Anthony Boni
5+ Year Contributor
- 213
- 23
- May 13, 2018
-
Wrightstown,
New_Jersey
Hello all.
Need to pick your brains real quick. At idle I can hear a hollow, misfire sound. Doesn’t affect my AFR, idle is steady.
While cruising, I hear the same hollow misfire sound, my AFR goes rich (12.7:1-12.2:1), and the car stutters for a split second. It’s random while cruising at partial throttle. During heavy acceleration, WOT, or any boost whatsoever, car pulls like a champ. No hesitation, no stuttering whatsoever.
I know most misfires cause a LEAN A/F ratio, but this one goes RICH. Which is why I’m confused.
I don’t want to make assumptions before I hear your guys’ answers, but I have an idea as to what the problem may be. I don’t want to make a recommendation and everyone focus on that one thing, so I’d like to hear some answers before I comment.
Mods:
I’m using FIC 1250cc low-z injectors, BPR7ES plugs gapped to .018”, datalogging with DSMLink V3. I’m also logging fuel pressure through a fuel pressure sensor, and using a fuel lab AFPR. Fuel pressure is rock solid, no spikes/drops throughout the misfire 450HP E85 fuel pump, currently on 93 octane pump.
NGK blue spark plug wires, stock transistor and coil pack. FP76HTA turbo, FP2 cams.
Base timing is set at 5°BTDC, base fuel pressure is set to 43PSI.
I’m currently at work so I can’t post a log from my laptop (posting this thread off my phone).
Need to pick your brains real quick. At idle I can hear a hollow, misfire sound. Doesn’t affect my AFR, idle is steady.
While cruising, I hear the same hollow misfire sound, my AFR goes rich (12.7:1-12.2:1), and the car stutters for a split second. It’s random while cruising at partial throttle. During heavy acceleration, WOT, or any boost whatsoever, car pulls like a champ. No hesitation, no stuttering whatsoever.
I know most misfires cause a LEAN A/F ratio, but this one goes RICH. Which is why I’m confused.
I don’t want to make assumptions before I hear your guys’ answers, but I have an idea as to what the problem may be. I don’t want to make a recommendation and everyone focus on that one thing, so I’d like to hear some answers before I comment.
Mods:
I’m using FIC 1250cc low-z injectors, BPR7ES plugs gapped to .018”, datalogging with DSMLink V3. I’m also logging fuel pressure through a fuel pressure sensor, and using a fuel lab AFPR. Fuel pressure is rock solid, no spikes/drops throughout the misfire 450HP E85 fuel pump, currently on 93 octane pump.
NGK blue spark plug wires, stock transistor and coil pack. FP76HTA turbo, FP2 cams.
Base timing is set at 5°BTDC, base fuel pressure is set to 43PSI.
I’m currently at work so I can’t post a log from my laptop (posting this thread off my phone).