LT1 EFI Question

[lkurek at smtpgate.anl.gov]

<SNIP>

  The scan tool is an AutoXray Xp240. It does indicate "fan: on". The
>realtime data seems reasonable. I am only running the primary fan. The 
>car seems to run very well, although slightly better somtimes. The one 
>thing that I have noticed that doesnt seem right (other than the fan) is 
>the idle seems to take a while to settle in. In other words, When you 
>start the car, It runs a low rpm (mabey 1100). As it warms, it raises to 
>as high as 1500. But even after the car is fully warmed, you come to a 
>stop, engage clutch, and its still idling 1300, and then slowly drops to 
>around 1000. By slowly, I mean several seconds. It never matches the 
>requested RPM. 
     
     Are the requested RPM and engine RPM the same or no? There are *so* 
     many things you can check, but just for the idle circuit the IAC 
     motor, the P/N switch, the VSS, the Distributor Reference Signal 
     (either high or low resolution), etc. If the scan tool is indicating a 
     requested 900 rpm, yet it is idling higher...I'd check the VSS/PN 
     circuit first. Did the PCM come out of an auto or manual trans car? If 
     it was from an auto, you will need to get it flashed for the manual 
     program. In this case, if the PCM gets a VSS signal, it will raise the 
     idle to prevent stalling.
     
     Later,
     
     Larry