Injuneer

https://www.gmpartscenter.net/oem-pa...bC12OC1nYXM%3D

BTC

Yeah, I noticed after the fact that some of those GM sites still reflect availability. I really don't know how those sites work, but I had always assumed they were pulling inventory information from the same database, but perhaps that is not the case. I have also noticed there are slight variations in pricing from one site to the next.

Rod Bender

Great! Now instead of a choice between expensive and questionable I have a choice between questionable and questionable.

BTC

Some of the GM parts sites do show the AC Delco as still available.

Rod Bender

Thanks. I will do some searching. Are there any places online where one could have his reliably rebuilt?

Rod Bender

I see an issue. Bolted directly below the throttle body is a solenoid of some sort that that has a broken off connector with a yellow wire and a black wire going to a tube that enters it.. The other end of this "solenoid" has a fitting with four wires going to it. What is it? What kind of problems is this situation causing?

Injuneer

Bolted to what? Intake manifold? Photo?

Rod Bender

right. It looks like it is bolted to the throttle body. It is about three inches long.

Injuneer

Like this:

http://shbox.com/1/iac3.jpg

Rod Bender

That's it! What is it and what does it do. Could that be my misfire?

Injuneer

The entire assembly is the base plate for the throttle body.

That is the idle air control (IAC) valve. The PCM moves the pintle on the right side of the valve to control the idle speed.

Are you saying there is nothing connected to the 4-pin connector? If it isn’t connected, the PCM can’t control the idle speed. If the pintle was all the way out, blocking air flow, it might make it harder to start. Could cause the engine to stall if the throttle blades were suddenly closed. You need to reconnect it in any case.

And then you indicate it has a tube connected to it with a yellow wire and a black wire sticking out? There are two pipes on the throttle body bottom plate. That is where the coolant lines (hose) connect, to heat the throttle body up, to prevent "throttle body icing" during extreme cold weather. Most people disconnect the hose to bypass the coolant. The coolant doen't seem to be necessary. And it won’t prevent the engine from starting, or cause it to run rough, whether it is there or not.

The question would be why did someone stick wires in the tubes, if that’s where they are, and where did those wires come from? There are yellow and black wires connected to the coolant temperature sensor in the water pump housing. If that wasn’t connected, you should have a code. Might make the engine harder to start, but not prevent starting, and could prevent the PCM from entering closed loop, but not cause it to run rough well after it's started.

I believe there are also yellow and black wires for the crankshaft position (CKP) sensor, at the bottom of the timing cover (96/97 only). The CKP sensor is only used for misfire detection, and would not prevent the engine from starting or make it run rough. The fact you got a code P0300 indicates the CKP sensor is working.

You need to trace the yellow and black wires to their source, and check to see what’s connected to the coolant temp sensor.

http://shbox.com/1/temp_sensor1.jpg

Rod Bender

You got it. The four wires are going to the IAC. However, as you said there is a yellow and a black wire, that are coming from the wire harness. I did not mean to say, however, that a yellow and black wire were protruding from the stem where the coolant line connects. Rather they were the above mentioned wires from the wire harness. And as you said, someone has taped over and possibly filled the fitting with permatex to keep from shorting out. So because of what the purpose of that valve is, it does not seem to be affecting my situation. Thanks for the explanation. You are definitely my guru. Bill

Injuneer

The IAC, IAT (inlet air temp) and CLT wires are all in the same harness bundle, based on Shoebox's 1995 harness photo. Wouldn’t surprise me if the CKP sensor wire was in there too.

If the IAC plug isn’t connected, you should reconnect it.

Rod Bender

I have been looking at the AIP Electronics unit. Has anyone had any experience with it? There is also a site called antivenomefi.com where the guy describes using a used Bailey Engineering LTCC conversion system and some coils. Although I do not know how available that would be.

Rod Bender

I am trying to follow Shoebox's directions for disassembling the front of engine. However I am stuck with the radiator removal. I cannot get the radiator separated from the ac condensor at the bottom. Can this be done leaving the radiator in place?