Truck running rough and trying to understand the code and live data that I see... via OBD2.
LONGFT1 & LONGFT2 are showing -82.8%. I believe this is long term fuel trims and so sounds like it thinks the engine is running to rich and throttling back fuel.
More concerningly the MAF reading is 0.0 lbs/s, which would suggest a failed MAF. I swapped it out for an older MAF that I had kicking around for the last 10+ years and that also registered 0.0 lbs/s.
Of the 3 wires going into the MAF - I have 12v across brown-orange and red-black and looks like the blue wire goes to the ECU.
Possibilities:
1. MAF value is not actually reported via ODB2 and so it's a red herring to chase it.
2. Both MAF sensors are bad
3. Blue 'sensor' wire between MAF plug and ECU is damaged.
Can anyone help rule out 1. before I go down the 3. rabbit hole. Would you expect the MAF value to show up in live data, or is the fact that the scanner detected a MAF field at all and showing zero mean that is is actually being sent vs. not supported.
A P1179 search here, yielded "replaced fuel filter and fixed it" - but that wouldn't make sense to me as the huge negative LONGFT1 values suggest it's way too rich vs. way too lean.
Any other theories?
LONGFT1 & LONGFT2 are showing -82.8%. I believe this is long term fuel trims and so sounds like it thinks the engine is running to rich and throttling back fuel.
More concerningly the MAF reading is 0.0 lbs/s, which would suggest a failed MAF. I swapped it out for an older MAF that I had kicking around for the last 10+ years and that also registered 0.0 lbs/s.
Of the 3 wires going into the MAF - I have 12v across brown-orange and red-black and looks like the blue wire goes to the ECU.
Possibilities:
1. MAF value is not actually reported via ODB2 and so it's a red herring to chase it.
2. Both MAF sensors are bad
3. Blue 'sensor' wire between MAF plug and ECU is damaged.
Can anyone help rule out 1. before I go down the 3. rabbit hole. Would you expect the MAF value to show up in live data, or is the fact that the scanner detected a MAF field at all and showing zero mean that is is actually being sent vs. not supported.
A P1179 search here, yielded "replaced fuel filter and fixed it" - but that wouldn't make sense to me as the huge negative LONGFT1 values suggest it's way too rich vs. way too lean.
Any other theories?
