Driving today on the freeway, I decided to downshift to 3rd and give it full throttle. Around 5-6k the car backfires, bogs down and lets out a huge black puff of smoke. I did another pull in 2nd gear and it seemed fine. Motor sounded fine.

Motor is a built (rod/piston) D16Y8, 16psi, 260whp, tuned on eCtune.

I think it may be ignition related. I'm running NGK BKR7Es gapped at .028, and crappy Advance Auto wires (probably just anwsered my question with the crap wires). Should I regap to a higher or lower gap?

Should I be worried about running lean or detonation?

Any other thoughts on why I backfired so bad?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by maxxd97 &raquo;</TD></TR><TR><TD CLASS="quote">Driving today on the freeway, I decided to downshift to 3rd and give it full throttle. Around 5-6k the car backfires, bogs down and lets out a huge black puff of smoke. I did another pull in 2nd gear and it seemed fine. Motor sounded fine.

Motor is a built (rod/piston) D16Y8, 16psi, 260whp, tuned on eCtune.

I think it may be ignition related. I'm running NGK BKR7Es gapped at .028, and crappy Advance Auto wires (probably just anwsered my question with the crap wires). Should I regap to a higher or lower gap?

Should I be worried about running lean or detonation?

Any other thoughts on why I backfired so bad?</TD></TR></TABLE>

Get your self a wideband

 

If you had shitty wires that didn't fire when the going got tough, you'd have a shitload of fuel not being burnt, meaning lots of fuel ready to ignite in the exhaust. Apparently it did (backfire), and stayed rich from continued misfiring.

I would definately put a wideband in to recheck AFR's, as they are usually different on the street vs the dyno, and certainly so if the tuner didn't play with the temp correction correctly.

 

Wideband is on my list to get for both of my cars, just have to find the money to buy one. Any other thoughts?

 

sounds like detonation or lean air/fuel mixture cause my 00 coupe did that when i first boosted it with stock injectors and fuel pump, but now i'm chrome chipped with DSM450's and i don't have a problem, it pulls all the way to rev limiter that was bumped up to 7500 rpms

 

have u thought about going with a step colder plugs?

 

Thats what I was asking. Should I try different plugs? Different gap?

This is the first time it has happened besides the time when I had the stock plugs and we were street tuning and the plugs got too hot.

I need a wideband, but don't have the money at the moment to get one.

 

Morning McBump.

 

If you can get access to a laptop check your MAP voltage. Sounds like you might be loosing your MAP signal