high idle help

[eucharistos]

gents and gent-ettes

Up until recently, my rt (hi flows, basic roe 93 octane sct tune, muffler del, k&n’s) has been a steady eddy idler at 500 rpm. Running hard, hot, cold, anytime I’d push in the clutch, engine would go to a steady 500 rpm’s.

Recently, it hangs at about 1250 rpm’s about 80% of the time. It is not consistent, sometimes hot, sometimes cold; sometimes hard running, sometimes just puttering around. It will usually stay at 1250 rpm’s until the car slows to about 15 mph, then it will usually drop to 500 rpm’s, though sometimes it will hand at 1250 rpm’s even while stopped.

I can always “drag” the idle down by keeping the car in gear and slowing so that the speed in gear is below 1250, then the idle (usually) drops to 500 rpm’s, though a couple of times it would jump back to 1250.

Tapping, revving, etc. the gas pedal will not drop the idle back down if idling at 1250.

I need an inspection next month and we have sniffer testing, and don’t want to fail (don’t know if it would or not, just want to make sure to pass the 1st time - - - - viper friendly inspections in Houston anyone )

I checked to make sure, no Toyota floor mats nor Toyota gas pedal assembly

What do you think…..



….about the high idle, cause and or cure



Thanks buds


(how ‘bout them caps )

 

[plumcrazy]

clean the Idle Air Control motor ?

 

[plumcrazy]

did a quick search and found these...

http://forums.viperclub.org/rt-10-gts-discussions/564200-newbie-needs-tech-help-high-idle.html

http://forums.viperclub.org/rt-10-g...om-high-idle-sticking-idle-master-thread.html

 

[eucharistos]

did a quick search and found these...

http://forums.viperclub.org/rt-10-gts-discussions/564200-newbie-needs-tech-help-high-idle.html

http://forums.viperclub.org/rt-10-g...om-high-idle-sticking-idle-master-thread.html

(new smiley---> )

this morning, while planning this thread, i told myself to do a search 1st, but i forgot

thanks plum,

off to read them

 

[eucharistos]

just read the threads

i sure hope cleaning the k&n's is it

but the a/c thing could be it as i started losing refrigerant about the same time (i don't use the a/c much even down here)

other opinions / solutions welcome

 

[Jack B]

just read the threads

i sure hope cleaning the k&n's is it

but the a/c thing could be it as i started losing refrigerant about the same time (i don't use the a/c much even down here)

other opinions / solutions welcome

Your car idles at approximately 670. The dial is confusing. The high idle is typically the IAC. My 97 had the issue, but, it was a bad ground on O2 circuit. That ground originates right at the ac compressor on the 97, I believe all Gen 2's are the same.

 

[DVSGTS]

I have battled the idle hang on my Viper and a built LS1 Formula. Both times, I have found that idle adjustment screw for the throttle stop played a BIG part. What I believe happens is the idle screw gets set too low and the system tries to compensate by opening the IAC more and more, allowing the revs to hang. There is an optimal position. I fixed both cars by playing with that screw and setting it just before it starts to actually increase the idle speed. My car idles at 750rpm as displayed on a scanner.

 

[bvk]

i had the same problem.

Reground your TPS, completely solved it for me, the stock ground is apparently not very good.

 

[Jack B]

I have battled the idle hang on my Viper and a built LS1 Formula. Both times, I have found that idle adjustment screw for the throttle stop played a BIG part. What I believe happens is the idle screw gets set too low and the system tries to compensate by opening the IAC more and more, allowing the revs to hang. There is an optimal position. I fixed both cars by playing with that screw and setting it just before it starts to actually increase the idle speed. My car idles at 750rpm as displayed on a scanner.

There is no idle adjustment screw, that is a throttle stop-plate screw. Adjusting it should not change the the idle. The ECU or a malfunction is the only thing that is going to change the idle from 670, other than the the SCT software. The ECU drives the IAC and/or retards timing to keep it at 670. As an example, i have the idle set at 750 via the SCT software and it opens the IAC so that the idle increases. In addition to tuning, If you look at base parameters in the stock ECU via the SCT software it will shed some light on the settings of our engine.

In short, if your idle is other than 670, you have a problem.

 

[eucharistos]

thanks for all the help

a couple of questions:

1) will the car pass a sniffer test if high idling? i don't know the exact testing procedures, but know they do test at different idle speeds?

2) if i do the pos cable to frame reset thing, will this help enough to pass the test?

3) should i do the iac ground quick and dirty to see if it helps or not 1st. (disconnect the old ground and run a new one without routing it) or is this something i should replace anyway

my 1st objective is getting my car inspected, then fixing the high idle

can't work on the car for a few weeks, had a minor booboo yesterday (non car related)

sorry if this isn't too clear, took my 1st vicodin of my life earlier

thanks again

 

[bvk]

If it's the same thing they do for CA smog inspections then the high idle won't worry the sniffer test.

my post suggested grounding the TPS, not the IAC. if you search long enough you'll find a few others that had their high idle solved by this, but it's still worth cleaning out the IAC and resetting your computer and TPS. If that fails then I'd try grounding the TPS black wire, but probably not while on vicodin

 

[eucharistos]

cross ref for posterity:

http://forums.viperclub.org/rt-10-gts-discussions/635186-brief-idle-hang-revival.html

..... but probably not while on vicodin

just caught your cross ref bvk

 

[Dan Aseere]

On my 97 the high idle was do to bad intake manifold gaskets.

 

[eucharistos]

hope you are unique, dan

 

[Martin]

On my 97 the high idle was do to bad intake manifold gaskets.

All of those bad gaskets should have been replaced by now - that was a big deal back then. The gaskets would shrink and warp and you'd get all kinds of problems, and virtually all of the cars got brought in for fixes.

At a 1250 RPM idle, you'll probably not pass the test. They'll run an idle test, and the car has to be running in a certain range for the test to even start - and then the car needs to hold it's idle within that range for the duration of the test. I believe on the Viper it's between 500 and 850 RPM.

It does sound like the TPS as people have noted. It's a cheap fix and not too hard to do if the sensor is bad. Even on Vicodin and with your arms immobilized, you could still point the neighbor kid at it and tell them what to do