What causes high idle on a TBI truck?

I found my solution here: [SOLVED] extream high idle problem on 1990 chevy 1500, 4.3 v6 TBI, with this post: Two things come to mind very quickly. 1. Leaky throttle body base gasket.Very comon on this engine.I don’t know if you serviced this when you pulled the intake.

Why is my 1992 Chevy ck1500 4.3 TBI not working?

My 1992 Chevrolet CK1500 4.3 TBI has been doing the same as yours for about 6 months and has gotten progressively worse. I would suggest checking the wiring that is going to all these sensors that have been replaced. Good possibility that little mice or ??? could have gotten in there and chewed some of the wires just enough to make things go awry.

How to reset the idle speed in a GM TBI?

Unplug the IAC valve located on the passenger side, rear of the throttle body. Start the engine. Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM.

What makes a 91 Chevy surging at idle?

My father in law’s ’91 Chevy was running poorly, so we put new plugs, wires, cap and rotor on it, and it’s running better, but it it still surging at idle. It basically almost dies out, and then surges back to life (probably a little higher than normal idle), then repeats continuously until you apply some throttle.

Why does my TBI 350 have zero power?

This weekend I put a new idle air control valve and o2 sensor in, and the symptoms still persist. Along with the erratic idle, the engine has absolutely zero power. It stumbles as if it’s missing a couple of cylinders when you accelerate.

What causes Extream high idle problem on Chevy 1500?

Two things come to mind very quickly. 1. Leaky throttle body base gasket.Very comon on this engine.I don’t know if you serviced this when you pulled the intake. 2.Misadjusted or bent throttle linkage.You don’t know what was done before you got to it.

What’s the idle speed on a 1990 Chevy?

Not open for further replies. I bought a 1990 Chevy 1500 pickup several months back. it idles around 1500 to 1800 rpm and it is tearing the transmission apart.

What should the idle speed be on a GM TBI?

Insert a T-30 size Torx driver into the Idle adjustment screw that is located behind the plug removed earlier. Turn the screw to adjust the idle speed to 650 RPM +/- 50 RPM. Turn off the engine and disconnect the negative battery terminal from the battery using a wrench.

What’s the idle speed on a GM Truck?

I recently got to the point of starting the new engine up, and it would idle at 2,000 RPM for 30 seconds or so and then drop to 1200 RPM. Both of these speeds are too high for idle.

Why does IAC control idle speed with TBI 350?

As for Bowtie-badboy’s problem, if he rebuilt the TBI unit and soaked the IAC in carburetor cleaner, or sprayed carb cleaner on it while holding the plunger pointing up, the IAC is most likely damaged from the cleaning. The IAC controls the idle speed ALL the time not only on a cold start up. Of course it does.

How to troubleshoot an automotive engine high idle?

The troubleshooting procedure for high and low idle conditions are similar, which are included in the following: Step 1 – If the check engine or service engine light soon has illuminated retrieving the diagnostic trouble codes could lead you in the right direction of what the problem is, or is related too.

Where is bowtie badboy’s Chevy TBI 350 located?

Loc: Twin Cities, Minnesota, U… As for Bowtie-badboy’s problem, if he rebuilt the TBI unit and soaked the IAC in carburetor cleaner, or sprayed carb cleaner on it while holding the plunger pointing up, the IAC is most likely damaged from the cleaning. The IAC controls the idle speed ALL the time not only on a cold start up.

Where is the vacuum tube on a TBI truck?

That’s essentially what mine ended up being, except it wasn’t located at a vacuum tube or port. I found my solution here: [SOLVED] extream high idle problem on 1990 chevy 1500, 4.3 v6 TBI, with this post: Two things come to mind very quickly. 1.

What’s the problem with my Chevy 350 engine?

I’ve had a rough idle problem with the Chevy 350 engine in the van and haven’t been able to solve the problem for over a year now. I installed the PCV valve and started the engine and warmed it up and the problem was still there, so I started checking things over making sure all the rubber hoses fit tightly.

Why is the idle on my TBI 350 so high?

Now i installed the TB back in the van and now the idle is super high , i connected my aftermarket tach and its idleing at 1700 rpm what should i check to see what the cause is?? High idle is most likely going to be a vacuum leak, whether due to something actually leaking (base gasket, hose, etc.) or a “controlled” leak a.k.a. the IAC.

Not open for further replies. I bought a 1990 Chevy 1500 pickup several months back. it idles around 1500 to 1800 rpm and it is tearing the transmission apart.