Idle Hang

[kowalski vanishing point]

Has anyone come up with a solution for this?
My '97 GTS still intermittently idles between 1200 and 1500 rpm.
Still no answers.

Have changed the battery, idle speed control motor, intake
manifold gaskets, spark pugs and wires, PCV tubing and valve,
and adjusted the throttle valve on the passenger side
all to no avail.

Maddening because about 50% of the time it idles correctly.

Will it pass smog in California idling at 1500 rpm?
If not will Dodge be obligated to repair it?

Seems like it is more prone to this after city type driving.
Any suggesions?

 

[Brad Manhattan Beach]

I've had this same problem happen on my GTS since I got the engine back from Arrow.

Brad

 

[SneakyPete]

Usually it is the intake manifold gasket.

I had same problem also. Push in clutch, car would idle at 1700 RPM. Put it back in gear and apply brake, idle come back down to 500 RPM.

I had a blown intake gasket, had dealer replair under warantee and problem went away.

who did your intake gasket replace, might want to check it again.

GOOD LUCK

 

[Diablo Joe]

I had the same problem and it was computer related.I was able to tune it out by adding fuel at partial throttle with my VEC1.My gaskets have been replaced as well before this problem started.


Joe

 

[kowalski vanishing point]

The dealership replaced the intake manifold gasket
the first time. I did it myself the second time
and used a pliable sealant. Still problematic.

The erratic nature of the problem make me think
it is not an intake manifold gasket leak which
would be more consistent in its malfunctioning.
Also the problem did not go away after replacing
the gasket which I
did quite meticulously (i.e. correct torque and sequence).
I did notice oil in my intake manifold runners when it was
out. The car does not eat oil.

Is it possible that low speed driving with the throttle
almost closed cause enough vacuum to pull oil out from
somewhere (past valves, through PCV system)?
Could that fool the O2 sensors? It seems the Idle Hang
goes away if I drive aggressively. Or is it a computer
glitch as I've heard before?

 

[kowalski vanishing point]

Tell me more about that VEC1.
Is it smog legal?
Where can I get one?

 

[LTHL VPR]

First questions:
Is your car stock?
Have you measured the MAP voltage, TPS voltage, and Vacuum. that's what I would do first. However, I do know that 96-97s have a tendency to hang a little; they have the most aggressive cam of GEN IIs. Don't know how bad yours is though.

Even more simple: Have you tried resetting the computer? Since if that has any effect.

Hope this helps!
-Wayne

 

[kowalski vanishing point]

I did measure the vacuum which was fine.

Can I measure the TPS and MAP voltages with a common voltmeter
or do I need a complicated diagnostic tool?

I have tried reseting the computer and that works for
about 200 miles.

Also if I unhook the TPS or the MAP the engine goes into
apparently a default mode and idles fine. I was fooled by that
and did replace the TPS only to be rewarded by 200 miles
of good idling before the problem came back.

 

[kowalski vanishing point]

Oh, and the car is stock.

 

[LTHL VPR]

Yes, you can use a standard volt meter to measure your TPS. MAP sensor may be more diffcult as usually the measurements are converted into 'real' world numbers.

What vacuum measurement are you getting?
Since it is recurring every couple hundred miles after restting the computer, it may the the hanging that is typical of 96 or 97s. Again, without seeing it, it's hard to tell.

Call me in the morning, and I'll have you try something to see if it helps.
408.562.1000
Thanks.
-Wayne

 

[Sean Roe]

I think I know why the newer cars are having this problem at times. Our GTS did not have this problem, but once when I was testing something, it did. If you have idle hang, drop me an e-mail for a simple test solution and we'll see if it works for others.

Sean

 

[Gerald]

YOu guys are gonna laugh your *** off, but here is what I found that helps...

I've messed with the throttle body bolts (not the cables), idle sensor, replaced IAC motor, cleaned it , etc etc etc etc. I do have a new intake mfd gasket so that's not an issue. When it hangs a quick blip of the throttle brings it down..

Now here is where you laugh.. If I take my foot and toes and bring them UNDER the front part of the pedal, lift it up and let it bounce back down, that brings the idle 90% of the time back to normal.. Don't ask me why...


Gerald

 

[Viper Specialty]

this is a PROBLEM??? My car has done it since day one! If I am driving and let off the gas, it hangs at about 1250 RPM. then when I reach about 2 MPH, it drops to idle. However, it does this EVERY time...and only after driving. wont do it is you rev and hold, drive at a very slow speed, etc.

EDIT- Come to think of it, on LATE Gen 2, this may be actually programmed into the computer to do this. I know that around here at least, LOTS of early gen 2 cars are having problems with stalling after letting off the gas. It would seem that by implementing a system such as slight "hanging", that problem would be cured... I'll check around today and see if any other 2001+ Gen 2's around here do it as well.

 

[dblankenbaker]

FinalGTS: that is normal for every Viper.

The idle "hang" (as it occurs on my girlfriend's '96 GTS) is when the idle stays at 1,700 rpm even when sitting at a stop. IM gasket replacement a couple years ago fixed it the first time. Now it just came back (after a dead battery last winter, hmmmm... ).

 

[Gerald]

Since SO many people experience this, it would be nice if someone really knew what caused this. I've had on occasions where the car would lurch forward thinking the idle was lower (car stereo is on and can't hear the idle speed when clutch is in) only to find out it's stuck at 1,500 rpm and like I said, suddenly lurch forward.

I can't believe there isn't a known cause since it's been happening since 96+ cars. ( Mine is a 98)


Gerald

 

[CBR Crazed]

Just wanted to point out I have been fighting the same high idle problem and I have a Gen I '94 RT/10. I have had the car 5 years or so and the problem started about nine months ago and I have yet to find a cure except for disconnecting the battery to reset the computer. This only lasts about 200 miles, just as previously posted. So I don't think its just a Gen II problem. If someone thinks they have found a cure, please post it.

 

[KenH]

It's the Viper version of cruise control. Mine '01 use to hang frequently, but hasn't been noticeable lately, not sure why. I could cruise down the freeway just letting it idle at around 60 or better with my foot completely off the gas.

--- Ken

 

[Viper Specialty]

KenH...I never even thought of that! technically, it should work... I'll have to try it tomorrow. if it tries to keep the RPM up when the speed is high, it shouldnt allow you to drop your speed below a certain point...

Anyways, here is the Low-Down:

IDLE HANG: ALL late Gen 2's I have seen DO hang. They hang over 1K RPM until your speed drops below a certain point, then they drop back to TRUE idle. EXAMPLE: Next time you are getting off an off-ramp, toss the car in neutral. The RPMS should hang at a certian point. then, as you approach a stop, it will drop back.

REVERSE LOCK-OUT: late 93+ Vipers have reverse lockouts, you cannot shift into reverse while moving forward, or with the key not in the "ON" position. This system is electronically cntrolled with a soleniod. However, The system does have an "Incase Sh*t" feature, which allows you to get into reverse if the system is not unlocking. To do this, push the shifter towards the right with a lot of elbow grease with a little "up"-(up as in towards the sky) force. the shifter will slide OVER the lock, and reverse becomes temporarily accessible. (the soleniod has a spring loaded ball edge, and that ball is either retracted electronically via the soleniod, or you have to manually "pop" the ball edge out of its grove by pushing up and over FIRMLY).

 

[Viper Specialty]

OK, I am going over to a couple peoples houses today, and I will put to rest all questions regaurding Idle Hang, Reverse Lockouts, and tranny shifting noises/properties. I will keep in touch.

 

[Gerald]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Final GTS:
KenH...I never even thought of that! technically, it should work... I'll have to try it tomorrow. if it tries to keep the RPM up when the speed is high, it shouldnt allow you to drop your speed below a certain point...

Anyways, here is the Low-Down:

IDLE HANG: ALL late Gen 2's I have seen DO hang. They hang over 1K RPM until your speed drops below a certain point, then they drop back to TRUE idle. EXAMPLE: Next time you are getting off an off-ramp, toss the car in neutral. The RPMS should hang at a certian point. then, as you approach a stop, it will drop back.

REVERSE LOCK-OUT: late 93+ Vipers have reverse lockouts, you cannot shift into reverse while moving forward, or with the key not in the "ON" position. This system is electronically cntrolled with a soleniod. However, The system does have an "Incase Sh*t" feature, which allows you to get into reverse if the system is not unlocking. To do this, push the shifter towards the right with a lot of elbow grease with a little "up"-(up as in towards the sky) force. the shifter will slide OVER the lock, and reverse becomes temporarily accessible. (the soleniod has a spring loaded ball edge, and that ball is either retracted electronically via the soleniod, or you have to manually "pop" the ball edge out of its grove by pushing up and over FIRMLY).

<HR></BLOCKQUOTE>

I wish it was that easy.. Mine hangs at stand-still even when speed comes down to zero (stop light etc). Only thing like I said that seems to cure it 90% of time is LIFT UP on gas pedal with toes and release quickly.. Don't ask me how this works...)
Sometimes this doesn't work and I have to blip throttle...

 

[Ulysses]

Gerald,

your problem sounds like the return spring on the throttle bar could be weak, OR somehow your throttle cable got tweaked.

 

[Viper Specialty]

Gerald- I have to agree, what your describing seems like the butterflies arent closing completely, for whatever reason. It could be a bad cable, weak return spring, jamming gas pedal, sticky butterfly... check all those. disconnect everything and try each part individually to see if it retains the problem.

 

[Tom Welch]

Just had this exact problem with my 97 GTS.

Larry Macedo ran diagnostics for me..we found nothing wrong. I then tried another computer and it solved the problem. My guess, if you have done everything else, its your ECU.

Best of luck,

Tom Welch Http://btrviper.com

 

[Newport Viper]

Mine was madding! It was a bad connection at the map sensor! Runs perfect now.

 

[VEETENN]

I have a late 98 GTS with 13K miles and have never had this Idle Hang problem.

 

[Brad Manhattan Beach]

I just found out from the dealership that I have an intake manifold gasket that is leaking on my newly re-built Arrow engine. I have a total of 2,000 miles on the new engine. How does something like this happen on such a new engine?

The ironic thing is that before I sent the engine back to Arrow, I didn't have this problem.

Brad

 

[Todd Richmond]

Nothing like pulling up on countless left lane bandits and having to slam on the brakes each time. My 97 GTS had exactly the same problem and having head and intake work done put me over the edge. Idle went up another several hundred RPM and would not kick down until I came to a complete stop.

Here is the info I heard from various sources

1) Stick a smaller diameter tube in the idle air tube. This reduced the problem a little but was definitely not the cure. Something easy to try for people with relatively minor idle problems
2) Replace the entire wiring harness because the wire to one of the sensors get brittle w/ heat and causes false readings - at around $1k - no thanks
3) Replace the intake manifold gasket - already did that w/ head work
4) Reset the PCM - I pulled out all plugs - no change
5) Replace the PCM. I had a Hennessey Stage I PCM and so out of frustration, bought a stock PCM from someone on the net. However, this had a "Dodge authorized software upgrade" sticker on it. SUCCESS!!!!! Nice normal idle - I'm not sure if the PCM upgrade is required, but it sure works.

Of course I fixed this 1 week before my left brake front caliper fell off on the freeway so the car is in the shop and I can't enjoy it. The story of the missing locktite to follow later

 

[RockyTop]

I am experiencing a hanging idle problem with my 97 GTS. Hangs at 1700 and sometimes 2000 rpm and often won't come down with a throttle blip once stopped. I can relate to others who are concerned about lurching at a stop light etc. as you have to pay attention ! Turn on the AC or leave the car in gear and brake to a near stop so there is load on the engine and it typically "unhangs" and gradually drops to its normal 750rpm.

When I first noticed the problem, I got a MAP sensor code. The tech traced the problem to the voltage coming from my VEC 1. We reset the PCM and I recalibrated the VEC and it went away for a short time. But, of course, it came back. I wil say that

My car recently displayed an idle air motor voltage code. I cleared it and that code hasn't come back, but the hanging idle did. My car is in again to be prepped for the VIR Viper Days event. The tech was able to duplicate the hanging idle. Unbelievably, and in violation of the auto repair corollary of Murphy's Law, the symptom actually presented itself while the car was in the shop !! The tech unplugged the VEC and said that the hanging idle went away. I am sceptical, but hopeful. Perhaps the problem is somehow caused by my VEC1. I am curious how many of us who are experiencing this issue have VEC1s. Perhaps my VEC 1 is freaking out or perhaps it's not the VEC 1 at all. I suspected a leaking intake gasket as mine has gotten a bit wavy, but last time in the tech says he sprayed some junk on it that would show a leak (I guess much like the way they test tires for leaks) and detected none.

This is obviously a widespread problem. My car first had this issue in 98 and upon replacing the intake gasket, it went away for 3 years. It's back and I am confused !

 

[GTS Dean]

Rocky,

Why don't you try having your JTEC reflashed by the tech? Before you do, check the adaptive memory blocks for each bank in the rpm range that you are having trouble with.

 

[GTS Dean]

My '96 is an early, 2-digit VIN car. (incidentally, I bought it July 15, 6 years ago) After reading some of the early posts on this thread, I wish to offer this for consideration.

At the first Viper Days Finals in Savannah, I experienced the 2000+ rpm idle hang issue. It was solved with new intake manifold gaskets.

I also experienced the occasional WOT ~5000 rpm stumble/shutoff that wouldn't set a MIL fault code. The fix was an updated flash for the JTEC controller. One thing I noticed immediately after the reflash was that the engine returned to idle in 2 steps. First - it would drop to around 13-1400 rpm and stay there for about 2-3 seconds. Then, it would drop to the normal ~700 rpm. I heard that this was done for emissions reasons. Perhaps the later cars have a higher target rpm for the first speed drop before idle.