Gen IV ECU Issue?

[redtanrt10]

At a road corse event today. My viper is backfiring at around 5,000 RPM. Not all the time, but enought times that I'm using 5K as the rev limit. ViperX thought it may be fuel, thinking it really needs 95 octane? I'm running around 93.25 mixing 100 and 91. Seems to do it more on the front straight where I'm pulling hard in 3rd gear from about 2K rpm. On the backstraight where I'm pulling from about 3K rpm it is not backfiring, although I'm shifting around 5200 to avoid issues.

'08 with 4K miles, has belangers and the Mopar ECU, ECU has been on the car for 500 miles. Did backfire once on the freeway at a hard pull at 5K.

Heading back to CA Speedway in the am. Knowlegable help is appreciated! Mike

 

[Newport Viper]

Hope you get it straightened out Mike! Not fun when in the middle of an event.

 

[mjorgensen Woodhouse]

Is it back firing or falling on it's face when this happens? I doubt that the fuel octane is the issue as the PCM would just take the timing out and the car would feel sluggish. Do you have the stock plug wires? I wonder if there is something with the wires and the headers that could not be right? Also why would you not be downshifting to 2nd if you are at 2K coming onto the straight?

At a road corse event today. My viper is backfiring at around 5,000 RPM. Not all the time, but enought times that I'm using 5K as the rev limit. ViperX thought it may be fuel, thinking it really needs 95 octane? I'm running around 93.25 mixing 100 and 91. Seems to do it more on the front straight where I'm pulling hard in 3rd gear from about 2K rpm. On the backstraight where I'm pulling from about 3K rpm it is not backfiring, although I'm shifting around 5200 to avoid issues.

'08 with 4K miles, has belangers and the Mopar ECU, ECU has been on the car for 500 miles. Did backfire once on the freeway at a hard pull at 5K.

Heading back to CA Speedway in the am. Knowlegable help is appreciated! Mike

 

[redtanrt10]

Mark, 1/3 of the time in goes into "limp" mode for about a second and I back off, other 2/3 times backfires once or multiple times, but I begin to pedal when it starts to happen so maybe that's why it doesn't go limp all the time. Ran the octane up today to about 95.5, sometimes I could see 5200 or so, but other times it just began backfiring around 5K. Seems worse on WOT but I didn't want to push to hard and used 5K as a shift point. 5K is the magic number.

Stock wires, Dan C did the belangers and put his shields on them. Viper X told me that Mike V in Vegas has had ECU problems and sent it back to Arrow for a re-flash. Vipers in the garage filty from 2 days @ CA speedway so it's not ugent.

Let me know what you think, I'm going to try and call Dan C tomorrow. Thanks!! Mike

 

[mjorgensen Woodhouse]

Mike,

Can you swap the stock PCM back in just to make sure that this is the issue for me? All but one of the PCM issues that I have helped with were corrupted install issues. I know Dan is great so this may not be the case for yours, but I would still like to verify that this is the case. The next step would be to re install it, clear all the codes and start a fresh install to see if that changes anything. The only reason for this is to prevent un needed down time sending the PCM back and forth for no reason.

Thanks and you can call me anytime if that is easier for you.

Mark

Mark, 1/3 of the time in goes into "limp" mode for about a second and I back off, other 2/3 times backfires once or multiple times, but I begin to pedal when it starts to happen so maybe that's why it doesn't go limp all the time. Ran the octane up today to about 95.5, sometimes I could see 5200 or so, but other times it just began backfiring around 5K. Seems worse on WOT but I didn't want to push to hard and used 5K as a shift point. 5K is the magic number.

Stock wires, Dan C did the belangers and put his shields on them. Viper X told me that Mike V in Vegas has had ECU problems and sent it back to Arrow for a re-flash. Vipers in the garage filty from 2 days @ CA speedway so it's not ugent.

Let me know what you think, I'm going to try and call Dan C tomorrow. Thanks!! Mike

 

[redtanrt10]

Mark,

Thanks! I've disconnected the PCM a few times on my old 06, I haven't taken a look at the 08's box but the swap should be fairly straightforward? If so I'll do it next weekend.

I'm assuming that you want to go back to stock, run it again up and beyond 5K and see if it still backfires?

Dan didn't do the ECU, I took it to a closer shop (Stack) that specalizes in Mopar, mostly Charger/Challenger work. They have done some viper ECU's. I got mine 30 days after the inital batch and the instructions in the box were the same as you posted.

Thanks again!! I really hope it was just the set up. I had run it on the streets 5-10 times hard up to 6K with never an issue. They re-dyno'd the car last week and didn't tell me if there was an issue.

Dan has a dyno day in early July so I'll take it back to him. Mike

 

[mjorgensen Woodhouse]

Yes the swap will be easy and then we can tell for sure.

 

[cheryl mccally]

Mike when my '09 ACR did the same thing on the track and the street, my Viper tech eventually found it was a cracked spark plug that happened when the Belanger headers were installed. I don't know if that's your problem but a $3.95 spark plug fixed mine.

 

[redtanrt10]

Cheryl, Thanks for the note! I'll take a look at the plugs too. Mike

 

[Viper X]

Hey Mike,

Based on what I'm reading, I'm guessing that the higher octane fuel didn't help. Weird situation.

As Mark says, maybe the ECU install just didn't go right.

Dan Cragin did my ECU install and I have had no issues - car runs very strong.

I did change the spark plugs at about 4000 miles and 8 track days and they looked pretty cooked. You should likely check to see if your spark plug wires are firmly connected.

I also went with a 170 T stat, 1 gallon of distilled water and two bottles of water wetter along with installing a spring in the upper radiator hose. Car didn't get over 200 F at the track last weekend.

Hope you get it sorted out.

Dan

 

[redtanrt10]

Dan, I spoke to Dan C today, he said it could be either the ECU or plugs. I'll swap the ECU this weekend but I'll check the plugs/wires first (thanks). Dan said a scan tool would tell the code but I don't have the time this week to go to DC or Stack. I haven't had the time to do anything but unload the viper, feel free to stop by and clean it, its been rode hard!! Thanks, have fun at Big Bear. Mike

 

[Viper X]

Hey Mike,

I'm in the same boat you are, ACR still sitting in the garage, dirty with slicks on.

I do have a basic code reader, so if you want to come by on Sunday, I'll be around, likely cleaning up the ACR. We can pull a trouble code if one is stored.

Dan

 

[redtanrt10]

Dan, that would be great, I'll give you a call Sunday morning! Thanks, Mike

 

[Flash1034]

Hey Mike, Ive got a code reader too if you cant hook up with Big-Dan.

Bill

 

[redtanrt10]

Bill,

Thanks! If I come over to your place, are you gonna use your taser on me and take your old sidewinder wheels back??

If I don't see you this weekend hope to catch up with you sometime and see your SSG. Also you can take my 08 and see/feel what the ECU does especially w/headers.

Mike

 

[utahviper]

I had a similiar problem with my 08, it was a wiring harness issue. The wire going to the cam sensor was faulty. Did you replace your cam sensor, I heard that is a common problem. PM if you want to discuss it further

 

[redtanrt10]

Utah, haven't done anything yet and the vipers untouched other than adding the ECU and exhaust. Figured I use the scan tool tomorrow and see before I pull the ECU.

Appreciate your offer, may reach out to you tomoorow from ViperX's garage. Thanks! Mike

 

[Flash1034]

Bill,

Thanks! If I come over to your place, are you gonna use your taser on me and take your old sidewinder wheels back??

If I don't see you this weekend hope to catch up with you sometime and see your SSG. Also you can take my 08 and see/feel what the ECU does especially w/headers.

Mike

Entirely possible, Mike.

Bill

 

[redtanrt10]

Well it isn't the Mopar ECU.

ViperX had a scan tool, no codes, checked the plug boots, all OK. Swapped the computer and 15 minutes later on the toll road, hit the wall at 5200 in 3rd gear.

Mark J and Utah, I'll send a PM.

For folks with the Mopar ECU, the swap to stock was easy and the viper ran fine. (except for having the shift lite and lockout back as well as the decel popping - like stock).

 

[Viperless]

Well it isn't the Mopar ECU.

ViperX had a scan tool, no codes, checked the plug boots, all OK. Swapped the computer and 15 minutes later on the toll road, hit the wall at 5200 in 3rd gear.

Mark J and Utah, I'll send a PM.

For folks with the Mopar ECU, the swap to stock was easy and the viper ran fine. (except for having the shift lite and lockout back as well as the decel popping - like stock).

The Mopar ECU doesn't have the shift light feature????

 

[redtanrt10]

The Mopar ECU doesn't have the shift light feature????[/quote]


The Mopar unit eliminates the yellow upshift light as well as the 1st to 4th low speed lock-out feature. The red shift light is still there on the top end.

 

[Viper X]

Hey Mike,

After some thought, this sure acts like a sensor or fuel filter / fuel system issue.

Hope you get it figured out.

Dan

 

[Viperless]

The Mopar ECU doesn't have the shift light feature????[/quote]


The Mopar unit eliminates the yellow upshift light as well as the 1st to 4th low speed lock-out feature. The red shift light is still there on the top end.

Ah, forgot about that nasty yellow one. Thanks!

 

[09 Venom]

Well it isn't the Mopar ECU.

ViperX had a scan tool, no codes, checked the plug boots, all OK. Swapped the computer and 15 minutes later on the toll road, hit the wall at 5200 in 3rd gear.

Mark J and Utah, I'll send a PM.

For folks with the Mopar ECU, the swap to stock was easy and the viper ran fine. (except for having the shift lite and lockout back as well as the decel popping - like stock).

Any updates?

 

[redtanrt10]

Any updates?[/quote]


Took it to DC today for a viper dyno day event. On the 3rd pull it began to backfire at 5200.

Dan Cragin thinks it could be the cam sensor. They used scan toll, checked plugs to no avail. I left my 94 RT/10 with him to look over, I'll swap him my 08 when the 94 is finished then they'll go over the car. I'll post an update when fixed.