my car is poping/sputtering over 10psi

[suprafanatic]

on the way to the chicago meet my car really started sputtering and sounded like it was missing. i pulled the plugs when we got up there and the 6 cylinder plug was bad. i replaced them all and the car drove perfectly fine. the next day was the dyno and on the dyno at high rpms under boost it started poping alot. i took it to the shop to see if they could figure out the problem, they checked the spark and said it wasnt missing. any other ideas as to what may be causing this poping/sputtering at high rpms under boost??

 

[ForcedTorque]

Timing?

 

[snake eyes]

your gonna hate this but.... I had the same thing happen with my supra

was BHG

<l><l>

 

[jdub]

What do have the plugs gapped at?
What brand/heat range plugs?

 

[suprafanatic]

well its not bhg while it was at the shope they did a compresion test and a leak tester. absolutly no signs of bhg. i just pulled out the spark plugs from cylinder 1 and 6. number 1 was really white, number 6 was brownish black. so number one is having some problems. i just got some new plugs AGIAN and we'll see what happens.

 

[suprafanatic]

they are auto lite copper core plugs 3923 gapped to .028

 

[jdub]

The Autolites are shorter than the (JIC standard?) plugs used on the 7M...about 1/8". On some wires, they work fine...on others they dont. I would get some NGK coppers in a "7" heat range, gapped to .027"-.028".

 

[Boost Lee]

Scott, We checked his timing at Sound Performance and he's right in the money range, so it's certainly not timing.

Yes, jdub is correct. Autolites are a bit shorter than what was standard.
Although if I remember correctly, He's been running Autolite 3923's for quite a while now with no problems.

I don't recall, so I'll ask. What plug wires are you using, Nate?

To add to the mix...He is running about 1.3 bar.

Jeff

 

[jdub]

And, did you change wires recently?

 

[suprafanatic]

it has NGK wires and they are still good. i just changed the plugs, one of the plugs was gapped at .045 FAIL so the car seems to be running great now.. although the shop did tests for BHG im not convience that it doesnt have bhg... its still showing signs of it. coolant dissapearing, and temp gauge keeps dropping, and the oil is pretty nasty looking in my catch can