What Is Causing My P0307 Misfire?!?!?!?
#1
12 Second Club
Thread Starter
iTrader: (77)
Join Date: Sep 2005
Location: BCS/DFW TX
Posts: 1,744
Likes: 0
Received 0 Likes
on
0 Posts
What Is Causing My P0307 Misfire?!?!?!?
I was going down the highway passing cars in 4th at 6,000 rpm and all of a sudden inbetween changes I would get big puffs of smoke come out the back like i blew up when i would go back into 6th. SES lights up for a while then a few minutes later starts to blink. I run the OBDII Scanner and pulls up P0307 #7 cylinder misfire.
1) I replaced the plug. Old plug looked good, only had about 3-5 months of life. cleared the codes and ran engine, still sloppy and puts out P0307 again.
2) Swapped entire coil pack rail with ls1powerhouse's rail. Inspected old pack and looked good. cleared the codes and ran engine, still sloppy and puts out P0307 again.
3) Swapped coil pack #7 pack on my rail with the first one. cleared the codes and ran engine. P0307 DAMN!!!
WHAT CAN I DO NOW??? Seriously people, I need help.
My car is running really sloppy and is smoking like crazy.
How do I run a fuel ingector test on #7?
Do ya'll think it's my valve spring seals? I've put about 16-17K miles since i got the car last FEB.
How can I tell if my seals are bad if I take the valve cover off?
Jerry
1) I replaced the plug. Old plug looked good, only had about 3-5 months of life. cleared the codes and ran engine, still sloppy and puts out P0307 again.
2) Swapped entire coil pack rail with ls1powerhouse's rail. Inspected old pack and looked good. cleared the codes and ran engine, still sloppy and puts out P0307 again.
3) Swapped coil pack #7 pack on my rail with the first one. cleared the codes and ran engine. P0307 DAMN!!!
WHAT CAN I DO NOW??? Seriously people, I need help.
My car is running really sloppy and is smoking like crazy.
How do I run a fuel ingector test on #7?
Do ya'll think it's my valve spring seals? I've put about 16-17K miles since i got the car last FEB.
How can I tell if my seals are bad if I take the valve cover off?
Jerry
#2
TECH Regular
iTrader: (2)
Join Date: Feb 2006
Location: NC
Posts: 427
Likes: 0
Received 0 Likes
on
0 Posts
What color is the smoke coming out??? I'm assuming its black smoke from excessive fuel being burned...my guess would be the injector is either hung open..or is damaged in some way that its allowing fuel to leak..If you still have cats i would not drive it until your pretty much sure you have it fixed...A blinking SES light indicates a catalyst damaging misfire..If you keep driving it, odds are you'll be replacing your cats to.
#4
try swapping the wire with one of the other cylinders and clear the code, see if it changes cylinders(i.e.p0301). If there is no change then more than likely its the injector. Pull the #7 plug after running it for a little bit (let the heads cool off though) and see/smell if its fuel soaked.
#5
you can also try tapping on the injector with the car running and listen to the idle and see if it clears up. If so, the injector was stuck open and it will probably happen again. You can measure the resistance across the injector even though gm stopped giving specs but I think it should be between like 5-14 ohms, but they can still be bad even if its within specs.
Trending Topics
#8
Closed ex-Sponsor Account
iTrader: (5)
Join Date: Nov 2006
Location: Tulsa, OK
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
You should do a hot compression check, a running compression check, and check your injector pulse, unplug and use a test light or noid light if your have one to check the pulse. (10 bucks @ harbor frieght tools) Next Ohm it out. Then if all checks out above, your injector could be clogged and not spraying well. They are easy to remove.
#14
Launching!
iTrader: (14)
Join Date: Nov 2006
Location: san jose ca
Posts: 217
Likes: 0
Received 0 Likes
on
0 Posts
i dont think a bad injector would casue smoke to come out the tail pipe. it would just cause stumbling and poor performance. the fact that it blew while high reving is a sign.
when oil gets into the cylinder, its usually from bad valves, rings. and the fact that its #7 cylinder makes me think of the 3
#7 ringland problem. esp it the injectors were clogged up to begin with
when oil gets into the cylinder, its usually from bad valves, rings. and the fact that its #7 cylinder makes me think of the 3
#7 ringland problem. esp it the injectors were clogged up to begin with
#15
TECH Apprentice
iTrader: (1)
Join Date: Mar 2006
Location: Burton, MI
Posts: 336
Likes: 0
Received 0 Likes
on
0 Posts
im having a simular problem, i swapped everything and the problem stayed wtih the same cyl. some body asked if i had a ticking noise and i do and they think it maybe coudl be a bent valve or bent pushrod
#19
12 Second Club
Thread Starter
iTrader: (77)
Join Date: Sep 2005
Location: BCS/DFW TX
Posts: 1,744
Likes: 0
Received 0 Likes
on
0 Posts
IT'S DONE. APPARENTLY I mistaked #7 with #8. I did a compression test on #8 thinking it was #7 then I saw the injectors were numbered (DAMN !!!!) Which by the way it was hard as hell getting that tool hooked up properly. After the compression test we (my friend Grant) found the problem. I took the plug out and it was GUNKED, It was full of oil and carbon deposits. #8 was inbetween 160 and 180 psi. #7 didn't even brake 30 psi... I'll be taking the engine out next saturday, new piston and rings. Well since the engine will be out.... forged/spray or heads and cam?
Really, thanks to all that put their $.02 and info.
Jerry
Really, thanks to all that put their $.02 and info.
Jerry
#20
TECH Addict
iTrader: (22)
#8 cylinder is not fun for doing any kind of work to!!
Sorry that this is such an in-depth problem for you. Whenever I read this posts I always hope it's just a plug or an injector or worst case, a pushrod. Personally I would go with heads/cam but it depends on what you want to do with the car.
Sorry that this is such an in-depth problem for you. Whenever I read this posts I always hope it's just a plug or an injector or worst case, a pushrod. Personally I would go with heads/cam but it depends on what you want to do with the car.