Motor Miss Firirng

[ford_lightning]

MOTOR MISS FIRING

Hi i recently put a 6#lb lower pulley on my lightning, and tuned it with the diablo predator. I have exhaust and a c&l intake tube with cold air and mass air flow sensor. I have 15lb pounds of boost. After 2 days of having the pulley, my truck wouldnt go any faster than 90 its like it lost compression. I took it to ford, and they said it was denating and that the spark plugs were miss firing, and the ends of them were eaten off. They fixed it and told me to add 5 perecent more fuel with my predator to stop the denation. And it worked fine untill last night, and when i hammered it it sounds like a jar of marbles, and it fells like its running off 7 spark cylinders. WHAT DO I DO I ALREADY PAID 250 DOLLARS TO GET IT FIXED THE FIRSR TIME

 

[ShockTherapy]

Sounds like you need to get a custom tune for your predator ASAP! Are you running the predator pulley tune? If so, please ADD 10% FUEL and TAKE OUT 10% TIMING. That will make it at least semi-safe until you can get a custom tune for it.

Also, what plugs and gap are you running in your truck? Hopefully the Ford place didn't put stock plugs back in with stock gap. If they did, I would imagine you have burned the ends off some more plugs.

If you don't get a proper tune in the truck with proper plugs and gap, you can possibly do more harm than has already been done. Hopefully some of the tips of the plugs didn't burn off and nick some exhaust valves and/or seats on their way out.

 

[Drewstein]

What he said.

You're very lucky you didn't snap a rod. Then you would be buying a new motor. Always check your air to fuel ratios before running hard on a new tune. You need better plugs, NGK TR6 is what I run. Gap them at .34ish.

 

[ford_lightning]

Thanks u guys seem to know what ure talking about. I think i have burned some ends off cuse its miss firirng. If i get new plugs will that help. Also does it cost anything to get a custom tune for my predator

 

[rods&pistons03]

you melted the plugs, it happened to me many times, with my old motor, get it dyno tuned!!!

 

[ford_lightning]

If i get new plugs with that fix it. Also how do i get a custom tune, i got my predator from RPM OUTLET.COM. Do i just call them and tell them i need a custom tune or what?

 

[2000L]

RPM outlet will not do custom tunes. I would go with PSP or JLP for a custom tune. Both do custom tunes for the predator and are very good. You need to go at least 1 step colder on the spark plugs. You can pick up a set of NGK TR6's for about $14's at your local advance auto parts. Good plugs for the price. Having plugs that are 1 to 2 steps colder heat range will help with the detnation. As was said above in the mean time take out 10% timing add 10% fuel, and take it real easy until you get the custom tune. After you get the custom tune get it on the dyno and check your air to fuel ratio. 11.6 to 11.8 it is safe. You can then send your tuner the dyno results and he can fine tune your program. The predator pulley tunes are dangerous and have caused many motor failures. Ask for part# 4177 for the plugs. These are the TR6's. Hope this helps, dont ignore your problem or it will become very expensive.

Eric

 

[ford_lightning]

Thanks how much are custom tunes from jpl