Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
2004 mercedes c240 2.6l v6 , p0101 maf circut poor performance... fuel trims were around +20 both banks. i found 2 vacume leaks that i fixed... and fuel trims are now stable bouncing between +/- 3 area. Code was cleared and then came back. At idle. Freeze frame data shows it was triggered in open loop aswell , with in range fuel trims...wich is strange. I get a little hesitation when snapping throttle so ive been concerned about exhaust blockage... manifold test went from 34kpa at idle to a steady 29kpa at 2500rpm... did not continue to drop. Im now at a loss, have already cleaned and tested with a known maf sensor to rule out sensor performance aswell. Any thoughts are greatly appreciated.
AT WOT, in low gear, the does the CALC LOAD PID reach 100%?
Can you post the MAF reading at Idle, and the Highest attained during the WOT run in (G/s) and the RPM at which it was attained?
With a 2.6L engine @ 4500 rpm, I would expect to see 82 -120 g/s.
If you have lower than those numbers and good Fuel Trim (which you have now from fixing the vacuum leaks) you have an airflow restriction, and I'll bet your CALC LOAD is LOW.
The 2500 RPM Exhaust restriction check is not always reliable.
Never stop Learning.
Last edit: 3 years 8 months ago by Paul P.. Reason: spelling
Topic Author
