Well I thought I was heading to the track tonight. But a Gremlin that I had been fighting awhile back is at it again.

This is what I have going on;
As the rpms come up and boost goes up, I get a miss fire that is bad enough for the ecu to kill a couple of cylinders for a couple of seconds, even after I back out of the throttle. Car rpm's up fine under normal or low boost driving (below 20psi) all the way to red-line without a hic-up. Turn up the boost and it starts to come in. 2 plugs look nice and clean, 2 plugs are dark.

This is what I have done to try and fix it;
Replaced both coils and power transistor today, put BPR7ES plugs back in (gapped at .026), replaced plug wires and cam sensor about 6 months ago which was throwing up a fault code also (for this same problem) . None of this helped.

I have Sunoco 116 in the tank and am getting no knock. Oh yeah I forgot, if anyone wants to know how tough the 2g headbolts are, I can tell you pretty damn strong. My Profec-b got out of adjustment and on the first few times I hit the boost to try and see how it was running it was hitting up to 29-30psi and pulling hard when it wasn't miss firing. Damn if I could just figure this shit out. No, I don't plan on running 29-30psi on this stock 2g.

Let the games begin :headache:

are you running 20 psi daily driving on a stock 2g?

no, nornal is 14-15psi

Stock headbolts and your pushing 25+ PSI?? Ughh I dont think that the 2g bolts are much, if any, stronger than 1g bolts...

As for the problem I dont know sounds strange... Its not fuel cut?

Running DSMLink which removes the fuel cut.

http://www.dsmstyle.com/forum/index.php?showtopic=25

Not everyone knows what you have done to your car.

It definately sounds ignition related. Have you tried reseating the wires after the engine is hot? Sometimes they can pop off because of the air expanding if you put them on when it was cold. Do you have a fuel pressure guage? Maybe the fuel pressure is dropping as demand increases?

The 92.5+ bolts are weaker due to being a 1mm smaller.

Bad injectors? Are they black from fuel or oil?

Semi-blown headgasket? Might only be blown enough to cause problems at high boost, but that might just cause it to overheat a little and push coolant, but not misfire.

Are you I/C pipes free of oil? A little oil from a slightly blown turbo seal or accumulated in the intercooler can cause misfires under boost.

So 92.5+ which would b all 7 bolts are acutally weaker than 90-92.5? So would his headgasket have blown? CVD is probably gone... but he atleast has some other problems.. like overheating.. its still runs good though...

Vicous- How could you not even obey your own posted rule about mods and stuff? :lol:

Have you tried replacing the ignition control modual?

I figured everybody knew what was on my car from the Featured Members post. :uh:

I have replaced the ignition transistor module.

I was having this problem before my car hit 29-30psi.

It still drives fine, no loosing coolant, no miss-fires under light boost.

The 2 plugs are dark from fuel, probably from miss-firing.

Modifications so far:

Engine · HKS 272/272 intake/exhaust cams - Fidanza Timing Gears - Balance shafts removed - Fluidyne radiator - FAL Twinline fans - (NOTE: I'm still running the stock 2g intake manifold, cylinder head, shortblock, and throttle body)

Fuel/Ignition · DSMLink v2 ECU Datalogger/Tuner Package (If you are not running one of these, you should be!!!) - MAFTranslator w/GM 3.5 LS1 mas - Apex-i S-AFC (only for display of rpm & tps) · DynoTune Digital O2 Meter - 750cc FIC Ball/Disc injectors · Upgraded fuel pump - Fuel pump re-wire w/10 gauge wire · MSD 8.5 spiral core wires - NGK BPR7EIX (Iridium) Plugs gapped at a tight .028

Turbo · VPE GT3056 TO4E B/B Turbo · Tial 40mm External Wastegate - VPE S/S O2 Housing Routed for External-Internal Dump - DN Performance Tubular S/S Manifold · HRC Upper/Lower Intercooler pipes · Dejon Tools intake pipe - K&N air filter - GReddy Type-S BOV · GReddy EGT · Autometer Phantom Boost Gauge · GReddy Profec-B Boost Controller · GReddy Turbo Timer · BIG GReddy 24R FMIC (upper part of bumper opening cut out behind upper black strip for improved air flow to FMIC) · Catch Can breather element

Suspension/Handling · Eibach Pro-kit 1.5" springs which have been cut to lower the car a total of 2 inches · KYB AGX 4-way adjustable shocks · Ingalls adjustable camber kits at all four wheels - Front/Back strut tower bars · 18x8 Rays Engineering/Volk Racing AV3 wheels · Nitto NT555 225/40ZR18 tires · Metal Master brake pads

Clutch · Clutch Masters 2500lb w/Ceramic 4-puck Sprung Hub Disc (custom kit good for 600+ HP) · Clutch Masters Billet Aluminum Flywheel w/Steel Face

Exhaust - RSR 3" downpipe · HRC 3" hi-flow cat · Apex N-1 3" cat-back exhaust

Since I really don't know much about this tech stuff I'm going to ask this, is there any sort of relay (or something serving as a type of relay) somewhere on the fuel system that when you're demanding the amount of fuel to match 29-30 lbs of boost, something isn't right causing the relay to shut down a couple of cylinders? I'm probably talking 100% out of my ass but it was an idea....

The ecu will kill cylinders that miss-fire excessively.

The 29-30psi is not causing the problem. It does the same thing at 20psi.

Well it sounds like you have covered everything ignition related for sure. With it just happening in 2 cylinders, I would agree with shane on the possibilty of a head gasket or something similar. Maybe do a leak down test on all the cylinders and compare at high pressure levels to see if something is leaking under boost. Maybe the head bolts are stretching enough under pressure to allow a leak only after you are over 20 PSI.

I may have found the problem, looks like the ASS that worked on my transmission under warranty at Mitsu cross threaded the upper bellhousing bolt that the negative battery cable attaches to. It sticks out about 1/4 inch and the cable end just wiggles on it. I can't get it out or in to tighten. STUPID FUCKER at Mitsu.

Yeah, I'd guess ignition, and I'm guessing both black plugs are on adjoining cylinders for one of the two coils. A bad ground could cause that. Aren't you getting a CE code?

No codes

Are the fouled plugs 1 and 4 or 2 and 3?

I don't actually remember which cylinders they were from. I was trying to get to the track and just pulled them out quickly to re-install the BPR7ES plugs I had to see if that helped because alot of people want to say the BPR7EIX (Iridium) plugs don't work well. Didn't make a difference though.

The car will be back at Mitsu Monday morning. I told them I am not paying for their fuck up on that bolt and they better not scratch the fucking car again. Everytime it has been there something happens to it. If it wouldn't have been for the warranty, it wouldn't have been there in there first place.

It's not a big issue if it is the engine itself. I would just like to know for sure before the new engine arrives. I'd rather figure this problem out on the old motor vs. fighting it on the new engine if it is something else.

Did you get the problem solved yesterday Mike?