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Discussion Starter #1
Well my S-trimmed 95 cobra misses like a motha now. The car had the heads off before dyno tune about 6 mos ago (still running the GT-40 irons with E-cam and 1.7s). I replaced the valve springs, seals etc, guides looked good. The car has been running like a raped ape, until last Sat., I bounced it of the 6k pill in the MSD and now it misses BAD. I figured I fouled a plug, so I drove home and its been sitting for a week. Today I pulled the plugs, they all looked good except #7, it was BLACK. I cleaned them put them back in, ran it for 2-3 minutes, and pulled them again, because it was missing still, #7 was BLACK again. So I replaced the plugs, cap, and rotor, still missing BAD. I'm pissed, tomarrow I'll put on better wires and see if that helps, but I think I holed a piston or busted rings. It didn't have the MSD6AL on it when I got it tuned, but A/F was 11.7-1, with 17* total timing. It put 389hp/403tq to the wheels @ 5k rpm and 10psi. Fuel and ignition are up to the task (42s no FMU,255 in tank, T-rex in line, adj [email protected], MSD6AL,blaster,FMS wires, and cold NGKs). I don't know what else to check, any suggestions would be great, as I'm not looking forward to tearing it down. Maybe time for the 331. Thanks Guys -Rob
 

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Hey bud, better do a compression test on the motor. Sounds like a valve problem to me. Good luck, Rick
 

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Probally bent a valve when you over revved. yank the head and take a quick peak.
 

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Formerly BLOWN1989SALEEN
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93TRANSAM said:
Probally bent a valve when you over revved. yank the head and take a quick peak.
i agree, try a compression test. does the plug smell like oil or gas?
 

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Yeah, I hate to be the bearer of bad news but you have a valve issue there. :(
Is the plug oily, or just carboned up?
If it's oily you may have bigger problems. I would start by pressure testing that cylinder. If it fails, pull the head off, your gonna have to either way. I hope it's just a valve dude.
Good luck.
 

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Discussion Starter #6
Thanks for the replies guys, I'll do a comp. test today and let you know what I find. I hope its just a valve too. The plug isn't oily, just really carboned up.
 

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Discussion Starter #8
Compression test showed a whopping 0 psi in #7. I'll be tearing it down this week to inspect the carnage, I'll keep you guys posted. I think its time for the 331.
 

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sounds exactly like what happened to me when I bent a valve. Hate to tell ya the truth, but sometimes the truth hurts. :(
 

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you could just replace the valve and put it back together man. I broke a timing chain and bent 8 valve not to long ago. Had a few "kisses" on the pistons but nothing major.

Troy
 

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347 sc said:
When you did the test did you take out all the plugs and hold the throttle open while cranking?
even if he DIDNT he would get more than 0psi:D with a reading of zero it is irrelavant
 

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Discussion Starter #13
I removed the plug for #7, held the throttle to the floor (so the injecters wouldn't fire), and cranked it, 0 psi. Then I did #6, for the hell of it, and it was like 180 psi. I'll do all of them eventually, its just too damn hot to work on it now.
 
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