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Any IAV Gurus here?

Ok, so here's the problem; My IAV doesn't compensate for load when I turn on the A/C. It just goes from 840rpm down to 640 and stays there. Same thing with the A/T. Put it in drive and it drops to 640 and stays there. I cleaned the valve, also quick checked it by pulling off the coolant temp sensor harness and the engine indeed surged and returned to normal. I'm trying to determine where the communication breakdown is, but I thought I'd ask the general question to see if anyone had any experience with this exact problem. Thanks

Tim

Reply to
Mr Jones
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Vehicle? Year? Model? Engine?

And, don't you mean ISV?

- Peter

Reply to
Peter Cressman

If the idle valve is working ok then you might need to change the ECU. Some early 2.0's had the ECU idle programmed too low. What's the ECU part number? Also I think somewhere I had information of increasing the idle via changing the block values within the ECU with the VAS5051. Should work with ross-tech too....

Reply to
Woodchuck

Ok, here's an update now that I know more.

  1. It works normal until it reaches operating temp!
  2. I swapped ECU's and have ruled that out.
  3. On the measuring blocks, the duty cycle of a normal operating ISV, jumps about 8% to compensate for load. Mine only goes up 1-3%. Don't know why, but a good ECU does the same thing, and the ECU in that car was swapped into another car and operates normally, so I'm thinking a component input, possibly heat related.

Today I'm going to compare all engine measuring blocks to the readings of a normally functioning car. If I don't narrow it down that way, I'll start by swapping out the throttle body (already did ISV). Then on to other components. Wish me luck!

Tim

Reply to
Mr Jones

I sure would like more info if it's out there about changing block values with the ross-tech tool if anyone has it.

Tim

Reply to
Mr Jones

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