Idle on stock s3 304 ute

[The J'rod]

really need to proof read posts 'so I put my old stock throttle body back on it, and it still seemed to have the same issue'

[The J'rod]

So my steps on the IAC is at like 225 on cold idle, so would this a stuffed IAC or something in the wiring or something else.

hoping attached is a log from the other night for you more learned gentlemen to have a look at.

[vlad01]

do they come down as it warms up? and if so the the idle change at all? Sorry I don't have my gear to look at the log atm.

[The J'rod]

vlad01 I will have a look at my log tonight and try and give you a run down on what the IAC steps is doing as it gets to temp and when its, idling at temp

[The J'rod]

I'm thinking that I might just replace the IAC again and see if I bought a dodgy replacement, it was a $30 aftermarket one, maybe I just bite the bullet and pay $70 for a genuine, but I will spew if it's something else, I also did the start ya bastard trick and I got nothing as far as finding a vacuum leak, would vac leak be showing in items list if the IAC was stuck or not going up down correctly or would the IAC be showing up in the items list that it's faulty.

vlad01 the steps do come down as it gets more temp into it but still not to correct idle, I have found that getting the at to temp than turning it off for 5 minutes than re starting it seems to settle the idle down best

[Dylan]

On pre VT the max steps is 196 maybe limit them?
Also it's not an LS1 IAC is it? They're compatible but different plunger.

[vlad01]

yes a stuck IAC could cause a vac leak error as the ECU only can assume the IAC moves, it may still move but maybe not correctly? Assume the OS code is smart enough to have a IAC error if the rpm has 0 response when signals are sent to step.

I am sure someone here can chime in an give insight to these conditions as errors. Not that familiar with MAF ECUs.

[MAGP]

Using something like ether (Startyabastard) isn't really the best way to do it, not to mention it is a flammable substance. You want to seal the leak area not feed more fuel through it. Get a small spray bottle with soapy water and go over things with that. If there is a leak you'll hear a change in the engine but also possibly see foaming at the leak.

[brindo]

I had very similar symptoms in my old VS ute ages ago, but this was before I had the NVRAM and Tunerpro. It was a stock VS Series 3 then with the 195 engine.

It would run terrible cold, and once warm was OK. Would throw a random error code relating to the TPS. Can’t remember exactly which one but think it was TPS stuck, but would only throw the code on a long highway run.

TPS was fine, but replaced it anyway. Ended up replacing the MAF and that cured it, but there was no error code related to the MAF at all.

Is there any way you could check the MAF to see if its OK, or swap it with a known unit to see if there's an improvement?

[charlay86]

vacuum leaks:
I swap out MAF for a PVC pressure pipe cap or whatever you can seal nicely in the place of the MAF.
Pull off a vacuum hose from the Fuel pressure reg or somewhere.
Turn your air compressor pressure right down, and get the blow gun with the metal tube end and stuff it up the vac hose you pulled off (this needs to seal nicely).
Slowly let some air into the system, and when you let your finger off the blow gun trigger have a listen for hissing, then spray soapy water around the hissing area.
N.B. you may need to rotate the crank a few degrees if the engine happens to be on overlap.

If this was a boosted vehicle I would continue looking for leaks and raising the pressure of the system until I was seeing operational manifold pressures.
It is really interesting to see how much everything moves around when you really get some pressure in; sometimes leaks only open up above a particular pressure.

Edit:
also note that it should be possible for the system to hold pressure.