misfire issue- greddy tt, haltech,rc750cc,RFS
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ok. i'll test that with a multimeter tonight or tomorrow. so if by tapping the supply and ground of the last coil (drivers side closest to firewall) then i can rule out the power supply being a problem correct?
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I would think you'd need a fast data logger or an oscilloscope to catch intermittent signal fade, interference, etc. But the multimeter might work if there is a grossly evident problem... Just testing continuity between positive and negative leads for all your coilpacks and cam solenoids might be a good starting point if you have only a multimeter.
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ok. i really dont think thats the issue but i am not ruling it out as a possibility. i will be checking it this weekend. i would assume that since i have had the cam sensor code ever since i put helltech on my car, it would have given me the problem long ago if that were the case.
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i had some time to plug in my lap top today. rcdash was right, there is a copythrough selection in the main table setup. mine was currently enabled. i disabled it, took it for a spin and it was still flashing the cel. but, i didnt clear the codes yet. waiting for my friend to bring over a code reader. thats as far as i got today. i'll toggle with it some more later.
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update:
ok so this weekend i swapped valve covers since i saw a tiny bit of oil int eh spark plug tubes and had an extra valve cover on hand already. i scanned my ecu for codes again and got a p0301. finally, something more specific than p0300 random misfire code. so now that i know its cyl 1, i can narrow down the search a bit. i pulled the coils and plugs. cyl 1's plug looked a little more lean than cyl 3 and 5. and i checked the continuity of the wiring for the coils, no problems found. i unclipped all the injectors and checked them to make sure they were clipped snug. then upon reassembly i swapped the coils around to see if the misfire would move to a different cyl. it did not. still cyl 1 missfire. so, i believe i have ruled out the ignition being a source of the problem. and it being just cyl 1 mis means it cant be a cam sensor or crank angle sensor. i believe that would cause the misfire to be in multiple cyl's. must be fuel injector related im thinking. i have my wideband on bank two and no wideband on bank 1. so im thinking i'll place it on the other side and see what kind of a/f im getting. i do have a set of stock injectors still. i suppose i could try those out. id say i'd just toss the stock injectors back in and connect back to the stock ecu but i dont know how that would run with a fuel return system. one thing i havent tried yet and maybe should is connecting my haltech to a stock g35 so i can surely rule it out of the question. but i really dont think thats the problem. any one else thinking of something i should try that i may be missing?
ok so this weekend i swapped valve covers since i saw a tiny bit of oil int eh spark plug tubes and had an extra valve cover on hand already. i scanned my ecu for codes again and got a p0301. finally, something more specific than p0300 random misfire code. so now that i know its cyl 1, i can narrow down the search a bit. i pulled the coils and plugs. cyl 1's plug looked a little more lean than cyl 3 and 5. and i checked the continuity of the wiring for the coils, no problems found. i unclipped all the injectors and checked them to make sure they were clipped snug. then upon reassembly i swapped the coils around to see if the misfire would move to a different cyl. it did not. still cyl 1 missfire. so, i believe i have ruled out the ignition being a source of the problem. and it being just cyl 1 mis means it cant be a cam sensor or crank angle sensor. i believe that would cause the misfire to be in multiple cyl's. must be fuel injector related im thinking. i have my wideband on bank two and no wideband on bank 1. so im thinking i'll place it on the other side and see what kind of a/f im getting. i do have a set of stock injectors still. i suppose i could try those out. id say i'd just toss the stock injectors back in and connect back to the stock ecu but i dont know how that would run with a fuel return system. one thing i havent tried yet and maybe should is connecting my haltech to a stock g35 so i can surely rule it out of the question. but i really dont think thats the problem. any one else thinking of something i should try that i may be missing?
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i didnt. this happened out of nowhere. what do you mean by re-time? are you talking about changing the ignition timing map? because i did make tiny adjustments to my ignition timing map. but just above 8 psi. i put in a safety timing retard just in case i jump over 8.5 psi it'll retard timing. but as far as changing the timing down low, i didnt touch anything. was running perfectly, then this outta nowhere.
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that was my initial thought. i have not done a compression test yet. i would think if it were a weak cylinder, that it would be consistant at least. sometimes it does it, sometimes it doesnt.
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the engine sounds solid. no slapping, clanging, anything whatsoever. oil is clean as well. i guess the next steps will be to try haltech on a stock g/z. and then try out some different injectors. i wonder if i can put my stock injectors back in and run it with the stock ecu. problem is, i have a return system. i dont know how that'll work. if i pulled the vaccum line on the fuel pressure regulator, would that make it a static fuel pressure like a stock returnless system?
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update:
i tried my haltech on a friends 350z. runs perfectly with the stock base map. - thats out of the question now.
i checked my compression. here are the results.
cyl 1 - 186
cyl 2 - 181
cyl 3 - 185
cyl 4 - 181
cyl 5 - 185
cyl 6 - 178
its safe to say its not just losing compression in one cylinder now. thats out of the question.
i looked at my plugs and cyl 1 looked very rich. so i swapped the injectors from cyl 1 to cyl 3. so if its my injector, i should get a misfire code of cyl 3 misfire. and not cyl 1 anymore. if it still says cyl 1, then i have no idea what else to check. i'll be getting a code scanner tomorrow and checking it. and yes, upon start up of the car after swapping injectors, still a misfire. its just a matter of the code being thrown again.
i tried my haltech on a friends 350z. runs perfectly with the stock base map. - thats out of the question now.
i checked my compression. here are the results.
cyl 1 - 186
cyl 2 - 181
cyl 3 - 185
cyl 4 - 181
cyl 5 - 185
cyl 6 - 178
its safe to say its not just losing compression in one cylinder now. thats out of the question.
i looked at my plugs and cyl 1 looked very rich. so i swapped the injectors from cyl 1 to cyl 3. so if its my injector, i should get a misfire code of cyl 3 misfire. and not cyl 1 anymore. if it still says cyl 1, then i have no idea what else to check. i'll be getting a code scanner tomorrow and checking it. and yes, upon start up of the car after swapping injectors, still a misfire. its just a matter of the code being thrown again.
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I thought about putting the stock injectors in but then figured if I swap my current ones around and its still not the issue, then I don't have to pull the intake manifold completely off again at least.
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update;
today i got a code reader from a friend. i had driven around a little bit with swapping the injectors from cyl 1 to cyl 3. before the swap, i was getting cyl 1 misfire. so i plugged the code reader into the port, wouldnt pick up anything. wtf?! i had a cel on, but it wouldnt read it. very frustrating. so i couldnt tell for sure if swapping the injectors from cyl 1 to cyl3 was the problem. so i decide to go through my wiring by my harness because i remembered that when i put my zeitronics wide band in, i spliced pin 62 the ignition coil port 1. everything checked out fine. but i noticed that the injector wire for cyl 1 had been badly beaten up and barely still connected. i cut and rewired a solid piece in the harness. thinking this would fix it, i turned on the car just shortly after. still the same misfire. dang. so i drove for a tiny bit more waiting for the cel to stay solid so i could run it for codes. nothing. i pulled the plugs to see what they looked like.........
cyl 1 was originally very rich. indicative of a stuck injector or weak coil. so this time i swapped cyl 1 injector with cyl 3 injector. so after the swap and some driving... now cyl 1 plug looks perfect and cyl 3 plug looks very rich. so my conclusion: i must have a messed up injector. they are dw 600's. thinking about going bigger for my built motor anyways (sometime down the road). so im 99% sure its an injector problem. only reason there is a skeptical 1% is because i simply have not tried another set of injectors to prove it. but, all things point to injector failure.
today i got a code reader from a friend. i had driven around a little bit with swapping the injectors from cyl 1 to cyl 3. before the swap, i was getting cyl 1 misfire. so i plugged the code reader into the port, wouldnt pick up anything. wtf?! i had a cel on, but it wouldnt read it. very frustrating. so i couldnt tell for sure if swapping the injectors from cyl 1 to cyl3 was the problem. so i decide to go through my wiring by my harness because i remembered that when i put my zeitronics wide band in, i spliced pin 62 the ignition coil port 1. everything checked out fine. but i noticed that the injector wire for cyl 1 had been badly beaten up and barely still connected. i cut and rewired a solid piece in the harness. thinking this would fix it, i turned on the car just shortly after. still the same misfire. dang. so i drove for a tiny bit more waiting for the cel to stay solid so i could run it for codes. nothing. i pulled the plugs to see what they looked like.........
cyl 1 was originally very rich. indicative of a stuck injector or weak coil. so this time i swapped cyl 1 injector with cyl 3 injector. so after the swap and some driving... now cyl 1 plug looks perfect and cyl 3 plug looks very rich. so my conclusion: i must have a messed up injector. they are dw 600's. thinking about going bigger for my built motor anyways (sometime down the road). so im 99% sure its an injector problem. only reason there is a skeptical 1% is because i simply have not tried another set of injectors to prove it. but, all things point to injector failure.
Last edited by deanfootlong; 04-06-2011 at 07:35 PM.