Cylinder misfire problems
#11
RE: Cylinder misfire problems
jane i actually got a p0304 which is for #4 not firing. What is weird is that it threw the code originally. I changed the plugs and wires first. Reset the computer. It threw the code again. Changed more stuff, reset the computer. Now the problem still exists but there is no code being thrown. Ohh the mysteries of the lovely new-age computer controlled systems. Everything needs to go back to computer-less andcarbs haha
#14
RE: Cylinder misfire problems
Instead of throwing parts at the problem, you need to go back to basic trouble shooting. There are three reasons for misfire: ignition, fuel delivery, and poor compression.
Ignition problems are usually due to bad plugs (including gap), bad wires, bad ignition coils, bad ignition control module, or a bad timing sensors. Tools include a scanner, a multimeter,ignition scope, coil tester, ignition module tester, and a good set of wiring diagrams.
Fuel delivery problems are usually due to a bad fuel pump, bad pump wiring, bad fuel pump relay,bad pressure regulator, injector not being fired (usually bad wiring), injector clogged, injector solenoid bad, injector stuck open or closed. Tools include FI. pressure gage, multimeter, NOID lights, injector flow tester, and a good set of wiring diagrams.
Bad compression (lower than FSM specs) usually due to bad valves, bad head gasket, worn out cam lobe, damaged parts in valve train, worn or broken rings, broken piston. Tools include a compression gage, and trained eyes and ears.
All of this assumes you know how to read and understand the FSM and have a good understanding of how stuff works. At least, this is what you expect to get when you go to a repair shop and put down a chunk of cash.
Ignition problems are usually due to bad plugs (including gap), bad wires, bad ignition coils, bad ignition control module, or a bad timing sensors. Tools include a scanner, a multimeter,ignition scope, coil tester, ignition module tester, and a good set of wiring diagrams.
Fuel delivery problems are usually due to a bad fuel pump, bad pump wiring, bad fuel pump relay,bad pressure regulator, injector not being fired (usually bad wiring), injector clogged, injector solenoid bad, injector stuck open or closed. Tools include FI. pressure gage, multimeter, NOID lights, injector flow tester, and a good set of wiring diagrams.
Bad compression (lower than FSM specs) usually due to bad valves, bad head gasket, worn out cam lobe, damaged parts in valve train, worn or broken rings, broken piston. Tools include a compression gage, and trained eyes and ears.
All of this assumes you know how to read and understand the FSM and have a good understanding of how stuff works. At least, this is what you expect to get when you go to a repair shop and put down a chunk of cash.
#16
RE: Cylinder misfire problems
if youve tryed plugs ,wires, coils, injectors, re gaping, icm,other parts of the feul system...... its time to take it to the shop for a compression said.... as the mighty pete saidlost compression is the thrid possible variable unfortunatly its also the most expensive
#17
RE: Cylinder misfire problems
Well mine is finally fixed. Still not sure the problem or the solution. I want to say it was a plugged injector.
After throwing new parts at it, the car was still misfiring. So last weekend I threw a gage at the hole. Did a compression and leak-down test and they were both in the acceptable range. Also, that was no easy task for #4 hole.
Let the car sit around all week. Went to go **** around with it more this past weekend and all of a sudden it runs fine. So all I can think is that the new injector took some time to get primed to start working right. I am not sure if thats even a possibility but thats my story and I am sticking to it.
After throwing new parts at it, the car was still misfiring. So last weekend I threw a gage at the hole. Did a compression and leak-down test and they were both in the acceptable range. Also, that was no easy task for #4 hole.
Let the car sit around all week. Went to go **** around with it more this past weekend and all of a sudden it runs fine. So all I can think is that the new injector took some time to get primed to start working right. I am not sure if thats even a possibility but thats my story and I am sticking to it.
#18
RE: Cylinder misfire problems
well after changing the cam and crank position sensor, nothing. Did learn procedure. A more advanced scan tool was utilited (Snap on vice Mac) which showed a more specific problem. #2 and #5 missing, well #2 and #5 share the same coil pack, changed it out and WALLA FIXED! I want to thank you all for your input...[sm=smiley20.gif]
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