93 Vin W - Unstable Timing at idle

[twin_rotor]

Originally Posted by 93_deuce

Diagnostic flow chart would be VERY helpful!

The IAC is not new. I just have thrown so much money at this thing I wanted to be sure before buying a $100 sensor. I just don't see what port can be blocked (I cleaned everything!).

How would I check the wires on the IAC?

Thats what the flow chart is for. My means of diagnostics are what I've already explained. Then I'll usually recheck it with a flowchart. Right now I've got you pinned for either a bad ground, no power, or bad valve. But thats just bench diagnostics.. I wasn't stand'n next to ya when you did it.. Hence, the flowchart. So don't go out and buy a vavle!

But there are plenty of artricles all over the net with the numbers.. You'll measure for resistance, voltage twice, and ground continuity. So you'll need a multimeter. I just like having the chart because you never know when they'll change a color of wire or a circuit(GM is actually one of the better companies that kept stuff simple, when it was simple engineering).. Plus, you cover all bases. Whatever susbsytem/circuit thats dependant on your IAC will also be covered. Even if its mechanical, a flowchart will get you to your solution. You test until you get a fail

So try and find the GM flowchart via web, or buy a FSM. The parts store books will take you so far; they suck ass... I bet you'll find it online though.. I'll look later when I have time.

[93_deuce]

Originally Posted by twin_rotor

Thats what the flow chart is for. My means of diagnostics are what I've already explained. Then I'll usually recheck it with a flowchart. Right now I've got you pinned for either a bad ground, no power, or bad valve. But thats just bench diagnostics.. I wasn't stand'n next to ya when you did it.. Hence, the flowchart. So don't go out and buy a vavle!

But there are plenty of artricles all over the net with the numbers.. You'll measure for resistance, voltage twice, and ground continuity. So you'll need a multimeter. I just like having the chart because you never know when they'll change a color of wire or a circuit(GM is actually one of the better companies that kept stuff simple, when it was simple engineering).. Plus, you cover all bases. Whatever susbsytem/circuit thats dependant on your IAC will also be covered. Even if its mechanical, a flowchart will get you to your solution. You test until you get a fail

So try and find the GM flowchart via web, or buy a FSM. The parts store books will take you so far; they suck ass... I bet you'll find it online though.. I'll look later when I have time.

One more thing. I know the IAC has power because when I turn the key with it out it cycles back and forth. I have seen it move with my own eyes

Thanks for all the help. I'll start looking into it asap. Let me know if you find a link.

Would a Haynes or Chilton have this info in them? Cuz I have both but haven't located anything like this.

[twin_rotor]

Well you know you have power then.. But it can still move and not be sending a reference signal.

You should be able to find the resistance and voltage test in a Chiltons..

[93_deuce]

Originally Posted by twin_rotor

Well you know you have power then.. But it can still move and not be sending a reference signal.

You should be able to find the resistance and voltage test in a Chiltons..

How would you test for the reference signal??? Would that be voltage or resistance?

Or am I crazy