Need Help!!!! Haven't Got Much Feedback On Posting In Dyno Section

[Henry Cone]

Need Help!!!! Haven\'t Got Much Feedback On Posting In Dyno Section

We posted our recent dyno results for our 2 96 GTS Coupes. Janni's car was VERY strong - mine wasn't. Can't have her having more power than me!!! More importanly, notice the major glitch in one of the runs - the car just shut off and then came back on. I had this happen to me several times at the Viper Days Finals as well...

Any and all help is appreciated!!! I believe that we reflashed the car last year but we're going to check it anyway..

The post is located at:

http://64.70.135.137/ViperUBB/Forum7/HTML/000102.html

Thanks!!!!!

 

[Marv S]

Re: Need Help!!!! Haven\'t Got Much Feedback On Posting In Dyno Section

Our '97 had an ECU flash done. I was told it "fixed" a cut-out problem than came up from time to time in that rpm range on the model year. Now there is a silver Mopar sticker south of the brake booster that lists the flash as being in carb compliance, etc. Maybe worth checking if this is applicable on yours.

 

[phiebert]

Re: Need Help!!!! Haven\'t Got Much Feedback On Posting In Dyno Section

I'm certainly not an expert on dyno's but from looking at it, and you have probably deduced the same thing, there are some interesting facts.

1. Henry's car has two peak torque points. One at 3600 and one at 4200 rpm. The car seems to stumble between there and can't regain up to the expected peak number because it has lost the smooth curve and momentum.
2. Janni's car only has one peak torque point, as it should be, at 4200 rpm. It gets a higher torque number because it doesn't have to play catch up, it is just building on a nice smooth curve.
3. With HP, it looks again like there is some higher rpm problem with Henry's car. Although at around 4400 to 4600 both cars are developing similar HP, after that Henry's car dies out and the curve flattens.

I don't know exactly what that means. I guess it is possible that Henry's car is bottle-necked by lack of air at higher rpms and the difference in the smooth tubes makes a difference. But as you said that should only account for a few HP. I would guess that whatever is causing the cut-off is also having a more mild occurence before it completely cuts out. Like a misfiring for some reason or starving for fuel or something? Assuming the problem is the computer, maybe the same thing that gets cleared out by flashing the ECU allows it to better learn the fuel/air mixture. Or maybe there is something simple like a faulty fuel pump or an electrical problem or something. Again, I ain't no expert, but it definitely looks like the car is performing pretty much normally until it requires all the air and fuel and electrical pulses it can muster, then it is short of something.

I actually had a Mercedes 280 SEL that had a very similar problem a few years ago. I never did find out what caused it. It would run fine all day long but under a little stress it would cut out and then cut right back in again. I changed numerous parts looking for the problem and finally sold the car without having figured it out. So when you do figure it out, please let me know, I don't think its just a Viper problem.

Maybe you could put the car on the dyno again and put a trace on the electrical system and the fuel to find out what is not keeping up.