I'm asking because I don't think the throttle blades are opening as far as they should. There is 3/8 to 1/2 inch play at the pedal before it starts to pull the cable. TB blades look like they are @ 15 degrees from horizontal with pedal fully depressed.
So... does the PCM think I am at less than WOT? Or does it learn from the range of voltage it sees from the TPS and apply that? Mike

 

There is a special curve with throttle opening percentages that defines the WOT condition for different RPMs.

 

Ion,
Can you explain further?
Does the PCM apply that curve to the range of voltage it sees, or is it thinking that I'm not opening it all the way? Mike

 

Doesn't the throttle position sensor indicate that, and at 80% (for our cars anyway) denotes WOT

 

The PCM appears to look at closed throttle voltage, and as long as it is in the range of 0.20 - 0.90V accepts it as the 0% throttle point. Then it appears to add 4V to that reading, and pro-rate between those points to determine "percent throttle open", or TPP. Then it looks in a table that defines at what rpm/TPP the PCM goes into power enrichment mode (or "PE" mode, often mislabeled "open loop"). In my stock 94 program, that table showed:

less than 2,800rpm - 66% TPP
4,000rpm - 38% TPP
5,600rpm - 28% TPP.

So, the PCM is probably going to go to "PE" mode, even if you aren't getting full blade rotation.

Best thing to do would be to put a scanner on it, get the closed throttle TPS voltage, TPS voltage with your foot on the floor, and the corresponding TPP.

 

Thanks Fred. I'll take a look at it this weekend. Mike