OMG! Viper running terrible!! Hard to describe symptoms but I'll try

[99BLKRT/10]

OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

A little background info. I've had my 99 RT/10 (35k miles now) for about 4 years and it's always had this intermittent problem. It has probably only happened about 5 times since I've owned it so have never taken it in. However, today I drove it today and it just wouldn't stop. Happened ALL day!

Ok, so here's my attempt to describe the symptom. While cruising (no matter what gear) it feels like I'm running over water puddles. :-O Like a sudden loss of power then suddenly back to normal. Like it's running on 8 or 9 cylinders then back to normal. This happened when I first bought the car so thought maybe I would just go ahead and change the plugs and wires. Car ran great for a few months then it happened again. When I got home today I checked the wires and everything seems snug. Car idles fine so it seems kind of strange that it only happens while cruising. I have to "blip" the throttle to get the symptom to go away. But then it just comes right back. :-(

Has this weird symptom happend to any of you guys? I thought I would check here before I take it in to the doctor.

 

[Russ M]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Sounds like you are experiencinng some sort of sensor failure or fuel pump failure.

Are you getting a check engine light? This might be stored as an error code in the computer, if you check logs.

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Sounds like you are experiencinng some sort of sensor failure or fuel pump failure.

Are you getting a check engine light? This might be stored as an error code in the computer, if you check logs.

About a year ago I got the check engine light. I don't remember the error code but it was the one that hinted about a bad gas cap or something like that. All I did was disconnect the battery and it hasn't returned ever since. Even after these symptoms. I hope it's something simple like a sensor and not the fuel pump. :-(

 

[ViperJohn]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

I think it sounds like the fuel pump to me too. Perhaps it's the pressure regulator. I have a simple solution on how you can eliminate the fuel pump. I had been told my fuel may be bad, so I did the following:

Went to Advance Auto and bought a fuel pressure tester for $40.00. Removed the wipers and the cowl, this takes about 5 minutes. On the passenger side of the intake manifold about 3/4 of the way back there is a gold shrader valve. I attached the pressure gauge to the shrader valve and used duct tape to mount it onto my windshield. Removing the cowl allows for the tube to pass through to the windshield without damaging the hood or cowl when the hood is closed.

The correct pressure is 55 psi, +/- 5 psi, per my 02 Service manual. Make sure you position the gauge on your windshield so you can read it while driving. It may look a little ghetto, but it works.

Before you start the car, make note of the pressure gauge. As soon as you turn the key to on, you will hear the pump come and the pressure should go to 55 psi. Then start the car and go for your drive. The pressure should stay at 55 psi the whole time your driving. If you notice the pressure drop at the same time you are experiencing your problem, then you have either a bad pressure regulator or fuel pump. Either way, the fuel pump as to come out as the pressure regulator cannot be bought seperate.

Good luck, feel free to PM me if you need any further help.

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

I think it sounds like the fuel pump to me too. Perhaps it's the pressure regulator. I have a simple solution on how you can eliminate the fuel pump. I had been told my fuel may be bad, so I did the following:

Went to Advance Auto and bought a fuel pressure tester for $40.00. Removed the wipers and the cowl, this takes about 5 minutes. On the passenger side of the intake manifold about 3/4 of the way back there is a gold shrader valve. I attached the pressure gauge to the shrader valve and used duct tape to mount it onto my windshield. Removing the cowl allows for the tube to pass through to the windshield without damaging the hood or cowl when the hood is closed.

The correct pressure is 55 psi, +/- 5 psi, per my 02 Service manual. Make sure you position the gauge on your windshield so you can read it while driving. It may look a little ghetto, but it works.

Before you start the car, make note of the pressure gauge. As soon as you turn the key to on, you will hear the pump come and the pressure should go to 55 psi. Then start the car and go for your drive. The pressure should stay at 55 psi the whole time your driving. If you notice the pressure drop at the same time you are experiencing your problem, then you have either a bad pressure regulator or fuel pump. Either way, the fuel pump as to come out as the pressure regulator cannot be bought seperate.

Good luck, feel free to PM me if you need any further help.

Wow! Thanks for the tip! I'll try that out first before I take it in to the shop. I have this nice stretch of road by my house I can try the "ghetto" setup. I'll keep you guys posted on what I find out.

 

[ViperJohn]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

The whole time I was riding around with it, I was just waiting for some ricers to come by and marvel and my awesome gauge.

 

[ViperJohn]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Almost forgot, one last tip, let the car sit a few hours before you remove the gauge. Once the pressure has fallen, take a rag and place it around the shrader valve base. No fuel came out when I removed mine, but put the rag there just to be safe.

 

[99 R/T 10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Throttle Position Sensor(TPS)?

 

[V10SpeedLuvr]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Throttle Position Sensor(TPS)?

When I had a bad ground going to my TPS sensor, the symptoms I had were idle hang and bucking/jerking when driving at almost any speed. He mentioned his car idled fine and "blippng"the throttle cured the problem. At least for me, my car idled like crap and blipping the throttle didn't do anything to help. The TPS could be the problem, but if so, he's having a different set of issues than I did when my TPS was acting up

 

[Viper Wizard]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Throttle Position Sensor(TPS)?

That's what I'm thinking.

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Is there a way I could test out the TPS just in case?

 

[Leslie]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

same thing happened on my vette, i am sure vipers are different

it was like my car wasn't running at full power

ended up being the TBS, it was causing intermittent bursts of fuel from the injector and an unstable idle, because the ECM thinks the throttle is moving.

 

[Mr Hemi Head]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Is there a way I could test out the TPS just in case?

There is a three wire plug on the TPS sensor, the middle wire is the sensor output.

Nick the insulation and with a digital voltmeter check for a smooth transition between .5V(idle) to about 4V(WOT). Black meter lead to chassis ground.

Perform this test with the key on without the engine running.

If the TPS is intermittent you could do windshield diagnostics with the voltmeter while driving.

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Is there a way I could test out the TPS just in case?

There is a three wire plug on the TPS sensor, the middle wire is the sensor output.

Nick the insulation and with a digital voltmeter check for a smooth transition between .5V(idle) to about 4V(WOT). Black meter lead to chassis ground.

Perform this test with the key on without the engine running.

If the TPS is intermittent you could do windshield diagnostics with the voltmeter while driving.

Ok, I tried the test with the engine off. I got .9 v closed and a smooth transition to 4.15 v fully opened. If there is an issue with the TPS would it be during the transitioning or the closed and open values? .9v and 4.15 is definitley more than the manual states. I will try the test again (on windshield) and see if the TPS values are erratic during the symptoms.

Thanks!

 

[Knight Viper]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

I picked up on of the OBDII diagnostic tools from ebay that will read your codes (tell you what they are) and give you live data such as fuel pressure and you can clear any codes you may end up with also, so you don't have to go through the trouble of disconnecting your battery. A great all around tool to have for your other vehicles and all you need to do is plug it in under your dash. All for under $100


John, I'm sure you have thought of using this but I know it would make it a lot easier for you to clear your codes with one of these also

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Is there a way I could test out the TPS just in case?

There is a three wire plug on the TPS sensor, the middle wire is the sensor output.

Nick the insulation and with a digital voltmeter check for a smooth transition between .5V(idle) to about 4V(WOT). Black meter lead to chassis ground.

Perform this test with the key on without the engine running.

If the TPS is intermittent you could do windshield diagnostics with the voltmeter while driving.

Ok, I tried the test with the engine off. I got .9 v closed and a smooth transition to 4.15 v fully opened. If there is an issue with the TPS would it be during the transitioning or the closed and open values? .9v and 4.15 is definitley more than the manual states. I will try the test again (on windshield) and see if the TPS values are erratic during the symptoms.

Thanks!

I tried the TPS test while driving. The values did not fluctuate while the car experienced the symptoms. :-( I was hoping it was the TPS instead of something more serious. I will have to try the fuel pressure test next time. It's a shame.. The weather is so gorgeous outside to be driving *******!

 

[ViperJohn]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

I picked up on of the OBDII diagnostic tools from ebay that will read your codes (tell you what they are) and give you live data such as fuel pressure and you can clear any codes you may end up with also, so you don't have to go through the trouble of disconnecting your battery. A great all around tool to have for your other vehicles and all you need to do is plug it in under your dash. All for under $100


John, I'm sure you have thought of using this but I know it would make it a lot easier for you to clear your codes with one of these also

I had thought about using that, however, depending on the read frequency, it could miss picking up a quick drop in pressure. Also, some of the OBD II scanners do not register fuel pressure on the Viper for some reason. I wanted immediate results, so doing it my way was quicker than purchasing something on ebay, that may or may not work, and waiting by the mailbox.

I have actually been monitoring many data points on my car with a laptop lately. It's very cool to see/record what your car is doing while being driven.

 

[Mr Hemi Head]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Is there a way I could test out the TPS just in case?

There is a three wire plug on the TPS sensor, the middle wire is the sensor output.

Nick the insulation and with a digital voltmeter check for a smooth transition between .5V(idle) to about 4V(WOT). Black meter lead to chassis ground.

Perform this test with the key on without the engine running.

If the TPS is intermittent you could do windshield diagnostics with the voltmeter while driving.

Ok, I tried the test with the engine off. I got .9 v closed and a smooth transition to 4.15 v fully opened. If there is an issue with the TPS would it be during the transitioning or the closed and open values? .9v and 4.15 is definitley more than the manual states. I will try the test again (on windshield) and see if the TPS values are erratic during the symptoms.

Thanks!

I tried the TPS test while driving. The values did not fluctuate while the car experienced the symptoms. :-( I was hoping it was the TPS instead of something more serious. I will have to try the fuel pressure test next time. It's a shame.. The weather is so gorgeous outside to be driving *******!

This voltage range is . The slighly higher voltage at WOT means the throttle position is optimal.

Unless electrical noise is the issue, requires a scope to diagnose, I would look elesewhere.

 

[fastfang]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

I had a similar problem with my 99 except it was backfiring when it felt like it had no power. The car would run fine for days, sometimes weeks on end and then it would backfire and lose power and sometimes stall out and not start again.

I had the car towed a few times and when it got to the shop, it started up like there was no problem at all. I thought that it could be an overheated fuel pump, but it did not do it all the time.

The car was at a Dodge dealership for a week and they got it to act up once. The mechanic said that the fuel pump pressure dropped and I needed a new one. He replaced it and no problems, until after I had the car three days later on a little ride around the block.

I called Roe Racing and talked to Dave and he said that he wouldn't be surprised that the battery was going bad and that vipers act very strange when that happens. I told him that my car cranks over fine and that I have no apparent battery issues. He insisted that I change the battery.

The next day I took the battery out and noticed that it was only one year old. I thought to myself how can this be bad. I decided to listen to Dave anyway and put a new battery in. Guess what? NO PROBLEMS!!!!!! It was the battery all along.

I hope your fix is as easy as this one. It just took me a couple of months and a lot of cussing on the side of the road to finally get the problem solved.

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

I had a similar problem with my 99 except it was backfiring when it felt like it had no power. The car would run fine for days, sometimes weeks on end and then it would backfire and lose power and sometimes stall out and not start again.

I had the car towed a few times and when it got to the shop, it started up like there was no problem at all. I thought that it could be an overheated fuel pump, but it did not do it all the time.

The car was at a Dodge dealership for a week and they got it to act up once. The mechanic said that the fuel pump pressure dropped and I needed a new one. He replaced it and no problems, until after I had the car three days later on a little ride around the block.

I called Roe Racing and talked to Dave and he said that he wouldn't be surprised that the battery was going bad and that vipers act very strange when that happens. I told him that my car cranks over fine and that I have no apparent battery issues. He insisted that I change the battery.

The next day I took the battery out and noticed that it was only one year old. I thought to myself how can this be bad. I decided to listen to Dave anyway and put a new battery in. Guess what? NO PROBLEMS!!!!!! It was the battery all along.

I hope your fix is as easy as this one. It just took me a couple of months and a lot of cussing on the side of the road to finally get the problem solved.

Hmmmm.. I have one of those Interstate batteries and it's less than one year old. After I do the fuel pressure test I might look into getting a "real" battery.

 

[AZTVR]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

The next day I took the battery out and noticed that it was only one year old. I thought to myself how can this be bad. I decided to listen to Dave anyway and put a new battery in. Guess what? NO PROBLEMS!!!!!! It was the battery all along.

I'd strongly agree with the TPS and fuel pressure tests as being what will reveal the most probable cause. If you have a voltmeter with a needle indicator, it would be better for detecting an intermittent than a digital display, which usually doesn't update fast enough. Otherwise you would need a 'scope. You could monitor battery voltage at the "jump" terminal. That would tell you if the battery itself is good. (an intermittent battery would be very unusual, but an internal intermittent short is possible.) When you check the battery, measure from one battery post to the other, and also measure from each the cable clamp to the other, and the positive post to the frame, or to the ground lug near the computer. All of those readings should be about the same if you have good connections. I'd definitely clean and brighten up both positive and negative connections to the battery, and at the other ends of the cables. A bad ground connection elsewhere could give you confusing results. It might give you a good reading between the TPS sensor and whatever ground you choose to connect the voltmeter's negative probe to; but it may not be good to the ground connection that the computer references to.

I'm not familiar with the Viper's grounding scheme; but, could blipping the throttle be jerking the engine enough to disturb a loose or corroded gound connection to the frame?

 

[RAYSIR]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

If it was a senser problem the check engine light would be coming on. Sounds to me like an injector is sticking mechanically. I have had same symptoms on many cars with the crappy gas we're getting up here and a good injector cleaner added to the fuel cured it. My Tahoe started to buck so bad I didn't think I would make it home. I added a product called (advertising) Seafoam that NAPA sells and fixed both cars. I also ues it in my repair shop as an injector clean with a pressurised cleaner system.
Also, if the car cranks and has charge voltage it's not a Battery problem!!! I keep see all these posts where change the battery is the Cure and it cranks and starts fine.

 

[ViperJohn]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

There have been many cases of a bad TPS sensor not throwing a code. The sensor voltage nees to be out of range for a certain period of time for the PCM to catch it.

 

[fastfang]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Also, if the car cranks and has charge voltage it's not a Battery problem!!! I keep see all these posts where change the battery is the Cure and it cranks and starts fine.

My car was cranking over just fine and the charge voltage was fine. That's why I didn't believe that it was a battery problem, but it sure was.

 

[AviP]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Like a sudden loss of power then suddenly back to normal.

This happened to me on my PT-Cruiser. I had an old battery and wanted to eliminate it as a cause so I replaced it but the symptoms still persisted. Debugged it this time to a MAP sensor that had cracked. Replaced it and it runs great.

In your case, I would look at:
- MAP sensor
- Fuel pump
- Fuel injectors
- Spark plugs
- Spark plug wires

There's more but this should keep you busy for now.

 

[99BLKRT/10]

Re: OMG! Viper running terrible!! Hard to describe symptoms but I\'ll try

Like a sudden loss of power then suddenly back to normal.

This happened to me on my PT-Cruiser. I had an old battery and wanted to eliminate it as a cause so I replaced it but the symptoms still persisted. Debugged it this time to a MAP sensor that had cracked. Replaced it and it runs great.

In your case, I would look at:
- MAP sensor
- Fuel pump
- Fuel injectors
- Spark plugs
- Spark plug wires

There's more but this should keep you busy for now.

Yup! This should keep me busy for a while. I haven't had a chance to test the fuel pressure (while driving). How can I test the Map sensor? I'm thinking it's not the spark plugs or wires since it's happend before and after I changed the plugs/wires. :-(

 

[RedSrt007]

updates?

 

[PatentLaw]

I agree with AviP on the last two. Nobody really chimed in on it. Change out the plugs, wires and battery. The sparks are a buck fifty each. Big deal. Wires are not that expensive. Battery 80 bucks. You are going to eliminate a lot of potential problems by doing those maintenance items. Then you can go to the bigger problems.

Never start taking your car apart until you check and replace the little things.

 

[supraman95]

Curious to see the outcome on this as well. I have this bucking/loss of power, power comes in suddenly when cruising when altering the Throttle just a bit..... I have done plugs, wires, etc.
My car is ROE SC'ed and I am getting a "system lean" code error. Chuck seems to think I may have a bad computer. I need to check my TPS too just to be sure!

 

[supraman95]

Well I have changed out the TPS, Computer, Plugs, wires, O2 sensors, Cleared codes in the pc and I still have this light miss (studder and bucking at low rpm). I guess teh last thing to change is the battery.

My car has a Champion battery, would that happen to be the factory battery? hard to believe it would have a 10yr old battery in it though unless the previous owner replaced it.