Problem with my GTS (feels like she missing spark/fuel)

[Drummerboy]

Welcome to the club brother..

I noticed you said you have larger throttle bodies - I have an X-Metal unit myself, I'm largely ignorant, but I've wondered if that could have anything to do with the issue. I've heard of idle hang and stuff, and wondered if maybe the throttle was getting stuck or something, but I would also assume that would lead to a whole 'nother set of symptoms..

Couldn't hurt to replace the O2 sensors at this point, along with the cam and crank sensors as well, right?

My ride has been in the shop for over a week now, and I don't have any updates yet. I'll be sure to post up any findings as soon as I hear from the tech.

- Rob

Hey Guys,

I have a similar issue as well. What I am noticing is when I first start up the car, it idles fine and sounds fine but when I start to drive, it feels like I have lost a boat load of power for a very short period of time. If I punch it, it eventually will recover and the car launches forward (haha.) It drives fine after that although occasionally, when I stop at a stop sign or light, it idles really low and rough and blipping the throttle seems to recover it. I honestly have been having this issue for about a year now and CAN'T FIGURE IT OUT! ******* me off actually.

Here are the things that I have replaced/done recently -
- Replaced my battery
- Replaced the map sensor
- Replaced the plugs
- Replaced the plug wires
- Replaced the fuel filter
- Replaced my fan shroud (not related)
- Replaced my radiator twice (pwr ***** so I got one from JonB, not related)
- Took it to a local shop twice to see if they could get it to happen (they didn't)

I have a 1998 gts with SVS cams, headers, exhaust, larger throttle bodies, high flow cats, etc. The car just rolled over 17k miles (got it with under 5k).

Should I just bite the bullet and get new O2 sensors? I seem to be on a roll for buying and putting in things I don't need (other than the radiator.)

 

[99 R/T 10]

Can't hurt to replace the O2 sensors. Call Chuck Tator. 914-763-3136

 

[dave6666]

Hey Guys,

I have a similar issue as well. What I am noticing is when I first start up the car, it idles fine and sounds fine but when I start to drive, it feels like I have lost a boat load of power for a very short period of time. If I punch it, it eventually will recover and the car launches forward (haha.) It drives fine after that although occasionally, when I stop at a stop sign or light, it idles really low and rough and blipping the throttle seems to recover it. I honestly have been having this issue for about a year now and CAN'T FIGURE IT OUT! ******* me off actually.

Here are the things that I have replaced/done recently -
- Replaced my battery
- Replaced the map sensor
- Replaced the plugs
- Replaced the plug wires
- Replaced the fuel filter
- Replaced my fan shroud (not related)
- Replaced my radiator twice (pwr ***** so I got one from JonB, not related)
- Took it to a local shop twice to see if they could get it to happen (they didn't)

I have a 1998 gts with SVS cams, headers, exhaust, larger throttle bodies, high flow cats, etc. The car just rolled over 17k miles (got it with under 5k).

Should I just bite the bullet and get new O2 sensors? I seem to be on a roll for buying and putting in things I don't need (other than the radiator.)

There's a whole list of sensors etc. there you have not replaced yet. IAT, TPS, IAC, Cam, Crank... Get busy son!


Curious what the bad experience with the PWR radiator was. I almost bought one until Roe came out with his. Which I have had in my car now for about a week.

 

[Dom426h]

******UPDATE******

Problem Fixed!!!!

Replaced the CAM Position Sensor & Front O2 Senors last weekend as i previously posted. Didnt want to jinks myself and claim victory untill i got some significant seat-time. Been riding All week running great.

I Suggest to Start with the O2 Sensors FIRST as they are Cheap 150bucks for the OEM pair and Very easy to install.
Next move on to the CAMpositionSensor as it is a royal PITA.
(you prob wouldnt believe me if i said what it takes to complete this task...)(pm me with your # if anyone would like for me to talk em though it the Wizard Approved way)

here is a couple pics of the new/old CAM sensors:

Man, It was a journey to get to this point
Here are a few of the highlights:

Finding these in my intake tubes:

Having one of my CATs overheat and nearly burn up my sidesill

Temporary Fix:

And having my rear-view mirror fall off from the viper sitting outside in the hot sun for a week as i refused to drive it untill i fixed it.

 

[Madduc]

Great to hear you found and fixed your problem!! Can't believe someone put those tornado things in it? And you are very brave crawling under it lifted like that! Not me. Get another set of stands to place at the rear and have it supported at all corners. I've seen too many vehicles with people under them. Be safe.

 

[AZTVR]

Do you know if the Tornado units were installed the right way around? Maybe they were twisting the intake air the wrong way and it was creating a standing wave in your intake runners under some conditions, causing lack of fuel to one of the cylinders?

Then again, maybe it was the CAM sensor. Congratulations on solving your problem !

 

[Rock Morgan]

Dom that's great news. I'll know how to fix mine if the insurance company decides NOT TO TOTAL IT!

 

[Drummerboy]

Great news Dom! I'll be sure to replace the O2 sensors myself then - glad to hear you car is back on the road!!

Enjoy the ride in good health!

- Rob

 

[dave6666]

Now be truthful... Could you have done it without the forum?

 

[tlcobra]

my 98 GTS, I replaced battery, unpluged 3 plugs into pcm, cleaned iac control, un pluged throttle sensor it was under a vaccum line and was pulling on run it on top of vaccum line. today no break up problem at any rpm.

 

[cornfish]

There's a whole list of sensors etc. there you have not replaced yet. IAT, TPS, IAC, Cam, Crank... Get busy son!


Curious what the bad experience with the PWR radiator was. I almost bought one until Roe came out with his. Which I have had in my car now for about a week.

There were actually a few issues with the PWR radiator. The first was that it was said to be a plug and play unit, which it was no where near. I had to take it in to a shop to have them mount the correct fan shroud bolts as well as the bolts on the other side that connect it to the car. The next issue is after I got it on and drove it like I stole it for a few months, I started to smell coolant. Hmm... The radiator blew on the welds. Not cool for a triple pass radiator. Anyway, I took it to a local radiator shop and had them look at it and they told me that it was a POS. The welds were crap and they couldn't believe that PWR actually sold those for the Viper. Anyway, I had them fix the radiator anyway after I already put in the new one from JonB. It didn't blow up as bad as the stock one did tho Still have that PWR in the garage but I should use it as a dart board.

This is the one I have in the car now:

PartsRack.com

Hey Dom, I am glad to hear those sets of sensors fixed the issue. I am going to try the front O2 sensors as well and if that doesn't fix the issue, on to the cam ones. This kind of stuff is why I love the viper boards.

 

[RTTTTed]

Congrats! It could have cost you another twenty sensors to find the problem... don't youn love computers?

Glad you won while there's so much summer left to drive it

Ted

 

[Drummerboy]

Well guys, I just put about 40 miles on my ride after getting it back from the shop. New Battery, plugs, wires, & Cam Sensor and after about 40 miles, not 1 hiccup. Tech said he put about 40 miles of road testing on it with the datalogger running with no issues.

I'm gonna drive the piss out of her today before I claim total success, but 80 trouble free miles so far, lookin good!

- Rob

 

[cornfish]

I got the new O2 sensors on as well. I haven't had time to thoroughly test the car but I did drive it around to make sure no code was thrown. I had a hell of a time getting them on though. The reason is because I have the SVS headers and the location of the sensors were actually in the bend inside the side sills. This means that they took the stock sensors and cut the wires to make them longer. I jacked up the car and said "where the *&%$! are the sensors. haha. Anyway, I took them off and went to the store to buy new wire. Got the wire and extended the wires on the sensors. Once I got them screwed in and ready to connect those connectors, I noticed that I had the wrong O2 sensors. ***?? Anyway, I exchanged them and after an all day affair, I got them in. Got to love aftermarket parts that you don't realize that certain things were modified. I guess that is what I get.

I will let you guys know tomorrow if this issue has been fixed or not. I hope so but if not, off to the cam sensors!

 

[Drummerboy]

Success! I feel I can confidently claim my issue to be resolved as I drove the car all weekend, and drove it hard trying to chase down a buddy in his Atom (Short video of my first ride in it: YouTube - latindrummerboy's Channel)

Thanks to Dom for starting this thread, and everyone else who chimed in in on it and pointed us in the right direction - without this thread, a few of us would have been lost in a bottomless troubleshooting abyss.

To recap, replacing the Cam Sensor (which seems to communicate somehow with the Crank sensor which I had replaced earlier) seems to have done the trick, although I did replace my plugs, wires and battery at the same time. I thought for sure it would be an O2 or fuel related issue - once again there are so many variables with these particular set of symptoms, It was very helpful to have everyone chime in with their experiences which helped to at least narrow things down to the most relevant possibilities.

Thanks everyone!

- Rob

 

[DrumrBoy]

Congrats Dom; glad you nailed it.

 

[Qualitywires.com]

Dom, glad things worked out for you.

Adam

 

[eucharistos]

funny pic:

favorite pic:

congrats on the fix

 

[Red Shift]

I just started reading this thread again. My car used to have the intermittent miss under rapid load increase. It went away for awhile and I forgot about it.

Then ANOTHER WORSE problem started!

This happened after I made a 1st gear pull to redline. Afterward the car idled poorly and felt weak. Didn't rev too well either. I was leaving town so my mechanic wanted me to drop it off. Swapped out plugs and coil packs, then it worked fine for awhile. He came back to it a few days later and it was funk again. I think the battery might have died somewhere along the way.

When I returned in town we went for a road test and it was hitting all cylinders for a little while, then crap again. It even did a weird thing where it locked out all gears after a restart (weird?). Cylinder 7 is missing, liquid fuel all over the plug. He's ran a leak-down - checks out fine. Before that cylinder 9 had a stuck open fuel injector during the compression test. They had the plug out and the cylinder started pumping out gas! He just called me and said he pulled out the VEC and it's idling normally again. Btw, it's a 96 GTS with a Roe. I'm quick to blame the VEC, but I'm not convinced at this point. It's confusing for me because I haven't been doing the work so I hear it 2nd hand. It seems other likely suspects are the CAS, O2 sensors and fuel injector connections. My AFR readings are also crazy. The car used to indicate a rich idle mixture (would cycle between 13.5-14.5 AFR @ idle). Now it starts at mid 14s, then climbs to hold at 18 AFR after 20 seconds. If it's missing I would expect a richer mixture...

I'm off tomorrow and I'll go by the shop to work on it. I may be sending out messages to get lessons learned from y'all.

Congrats on the fix Dom, and sweet wheels.

 

[Kiaser]

I just started reading this thread again. My car used to have the intermittent miss under rapid load increase. It went away for awhile and I forgot about it.

Then ANOTHER WORSE problem started!

This happened after I made a 1st gear pull to redline. Afterward the car idled poorly and felt weak. Didn't rev too well either. I was leaving town so my mechanic wanted me to drop it off. Swapped out plugs and coil packs, then it worked fine for awhile. He came back to it a few days later and it was funk again. I think the battery might have died somewhere along the way.

When I returned in town we went for a road test and it was hitting all cylinders for a little while, then crap again. It even did a weird thing where it locked out all gears after a restart (weird?). Cylinder 7 is missing, liquid fuel all over the plug. He's ran a leak-down - checks out fine. Before that cylinder 9 had a stuck open fuel injector during the compression test. They had the plug out and the cylinder started pumping out gas! He just called me and said he pulled out the VEC and it's idling normally again. Btw, it's a 96 GTS with a Roe. I'm quick to blame the VEC, but I'm not convinced at this point. It's confusing for me because I haven't been doing the work so I hear it 2nd hand. It seems other likely suspects are the CAS, O2 sensors and fuel injector connections. My AFR readings are also crazy. The car used to indicate a rich idle mixture (would cycle between 13.5-14.5 AFR @ idle). Now it starts at mid 14s, then climbs to hold at 18 AFR after 20 seconds. If it's missing I would expect a richer mixture...

I'm off tomorrow and I'll go by the shop to work on it. I may be sending out messages to get lessons learned from y'all.

Congrats on the fix Dom, and sweet wheels.

Hmmm, I've had the same hesitation before on rapid load increase but it's very random, and I have a VEC 1.

I've also had the problem where all throttle response completely stops for a few seconds at a time randomly (I can put the foot to the floor and it just deccelerates like nothing is going on) and then comes back online like nothing happened.

I just dropped mine off at the shop a day ago to get the following replaced:

TPS
Crank Sensor
Cam Sensor
02 Sensors
MAP
AIC
Coil Packs

And then some injector and throttle body cleaning.

Keep updating this thread!

 

[Red Shift]

Hmmm, I've had the same hesitation before on rapid load increase but it's very random, and I have a VEC 1.

I've also had the problem where all throttle response completely stops for a few seconds at a time randomly (I can put the foot to the floor and it just deccelerates like nothing is going on) and then comes back online like nothing happened.

I just dropped mine off at the shop a day ago to get the following replaced:

TPS
Crank Sensor
Cam Sensor
02 Sensors
MAP
AIC
Coil Packs

And then some injector and throttle body cleaning.

Keep updating this thread!

Keep us in the loop!

I am still working on the problem. Let's begin bullet mania!

Here's a list of parts I've replaced:

• Coil packs
• Spark plugs
• Front O2 sensors
• Charged battery with Battery Tender to full

Other work:

• Spark plug wires are MSD, haven't completely swapped them out to test
• Leak-down test checked out OK
• Compression test was fine except one cylinder got washed down with fuel and didn't hold pressure - mechanic said fuel injector spraying wide open at one time
• Overwrote VEC3 program in case anything changed
• Checked TPS with scan tool and it returned expected values
• Fuel injector connectors are aftermarket clip in type - supposed to be more reliable than factory connectors
• Removed VEC3 from system and it seemed to hit on all cylinders. Then clipped it back in and it worked again. Then the problem returned again!
• Smoked the intake piping - repaired leaks on tubing connections on rear end of Roe piping and 1 L-tap

Possible components to check/replace:

• Spark plug wires - Spark seems fine, but I've heard spark plug wires may cause intermittent problems - swap out with known good ones or replace
• PCM or VEC3 - engine bay heats up and creates problem somehow (note: the exhaust manifold heat shields are removed)
• Fuel injectors - seems unlikely because the problem appears to affect more than 1 cylinder. It's like half the engine is gone when it's running rough
• Crank Sensor - does this cause intermittent problems? Sean Roe said if this fails the car usually won't start
• Cam Sensor - does this cause intermittent problems?

Note - the car is modified:

• 96 GTS
• Roe w/ 5psi pulley
• Smooth tubes/headers/high flow cats/exhaust
• VEC3
• MSD Fuel Pump voltage booster - wired in but I've heard it's not working
• AEM wideband on bank 1 collector

One sign ALWAYS pops up when the car is running rough. The wideband will climb to ~18 AFR and stay there at idle/cruise. If it's running properly it will hover around 14 AFR. This puzzles me because I get lots of extra exhaust popping during engine braking or engine revving. Does the O2 sensor only measure combusted mixtures and if unburned gasoline vapor passes it won't pick it up? I wonder if the wideband is faulty after running with possible ignition misses and other 'interesting' conditions.

 

[BOTTLEFED]

I don't have time to help with all of your questions, but here are some answers.

My car idles at about 15-18afr, so your issue doesn't sound odd to me.

It doesn't sound like anything is wrong with your WB. Even if there is raw fuel pouring through the exhaust, the WB will read the displacement of O2 in the air.

IMO, I think you have a faulty VEC or grounding/wiring to the VEC. Do you have a friend that you can swap out with?

 

[Red Shift]

I had some strange issues.
1. had wiring rub on a screw below ECU, took 8 months to find. (did see trouble codes)
2. Bad gas cap. Not sure what this casues but it was an issue.
3. MY VOTE, replace battery. Big mess for mopars if they have any issues. Had issues with viper with two year old battery, and truck with three year old battery. Any time car acts up, replace battery. try to do this while battery under warranty.....

I'm reading lots about how the cars are picky about batteries. Has anyone given the battery a trickle charge and the problem remains, then replace battery and it's fine?

My car starts fine and the problem is at all rev ranges, not just idle. The battery has gotten low enough that it wouldn't start a couple times before. Does this seem like the battery is a strong possibility? Does the ECU reset when changing batteries (this is another option I haven't done yet)?

 

[Red Shift]

I don't have time to help with all of your questions, but here are some answers.

My car idles at about 15-18afr, so your issue doesn't sound odd to me.

It doesn't sound like anything is wrong with your WB. Even if there is raw fuel pouring through the exhaust, the WB will read the displacement of O2 in the air.

IMO, I think you have a faulty VEC or grounding/wiring to the VEC. Do you have a friend that you can swap out with?

I got frustrated thinking through different scenarios and gave The Wizard a call

I mentioned that during a compression test #9 cylinder filled with fuel with the key on. He saw the same thing on Tony's Viper and it was the VEC. It's looking like the VEC/wiring/grounding.

I can check the box by removing it from the loop. The box/harness will require a swap with a buddy or sending it to Sean. I'm one of two Roe Vipers I know of in Houston (that's the only VEC I've seen here). The other is on the north side and I forgot his name. Anybody know of a VEC in Houston? I want to get back to !

 

[AviP]

Holy jackstand! That gives me the shivers. And I don't see the wheels chocked either. I sincerely hope someone was spotting you while you were underneath it.

BTW, I'm glad you fixed the problem.

 

[Kiaser]

I'm reading lots about how the cars are picky about batteries. Has anyone given the battery a trickle charge and the problem remains, then replace battery and it's fine?

My car starts fine and the problem is at all rev ranges, not just idle. The battery has gotten low enough that it wouldn't start a couple times before. Does this seem like the battery is a strong possibility? Does the ECU reset when changing batteries (this is another option I haven't done yet)?

Once a battery has hit near empty, you'll need to replace it (especially if it has any age to it). Letting it run out of juice can damage the battery system. It can cause lots of intermittent problems.

 

[Kiaser]

I got frustrated thinking through different scenarios and gave The Wizard a call

I mentioned that during a compression test #9 cylinder filled with fuel with the key on. He saw the same thing on Tony's Viper and it was the VEC. It's looking like the VEC/wiring/grounding.

I can check the box by removing it from the loop. The box/harness will require a swap with a buddy or sending it to Sean. I'm one of two Roe Vipers I know of in Houston (that's the only VEC I've seen here). The other is on the north side and I forgot his name. Anybody know of a VEC in Houston? I want to get back to !

Hmmm, I hope mine isn't the VEC, I've got larger injectors and I can barely get the car to stay running with the factory settings.

 

[BOTTLEFED]

Once a battery has hit near empty, you'll need to replace it (especially if it has any age to it). Letting it run out of juice can damage the battery system. It can cause lots of intermittent problems.

absolutely
keep this scenario in mind as well

 

[Red Shift]

Hmmm, I hope mine isn't the VEC, I've got larger injectors and I can barely get the car to stay running with the factory settings.

I pulled the VEC out of the loop and started the car. It was running pig rich with the larger injectors and it wasn't warmed up enough so it was Open Loop warm-up mode - no fuel adaptive correction. I plugged the VEC back in to run it until it got to closed loop then try again without the VEC. Once I reconnected the VEC it pulled 2 codes:

1. P0207 - Cylinder 7 Injector Circuit Malfunction
2. Forget number - Vehicle speed sensor

I checked the wiring and cleared the codes. P0207 kept returning and the car stayed in open loop. I think it stayed there because of the code. Since it never entered closed loop I couldn't remove the VEC and get a feeling for the running condition. I emailed a fellow Viper owner to see if he's around to swap out the boxes. I want to pinpoint that as the problem before sending it off to Sean Roe. If it's not the box/wiring it's time wasted because I won't be able to work on the car while the equipment is out.

Is battery still a possibility? Seems most likely that the VEC is flipping out when it held an injector open.

 

[Red Shift]

No signal to injector 7. Traced it back to PCM. Replaced battery and reset PCM, still no signal to injector 7.

Where's the best place to repair/replace a 96 PCM? I hear the 96 PCM is the most tolerant and doesn't throw codes as much. Any other years acceptable too?