Idle Hang Revisited

ViperGTS

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I got the newest PCM software - version "AF" - idle hang is still there
 

Jerry Dobson

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Today the humidity was about 100%. This was my test. I wanted to know if it was temperature or humidity causing my idle issue. It is humididty. I have not had any problems for over a month. It idled at 1500 tonight. Still no real fix.

Jerry
 
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My care still hangs at idle about 50% of the time.
I haven't had time to work on it much
but
I've gotten some ideas.

1. I've had the "Check Engine" light go on a few times
and the DTC code indicates bad O2 sensor.
I've bought new sensors but had not had time to install them.
The warning light goes out after a few cycles of engine on/off
so this is an intermittant problem.

2. When I changed the intake manifold gaskets about two years back I noticed that there was motor oil in the intake runners. No real reason I could find for it being there.
Before my last oil change I noticed the Idle Hang was gone.
I checked the dipstick and it was towards the low end.
Brought the car in and had the oil changed
and the oil was brought back up to the full line.
The Idle Hang came back.
I'm wondering if the full line is too full for oil
and if oil is not getting sucked back through the PVC system
leading the erratic idling as the O2 sensors compensate for burning oil.
Maybe next oil change I'll have the fellas leave one quart out and see if that helps.
 

01sapphireGTS

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Add my car to the long list of cars with this problem. When my idle sticks at 1500RPM, there seems to be nothing I can do to regain normal idle speed. It just goes back down to normal when and if it wants to. I am running the stock computer program, stock throttle bodies, with the only flow changes residing with the K&N's, smooth tubes, and Corsa cat-back. It's a 2001 with 1700 miles on it, so the problem occurs early not due to worn or dirty induction parts.

The fact that the problem is "here and gone" with no seeming pattern would lead me to think it is an electrical issue. Be it the PCM or TPS's etc. A vacume leak or idle mixture issue would be constant maybe only changing under severe climate changes. I have had my very annoying & embarrassing problem occur at all air temps from 40-90F. Although I never drag the motor along when braking, I only use the brakes for stopping.

I would guess that the Gen III's probably don't have this problem as they only have one throttle body to deal with. It may very well be an isuue of trying to synchronize two throttle bodies that gives the computer such a dynamic problem to manage.

And as "Vanishing Point" pointed out. Why does the car idle lean ? What is the purpose of adding undue heat ? Maybe it needs to be done for emmission purposes... ?

I'm going to call Dan Cragin @ DC Performance this week to see if he has any advise for my year car and tuning set up.

PLEASE HELP !
Signed - All Reved Up...
 

STUGOTS

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My 99 R/T never did it UNTIL i put in k&n filters then boom and only after its just started (and temp has nothing to do with it it can be totally warmed up at 95 degrees and still do it) and it only does it for about 8 minutes then its perfect and it does not happen everytime.

I see most or even all of the people who expirence this have k&n filters
 

93Cobra

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Mine does it 50% of the time and it usually goes away. There has to be a fix to this very common problem. Has anybody tried replacing the TPS?
 

Gerald

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I've finally gotten rid of my idle hang after 3 years... Been 4-5 days now and still gone.. I THINK I'VE FIXED IT!!!!!!!!!!

what'd I do? New 02 sensors (upstream)( I have simms on the rear)



(I've tried EVERYTHING else)

Perhaps the computer is so sensitive if the 02 sensors vary SLIGHTLY it will compensate by adjusting idle up, causing the hang. But not enough to "throw" a code.?? LIke I said, new 02's did the trick for me and i'd venture to say if someone else tried it they'd have (hopefully) the same results (don't foget to unplug the computer for a few minutes, and change both upstream sides).. I can't beleive how well it idles now!! I'd bet anything after a 5-10k miles my car will start to hang again. Then I'd have to get new 02's and it would sove it again...


G
 

NDW

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I fixed my idle hang with a simple wooden dowel with a hole drilled in it via Sean Roe's instructions. It solved it for me at the total cost of $.99.
 

Gerald

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I tried that too. My car would drive down the road whistling at about 100 decibles.. Horrible experience.. Didnt' solve my problem though.. That's not a fix only a bandaide. What causes the problem to begin with?
 

Jerry Dobson

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Any updates?...my idle hang was gone for about 3 months. Now that the outside temperature has dropped....Idle hang is back.

Jerry
 

Andrew/USPWR

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My cars idle hangs up every now and then. Never thought much of it till I started reading this forum. Normally just blipping the gas fixes it. I'm hoping it doesn't get worse.
 

thebigsnake

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I guage what type of day I'm going to have by where my Viper is idling that morning on my way to work. Its never at the same speed.
My 911 idles like a watch at a perfect rate and the build quality is hella better, but the Viper is the one that blows my skirt up.
It's part of all the traits that keeps Gen I/II Vipers exclusive to the inthusiasts, and keeps out the women drivers and overindulgent weaners.
And that's priceless.
 

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