cold start and decell stalling

[leathalbusa]

Ok guys. we got it all tuned and tame now have 2 little issues.
1st. cold start is crazy . it floods the motor completely out... stalls it and a major flood. where is it that I can reduce that?

2nd. on deexcelatring down through the gears to first it will stall. have caught it so far but not sure if it is flooding again or just dropping down below idle. it will idle down and stall as your coming up to an intersection. worse if the aircon is on.
Your thoughts?

[Holden202T]

when exactly is this happening, while its cranking over or after it starts ?

when the car is idling at running temperature what is the IAC steps on ?

[leathalbusa]

it's worse first in the morning. it will crank and start fine. but try to get it to lift off idle and it stalls flat out. the you have to crank it heaps to get it to pick up.

when the car is warm it's fine spot on afr's .
I haven't checked Iac steps. what should I have?

[VL400]

Grab a couple of logs of it happening and post it up, may help to see whats going on.

[antus]

And definitely check your IAC steps. Are you running a speed sensor?

[leathalbusa]

no speed sensor as it's a VP commadore manual. I just found a cracked hose to the map sensor.. so fixed that but the idle is still low. so will check it.

Where do I adjust the base idle for the IAC? in the program?

[VL400]

Set the IAC to be around 20 steps when at a warm idle, this is done with the stop screw on the throttle body. Might need to have less than 20 if your not going to run a VSS and dont want it stalling all the time.

[antus]

Edit: VL400 just beat me to it, but heres the long winded explanation:

There should be no problem with running a speed sensor on a VP commodore manual - that is how they came out from factory, and the auto and manual ECUs are the same. Without the speed sensor the ecu is trying to idle while you are moving and at higher rpm so the IAC fully closes and fails to bring the revs down and stays closed. When you do stop the IAC is then fully closed and there is not enough air which causes a dip in RPM before it sees this and re-opens a bit. This can cause stalling. The proper fix is to install a speed sensor. The work around is to open the TB a fraction so the minimum amount of air is enough to not stall the engine. But then you might find the idle is a bit high, and you just need to balance it out. There is some info about how to setup the IAC normally in the faq here https://pcmhacking.net/forums/view ... f=7&t=1396 under "How do I get my idle speed right".

[vlad01]

Edit: VL400 just beat me to it, but heres the long winded explanation:

There should be no problem with running a speed sensor on a VP commodore manual - that is how they came out from factory, and the auto and manual ECUs are the same. Without the speed sensor the ecu is trying to idle while you are moving and at higher rpm so the IAC fully closes and fails to bring the revs down and stays closed. When you do stop the IAC is then fully closed and there is not enough air which causes a dip in RPM before it sees this and re-opens a bit. This can cause stalling. The proper fix is to install a speed sensor. The work around is to open the TB a fraction so the minimum amount of air is enough to not stall the engine. But then you might find the idle is a bit high, and you just need to balance it out. There is some info about how to setup the IAC normally in the faq here https://pcmhacking.net/forums/view ... f=7&t=1396 under "How do I get my idle speed right".

I get this, but only when gearing down fast. then it stumbles when the clutch is in. Any other way I stop its fine, its only when I gear down hard.

also in the past I got VSS error. I think code 24 when, get this. the car wasn't moving lol. duh of course there is not VSS signal when I am not moving.


what could cause that? I guess its the IAC steps? I have a 66mm TB yes 66mm its a bored out 60mm one i made myself. And I haven't tried the stop screw yet.

[VL400]

Code 24 checks firstly if vehicle speed is 0 before checking if MAP < 'Malf 24 - Maximum MAP load limit' and its in a normal driving range RPM (Malf 24 - Engine speed lower limit to Malf 24 - Engine speed upper limit) ie likely coasting down a hill or very light throttle but maintaining RPM while seeing no VSS pulses.