DBecke504
05-08-2024, 08:19 AM
This will be a long one and it's my last ditch effort to hopefully solve this mystery misfire my 02 540i touring has.
Background: I just completed timing chains/guides, Vanos (new units from Dr Vanos plus new solenoids) and every gasket I could get to (including intake, TB, and CCV). After that, I completed a 6 speed manual swap on the car. I used a new Luk dual mass flywheel and Luk clutch. I programmed the EWS and DSC following Geargrinder's guide along with flashing the DME as a manual. The car was running great prior to all of this and only has 90k miles.
After I got the car up and running, everything seemed fine until the first test drive where the SES light started flashing. Codes P1431, P1443, and P1453 (Multiple cylinder misfire with fuel cutoff and Cylinder 1 and 6 misfire with fuel cutoff respectively) came up. The SES only began flashing when the car was revving >2k RPM with steady input. It did not flash under heavy acceleration and the car felt fine, does not feel down on power at all. It will also misfire when free revving in neutral. The misfire is just barely detectable though. Its a minor shake felt within the car when it occurs. I cannot feel any hard cuts or anything serious like that.
I began diagnosing and this is what I've gone through
1. Swapped new plugs with old plugs and no change
2. Swapped coils from 1 and 6 with other coils, no change
3. Swapped injectors, no change
4. Tested compression and all tested >170psi
5. Pulled intake back off to inspect all new seals, reinstalled and retorqued, no change
6. Checked for vacuum leaks as best I could with no luck
7. Checked roughness test in INPA and car seems to be running on the rougher side at idle on all cylinders. Cylinder 5 was worst with value >200, cylinder 6 was best with value around 20-30
8. Read codes in INPA and noticed the engine temperature always reads -48C for the misfire codes. Coolant temp gauges are working fine though
I have thrown everything I have at this car and no matter what I do the misfire codes always stay the same, and it always misfires under the same conditions. I'm out of ideas now.
Background: I just completed timing chains/guides, Vanos (new units from Dr Vanos plus new solenoids) and every gasket I could get to (including intake, TB, and CCV). After that, I completed a 6 speed manual swap on the car. I used a new Luk dual mass flywheel and Luk clutch. I programmed the EWS and DSC following Geargrinder's guide along with flashing the DME as a manual. The car was running great prior to all of this and only has 90k miles.
After I got the car up and running, everything seemed fine until the first test drive where the SES light started flashing. Codes P1431, P1443, and P1453 (Multiple cylinder misfire with fuel cutoff and Cylinder 1 and 6 misfire with fuel cutoff respectively) came up. The SES only began flashing when the car was revving >2k RPM with steady input. It did not flash under heavy acceleration and the car felt fine, does not feel down on power at all. It will also misfire when free revving in neutral. The misfire is just barely detectable though. Its a minor shake felt within the car when it occurs. I cannot feel any hard cuts or anything serious like that.
I began diagnosing and this is what I've gone through
1. Swapped new plugs with old plugs and no change
2. Swapped coils from 1 and 6 with other coils, no change
3. Swapped injectors, no change
4. Tested compression and all tested >170psi
5. Pulled intake back off to inspect all new seals, reinstalled and retorqued, no change
6. Checked for vacuum leaks as best I could with no luck
7. Checked roughness test in INPA and car seems to be running on the rougher side at idle on all cylinders. Cylinder 5 was worst with value >200, cylinder 6 was best with value around 20-30
8. Read codes in INPA and noticed the engine temperature always reads -48C for the misfire codes. Coolant temp gauges are working fine though
I have thrown everything I have at this car and no matter what I do the misfire codes always stay the same, and it always misfires under the same conditions. I'm out of ideas now.