ricky914

I have a '14 GT that has a Ford Racing/Whipple supercharger with a 3 inch pulley, long tubes with off-road exhaust, and it's on E85. I changed the coil packs from stock to Accel Super Yellow's and also put in NGK Laser Iridium spark plugs because under hard acceleration, the car had a minor sputter (only way I can think to explain it). After changing the coils and plugs, it made the issue worse. I was told that the stock coil packs are the best choice for the 5.0 engine and to get the Accel's out of there. Could this issue be a tuning issue? Could the plugs be wrong? Has anyone else had this problem? I need to figure this out because I want to get it to the track to see what it can do now that all the other mods are done. Thanks guys.

08'MustangDude

Yeah, you probably did not gap the plugs. If you bought plugs, and put them in out
of the package, they're gaped too wide for boost. NA Gap is .045, you're boosted,
so you should be as low as .028. It will pull timing with the .045 gap under hard
boosted acceleration, then it can do it again at higher RPMs.

Set your GAP to .028.

ricky914

I'll try that, thank you.

Derf00

and what heat range are the plugs? If you're boosted you should be running range colder than OEM in addition to the smaller gap.

ricky914

They are NGK Laser Iridium heat range 6 part #ILTR6A-13G. I didn't put them in so I don't know what they were gapped. The car runs fine for normal driving but when I hammer the pedal, it sputters or misses badly until it gets rolling.

08'MustangDude

I think for yours, OE heat range is 7, so 6 is, better.

When you hammer the pedal, this is when the ECU advances timing more
aggressively. The misfires and sputtering happens when the advance causes
detonation, spark delay, spark blow out, due to the wide gap, so it pulls
timing. Also, if you are running 87-89 octane under boost, it's detonation.

I have a 1.8T running +6 boost, new plugs, with factory gap, had the same issues.
I regaped the plugs, and it was fine, unless I ran crap gas. Those plugs have
been in for about 45,000 miles already, and the sputtering at WOT or hard
acceleration is back, so, that means the electrode has worn, and widened the
gap. The OE ones I took out, where .042, worn, I put the new ones.032, then
had to go down to .028, and used Audi RS3 Coil Packs for a stronger spark;
again, with +6 boost. Factory was fine, and +4 was okay. Running +6 needed
the fine tuning there...

Even for you, the factory gap will not suffice under boost. It has to go at least .010
down. A colder plug also helps prevent detonation. The sputtering without a CEL
is timing being pulled. Misfire with the blinking CEL is detonation, spark blow out,
or spark delay, which is micro seconds, with the larger gap.

There was another user here with the same issue, I said to regap the plugs, he did
and said it now runs fine.

ricky914

My mechanic said that he gapped the plugs at 22-.25. I have an appointment to get the car on the dyno on Tuesday and the owner of the shop said that I should take out the Accel coil packs and replace them with the stock ones. I don't understand how replacing the new upgraded parts with the stock ones will fix the detonation issue?

Derf00

because in many cases the OEM Ford coils are as good or better than the aftermarket regardless of brand.... Also, when you start having issues after putting in new parts, and problems come up that could be related, you always put back the previous parts to see if the problem still exists. That way you can rule out the new parts. New does not always mean guaranteed problem free.

Coosawjack

OEM Ford coils have been better than any aftermarket product for at least 15 years!!

Aftermarket coil product hype is just that!!

ricky914

The Accel coils and the new spark plugs were taken out and replaced with the OEM coils and NGK spark plugs that are not iridium with a gap of .30 and that fixed the issues. Lesson learned. Thank you for the help guys.