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Car running lean, not MAF or Vaccum Leak! FIXED!!!!
What testing have you done to confirm it is not maf or vacuum leak? I see the pid that says lean and 02 voltage is lean but it is not a graph so it does not mean it's actually running lean just that it was n the lean side of the fuel table at the time of the snapshot, fuel trims are a better indication of an engine running lean or rich, than we need to know when it's lean or rich and by how much (+-10% is normal 20% is a problem that needs adressed) and what rpm/load it was went lean or rich to identify what's causing it
What testing have you done to confirm it is not maf or vacuum leak? I see the pid that says lean and 02 voltage is lean but it is not a graph so it does not mean it's actually running lean just that it was n the lean side of the fuel table at the time of the snapshot, fuel trims are a better indication of an engine running lean or rich, than we need to know when it's lean or rich and by how much (+-10% is normal 20% is a problem that needs adressed) and what rpm/load it was went lean or rich to identify what's causing it
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With vacuum leak, i have sprayed water/ carb cleaner in the engine bay close to all hoses. Also smoke test the car none was found.
Lastly monitoring fuel trims (STFT) with rpm held at high doesnt change fuel trim in all driving conditions even in 4k rpm.
Swapped MAF sensor multiple times and it didnt change the situation; but i am afraid i am facing a MAF wiring integrity issue. Why do i say this?
A known other same brand car on KOEO read MAF A/F SE-B1 =0.30volts, mine reads 0.40volts switching between 0.39-41volts it doesnt stay stable. When i hit the wiring briefing with my hands it stays switching in-between this volts.
How about checking fuel pressure? What is the calculated load value at wide open throttle?
Fuel pressure is not checked since i dont have the equipment but I have swapped good condition and working ones to my car and the same problem existed; never solved
What engine and Can you post the trim values at idle and with increased RPM. Also what are the upstream 02 voltage values.
My engine MR20DE
Trim values at idle and crusing is STFT +25% and LTFT is +0% (Doesnt change with all driving conditions)
My upstream o2 is wideband sensor KOEO is 2.19v
Have added some data pids from my OBD for your study
Lastly as per FSM MAF unplugged resistence should be 1.88v~2v.+ (77F) but i am reading 1.3v
STFT should change at different RPMs. Have you tried disconnecting a vacuum hose and spraying some carb cleaner to check A/F and O2 sensors operation and to see if stft changes?
Yes, thats how it made to be but it dooesnt. Always stuck at +25% on the AF sensor monitoring
No, havent done that; which vacuum should i disconnect purge valve, close to throttle or maf sensor?
Please how do i do ONLY heater wire integrity wire with basic multimeter ?
Several tests are possible:
when the engine is running and theheater is commanded on you should see full supply voltage while backprobing the feed wire at the sensor connector. When backprobing the control wire in the same connector you want to see close to 0 volts when commanded on and supply voltage when not commanded on. This would be the test of preference but you need a good(quick) DVOM, best with min/max function.
Another option is a resistance test. To do so shut off the ignition.Then you would pull he fuse that powerfeeds the O2 heater and disconnect the harness/connector at the O2 sensor itself. Also disconnect the pcm connector where the heater control wire connects to the pcm. Now you can take a resistance measurement with your ohmmeter between the fuse socket and the powerfeeds wire at the connector close to the disconnected OW sensor. Take a second reading between the control wire terminal in this very connector and the corresponding terminal of the (disconnected) pcm connector.
Instead of ohm testing you also can use the voltmeter function , an open wire will show "ghost voltage" while a perfect 0 volt reading confirms continuity.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Please how do i do ONLY heater wire integrity wire with basic multimeter ?
Several tests are possible:
when the engine is running and theheater is commanded on you should see full supply voltage while backprobing the feed wire at the sensor connector. When backprobing the control wire in the same connector you want to see close to 0 volts when commanded on and supply voltage when not commanded on. This would be the test of preference but you need a good(quick) DVOM, best with min/max function. The feed wire: you mean the 12volts power feed waiting to be grounded by the heater control wire?
Simple terms, KOEO what volts should be present in the heater control wire backprobed?
Another option is a resistance test. To do so shut off the ignition.Then you would pull he fuse that powerfeeds the O2 heater and disconnect the harness/connector at the O2 sensor itself. Also disconnect the pcm connector where the heater control wire connects to the pcm. Now you can take a resistance measurement with your ohmmeter between the fuse socket and the powerfeeds wire at the connector close to the disconnected OW sensor. Take a second reading between the control wire terminal in this very connector and the corresponding terminal of the (disconnected) pcm connector. OW=??
"Thank you, will check and revert".
Instead of ohm testing you also can use the voltmeter function , an open wire will show "ghost voltage" while a perfect 0 volt reading confirms continuity.
"With this test, will you disconnect the Af sensor harness and the ECM to test this?, if so where will the ghost volt reading come from as you have disconnected both ends if the is perhaps a short to power problem? Or can still show a volt with both ends disconnected?
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