VN SS hunting during idle

[maggot3064]

yep tried that and it was back firing through the exhaust because it had fouled the plugs that bad. checked codes and its flashing no12 so all clear.

 

[maggot3064]

Changed the Ecu back to the one from the donor car and it idled smoother but at about 1200rpm the whole time. So I put the stock one from my car back in and it ran at about 750 but hunted the whole time. I even retentioned the inlet manifold thought I may have a leak but made no difference

 

[Deuce]

If you put your ecu in and wind the idle screw up to around 1200rpm does it also idle smooth?

I think Brisbarnz is on to something with the cam idea.

 

[FXST01]

Try using the donor ECU and your MEMCAL and vice versa, see if they both run the same.

 

[maggot3064]

yeah as soon as you open the throtle evn the tinist bit it doesnt hunt.

ill try that with the ecu tonight!

 

[Circlotron]

Try unplugging the idle air control valve from the wiring harness. The engine may or may not idle at the correct speed, but if now idles smoothly you have ruled out fuel and ignition problems. Have you tried running at 2000rpm(?) for 30 seconds in neutral to reset the IAC?

 

[maggot3064]

I dissconnected the IAC and the idle went just over 1000rpm and idled absolutely perfect although just that little bit high, does that point to a faulty IAC?

 

[Circlotron]

I'm thinking that perhaps it's more of a tuning problem. There are a butload of setting in the ECU just for the IAC. See pic. Maybe ask the guys over at pcmhacking.net what they think. -> pcmhacking.net - Index page

 

[maggot3064]

Yeah apparently it has a "baby" cam in it bit sure what, but a mate was saying it more then likely needs a tune. I'll have to finish off the rest of the car and take it somewhere and go from there. Will keep ya posted