Trying to get IAC set right

[usetaboost]

So I spent a few hours trying to get my IAC and TPS to play nice with each other, but no dice. I did do the procedure straight from gnttype.org for setting the IAC. I got it in the range a few times but it slowly drops to zero and stays there. I then took some O2 safe carb cleaner and sprayed the vacuum hoses to see if I have a vacuum leak that is letting in unmetered air. No change in idle. I understand this isn't an exact method..but it is the only one I know. All hoses appear snug on their connections and no obvious leaks. I think I MIGHT hear a hiss coming from the passenger side..but can't tell for sure.
Had the IAC open enough to where it was 175 and idle was around 750-800, but that isn't where it was supposed to be and that is why I started this, plus anytime the idle dropped below 800 the car sounded like it wanted to stall..and WOULD stall when cold.

Car has a turbo tweak chip. Scanmaster. 009 injectors. Line off pressure is 43psi, line on 38psi. Walbro pump from 2 years ago, with less then 2500 miles on it. Stock intercooler, 3.5 lt1 MAF w/GEN II (verified settings per manual)
Here are my scanmaster numbers:

(AT WARM IDLE)
O2 jumping from hight 100's to 400's
AF 07ish
L8 34
INT 128
BLM 125
CLT 190
ATS 80
r 1070
TPS .44 (4.3 at WOT)
IAC 00
cc jumpng from low double digits to mid 200's

Side note: on a suggestion from search results moved the screw for the IAC out to a thread and a half exposed on the other side and the BLM's dropped to 119 and the IAC still wasn't in range.

DId this start happening after installing a new iac or after you disconnected the battery?

 

[WH1_T-Type]

LOL a 12 hour day must have made me stupid! I meant to say it goes up.01 with the car started.

ahhh..ok. lol...I'm finishing up two days of 12's today...so I know how that is!

DId this start happening after installing a new iac or after you disconnected the battery?

This has been going on for awhile now, just finally trying to get it done. Since I got back from IA I have a stronger desire to stay on top of my hobbies. No new IAC (yet, I have one) Battery has been disconnected several times. Had plenty of time since the last one to relearn everything

Had a work weekend, so hoping to get back on this tomorrow, weather permitting.

 

[usetaboost]

Don't bother with trying to follow that iac reset procedure. Get that thing good and warm. Drive it around for about 20 minutes. then use the screw to adjust your iac. You will have to go back and forth oin the tps and iac to get it all set. One more question, what's your vacuum at?

drop the tps down to .41 with key off before you go on your next ride. Your cc's should steadily rise once the car is warm

 

[WH1_T-Type]

Still at work..but I've been watching the vacuum when driving and it is at 17.

 

[usetaboost]

Drop your tps down to .41 key off and drive it for a while and report back. It doesn't matter how high it reads at wot as long as it's over 4 volts

 

[WH1_T-Type]

Drove it for awhile...has a new IAC motor in cause I had the car apart to replace the thermostat with a 160 anyways...still won't stay above zero. Tried waving a unlit torch around and WD40 (tip of a friend with another turbo car), can't find a vacuum leak. There is a plug on the passenger valve cover that appears to have a vacuum line going to it and there is a nub with no hose next to it. Plugged the open nub with my finger, no change. Lighter next to it, no change. No idea what it is for or if it is supposed to have a hose coming off of it.

 

[breiter]

Not sure what the voltage should be and on which pins of the 4-pin connector for the IAC but it sounds like there could be a electrical problem at the IAC plug. Maybe by chance you got a 2nd bad IAC? Obviously at 0 the engine gets no air at idle through the throttle body. You could run the screw in to open the throttle blade a little just for testing. Find the fuse or relay for the IAC and test it.

 

[WH1_T-Type]

When driving around the IAC numbers do move around though...shouldn't that mean it is good? I do have a MAF pipe from TR Custom Parts on there that hits it..and one of the wires looks like it has a bit exposed now..but nothing is touching it. Gonna get it wrapped in tape next.

 

[usetaboost]

I think you need to turn your idle screw up and then put your tps at .41 and see what happens

 

[WH1_T-Type]

Up? Like all the way clockwise till I can't turn it anymore?

There is a plug on the passenger valve cover that appears to have a vacuum line going to it and there is a nub with no hose next to it. Plugged the open nub with my finger, no change. Lighter next to it, no change. No idea what it is for or if it is supposed to have a hose coming off of it.

Here is a pic of the plug that I'm talking about on the passenger valve cover. Not my engine (I wish..), picture is from Jaw Dropper thread via RMAR's post. My plug has only ONE hose coming off of the portion closer to the manifold and that hose goes to the turbo where it hits a Y connection to two more hoses. The other side is open.

 

[Steve V]

Thats the factory setup for waistgate solnoid,does not affect idle.

Up? Like all the way clockwise till I can't turn it anymore?



Here is a pic of the plug that I'm talking about on the passenger valve cover. Not my engine (I wish..), picture is from Jaw Dropper thread via RMAR's post. My plug has only ONE hose coming off of the portion closer to the manifold and that hose goes to the turbo where it hits a Y connection to two more hoses. The other side is open.

View attachment 143404

 

[WH1_T-Type]

Is the second side supposed to not have a hose at all though? I would think having an open port like that would create a vacuum leak? I've looked at pics of others and it SEEMS that they all have TWO hoses coming off of them. I've also been reading about changing that to a breather to prevent oil in the up pipe (which I do have). Am I way off base here?

 

[usetaboost]

no hose. It's just a bleeder. I unhooked the hoses off mine and put on a mbc. If you are going to bypass the valve cover tube, leave the filter part in the valve cover and just put a breather in the small rubber hose sticking out of it. That way the filter is up and you don't risk any oil leaking. I can take a pic next week so you can see what I'm talking about.

 

[Steve V]

Pressure comes from the turbine housing goes up that hose then when the solnoid creates a restriction and air backs up down the other hose and opens the waistgate. How much depends on rod length and chip.
If you have oil in the up pipe either turbo seals or the tube/breather from right side valve cover to turbo is still hooked up.

Is the second side supposed to not have a hose at all though? I would think having an open port like that would create a vacuum leak? I've looked at pics of others and it SEEMS that they all have TWO hoses coming off of them. I've also been reading about changing that to a breather to prevent oil in the up pipe (which I do have). Am I way off base here?

 

[WH1_T-Type]

no hose. It's just a bleeder.

I just seems odd to me that it isn't supposed to have a hose. The piece of plastic has a flared end and everythign just like one that is fitted to have a hose on it. Also, all the pics I can find of the passenger side that still have this piece APPEAR to have a hose on it?? I will take a pic of exactly what I mean when I wake up in the afternoon. I'm on another mid-shift right now.

 

[groumoutis]

That port you are talking about originally had a little filter on it. Which side is the hose hooked to. If you are leaning over the passenger side fender it should be hooked to the one closest to you. I had a vacuum leak in my car and I used a golf tee to find it by plugging off line and doing the wait and see game. I don't think it is a vacuum leak you have just for the fact that your blm's seem to be good. When I had my leak mine were way high like 139-142. Take a pic of your iac screw and post it. While you have the camera out take another pic inside the throttle body with the blade open. The 4.3 wot on the tps is probably due to thick carpet. I would try adjusting the tps like usetoboost said. What can it hurt? He is right mine goes up .01 as well.

 

[WH1_T-Type]

The hose is hooked to the one closest to the intake, not closest to the fender. Would that make a difference?

If not a vacuum leak, what could cause the IAC to fail like it is? I checked the TB blade already and it seemed clean, though I will post a pic as requested. As well as the screw.

I did make sure that my floor mat was out of the way when I checked the WOT TPS and later when I was screwing around with the IAC screw I had to readjust the TPS and got the WOT closer to 4.5 now. So I don't think there is anything there.

 

[usetaboost]

Don't worry about what WOT tps is. Like I said, anything for 4 volts is going to go into PE anyway. You need to adjust everything at base. Turn the screw up little by little until you see the iac counts move. Do like 1/4 turns or somthing. Do one 1/4 turn, see what happens on the scan, shut car off, adjust tps to .40-.41, start car and see where the iac settles. Repeat process until you get it around 10-15 iac counts then take it for a drive and check again. Get these set and the car should run perfect. Mine does

 

[WH1_T-Type]

Sorry; no updates due to adjustments yet..working and raining (no garage).

However, had to move it the other day so I let it warm up and something I noticed is that the IAC hangs out a LOT longer in the number ranges before it starts driving. I had it warmed up and running for about 10 minutes and it was between 11-13. It did start to drop before I shut it down..but VERY VERY slowly. I actually didn't have it on long enough to see it go to zero. Does this mean anything?

 

[Steve V]

where are your idle rpms?