Need some input on misfire
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From: Padded cell
Need some input on misfire 'Bout ready to set fire to my junk guys. H/C car. Flashing SES. BS Actron won't pick up the code. It did throw a crank position sensor malfunction(don't remember the PO#). Dealer Tech II showed a BUNCH of misfires on all eight holes. Did a new crank sensor and re-learn along w/new 02's. Misfire count went WAY down afterwards, and ran great for a few days.
Now it's throwing the flashing ***** me light again.
Test light shows I've got fire at the coil side and the plug side of all eight wires. Rail shows bookoo fuel. I did do a coil pack re-location, but this prob was present before I did the re-lo, which was part of the logic in the CP relocation. New plugs, new wires, all plugs at coil packs tight, main plug at harness tight.
Don't have any diagnostic software other than my POS code scanner.
Gotta be something simple I'm not catching, but have triple checked everything. This has been kickin' my *** for a few weeks now....
Only thing I can think at this point would be an injector(s) not hitting. Just pulled the valve covers and checked for a popped valve spring.... all good.... that would've been too easy
Any thoughts/advice are welcome....
Now it's throwing the flashing ***** me light again.
Test light shows I've got fire at the coil side and the plug side of all eight wires. Rail shows bookoo fuel. I did do a coil pack re-location, but this prob was present before I did the re-lo, which was part of the logic in the CP relocation. New plugs, new wires, all plugs at coil packs tight, main plug at harness tight.
Don't have any diagnostic software other than my POS code scanner.
Gotta be something simple I'm not catching, but have triple checked everything. This has been kickin' my *** for a few weeks now....
Only thing I can think at this point would be an injector(s) not hitting. Just pulled the valve covers and checked for a popped valve spring.... all good.... that would've been too easy
Any thoughts/advice are welcome....
Last edited by SLowETz; Dec 31, 2005 at 07:36 PM.
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From: Padded cell
This motor has been in various combo's of H/C all it's life. Never had this prob other than the occasional PO300 w/the first T1 cam before the first edit tune back in '01. Only time it's thrown a flashing light is when I've bent the stock(at that time)push rods or popped one of the old 918's.
The car ran fine before the last track visit. Dropped the exhaust/ added 5 gals. of 101 to help w/the spray and after the first motor pass she started acting goofy.... stalling after the burnout.... not holding idle at the line.
When I changed the plugs afterwards they did look washed. Motor feels good at WOT but is acting brain dead at idle(which is when I get the flashing SES).... rough idle/hunting like a bitch..... same "feel" as if it popped a spring, but again, springs are in tact, feels good at partial/WOT, and isn't making any noise.
I appreciate the replies...... keep the ideas coming guys.....
The car ran fine before the last track visit. Dropped the exhaust/ added 5 gals. of 101 to help w/the spray and after the first motor pass she started acting goofy.... stalling after the burnout.... not holding idle at the line.
When I changed the plugs afterwards they did look washed. Motor feels good at WOT but is acting brain dead at idle(which is when I get the flashing SES).... rough idle/hunting like a bitch..... same "feel" as if it popped a spring, but again, springs are in tact, feels good at partial/WOT, and isn't making any noise.
I appreciate the replies...... keep the ideas coming guys.....
Thread Starter
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From: Padded cell
Yep..... changed them out when I did the CP relocation. Going out now.... R/R all of them, re-check the plug wire terminals(redundent but foolishly optomistic), start the car w/out the valve covers and have a look at the springs while in motion.
Air + fuel + fire = cylinder goes boom. Got the first three.... just need the boom part
Air + fuel + fire = cylinder goes boom. Got the first three.... just need the boom part
Originally Posted by SLowETz
The car ran fine before the last track visit. Dropped the exhaust/ added 5 gals. of 101 to help w/the spray and after the first motor pass she started acting goofy.... stalling after the burnout.... not holding idle at the line.
Running too much octane will definately cause some problems.
I would drain the fuel and put in some 87 to get it running right again. I'd also power cycle the PCM to clear the fuel trims.
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