Breaking up under hard acceleration

[ITL Cobra]

2003 Cobra - Car has 3200 miles on it, had the Whipple installed in 09 (with 29xx miles) and running 18lbs of boost, BAP and wiring upgrade, 60# injectors, tuned by Kurgan. Due to work and family obligations I haven’t had much of a chance to drive her that much (ok at all), and never really got on her, really the hardest it was ever driven was on the dyno when Kurgan tuned it. 3 or 4 weeks ago had the coil over kit installed, ran the tank down to almost nothing and put in some fresh gas before dropping it off for the coil overs, got the car back, wanted to drive her around to blow the dust off her, drove it till I was back below a 1/4 tank, put in some fresh gas and was out screwing around a little not much, got on her a little around 5500rpm after 2nd and when shifting to 3rd she kind of broke up and sputtered fell on her face and then kicked right back up it all happened so quick couldn't see what the wideband was reading , so I backed off right away. So taking the path of least resistance 1st I decided to replace the plugs. Called lethal performance and they told me to go with the brisk Silver Racing Spark Plug (600hp+) for my set up.
Old Plugs

Installed the plugs... gap set @ .028. Ran the gas down to 1/4 tank again car runs fine under normal driving conditions filled her up got on her a little bit and she seemed fine.. Did a few more pulls and it seemed ok, under moderate acceleration she seems great, but going from 2nd to 3rd under really hard acceleration she broke up again, and I missed what the wide band was reading as I was paying more attention to the road...

Sent an email to Bob k and he seems to think its spark blow out and recommends I gap the plugs between .018 and .020. Been searching svtperformance, and came across a few that seems to have this issue, and the most of them pointed to the fuel filter?? With less than 4k does that seem possible?:shrug:

I want to regap the plugs as Bob K recommended and change the filter, while I am waiting for my serial to usb connector come in for my predator so I can data log.

Any suggestions?? Maybe new coils too? :shrug::shrug:

 

[APMECH]

If you have an 03-04, have you done the PPRV delete? If it's momentarily cutting out after you shift, that could be it.

 

[ITL Cobra]

If you have an 03-04, have you done the PPRV delete? Never mind, I see the GT500 in your sig.....

I think that the PPRV delete is for hesitation between shifts.

 

[ITL Cobra]

If you have an 03-04, have you done the PPRV delete? If it's momentarily cutting out after you shift, that could be it.

But wouldnt that do it under all shifts, not just under hard pulls?

 

[APMECH]

But wouldnt that do it under all shifts, not just under hard pulls?

Only under hard acceleration, and shifting. When you hit the next gear and put your foot to the floor, does it cut out then? Normally, if it does it under hard acceleration, it's spark blow-out, like you were originally looking at. Could also be a coil pack, could be in the tune, you'll know more when you data log it.

 

[ITL Cobra]

Only under hard acceleration, and shifting. When you hit the next gear and put your foot to the floor, does it cut out then? Normally, if it does it under hard acceleration, it's spark blow-out, like you were originally looking at. Could also be a coil pack, could be in the tune, you'll know more when you data log it.

Thats it...

 

[03 TOPLESSSVT]

Pprv

 

[Black*Death]

COPs? Ford OEM or aftermarket?

 

[ITL Cobra]

COPs? Ford OEM or aftermarket?

Ford OEM

 

[ITL Cobra]

Brief Update..

So yesterday afternoon, I had a few hours free, so I replaced the plugs, replaced the COP's, replaced the FRPS, Installed the KB Disc, and replaced the fuel filter. Started her up to check for leaks and all seemed fine, took her for a short drive and noticed a slight whine "not in boost" gave it a few RPMS and the whine increased with RPM speed. Car is usually on a charger when not in use, so when I got home put her back on the charger and checked this am and its still not charged... I am thinking I might have a charging issue..

 

[racebronco2]

It seems like alot of us on high boost are gapping our plugs too wide causing spark blow out which is when you are in one gear and it seems to be hesitating ever so slightly at the higher rpm. I would listen to Bob.

If the car hesitates between shifts then it's the pprv, if you shifted faster you would not feel it. I don't have the pprv delete and the only time i feel the hesitation is when i am open tracking. It is caused by lifting off the gas, the fuel pressure rises to over 60psi, the ecu cuts voltage to the pumps momentarily, by the time your back on the gas the fuel pressure goes below about 36psi and then the ecu increases the voltage to the pumps again, there is a slight delay before the fuel pumps kick in and the pressure go to 39psi of above.

You can data log on the predator. You will see the fuel pressure rise and drop between the shifts.

 

[ITL Cobra]

Ok, after replacing the Alternator, with a 300amp Alternator, and a Optima Red Top Battery, Fuel Filter, COP's, FRPS, Plugs, and KB Disk, I took the car over to Modular Performance to check the tune... Turns out the tune was the issue, it seems all the mappings were off, not sure how that happened, as Bob K tuned it and put on 100 miles in 3 years and not changed anything...