Advise tuning 7747 ECU on '92 Chevy Van

[Dunksterp]

The 299 chip Will Not work in the '7747.

Are you able to data log the '7747? There might be useful idle troubleshooting information in the data log, like TPS volts and IAC steps.

dave w

Hey,

Just managed to record a quick log file or idling, then going for a 5 minute drive down the road and back. It was idling high at 1000 rpm before, but once returned it wanted to sit at 1650ish.

[dave w]

Do the IAC steps look normal. Are the TPS volts normal?

dave w

[Dunksterp]

Do the IAC steps look normal. Are the TPS volts normal?

dave w

The TPS Voltage looks ok to me? I live in a built up area, so was only able to get up to about 30 mph at part throttle. The IAC steps on the other hand look crazy high and seem to just steadily rise. I'm currently going through the BIN trying to work out why. I'm very new to this and still learning.

EDIT 3..... I turned off ALDL mode... Now everything is absolutely perfect! Wonderful! Now to tuning the SA for LPG....

EDIT... Hmmmm... looking at the TPS again, the voltage looks correct to me at idle, around .57 but that lists the TPS at about 5% open. Looking through the IAC settings, I can see that the IAC - TPS Percent for Closed Throttle is set to 2.34%, so is the IAC never seeing the vehicle as idling?

EDIT 2.... So I went out and had another look. I've disabled ALDL mode, I had the 10k resistor switched on. Also, playing around with the TPS, at fully open throttle, it's calculated open at only 80%. Would this suggest that I need to calibrate my TPS?