Random Misfire after power shift....ODD
Random Misfire after power shift....ODD Here is the deal, my c5 out of the blue just started misfiring after a powershift. If I powershift 2 to 3 and sometimes 3 to 4. I have datalogged the misfires. They are random, and randomly when it misses it will be one cylinder that misses 40 plus times. then the next time it will be another cylinder. Here are the things that I have done so far...car is a 01 c5 all bolt ons and a tune.
1. plugs
2. wires
3. checked tune
4. pulled valve covers. mechanical components good.
5.checked grounds
I have noticed that it doesnt really pickup any major misfires at idle. it will be like 1 or 2 sometimes 4 misfires at idle on random cylinders. and you can tell its missing a tad at idle.
1. plugs
2. wires
3. checked tune
4. pulled valve covers. mechanical components good.
5.checked grounds
I have noticed that it doesnt really pickup any major misfires at idle. it will be like 1 or 2 sometimes 4 misfires at idle on random cylinders. and you can tell its missing a tad at idle.
TECH Fanatic
Joined: Sep 2007
Posts: 1,244
Likes: 7
From: hattiesburg, Ms
Sounds like the same problem i am having. Cuts out a little bit right after power shifting, then clears up right? Not sure what mine is but it started after i put a external fuel pump in and made it a return style system.
yes. exactly. I have been thinking it might be a fuel issue. Im thinking its being caused by the high rpm pull sucking the fuel almost dry and then on the powershift theres not enough fuel after the shift. Did it appear out of no where and the only thing you done was do the fuel system mod?
TECH Fanatic
Joined: Sep 2007
Posts: 1,244
Likes: 7
From: hattiesburg, Ms
yes. exactly. I have been thinking it might be a fuel issue. Im thinking its being caused by the high rpm pull sucking the fuel almost dry and then on the powershift theres not enough fuel after the shift. Did it appear out of no where and the only thing you done was do the fuel system mod?
It did not do this before the cage and fuel system. Its amazing tho, i can run it from idle to redline and it wont show any sign of it. Only after the shift.
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Changed fuel filter, still missing. This is getting to be super frustrating. one new thing happened, I was test driving it and I missed third and bounced the rev limiter momentarily and the car just shut off...
Im starting to get pissed, and I really dont want to take it to the gm garage, cause 90% if the time I know more than their tech does.
Im starting to get pissed, and I really dont want to take it to the gm garage, cause 90% if the time I know more than their tech does.
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TECH Fanatic
Joined: Sep 2007
Posts: 1,244
Likes: 7
From: hattiesburg, Ms
Changed fuel filter, still missing. This is getting to be super frustrating. one new thing happened, I was test driving it and I missed third and bounced the rev limiter momentarily and the car just shut off...
Im starting to get pissed, and I really dont want to take it to the gm garage, cause 90% if the time I know more than their tech does.
Im starting to get pissed, and I really dont want to take it to the gm garage, cause 90% if the time I know more than their tech does.
I am gonna check the cam poisition sensor and crank sensor and reluctor wheel. Whatever is on the car and decent to get to.
TECH Fanatic
Joined: Sep 2007
Posts: 1,244
Likes: 7
From: hattiesburg, Ms
Here is the deal, my c5 out of the blue just started misfiring after a powershift. If I powershift 2 to 3 and sometimes 3 to 4. I have datalogged the misfires. They are random, and randomly when it misses it will be one cylinder that misses 40 plus times. then the next time it will be another cylinder. Here are the things that I have done so far...car is a 01 c5 all bolt ons and a tune.
1. plugs
2. wires
3. checked tune
4. pulled valve covers. mechanical components good.
5.checked grounds
I have noticed that it doesnt really pickup any major misfires at idle. it will be like 1 or 2 sometimes 4 misfires at idle on random cylinders. and you can tell its missing a tad at idle.
1. plugs
2. wires
3. checked tune
4. pulled valve covers. mechanical components good.
5.checked grounds
I have noticed that it doesnt really pickup any major misfires at idle. it will be like 1 or 2 sometimes 4 misfires at idle on random cylinders. and you can tell its missing a tad at idle.
Broken reluctor wheel......
Crank Shaft Position sensor on its way out.......
Maybe the Cam Shaft position sensor too.......
I built a config file for checking all of the sensors. Im going to data log it to see if any sensors are acting funky.
Do you data log your stuff, i do with mine on hp tuners. I know it helps me some just to see what is going on with everything at that certain time. I do have a problem with my engine temp sensor connector not wanting to stay on. When it comes loose while data loggin it shows -31 degrees and cuts the car off. The damn thing started this right after it came off and i thought i got it back on good enough. Maybe i didn't. I gotta get me a new one. Hell that could be my problem but it does not show up like that on the data log when the misfire happens.
I am gonna check the cam poisition sensor and crank sensor and reluctor wheel. Whatever is on the car and decent to get to.
I am gonna check the cam poisition sensor and crank sensor and reluctor wheel. Whatever is on the car and decent to get to.
I will check this and post back.
TECH Fanatic
Joined: Sep 2007
Posts: 1,244
Likes: 7
From: hattiesburg, Ms
yeah, my pedal just dropped to the floor and stayed. If I tried to pull it up it would suck it right back down. I was just cruising and went to shift gears and as soon as I hit about halfway on the pedal it just dropped. Couldnt put it in gear or anything, just stuck in neutral. Funny thing is, there were tons of people asking to help just so they could stop and look at a vette. lmao.
I have been trying to datalog, but the weather isnt permitting. when the rain finally clears up, ill get a good datalog in and hopefully see whats going on.
Have you had any luck finding out whats going on?
Have you had any luck finding out whats going on?
TECH Fanatic
Joined: Sep 2007
Posts: 1,244
Likes: 7
From: hattiesburg, Ms
Na i had my clutch disc come apart at the lsx shootout so its been down a bit. I got the new assembly yesterday and probably gonna be putting it in tommorrow. Then i gotta break it in so it will be a week or two before i will be able to test anything. Hopefully i can figure it out quickly!!!