Chevy 3.8

I use the Alldata wiring diagrams for my automotive repair work because I find that they are the closest I can get, to what the GM Factory Service Department uses. I need clarification on the wiring diagram for a 98 Camaro 3.8 V-6 engine. The Alldata wiring diagram for the ignition control module shows terminal (F) running to cavity pin 7 of the C1 circuit of the PCM. The diagram for the iac valve also shows terminal (D) of the iac valve running to cavity pin 7 of the C1 circuit of the PCM. This is impossible. They both can't operate from cavity pin 7 of the C1 circuit. Can someone explain what is happening here? Or do you have a wiring diagram showing something different? Thank you, Tommy.

archemedes

have you checked the grand prix diagram, they use the same pcm, so those wires should be the same

Chevy 3.8

No, I have not. I will now. I know that the 98 Camaro has a stand alone PCM. It is used on other models and years. However, for the 98 Camaro with the 3.8 V-6, there is only one PCM with a specific serv number used and this is it: 16236757. So, if the 98 Grand Prix uses the same PCM, this is the part number it would be. I'll check on that. Thanks for your support, Tommy.

Chevy 3.8

You were correct. I checked on the PCM part numbers. They are the same. And you are also correct about the engine harness being the same as well. This is just blowing me away. My original post is based on what I got from the GM Dealership today. Their computer files show the iac wiring pins 7, 44 and 49 for the 98 Camaro 3.8 V-6 on the C1 circuit. I just checked the 98 Grand Prix iac wiring diagram. It shows pins 7, 44 and 49 on the C2 circuit. How is that possible? The same PCM, engine harness and engine, yet there are variations. Why is that? Can anyone explain this? Is there a misprint somewhere? Thank you for your support, Tommy.

archemedes

someone can't type at gm lol

Chevy 3.8

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I tried following the diagram I got from the GM Dealership. No Good! I could not even pick up iac voltages with that wiring configuration. I ended up using the 98 Grand Prix 3.8 V-6 wiring diagram. With the 98 Grand Prix diagram here's the voltages I'm getting at the iac valve with the engine running:
Terminal (A) 0.88 volts (Lt green/black wire)
Terminal (B) 12.44 Volts (Lt green/white wire)
Terninal (C) 0.88 volts (Lt blue/black wire)
Terminal (D) 12.43 volts (Lt blue/white wire)

There is one problem remaining, which has been my problem all along. The iac valve is getting hot. After the engine has been running for about 5 minutes, the iac valve gets very hot. I'm able to touch it, however, I'm only able to hold on to it for a few seconds then I have to remove my fingers or I'll get a burn. I must admit that with this wiring configuration, the engine runs much better. Not perfect, but better. I just need to find out what is causing the iac valve to get that hot. Has anyone experienced this problem before? Any suggestions? Thank you, Tommy.

archemedes

I'll check my voltages tomorrow and see what I get. Have you done the IAC relearn?
Start engine get to operating temp
make sure AC is off
put trans in drive
turn ac on
your done

Chevy 3.8

archemedes, no I have not. The ac plumming is not complete, and the driveshaft and rear end are not installed yet. I just have a yoke installed at the end of the trans secured with plastic ties, to keep the oil from leaking out. Thank you, Tommy.

archemedes

I forgot to check voltages, will do that in a bit

archemedes

my IAC valve was pretty hot I will have to recheck in the light I couldn't see wire colors well, but had only 1 hold a steady voltage at 13 volts (battery voltage) all the others but 1 were going from .75-12 hovering around 1 volt the one otehr that didn't fluctuate had no voltage (I will check if it's a ground tomorrow)

Chevy 3.8

It would be extremely helpful if you could identify what the colors of the wires are at terminals (A) (B) (C) and (D). I'm hoping that it matches up with what I have listed below:

Terminal (A) (Lt green/black wire)
Terminal (B) (Lt green/white wire)
Terminal (C) (Lt blue/black wire)
Terminal (D) (Lt blue/white wire)

Thank you for your support, Tommy.

archemedes

my colors don't match up (mine is a '97 gp so that may have changed)
I have (from top to bottom when connected) No black on any of the wires
Light blue
light blue white stripe
light green
light green white stripe

Chevy 3.8

Yes, you are correct. That wiring configuration is also for a 95-97 Camaro with the 3.8 engine. I tried that configuration and the engine did not run right and my iac problems got worse. I'm quite confident that the current wiring configuration that I'm using is the correct one for a 98 Camaro with a 3.8 V-6 engine. I just need to figure out why my iac valve is still getting hot. How hot does your iac valve get? The next time you take the car for a drive, before you turn off the engine, touch your iac valve. Let me know if you are able to hold on to it, or you have to remove your fingers after a few seconds. Be careful. Thank you for your outstanding support, Tommy.

archemedes

it gets real hot, you can't stand to grab it for long

Chevy 3.8

Well, with that said, let's see what happens. I'll start up the engine tomorrow and bring it up to around 190 degrees and see what happens. I'll keep you informed. Thank you for your support, Tommy.