If Idle Hang were a person.......

[PhoenixGTS]

Good news - bad news update. First the good news. Idle hang is still totally gone after maybe 150 miles. Bad news is throttle-body synchronization is still an issue. I had the butterflies to they were exactly even. Then I backed off the adjustment screw two full turns so that the passenger side was slightly behind the driver's side. Big improvement and low speed bucking almost totally gone. But I could make it buck at super low speed if I tried, so I figured maybe I could do better and backed the adjustment screw back out another whole turn so the passenger side was even further ahead of the driver's side. Bad Idea. Buck came back. My thought was that there must be a sweet spot and I went too far. This morning I tightened the adjusting screw one half turn and it still bucking a little. I guess I'll put it in another half turn, and see if I can get it back to the sweet spot. Lesson learned is if it will only buck of you try really hard to make it buck, leave it alone. But still no idle hang. BTW, I have an alumninum spacer with a 3/8" hole in it in the IAC air hose.

 

[AJT]

OK I finally have to ask a few questions:
Which one is the IAC hose?
Whay does IAC stand for?
What are you using for restriction in hose?
Where are you putting it in the hose, which end?

Thanks
Andy

 

[PhoenixGTS]

OK I finally have to ask a few questions:
Which one is the IAC hose?
Whay does IAC stand for?
What are you using for restriction in hose?
Where are you putting it in the hose, which end?

Thanks
Andy

1) The IAC hose is the hose that is on the far passenger side of the air box going to the IAC unit which is on the front passenger side of the intake manifold. It looks like a heater hose, maybe 3/4" ID.

2) I believe IAC = Idle Adjustment Control

3) Many are using a section of wooden dowell. Having wood in the intake track gives me the creeeps so I have an aluminum spacer maybe 3/4" thick. It is basically like a really thick washer.

4) my spacer is in the manifold end of the hose right up against the IAC ****. When I was having idle hang, the restrictor did nothing to change it. Maybe it is helping now but I do not know.

Here is what I have done so far: 1) air hose restriction, dielectric grease on PCM harness plugs, synchronize throttle-bodies.

 

[AJT]

Thanks I will give it a try this weekend.

Andy

 

[Gerald]

/time saver/

If you have any old spark plug wires, keep the boots that connect to the PLUGS (not the coil packs). Seperate (cut, etc) them from the wire and VOILA you have a perfectly sized restrictor hose that will fit perfectly INTO the IAC motor tube to restrict air flow to help your IDLE HANG.

You'll have to cut about 1/2" or so from the length of the boot so it doesn't hang out too much from your IAC motor tube. The hole left from the spark plug wire is MUCH smaller then the diameter of the IAC motor tube and will restrict air hopefully enough is some cases of the dreaded IDLE HANG..

This just saves time,etc from getting a metal tube, wood dowel or tube and drilling a hole in it to acheive the same effect.


Good Luck

Gerald

 

[BadVenm]

Here's my saga update.

Today after reading Phoenix's update I took out my IAC restrictor and drilled it from the 21/64th Sean Roe recommended size to the 3/8th size hole mentioned in PX's post. The restrictor I was using was 1 and 1/4 inches long.

Man things got worse! I ran the car hard and the hang was worse than ever.

2,500 RPM's and it would NOT drop AT ALL! I had to let the clutch out and hit the brakes at the same time to get it to drop. Otherwise it would stick there forever.

So just about an hour ago I made a new IAC restrictor. This one is 2 inches long. This time I drilled a 19/64th's size hole in it. Which is two sizes smaller than Sean Roe's recommendation.

I took it out for a 5 mile quickie. Easy cruise, and a few hard lunges, 2nd and 3rd up to 5,500 RPM's. Now it's a little better than it was when I had the 1 and 1/4 inch long restrictor with the 21/64th's size hole. When I put in the clutch, it's a slightly slower than normal drop from whatever RPM's to normal idle. With the old restrictior, it would hang after an easy cruise. Now it's not really a hang it just takes about 2 seconds to drop to normal. And what it was doing a few days ago, which was dropping so fast it just died, has stopped. Needles to say I need to put quite a few more miles on to really see what is going to happen.

In the morning I am going to try putting the restrictor on the manifold side of the hose, not right at the air box like I have been doing.

I was thinking maybe Jerry was on to something in his post when he said something about the K&N's and the oil possibly messing up the sensor. But at least with my GTS, I have K&N's and smooth tubes and there is no idle hang. Nor was there any idle hang with the RT when it had K&N's and smooth tubes prior to engine mods. I think his idea needs some more research, the idea does have a lot of merit.

I've tried resetting the PCM's - more than once, I've checked the adjustment on the t-body butterflies, but I haven't tried the di-eletric grease, yet....

It is weird that some things work for some cars but not all. If each of us hear enough different fixes that worked for the other guy, we will finally try one that will work for us too.

Keep the fix stories and info coming. We'll beat this dam thing in time!

 

[PhoenixGTS]

Hopefully final update. Reduced the lead of the driver's side butterfly and the bucking is gone, plus no idle hang whatsoever. The big breakthrough on the idle hang was getting the throttle-bodies synch'd. Understanding that I have 70mm t-bodies, for baseline purposes, I got the butterflies dead even (easiest way it to use a feeler guage where the stops touch the body) then I backed the passenger side adjusting screw out two full turns so the the driver's side butterfly opens two turns of adjustment before the pasenger side.

 

[Jerry Dobson]

Phoenix,

Did the problem come back?

Jerry