bubba4

I've been battling a problem for about a month that is getting worse and need some help. It started off as a wot intermittent pop,but the car runs great cruising around Changed plugs,o2's ,no change. Now it will pop like its on the limiter the first time I hit it , then run good the second time at wot with no pops. Today it popped and shut off (about two seconds) at wot and then came back to life like nothing happen and drove good back to the house. No SES,no current or history codes. I haven't made any changes to the car in a while. LF

camzaro28

Possibly fuel pump. Put a gauge on it to see.

bubba4

Possibly fuel pump. Put a gauge on it to see.

I added a walbro 255lph, back when I installed nos, it could be bad. I'll put my gauge on it,tape it to the hood, and give it a try Tomorrow. Thanks for the input. LF

Wild1

If it happens at higher RPMs then it could be the Coil Wire... run a resistance check on all your wires and see if any are abnormally high.

LearJet

try it without the MSD box hooked up once and see if it goes away. If you have another coil you could try it too.

bubba4

I wasn't able to test fuel pressure today due to the rain. When this problem started I replaced plugs (NGK TR55's) O2's and (also put on a new blaster 2 coil and checked the coil wire , less than 1 ohm),sorry I didn't mention that part in my first post,but haven't checked the rest of the wires. I'll pull the wires and check them out.Then tape fuel gauge to the windshield and make a pass, then bypass the msd for another pass. I'll post the results. Thanks for the help. LF

si

i got almost the same prob with a customers car. we put it on the dyno and it ran lean on high end 5800 and up. sent the tune back in (93 chiped) and had i retuned. same thing. its not spark knock. it is def. misfire.. car pops and bangs, back fires... I dosent do it on a regular basics. ive changed fuel pump, another brand new opti, coil, module, fuel filter again, checked fuel psi over and over again. nothing... hope you find some thing. the only thing i can think of is maybe the brand new injectors he has (from racetronix) might be bad?? hard to believe..

JAKEJR

You wrote is happens at WOT, but at what RPM is this happening? Happening in ALL gears?

Give us a detailed account of what you're doing before and when this occurs.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

bubba4

To describe it best. Half throttle pulls hard, 3/4 throttle might have one or two (misses) in 1-3 gear It doesn't backfire. 3000-5000 rpm. If I stop and go full throttle from a roll it had a few misses and usually clear up half way through second and not do it again (wot shift point 6200rpm). Then Thursday from a roll in first it sounded like it was on the limiter around 5000-5500rpm and cleared up I tried several more wot's and it pulled great with no misses. Saturday I warmed it up and tried it again from a roll in first and it sounded like it was on the limiter again and died (I had time to pat the gas a couple of times) then it came back to life like nothing happened. LF

bubba4

After pulling the wires to check resistance, I found the distributor cap electrodes for cylinders 3,4,&8 to be heavily corroded and deformed. So I pulled the opti and I'm installing my backup unit and my spare set of wires and will try it again to see if that was it. LF

MikeGyver

Whats your spark plug gap?

JAKEJR

Looks like you're getting somewhere. Congrats!

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 20 May 2010!!!

blown94

yeah i was going to say opti, surprised no one else has already. They cause a ton of different issues, and this is one. Ask me how I know. Mine was only at WOT and almost near the rev limiter, so it had me fooled as well. I thought it might be fuel as well at first. When I pulled my opti apart I found the bearing was a tad wobbly, and Im assuming it was causing the pickup eye to get false or no readings at 6k+ rpm. I swapped it out to an ebay unit that I put my msd cap and rotor on and haven't had a problem since.

bubba4

I just took it down the road. It runs great and pulls hard all the way to 6200rpm in every gear, several times, had to put it up. To many police making their rounds. I gapped the TR55's at .042 for motor and run Autolite AR3923's gapped at .032 for nitrous. This is the first time I've seen a dist. cap have that much corrosion, but , I've only had this car for three years and I'm sure it wont be last crazy thing I find on this car. Thanks for everyone's help. LF