Issue with fuel cut, backfiring, and rev limit at ~4k
Posted: Wed Jul 26, 2023 12:40 am
I have a 92 MR2 with a K24 I just picked up and am working through. It came with a dyno tune. It had a high idle ~2.5k, but ran well out to the 7600 rpm redline otherwise.
I adjusted the throttle body screw so that the valve gets as close to closed as possible without sticking. Maybe a 2 degree adjustment. It has an IACV. Now it idles nicely at 1k rpm. I calibrated the TPS in software.
Now it backfires and rev limits at ~4000-4500 rpm and MIL flashes.
Asking for help because I am seeing some things in the log that I don't quite understand. I attached 2 snippets from a 45 minute drive
In the "Rev limit and sensor cutout" log, VSS, AF and Gear all go to incorrect values as it stutters and backfires. Then rev limit comes on after I have let off throttle.
In the no sensor drop log, rev limit comes on after a weird TPS drop and blip. I did not feel this happening at all in the car.
Then I slowly rev up to 4500 rpm and get some more backfires and release throttle to 0 and then rev limit comes on.
Could this be caused by bad TPS? It is an Acuity unit I have had on for less than 100 miles.
If it is from the throttle body adjustment, what should I adjust? I am not seeing anything obviously off.
Thanks for the help
Logs and calibration attached
SN: 59817
Kmanager 4.5.6
Type S ECU
RBC, Skunk2 70mm TB, Type S oil pump
I adjusted the throttle body screw so that the valve gets as close to closed as possible without sticking. Maybe a 2 degree adjustment. It has an IACV. Now it idles nicely at 1k rpm. I calibrated the TPS in software.
Now it backfires and rev limits at ~4000-4500 rpm and MIL flashes.
Asking for help because I am seeing some things in the log that I don't quite understand. I attached 2 snippets from a 45 minute drive
In the "Rev limit and sensor cutout" log, VSS, AF and Gear all go to incorrect values as it stutters and backfires. Then rev limit comes on after I have let off throttle.
In the no sensor drop log, rev limit comes on after a weird TPS drop and blip. I did not feel this happening at all in the car.
Then I slowly rev up to 4500 rpm and get some more backfires and release throttle to 0 and then rev limit comes on.
Could this be caused by bad TPS? It is an Acuity unit I have had on for less than 100 miles.
If it is from the throttle body adjustment, what should I adjust? I am not seeing anything obviously off.
Thanks for the help
Logs and calibration attached
SN: 59817
Kmanager 4.5.6
Type S ECU
RBC, Skunk2 70mm TB, Type S oil pump