Rebuilt fuel pressure regulator, and all new gaskets and seals in TBI unit
Idle air valve
Coolant temp sensor
Have tried a new map sensor, but used one is on there now. I have also checked for vacuum leaks.
The throttle position sensor appears to work although I have no specs for it.
Fuel pump is quiet, have checked it's relay and fuse and all look good.
I have checked for codes and found none. Have unhooked battery trying to reset ECU.
Could it need a new timing chain, I have not checked the timing recently.
All comments welcome.
Thread Starter
CF Beginner
Joined: Jun 2011
Posts: 7
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It appears to have good compression, but I will check it. I also need to check for blockage in the exhaust.
Do the computers for the fuel system go bad? Are there any online sources of troubleshooting info guides? Places I can find specs for fuel pressure and sensor specs?
Do the computers for the fuel system go bad? Are there any online sources of troubleshooting info guides? Places I can find specs for fuel pressure and sensor specs?
Thread Starter
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Joined: Jun 2011
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When I replaced the idle air valve, it fixed the idle problem for about a day. Is there something more I need to do to fix the no idle condition?
I am going to "T" in at the fuel filter and check fuel pressure. If it is low I guess I can shim the spring to raise the pressure. Is this the correct way to raise the pressure?
I am going to "T" in at the fuel filter and check fuel pressure. If it is low I guess I can shim the spring to raise the pressure. Is this the correct way to raise the pressure?
Thread Starter
CF Beginner
Joined: Jun 2011
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37 people have viewed this thread and not one comment, your forum apparently sucks. Does anyone here know anything about a GM product? Guess not.
Edit: I got 10 comments on turbobricks.com in off topic no less.
Edit: I got 10 comments on turbobricks.com in off topic no less.
Last edited by Vlvman; Jun 5, 2011 at 2:45 PM.
CF Senior Member
Joined: Feb 2011
Posts: 345
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From: Middletown DE
whats the fuel pressure?did you clean the area where the IAC goes into that can become dirty are you getting good voltage to the IAC,it should idle unless the cat are plugged really bad will it run if you hold the throttle cracked open slightly,is the PVC valve working properly
Sean
97 4x4 burb
Sean
97 4x4 burb
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