High idling L05
04-26-2009, 09:07 PM
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Car: 91 rs
Engine: Blow through 383, 10 psi, xr288hr
Transmission: Manual th350 ATI 3000
Axle/Gears: 3.50 9"
High idling L05
I fixed the throttle body gasket, it was leaking bad, but the idle is still a little high. Before I had the truck, some shop tried to fix it by backing out the idle speed screw. Says the paperwork. The shaft doesn't even contact the screw. So something else is wrong.
The IAC appears to be working. Its relatively new, and vibrates with pins A and B jumped. I'm guessing that means its working.
Suggestions?
The IAC appears to be working. Its relatively new, and vibrates with pins A and B jumped. I'm guessing that means its working.
Suggestions?
04-28-2009, 05:57 PM
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Car: 91 GMC 1500 pickup, reg. cab shorty
Engine: 350 5.7 TBI
Transmission: 5 speed manual, HLM60
Axle/Gears: 10 bolt, 3.42 G80 posi. all factory
Re: High idling L05
Coolant temperature sensor?
It sends signals to the computer to increase injector pulse width.
The sensor on the front of the engine next to the water neck.
It sends signals to the computer to increase injector pulse width.
The sensor on the front of the engine next to the water neck.
04-28-2009, 07:29 PM
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Car: 91 rs
Engine: Blow through 383, 10 psi, xr288hr
Transmission: Manual th350 ATI 3000
Axle/Gears: 3.50 9"
Re: High idling L05
Its pretty new looking. It seems someone worked on it before. The IAC appeared new too and they adjusted the idle screw, but failed to replace the base gasket.
Since I fixed the gasket the idle is inconsistent now. Sometimes it idles right, but when I hit the gas and let off, it comes back up a little too high.
Maybe I need to adjust the screw back to near factory setting and let the IAC do its job correctly?
Since I fixed the gasket the idle is inconsistent now. Sometimes it idles right, but when I hit the gas and let off, it comes back up a little too high.
Maybe I need to adjust the screw back to near factory setting and let the IAC do its job correctly?
05-19-2009, 02:02 PM
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Car: 91 rs
Engine: Blow through 383, 10 psi, xr288hr
Transmission: Manual th350 ATI 3000
Axle/Gears: 3.50 9"
Re: High idling L05
I tested the coolant temp sensor and it was bad so I replaced it, no change.
Tested the TPS all good except the idle is a little high at .72 volts.
EGR is good.
Can't find any vacuum leaks. With the map sensor disconnected electrically the idle comes down just a little. If I disconnect the vac line it comes way down for 2 seconds then back up again.
If I use my finger to plug the IAC hole the idle comes down to where it should be.
How does the IAC get its input? TPS and MAP? Then the ecm sends out a voltage to regulate it? It has to read rpms right? I don't think the IAC is being regulated properly.
Tested the TPS all good except the idle is a little high at .72 volts.
EGR is good.
Can't find any vacuum leaks. With the map sensor disconnected electrically the idle comes down just a little. If I disconnect the vac line it comes way down for 2 seconds then back up again.
If I use my finger to plug the IAC hole the idle comes down to where it should be.
How does the IAC get its input? TPS and MAP? Then the ecm sends out a voltage to regulate it? It has to read rpms right? I don't think the IAC is being regulated properly.
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