i am trying to tune my brothers car and the main thing he wants fixed is the start up. It will fire up good, then stumble, and then catch itself again. i run the same tune on my car and don't have this issue. both cars are 87 '165 6E. mine is a 5.7 and his 5.0. Thanks for any input

Here is the start up of my car. the IAC positions are completely different despite being the same settings. any ideas?

I would first set the minimum air and the TPS at idle.

I really can't see that the ECM would set the IAC at 0 (closed, maybe 1 or 2 steps) for cranking. Doesn't make sense.

And having the IAC at 160 for cranking is rather high.

Are these both cold starts at the same engine temperature?

Would be better if we could look at the BINs. A short data log of each would also help (in formatted text or .csv format)

RBob.

Rbob, thanks for the help. How do i go about setting the min air and TPS?

Both are cold starts.

I couldn't get the bin and logs to upload so i hope these links work.

Bin:
https://www.dropbox.com/s/93ufoqcbbpjcoyw/ARAP-5.bin

5.0 with loop:
https://www.dropbox.com/s/l8wdyn3gekkziwn/3-14a.csv

5.7
https://www.dropbox.com/s/vd31ptimcb...14-Startup.csv

Let me know if these don't work. i hope they do, and thanks again for the help

I think RBob is referring to this. http://forum.grumpysperformance.com/...php?f=32&t=168 scroll down a bit to get to the actual instructions.

The short version:

https://www.thirdgen.org/tpimod2

One item not mentioned is the maximum TPS voltage at WOT. This needs to be no more then 4.6 volts. Otherwise the ECM can think that the TPS is bad and will drop out of PE mode.

RBob.