IAC issue VX II V6 3.8

[kais3r]

Yeah, if all injectors are being pre-pressurised at the maximum pressure levels, same condition as full throttle as the fuel regulator adjusts to provide maximum pressure in a non-vacuum condition, which exists during full throttle and also during startup, so the AFR is very rich, and why you might see a bit of carbon from the exhaust at startup, but again it was more about what's normal rather than if they should be higher.
Just checked again and on cold start it gets up to 1600RPM initially then drops quick but it's also a cold day and when engine is hot it's considerably less peak RPM.
Also my battery has high CCA 550 I think, so this might also be increasing the effect.

 

[billythakid]

Turn the ignition to on till the warning lights go out 2-3 secs later instead of straight to "starting" and see if it makes a difference
Usually hear the fuel pump prime for 3 secs or so then kick it in the guts

 

[devilly]

hold up and down arrows then turn ignition on wait for RESET to appear release up and down arrows then press mode to accept RESET and see if that makes a difference.

 

[kais3r]

Ok I've tried those last 2 things posted, made no difference.

I'm thinking there's something else going on not related to the IACV, sometimes, the engine will rev extremely high up around 3000+ on startup and not come down again, so I cycle the engine off and on again waiting a bit in between , then after 1-3 start attempts it normalises again, and this is completely random but happens mostly during cold starts, sometimes not at all.
This has been one of the issues from the beginning and was doing this since the original IACV.

Will likely just have to take it to get checked with a tech 2 but if anyone knows the cause of this, that would be great thanks.
My guess would be faulty PCM, as cycling the engine a few times does usually get rid of the issue till next cold start.

 

[devilly]

tps=throttle position sensor faulty ,any leaks at the egr value.coolant sensor ,if you bridge pins 5-6 any fault codes come up ?

 

[TI3VOM]

Have you ever cleaned the throttle body at all? Might need a clean.

 

[Nut Kracker]

Don't know if it's been mentioned before (can,t be bothered reading though the previous 3 pages),
but is the throttle cable properly adjusted?
Maybe the IAT (intake air temperature) sensor is faulty?
Blocked air filter, MAF, IAT, TPS sensors.
Any one of these, if faulty/blocked will give an erroneous fuel delivery. Especially the TPS.

Please don't go go squirting cleaning solution into the IAC and TPS.
They are non-serviceable components and are not very susceptible to this kind of treatment.

And remember. Just because there could be a fault some where, it doesn't always log a DTC.