kanusky1990
10+ Year Contributor
- 95
- 8
- Sep 14, 2011
-
Easton,
Pennsylvania
Hey guys,
I am trying to diagnose and repair a misfire that I recently started having.
I’m going to start by giving some background, and list the things I’ve done so far.
I was cruising around one night and my car started missing. My wideband was reading “- -“ meaning lean. My car sounded like a Subaru, with no power. The misfire was consistent once it started, but would go away one I completely let off the gas and it returned to idle.
Onto my diagnosis. It would only start missing if RPMs stayed above roughly 3,500 for more than ~5 seconds. Load did not matter, I can induce the misfire at idle (no load) or while driving (load).
I was confused to why a misfire would cause my wideband to read LEAN. So I used a screw driver to listen to each injector at idle. You can hear each one “clicking” as it opens and closes.
I induced the misfire under idle and listened to the injectors again, and my #4 injector was no longer clicking. I figured the injector must be bad, but it was weird to me that it would work at idle, and below 3500 RPM, but I said whatever and switched in my old stock 450cc injectors. Obviously reflashed my ECU for the 450’s.
The problem went away. I drove with them for a couple days and I cleaned my FIC 1050cc’s (I made a ghetto tool to do this, and I wouldn’t say they were cleaned 100%). I was running out of injector with my EVO 16g so I figured I’d try my freshly “cleaned” 1050cc injectors again. (flashed again for 1050’s) Drove around for a few days with them in the car putting on about 200+ miles mostly highway, with a good number of pulls. No issues.
Now last night, the same misfire happens again. I check the injectors, same #4 isn’t clicking. Changed PTU / ignition module with a used one that I was told came off a working car, replaced it and still had same issue but, so I switched back to my original PTU.
I pull my fuel rail and switch #3 and #4 injectors to see if it’s the wiring or the injector. I induce the misfire, check the injectors… and now #2 isn’t clicking! I’m completely confused and figure it must be wiring. I manipulate all the wires, and try again and then #1 does it…
TLDR;
Only one injector stops working at a time.
Only happens above 3,500 RPM, but doesn't start working again until it returns to idle
Drove the same amount of time on both 450cc’s and 1050cc’s only have the issue with 1050cc’s.
Besides wiring, what else could be failing? Maybe I have a bad ROM flashed? The 3,500 RPM is well below my antilag / launch control.
I plan on switching in the 450cc again to see if it will happen with those, given more time.
Any help will be greatly appreciated. Thanks.
I am trying to diagnose and repair a misfire that I recently started having.
I’m going to start by giving some background, and list the things I’ve done so far.
I was cruising around one night and my car started missing. My wideband was reading “- -“ meaning lean. My car sounded like a Subaru, with no power. The misfire was consistent once it started, but would go away one I completely let off the gas and it returned to idle.
Onto my diagnosis. It would only start missing if RPMs stayed above roughly 3,500 for more than ~5 seconds. Load did not matter, I can induce the misfire at idle (no load) or while driving (load).
I was confused to why a misfire would cause my wideband to read LEAN. So I used a screw driver to listen to each injector at idle. You can hear each one “clicking” as it opens and closes.
I induced the misfire under idle and listened to the injectors again, and my #4 injector was no longer clicking. I figured the injector must be bad, but it was weird to me that it would work at idle, and below 3500 RPM, but I said whatever and switched in my old stock 450cc injectors. Obviously reflashed my ECU for the 450’s.
The problem went away. I drove with them for a couple days and I cleaned my FIC 1050cc’s (I made a ghetto tool to do this, and I wouldn’t say they were cleaned 100%). I was running out of injector with my EVO 16g so I figured I’d try my freshly “cleaned” 1050cc injectors again. (flashed again for 1050’s) Drove around for a few days with them in the car putting on about 200+ miles mostly highway, with a good number of pulls. No issues.
Now last night, the same misfire happens again. I check the injectors, same #4 isn’t clicking. Changed PTU / ignition module with a used one that I was told came off a working car, replaced it and still had same issue but, so I switched back to my original PTU.
I pull my fuel rail and switch #3 and #4 injectors to see if it’s the wiring or the injector. I induce the misfire, check the injectors… and now #2 isn’t clicking! I’m completely confused and figure it must be wiring. I manipulate all the wires, and try again and then #1 does it…
TLDR;
Only one injector stops working at a time.
Only happens above 3,500 RPM, but doesn't start working again until it returns to idle
Drove the same amount of time on both 450cc’s and 1050cc’s only have the issue with 1050cc’s.
Besides wiring, what else could be failing? Maybe I have a bad ROM flashed? The 3,500 RPM is well below my antilag / launch control.
I plan on switching in the 450cc again to see if it will happen with those, given more time.
Any help will be greatly appreciated. Thanks.
