Hi, I'm trying to diagnose a problem with my 2011 Acadia. I've had some codes set and long term fuel trims seem to stay pretty negative -25 to -30. Short term bounces around +/- 10% maybe. Both banks run about the same. Doesn't seem to matter if its idle, cruising or hard accel. I'm thinking its probably the MAF. However, my scanner (Torque Pro on Android) is showing like -40 (if I remember correctly) for maybe ambient air 2. So I'm not sure if this is an incompatible sensor definition in torque or a real reading of a faulty sensor. DIC external temp seems about right. I've checked for vacuum leaks (though that seems pointless). Fuel pressure is reading in the 700+ psi at idle and runs >1000 when engine revs (its been a few weeks, I think it got up to maybe 1300-1400)
Background:
Car is at about 130k miles. Recently changed plugs, cleaned the MAF (with MAF cleaner), cleaned the throttle body, and changed the air filter. Also been fighting an AC issue, leaks then more leaks then compressor..... Still not working right but I don't think AC is related to the engine. However, engine could be related to the AC. If it thinks its way colder outside I'm thinking it might open up the expansion valves because less cooling would be needed and it might try to run at a lower high side pressure. I'm not really sure what the control for expansion valves are this is just a wild guess. In any case noticed codes after compressor was replaced but this is all within maybe 300 miles.
Might be a little sluggish off idle but I think this thing has always been that way but I haven't been driving it since its hot and AC isn't working. Its always felt a bit heavy handed with the filtering of the throttle.
Other random background bit, its always been a little "hunty" at idle. Doesn't really feel rough but tach is just +/- maybe 50 to 100 RPM. Been this way since I got it at 60k miles. Only reason I mention it is maybe this has been a long running issue with the MAF or temp. Rich codes are recent though.
Even now it still seems to drive pretty well, I think acceleration is normal but I don't have a metric to compare it to so could be down 10-15% and I probably wouldn't notice.
Questions:
Is the DIC temp sensor the same as the one used in combination with the MAF?
Is there some other thing I'm not thinking of that can cause a lack of metered air?
Injector doesn't seem like the problem since both sides are off. Pressure seems right from what I've seen on the internet. Anything else I should check before getting a new MAF?
Background:
Car is at about 130k miles. Recently changed plugs, cleaned the MAF (with MAF cleaner), cleaned the throttle body, and changed the air filter. Also been fighting an AC issue, leaks then more leaks then compressor..... Still not working right but I don't think AC is related to the engine. However, engine could be related to the AC. If it thinks its way colder outside I'm thinking it might open up the expansion valves because less cooling would be needed and it might try to run at a lower high side pressure. I'm not really sure what the control for expansion valves are this is just a wild guess. In any case noticed codes after compressor was replaced but this is all within maybe 300 miles.
Might be a little sluggish off idle but I think this thing has always been that way but I haven't been driving it since its hot and AC isn't working. Its always felt a bit heavy handed with the filtering of the throttle.
Other random background bit, its always been a little "hunty" at idle. Doesn't really feel rough but tach is just +/- maybe 50 to 100 RPM. Been this way since I got it at 60k miles. Only reason I mention it is maybe this has been a long running issue with the MAF or temp. Rich codes are recent though.
Even now it still seems to drive pretty well, I think acceleration is normal but I don't have a metric to compare it to so could be down 10-15% and I probably wouldn't notice.
Questions:
Is the DIC temp sensor the same as the one used in combination with the MAF?
Is there some other thing I'm not thinking of that can cause a lack of metered air?
Injector doesn't seem like the problem since both sides are off. Pressure seems right from what I've seen on the internet. Anything else I should check before getting a new MAF?