I'll try to keep this to the point here. So Ive read and myself and experienced abnormally high idle speed after replacing the TPS then the IAC. Not the 3000 rpm+ new install delima I read of, but a 1000+- rpm issue. Here is my question or thoughts The factory IAC is not adjustable. The New Standard Ignition products IAC is by screwing in or out the pintle. The recommended setting before installing it was something like 1 1/8" IIRC from mounting base to tip of pintle. That was done and my idle from then on was 1000 +-. For chits and qiqqles I put the OEM one back in and when I took out the standard one the pintle is at 1.332 " from the base. This was likely the "at idle" setting it achieved after being used for a few weeks. So...does the computer see a RPM or a suggested voltage setting when the TPS is at its bottom voltage signal of .7 IIRC / foot off the gas setting? Basically at idle the computer only says supply X voltage to the IAC which in turn means it really has no idea what the actual RPM is, just what a voltage reference should be at idle. Therefore if I adjusted the new standard ignition IAC from its said 1 1/8" or 1.125" to say 1.135" would it actually slow down the idle? Any thoughts?? Im hopefully gonna mess around this afternoon experimenting with this and see what happens. But till then curious on any thoughts on the voltage VS RPM question.
Idle speed and pintle length
- Thread starter Gilaguy23
- Start date
I did some digging and the correct lenght before installing a new adjustable IAC is 1 1/8" mounting base to pintle tip. I also read on the install PDF from Standard Products, if correct for a 2.5 jeep, that the distributor sends a RPM signal to the ECM which answers my question. Ah well...I'll try anyhow and see what happens. Ya never know.
The computer absolutely knows what the rpm of the engine is as it is the same device sending the rpm reading to the tach gauge. Pretty certain the PCM uses the rpm and readings from 5-6 sensors to set the idle speed as it sees fit. Whether or not that is a comfortable rpm to us owners is a different story.
Is it idling at a lower rpm with the oem IAC in place and extended to 1.3” like you said?
And yes, if you extended the iac outwards it will idle slower as that blocks off more of the idle air running through that part of the throttle body. However if the computer determines it doesn’t like that, it will pull the pintle back in more so it can idle up some again.
I am really surprised Standard tells you to set it to a specific length. I have never heard of that and I don’t see what the point of that is because the computer is going to constantly change it anyways. The aftermarket one I got from oreilly I believe was standard and was not adjustable, although maybe being for a 4.0 was different than 2.5 because I know they are different parts. Still don’t see why it would need to be adjustable though.
Is it idling at a lower rpm with the oem IAC in place and extended to 1.3” like you said?
And yes, if you extended the iac outwards it will idle slower as that blocks off more of the idle air running through that part of the throttle body. However if the computer determines it doesn’t like that, it will pull the pintle back in more so it can idle up some again.
I am really surprised Standard tells you to set it to a specific length. I have never heard of that and I don’t see what the point of that is because the computer is going to constantly change it anyways. The aftermarket one I got from oreilly I believe was standard and was not adjustable, although maybe being for a 4.0 was different than 2.5 because I know they are different parts. Still don’t see why it would need to be adjustable though.
At least yours' runs.
Just got home after dragging mine out of the desert.
Helped a buddy retrieve a spare tire that fell off his kids truck and it just died, right there.
A mile and half walk and an hour and hours it's parked in his yard.
I guess no good deed goes unpunished.
Just got home after dragging mine out of the desert.
Helped a buddy retrieve a spare tire that fell off his kids truck and it just died, right there.
A mile and half walk and an hour and hours it's parked in his yard.
I guess no good deed goes unpunished.
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Im pretty sure the Standard one when new out of the box had a pintle length that was close to the required 1 1/8" but off somewhat. Which way I cant recall. They warn of installing it with the pintle not set correctly or damage may happen to the driver motor. I fired it up yesterday and let it idle with the OEM one installed. The one Ive been using for the last couple months. Idles at 1000 or so. Shut it down,removed the OEM IAC and mic'ed the pintle length. At that 1000 rpm the pintle is 1.332 out. I then measured the new used standard that was boxed which also idled at 1000 or so and read the same value. I unscrewed the pintle to 1.445 and installed it. Fired it up and it idled at the same rpm after it settled down. Pulled it and remeasured it and got the 1.332 again. In either case I can see slight wear marks where the pintle tip is seating in the TB. It is weird that from when I got it with the OEM IAC and TPS working fine really, but idling at 600 rpm, which bothered me, to now using a combo of old/old,old/new or both new units it idles at 1000. Ah well.. the jeep Gods are saying to leave well enough alone apparently. Time to move on to the my anal retentive mental delima ha,ha.
Flyer58
YJ Enthusiast
Also spray some throttle body cleaner into the throttle body/plate area and inside the big opening you see in the sidewall which leads to the IAC. I had a problem with idle control and found lots of tar built up along the passage leading to the IAC. My guess was the gunk was preventing the IAC to operate fully to control the speed.
Initially when I tried to slap on my new TPS the screw heads were wasted due to a factory thread locker being used. I removed the TB and ground off the tps heads and unfortunately ground up the OEM TPS as well then tossed it in the trash. The screws then were removed with a slow back and forth with a soaking of penetrant. I fully inspected the TB and cleaned the seat for the IAC. Ive since removed the TB twice and regasketed it to make 100% sure I had no Vac leaks. Same results every time though.
Weird. Maybe your OEM TPS was causing it to idle too low and 1000 is relatively normal for a 2.5? I honestly have no idea, have not spent much time in the 2.5s at all, I would expect them to idle around 800 or 700. I still don't even know where a 4.0 is supposed to idle because after all these years mine has always been so inconsistent that I don't really know what normal is.
Maybe I'm just old school, or maybe I'm just old, but I thought a pintle was one of those sloppy hook and ring hitches.
The ones the Military and commercial vehicles use (like I've seen on transfer trucks) ...
The ones the Military and commercial vehicles use (like I've seen on transfer trucks) ...
Flyer58
YJ Enthusiast
I call it an " idle pecker" but we must be politically correct in our world of candy ass woke pussies 
Amen Brother! You hit the nail on the head.I call it an " idle pecker" but we must be politically correct in our world of candy ass woke pussies
Nothing more needs to be said.
Please call it a pintle! I’m 25 so I’m automatically a candy ass woke pussy. I need to be coddled. Not sure why I own a YJ because it really doesn’t coddle me.I call it an " idle pecker" but we must be politically correct in our world of candy ass woke pussies
JK of course, idle pecker is much better.
LOL! Macho you are definitely NOT in the participation trophy crowd!
As far as the YJ not coddling, I can relate, it would be nice, but that's just what they do...
As far as the YJ not coddling, I can relate, it would be nice, but that's just what they do...