This Car has headers and probably different cams etc... Not sure if its factory injectors but will assume they are for the moment . when you start car when cold it will idle though rough when driving around when car gets hot It will Hunt up and down on the idle even when free revving to around 2k rpm idle will hunt approx 3 to 5 hundred rpm . It will stall at anything under 1000 rpm on idle and you have to keep feathering throttle at traffic lights . It has new plugs porcelain is clean but inside of plug on Id is soot black . Do these cars have two O2 sensors I see the one by the rear tires Is there probably two more in the collectors of the headers? Not sure if race gas was ever used in this car or not as not sure about to much of the history on it . Can the computers be recalibrated on this car? thanks car has approx 20k miles Oh and the oil light is on constantly well it goes off once in a while and it just had oil change car has done this for a while from what Im to understand but gauge on Dash reads fine . and car has approx 8.5 litres of oil 20/50 royal purple synthetic .
96 gts runs very rough when warm and stalls
- Thread starter dandimand
- Start date
dave6666
Enthusiast
Was this car a gift or did you consciously buy this project LOL?
eucharistos
Enthusiast
yeah dave 
(trust me, i've known dave6666 for the past 7000+ posts, this was a helpful response)
cam position sensor
(trust me, i've known dave6666 for the past 7000+ posts, this was a helpful response)
cam position sensor
4 Oxygen sensors, 2 usually in middle header tubes on inside of headers (near engine block) and aftermarket headers are usually the same. If wires have been extended to headers often these wires get burned and short out. Barring that being the problem with clean (correctly colored?) plugs (all 10?) the AIT and the IAC should be checked. Probably only an IAC motor problem if the only fault is the idle speed.
Yes the computer/program (stock? Vec 2?) can be programmed and adjusted, we call it a tune. Since you have as your address we can offer no tuner shop recommendations. Assuming an oil pressure light would cause a CEL?
Ted
Yes the computer/program (stock? Vec 2?) can be programmed and adjusted, we call it a tune. Since you have as your address we can offer no tuner shop recommendations. Assuming an oil pressure light would cause a CEL?
Ted
problem is when its revving higher as well as it hunts at even 2 k if you just bring the rpm up so not sure about the iac at the moment . Im in van bc if you have any reccomedations for where to get a pcm programmer ? and brand of programmer as well thanks .
eucharistos
Enthusiast
ted knows vipers
Thanks, Euch, but Vancouver is a little over 500miles away. The owner of Willowbrook Chrysler owns several Vipers (including a 97(?) Venom 650R and would know which North Vancouver Chrysler Dealership has a viper tech. He should also know of any tuners with SCT for Vipers. I'll send you an email address or two for VCA members in your area that can help.
Ted
Ted
I will do that in the morning thanks for your help .car has sat for many years as it was undrivable and the dealership refused to do a recall on the rear suspension as the car had been raced not sure why but that is the story I got from richmond chrysler they did the front end but wouldnt do the rear could be some bad gas in there as well as not sure when the last time they put fuel in this car . but I think its been bad the whole time someone really screwed this car up at one point . At least the car is drivable now shame as car only has 32 k kilometers. I honestly think they refused to do the rearend on this car as it didnt pay enough hours as its a big job and they screwed the owner this happend in 2003 .
uvbnbit
Enthusiast
If it sat for many years, could it be battery? reset PCM?
Why would you never buy one of these cars ? And nice attitude. Dave is one of the more knowledgeable and helful guys here... way to go.
More info on the car will help. Does "your friend" have anymore info on what has been done to it to help us ?
99 R/T 10
Enthusiast
Second that, try to be a bit more polite and remember where you are trying to get help.
That said, old gas, old battery should be your starting point. Get the injectors cleaned by this guy(http://forums.viperclub.org/rt-10-gts-discussions/601001-injector-flow-bench-cleaner-up-running.html), drain the fuel and get a new battery.
dave6666
Enthusiast
No hard feelings dandimand. I just wonder when I see posts like you started with, how people end up in that position. Sounds like a car that's been maybe rode hard, jacked with along the way, and ended up in someone's stable using a philosophy that is completely opposite of what is commonly preached here, which is to buy a well known or well inspected car.
Good luck with it. Most of the starting points have already been posted. I mean um, the useful posts.
Good luck with it. Most of the starting points have already been posted. I mean um, the useful posts.
well vacuum is quite low at idle though steady I have a friend who is a mechanic looking at it now and He says its running very rich yet its not throwing any codes . we are going to start with a compression test does anyone know the base fuel pressure for this car ? Thank for all your help and reason I would'nt buy one of these cars is already have to many toys . Iac does seem to be working as when starting first cold it runs up to around 1000 rpm then after it warms a bit drops down to around 550 rpm vacuum is only around 7" at idle
55psi is the Fuel Pressure spec. I suggest duct taping the guage to your windshild to see what she reads when acting up. It should be 55psi allthetime(idle/runing/WOT)
If the prob isnt Fuel I would do the following in this order untill the prob is solved:
-Replace battery (also, while replacing it ground the +terminal on a wirebrushed part of the tray for 10seconds. this will reset the ecm clearing all memory)
Check/Replace:
-IdleAirControl
-ThrottlePositionSensor
-MAPSensor
All of these items can easily be swaped with another viper to determine the bug before spending $$$
Also, I do not think the prob has to do with wires/plugs/injectors. However, i would still replace the plugs/wires and dump a quart of techron in the tank since the car is 10+yrs old and has been sitting for awhile.
keep us posted on the progress
If the prob isnt Fuel I would do the following in this order untill the prob is solved:
-Replace battery (also, while replacing it ground the +terminal on a wirebrushed part of the tray for 10seconds. this will reset the ecm clearing all memory)
Check/Replace:
-IdleAirControl
-ThrottlePositionSensor
-MAPSensor
All of these items can easily be swaped with another viper to determine the bug before spending $$$
Also, I do not think the prob has to do with wires/plugs/injectors. However, i would still replace the plugs/wires and dump a quart of techron in the tank since the car is 10+yrs old and has been sitting for awhile.
keep us posted on the progress
well the car had new gas in it so not sure if that was the problem . Here are the symptoms in a nutshell when you first start the car it will idle around 550 rpm though a little rough but not run to bad it will drive for a bit fine then after a while it will hunt on the idle and you have to two foot it at stop lights to keep it running if you let it stall and restart it again it will Idle again no problem It has new msd wires that are jacketed the car has a nice hi end set of headers as it has a merge collector and the O2 sensors the front ones are basically in the collector where it turns into the rocke panel so not sure if they are to far away or not ? the one thing that puzzles me is no check engine light maybe someone disabled that part of it at one time there is a check engine light in the car that is functioning but wont throw any codes . also it seems a computer problem as when you let the car stall and restart it again then why will it idle ? The car is definitly running very rich and on decel it pops and bangs in the exhaust quite a bit, I can either get bosch or ntk O2 sensors not sure which would be better or if Im barking up the wrong tree on this and should try some other things first . I think I will verify with a leak down or a compression test the engine is good before proceeding to changing out the sensors ps plugs were just replaced
Believe it or not, an old, trickle-charged, barely-working battery causes a LOT of these kinds of issues!
Dom is 100% on:
-Replace battery (also, while replacing it ground the +terminal on a wirebrushed part of the tray for 10seconds. this will reset the ecm clearing all memory)
Check/Replace:
-IdleAirControl
-ThrottlePositionSensor
-MAPSensor
Dom is 100% on:
-Replace battery (also, while replacing it ground the +terminal on a wirebrushed part of the tray for 10seconds. this will reset the ecm clearing all memory)
Check/Replace:
-IdleAirControl
-ThrottlePositionSensor
-MAPSensor
Its not the battery just had it checked Yes car is idling around 750 I was incorrect In how I was reading the tack and the hose isnt plugged to the Iac but when you disconnect the Iac the idle doesnt change would assume as its pintle is already open and would take power to close it ?Ps where is the oil sending light switch located reading the forums its a common problem I have come to find out so I will replace this as well .I honestly dont feel its the iac at the moment because the car even if you rev it to around 1800 rpm when its doing this the idle will vary up to 300 rpm and it will reset itself if you let it stall and restart the engine again and then it runs ok again .I think its a pcm problem or o2
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When my car idles at 750rpm warm, it works perfectly.
You're saying that the idle searches even when the Idle Air Control is disconnected? That would incdicate a vacuum leak.
Idle and speed 'searching" indicates a LEAN mixture. A Rich mixture would be indicated by a "softer, deeper" exhaust sound and usually the engine is a little lazy to rev. You'd have to know what the car sounded like normally before you'd be able to hear a difference at idle however. On my iac the hose doesn't matter - disconnect the wiring.
I don't think that tune could cause a 7# idle vacuum reading(?) I'd search for a vacuum leak. Spray Ether/Starting fluid around the intake manifold and see if that does anything to the idle? Any change would indicate a leak.
If you can get another Viper to switch parts with, JomB indicated the parts to start with.
The
You're saying that the idle searches even when the Idle Air Control is disconnected? That would incdicate a vacuum leak.
Idle and speed 'searching" indicates a LEAN mixture. A Rich mixture would be indicated by a "softer, deeper" exhaust sound and usually the engine is a little lazy to rev. You'd have to know what the car sounded like normally before you'd be able to hear a difference at idle however. On my iac the hose doesn't matter - disconnect the wiring.
I don't think that tune could cause a 7# idle vacuum reading(?) I'd search for a vacuum leak. Spray Ether/Starting fluid around the intake manifold and see if that does anything to the idle? Any change would indicate a leak.
If you can get another Viper to switch parts with, JomB indicated the parts to start with.
The
I just spoke to the owner he says the car takes three days to relearn itself when batt is diconnected but never did Idle that great It has a tnt ported intake heads and cam and I guess there pcm not sure if that is a modified stock unit or after market I cant find much info on tnt and after speaking with the owner he said he thought the owner died in a crash racing or something ? Anyways at this point should I just drive the car for a bit to get pcm to relearn itself because Im not sure If I should replace the 02 sensors and race gas was run at one time in this car at the track with nitrous so that may have caused the 02s to have some issues . ps thanks to all on this board for trying to help me get this car back to life .
I would find out about the PCM. Its possible the viper was running on VEC and whoever was selling it wanted it to appear stock so they ripped it out. Ive seen this done before on other vehicles...
Any car with the extensive NA modds like this one has should be dyno-tuned wether its moddifiying the stock program(only few have this software)(DCperformance), or using an aftermarket controller like SCT or VEC.
However, this might not necessarily be your specific problem that is leading to the idle hunt & stalls.
I still think you should follow the path that i posted above.
Here is some more info that might be helpfull to you,
Read through this thread and click on all of the links that i posted in it:
http://forums.viperclub.org/rt-10-gts-discussions/629679-motor-stalls-idle-need-help.html
Any car with the extensive NA modds like this one has should be dyno-tuned wether its moddifiying the stock program(only few have this software)(DCperformance), or using an aftermarket controller like SCT or VEC.
However, this might not necessarily be your specific problem that is leading to the idle hunt & stalls.
I still think you should follow the path that i posted above.
Here is some more info that might be helpfull to you,
Read through this thread and click on all of the links that i posted in it:
http://forums.viperclub.org/rt-10-gts-discussions/629679-motor-stalls-idle-need-help.html
No matter what, once you get her running good, get her on the dyno to check A/F ratios. You say she is "def running rich" and makes alot of noise on decel But i got news for you: It is standard for A viper with exhaust modds to make alot of noise on decel. Especialy with headers and if your running hi-flow or no cats. Have you had the sidesills off yet?
My only modds are headers and 3"exhaust and she sounds like WWII when i remove the cats...
With all the flow mods you have, common sence would tell you that the motor will have more air than fuel. aka Lean.(unless there is aftermarket programing to compensate for it)
My only modds are headers and 3"exhaust and she sounds like WWII when i remove the cats...
With all the flow mods you have, common sence would tell you that the motor will have more air than fuel. aka Lean.(unless there is aftermarket programing to compensate for it)
Thanks after a long drive last nite car now idles its very loud so would assume there is no cats I think resetting the pcm and giving it some time to relearn itself was the major problem though car does hunt a bit still at part throttle around 1750 to 2000 rpm but that is only very light throttle in traffic at least the stalling has remedied itself now for front brakes and rotors are the power slots any good for street driving or would you reccoment the hawk ones ? Thanks for everyones help and ps where is the oil light sender unit located on the engine as the oil light keeps coming on and off and need to replace this unit?
Power slots? 13" or 14". Lightweight or solid rotors?
Best brakes for any Viper are lightweight Gen 4 ACR brakes on front. Minimium requirement for pre'01 rear calipers are 40mm rear caliper piston upgrade. There are many upgrade kits for Viper brakes and various prices. For a '96 I recommend Tom's rear caliper piston upgrade with lightweight rear rotors. I recommend the Roe Racing Viper Performance Parts 14" lightweight front brake kit. Otherwise, I have Stop-tech 13" lightweight slotted/drilled rotors and near new Gen 2 Brembo front calipers (10,000mi.) kit for sale.
Ted
Ted
Best brakes for any Viper are lightweight Gen 4 ACR brakes on front. Minimium requirement for pre'01 rear calipers are 40mm rear caliper piston upgrade. There are many upgrade kits for Viper brakes and various prices. For a '96 I recommend Tom's rear caliper piston upgrade with lightweight rear rotors. I recommend the Roe Racing Viper Performance Parts 14" lightweight front brake kit. Otherwise, I have Stop-tech 13" lightweight slotted/drilled rotors and near new Gen 2 Brembo front calipers (10,000mi.) kit for sale.
Ted
Ted
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