What was concensus of the hesitation during shifts at wot?

[lx347cid]

so car got tuned on dyno and finally got it to drive on street for some wot pulls. Duing shifting between gears i get bog/hesitation which feels like it shuts down then pulls hard again.
I let the tuner know and im sure it will get fixed but wondering what the problem has been to fix this. I got vmp. Injectors. Bap.
Just happens during shifting. Lazy speed shifting. Not powershifting.
So i am letting off and on gas during shifts.

 

[SVTag]

Do you have a pprv delete?

 

[lx347cid]

No i do not have the pprv delete. I didnt think it was a must have for 600 hp cobras?

 

[SVTag]

That's likely what is causing your hesitation...I would start with that

 

[Soap]

Agreed....get rid of the PPRV.

--Joe

 

[01yellercobra]

The PPRV delete should get rid of it. However, depending on how much head room you have in your fuel system it can be tuned out too.

Misspelling brought to you by Tapatalk

 

[lx347cid]

Thats what i am thinking that it should be able to be tuned for hesitation not to happen.
So why am i having this problem now and not before? Does it only happen on high hp cars only? Because i have heard it has happened even on lower hp bolt on stock eatons too.
I dont feel like dropping my tank. If im going to drop my tank then i minus well do retutn system and go e85.

 

[01yellercobra]

Thats what i am thinking that it should be able to be tuned for hesitation not to happen.
So why am i having this problem now and not before? Does it only happen on high hp cars only? Because i have heard it has happened even on lower hp bolt on stock eatons too.
I dont feel like dropping my tank. If im going to drop my tank then i minus well do retutn system and go e85.

I really don't know why it's happening now. I had a big bore stroker with a D1 and never had the issue. Took the D1 off and went N/A and all of a sudden I had the hesitation. I had the PPRV delete too. Of course it didn't decide to happen until I was at the strip. So everyone thought I couldn't shift. I was able to tweak the tune to get rid of it though.

Misspelling brought to you by Tapatalk

 

[Bdubbs]

Another great reason why I went return, no hesitation and no blown frps.

 

[CobraBob]

Another great reason why I went return, no hesitation and no blown frps.

Gotta love a return system! Nice to have a fuel system that needs less attention over time.

 

[whitedevil95]

Yup Ive had my whipple set up tuned by Kurgan and 04Sleeper both great tuners. Can still has it happen sometimes if I dont shift like lighting. Cant wait to go FORE return and get rid of that BS.

 

[choate]

Same here but my tuner didn't give the car back like that. He dropped the tank and delete the PPRV. I'm now having other fuel issues as the car cranks and won't start. I'm seriously about to go full return with it b/c now it has to go back to the shop and the tank is coming back out

 

[01yellercobra]

Same here but my tuner didn't give the car back like that. He dropped the tank and delete the PPRV. I'm now having other fuel issues as the car cranks and won't start. I'm seriously about to go full return with it b/c now it has to go back to the shop and the tank is coming back out

Turn the key on for a second before cranking. The system needs to prime and pressurize since the PPRV is gone.

Misspelling brought to you by Tapatalk

 

[SVTag]

Same here but my tuner didn't give the car back like that. He dropped the tank and delete the PPRV. I'm now having other fuel issues as the car cranks and won't start. I'm seriously about to go full return with it b/c now it has to go back to the shop and the tank is coming back out

Do it. You won't regret it

 

[choate]

Turn the key on for a second before cranking. The system needs to prime and pressurize since the PPRV is gone.
Misspelling brought to you by Tapatalk

How long? If that's it's I'll faint. We've tried a new FRPS so far and fuel pump driver module in the truck. Nothing. Still just cranks and cranks. We've turned the key on and off several times to listen for the pumps coming on so I think it should be primed. The service manager at the shop who's owned several cobras is the one helping me and he seems confused which isn't helping me not worry it's something bad. Going back to the shop this week since he thinks a line in the tank may have fallen off or something. There was a blown mini fuse but I'm not sure which one at this point and didn't have a small one to replace it. He left yesterday scratching his head but could that be it?

 

[01yellercobra]

How long? If that's it's I'll faint. We've tried a new FRPS so far and fuel pump driver module in the truck. Nothing. Still just cranks and cranks. We've turned the key on and off several times to listen for the pumps coming on so I think it should be primed. The service manager at the shop who's owned several cobras is the one helping me and he seems confused which isn't helping me not worry it's something bad. Going back to the shop this week since he thinks a line in the tank may have fallen off or something. There was a blown mini fuse but I'm not sure which one at this point and didn't have a small one to replace it. He left yesterday scratching his head but could that be it?

I thought you meant it takes longer to catch. If it's just spinning and not catching than yeah, you probably have a mechanical issue. I did some work years ago on another cobra and a line popped off one of the pumps. We could hear them prime, it just wouldn't start.

Misspelling brought to you by Tapatalk

 

[MG0h3]

Thats what i am thinking that it should be able to be tuned for hesitation not to happen.
So why am i having this problem now and not before? Does it only happen on high hp cars only? Because i have heard it has happened even on lower hp bolt on stock eatons too.
I dont feel like dropping my tank. If im going to drop my tank then i minus well do retutn system and go e85.

Brilliant! You'll be saving $$ on not buying the pprv. That's what I would tell myself anyways.....


Sent from my iPhone using the svtperformance.com mobile app

 

[whitedevil95]

Yeah sometimes the deletes come apart and cause issues. Good lick


Sent from my iPhone using svtperformance.com

 

[racebronco2]

I have found out if you shift fast it doesn't happen, i do not power shift my car. Also while open tracking if you don't lift off the gas all the way it also doesn't happen. It happens when you lift off the gas all the way. If you completely lift off the gas, the pressure spikes, because of excessive pressure the pumps turn off, when you get back on the gas you have to use enough gas to get the pumps pressure to get low enough for the pumps to turn back on. The pressure spikes depending how much the pressure rises will cause your pprv or your pumps to fail. I have replaced two sets of pumps. My car only has 56,000 miles on it but i used to open track about 40 days a year for the first 6 years or so.

 

[lx347cid]

Well i was told the tune cant fix it. Oh well - wish vmp told me this was going to happen. I would have just skipped the bap and got the return system. Oh well. Car still pulls like a freight train. Love the vmp blower so far.