Won't idle all of a sudden

[ZX1100]

Car was running fine the last time I drove it but went to start it the other day and it wouldn't idle. It fires right up but if I don't continue to blip the throttle it dies immediately.

Replaced the battery and it now idles high for a few seconds then dies out. Took it around the block and if I ease on the throttle the motor seems to cut out at certain spots and then surge, like a big hiccup. Cleaned out the TPS but I think I should just replace it. Plug wires were new last year along with plugs.

Any other items I can easily check that might cause this?

Thanks!

 

[plumcrazy]

year ?
mods ?

might be a bad battery ?

 

[vipertanz]

I started having the exact same problem on my 96 gts today.

 

[uvbnbit]

Did you re-set the PCM after battery install? try cleaning the IAC too.

 

[InjectTheVenom]

Maybe a tank of bad gas? 1 year old gas made my daily driver not want to idle either unless I kept the throttle up, sounded just like the new year's eve fireworks and there is a firestation right next to where I work too

 

[Roy]

Did you re-set the PCM after battery install? try cleaning the IAC too.

How do you reset the pcm?
I didn't reset anything when i've putten the battery back in after winter, should I?
(litlle thread hyjack)

 

[KNG SNKE]

How do you reset the pcm?
I didn't reset anything when i've putten the battery back in after winter, should I?
(litlle thread hyjack)

To reset the PCM remove the positive lead from the battery and ground it for 10 seconds. Reattach the positive lead to the battery.

Go in your vehicle and turn your car to the on position but don't start. Press the gas slowly to the floor a couple times to reset the WOT position. I don't think this will help the thread creator with idle issues though.

 

[Sam Goldfarb]

Sounds like IAC ( Idle Air Control) to me, if there is really a problem. There are some old threads about them! Try driving it a little with fresh gas, sometimes takes a little while to get things right again after a battery replacement.

 

[ZX1100]

Thanks for all the suggestions. My car is a '99 RT/10 with headers, rockers, and no cats.

I did replace the battery and cleaned the IAC best I could (wiped the pintle clean) along with the passage. Cleaned the TPS and IAC connections and made sure all the plugs and wires were secure. Cleaned my throttle bodies and checked the cable and all looks good. I didn't reset the PCM after the new battery install.

I'm not sure how to take readings from the sensors so I might just go ahead and purchase a new TPS first and see if that solves it.

 

[vipertanz]

I replaced the battery (sorry to jump in here) had a exactly 12 month old red top which once replaced solved all of the issues I had, it was dying like it wasn't getting enough fuel when stopping for red lights and things unless I kept my foot on the gas and kept goosing it. Thanks and sorry again it just so happened I was going to ask the same question today

 

[ZX1100]

I replaced the battery last week and the only thing that seemed to have changed is now when I blip the gas it will idle high for a few seconds before it dies unless I keep blipping the gas.

 

[aloushi]

same problem and TPS was my culprit ( with more than one car)

 

[plumcrazy]

did an easy search and found these 2 posts. hope it helps.

http://forums.viperclub.org/2749773-post21.html

http://forums.viperclub.org/2751996-post24.html

 

[JPL]

After you change a battery, you should start the car, rev the engine to 2k rpm, hold it there for a sec and VERY SLOWLY back off the gas to idle. If I were you, I would disconnect the battery and try this, it's quick and easy, and a possible quick fix.

 

[ZX1100]

Put in a new TPS and now it doesn't die but idles very high or at whatever rpm I bring it too.

I'm going to do the PCM reset and do what JPL suggests and see what happens.

 

[ZX1100]

I disconnnected the battery to reset the PCM and now the car won't idle again

If I ease on the throttle to bring up the revs everytyhing seems smooth until it hits 3500 rpms and it starts to cut in and out and the revs start to bounce. Like it's hitting the reve limiter at 3500 rpms

 

[99 R/T 10]

I bet it could be the cam or crank sensor if the TPS was programed properly. Any code getting thrown?

 

[Black Moon]

Did you adjust the TPS or just stick a new one in? The holes are sloted so that you can adjust for proper idle and WOT voltage. Mine was way off after removong mine for polishing. Made a huge difference!!!!

 

[uvbnbit]

Take the IAC off and clean with "mass air flow" cleaner. Be careful not to tear the gasket. Couldn't tell if you actually took it off or not. But I don't think that has anything to do with the 3500rpm issue. Agree it could be a cam/crank sensor issue too

 

[ZX1100]

I just stuck the new TPS on without any adjustments. How do you adjust it?

I'll try to get the codes off the car this weekend and also clean the IAC again.

 

[Black Moon]

I just stuck the new TPS on without any adjustments. How do you adjust it?

I'll try to get the codes off the car this weekend and also clean the IAC again.

I used a Snap On scan tool but I think you can just use a volt meter. The scan tool told me what the settings were supposed to be. Check a service manual but I believe closed was 0.35 volts and wot was 3.5-3.7 volts. Mine was off and changed when the car went into open loop, idle and hp changes up top.

Loosen the screws and you'll notice a few degrees of travel in either direction.

 

[Black Moon]

POWERTRAIN DIAGNOSTIC PROCEDURES Pages 48 and up. Looks like they say 0.8 volts up to 3.5 v with a smooth transition. I remember it being different. Let us know.

 

[ZX1100]

Pulled two codes. Looks like 99 RT/10 was correct in guessing it's a cam sensor issue. Not sure on the other code if it's something that needs to be addressed. Will try to install this sometime during the week so it's ready for next weekend. Hopefully this does it

Where and how is the best way to get to the sensor to replace it?

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[ZX1100]

Installed the cam sensor but still shutting down at around 3500rpms. Still won't idle on it's own but seems a little better. Wonder if I need to drive it some so it relearns after I reset the PCM?

 

[Jack B]

Installed the cam sensor but still shutting down at around 3500rpms. Still won't idle on it's own but seems a little better. Wonder if I need to drive it some so it relearns after I reset the PCM?

I believe that P1296 is the coolant sensor code, that could affect the a/f dramtically and therefore the idle.

 

[uvbnbit]

I believe that P1296 is the coolant sensor code, that could affect the a/f dramtically and therefore the idle.

If so, doesn't the temp gauge "typically" peg to 250 at start up? (at least that's what mine did). If you do have a bad coolant temp sensor, make sure you get OEM, NOT aftermarket!

 

[ViperTony]

If you do have a bad coolant temp sensor, make sure you get OEM, NOT aftermarket!

Good tip. I've had issues using aftermarket sensors. Make certain it's a Mopar part if going OEM. The last sensor I purchased, a TPS, came in a Mopar box was a CTS sensor.

 

[ZX1100]

I just went to Advanced Auto for the CAM sensor, should I swap it out for a OEM? The CEL is still on so I'll see what codes are still there this weekend.

Thanks for all the help. This is my first crack at trying to debug an issue and really new to everything. I'll try to do the most I can before it goes to the shop.

 

[Black Moon]

Have you checked the TPS yet???

 

[Jack B]

If so, doesn't the temp gauge "typically" peg to 250 at start up? (at least that's what mine did). If you do have a bad coolant temp sensor, make sure you get OEM, NOT aftermarket!

There are two temp sensors, I am not sure how and if they interface. The initial idle is open loop and then times out, therefore, if a false coolant temp affects the time-out algorithm, it could cause an idle issue, that is a guess. However, that code is definitely the coolant temp sensor.