Evo 8 Missing/Stuttering while Cruising (Log attached)
1 Attachment(s)
Been fighting this stutter/misfire issue for a while now. Finally got around to getting the computer logging so I could try to get some answers. During cruising, seemingly at any rpm/speed, the car will randomly jerk/cut out/stutter/misfire whatever you want to call it. I am not logging my wideband but it goes full lean when this occurs. Sometimes it is a quick blip, other times it lingers for a second and then the car will go back to normal. It has never happened during WOT although at times wot doesn't feel smooth.
List of what I've tried: New plugs New Coils Different ECU Omni Map Sensor installed Injector Resistor pack cleaning the injectors new fuel filter new fuel pump new fuel pump housing new MAF Cam angle sensor Crank position sensor Swapped to Evo 9 BOV Stock intake pipe and an extremepsi intake pipe (both w/K&N) Switch to Speed Density (see log from first cruise still stuttering) Background on the car, took it as a blown engine/jumped timing. Rebuilt the head, replaced the block, and put everything together. It ran 50-100 miles from there until this started. It has had several times where I'll replace a part and it'll go 50-100 miles before stuttering again. Other times, it's undriveable as I can't even go a block without it stuttering over and over. It has thrown a PO120 code a few times (TPS) but it checks out with a multimeter. What I see in the log is O2feedbacktrim will often 0 proceeding the injectorduty from going to 0 as well. As best I can tell these are those hiccup/stuttering points while driving. The front O2 will 0 out when the injectordutycycle and injectorpulsewidth 0 out. Maybe a dying front O2? I'm really at a loss and starting to wonder if there is a short in a wire somewhere, truly starting to think about cutting my losses. |
Have you tried disabling closed loop?
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Originally Posted by Project_Broke
(Post 11831331)
Have you tried disabling closed loop?
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Keep us posted. When I had a similar issue with was my Exhaust cam position sensor. However, I see you've replaced that already.
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Are all 4 Cylinders cutting out? or is it a miss on 1 cylinder?
I recently had a similar issue, after about 15-20 minutes of cruising, the car would start cutting out really bad (all 4 cylinders). This would not go away until the car cooled off. The culprit ended up being an OMNI 4 Bar sensor |
Originally Posted by LTEDDER
(Post 11832468)
Are all 4 Cylinders cutting out? or is it a miss on 1 cylinder?
I recently had a similar issue, after about 15-20 minutes of cruising, the car would start cutting out really bad (all 4 cylinders). This would not go away until the car cooled off. The culprit ended up being an OMNI 4 Bar sensor |
Well, I'm lot 100% sure as I had checked it a few months ago. But, the TPS was way out of adjustment. Drove almost 100 miles without it happening now. I'll update if it comes back, but for now I'm hoping that was it.
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As a follow-up / conclusion to this for anyone searching in the future. Adjusting the TPS seemed to make the problem go away, but it returned, albeit with much less severity, after about 200 miles of driving. I made it to the shootout this year with light hiccups along the way. Figuring it still had something to do with the TPS I swapped them with a buddy who was planning on trailering his car home anyway. Pulling off my TPS we found it was a ISUMO branded TPS which appears to be a 13-14 dollar amazon/ebay special. Obviously, the oem unit runs you about 200 brand new and I would venture to assume this cheapo has pretty poor resolution. His oem tps has made the car run flawlessly and it even pulls harder without a doubt at WOT.
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Originally Posted by sbstar
(Post 11835973)
As a follow-up / conclusion to this for anyone searching in the future. Adjusting the TPS seemed to make the problem go away, but it returned, albeit with much less severity, after about 200 miles of driving. I made it to the shootout this year with light hiccups along the way. Figuring it still had something to do with the TPS I swapped them with a buddy who was planning on trailering his car home anyway. Pulling off my TPS we found it was a ISUMO branded TPS which appears to be a 13-14 dollar amazon/ebay special. Obviously, the oem unit runs you about 200 brand new and I would venture to assume this cheapo has pretty poor resolution. His oem tps has made the car run flawlessly and it even pulls harder without a doubt at WOT.
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