I just put a t56 in my L98 monte (1987 165 ECM, harness on TPI) and noticed that now it doesn't want to idle under 1000 rpm. Everything is hooked up fine (ECM's vehicle speedo sensor input registers fine through scanner, no codes present).

I have checked for obvious vacuum leaks and I dont think there are any. The car is hard to drive slowly because of the high idle. Could this be caused by the reduction of the automatic transmission's front pump's constant load on the engine? If so, what should I do?

MODERATORS- sorry if this shouldn't be in the DIY PROM section, couldn't figure where it would be best- please move to correct forum if neccessary

 

Check the park/nuetral switch. I believe your ECM thinks it's in Drive. This should show up on your scan tool.

 

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[This message has been edited by leirch (edited September 05, 2001).]

 

If you running a manual tranny then you should be running a memcal for a manual tranny.

There are strategy differences between the two.

What did you do with the 3rd 4th gear tranny switch inputs, and P/N switch?.
Does the wiring diagram your referring to show any gear select switch inputs needed for what you installed?.

 

I forgot to mention that my Prom and harness are out of a 5 speed 1987 TA, so there was no TCC harness to worry about. Automatic lockup and 4th gear were previously controlled by a vacuum swith out of a 700-4r suburban without computer control.

Using Craig's software, the P/N switch always reads value "1" dependent on weather I jump the connector (that was connected to the switch) or not. I dont know if a 1 means it is in park/neutral or in gear.

 

Did you redo the IAC/tps adjustments? Or what are they reading when you notice the high idle?

 

I haven't yet adjusted IAC or TPS voltage. I'm not sure how to do it on a manual trans car. I know that on an automatic it is supposed to be in gear with the parking brake on or something like that. The scanner lists actual idle around 1000 and target idle around 680 but it never seems to try that hard to get it down there.