MAF Sensor Problems

[williamlowe]

I have a 2002 Duramax LB7 engine in a boat with an ongoing problem. The MIL keeps getting set by the P0101 Mass or Volume Air Flow Circuit Range/Performance Problem. When I hook up the laptop with Autoenginuity, the sensor's values at idle (600rpm) is constantly 51gm/sec for 20 secs, then it drops to 2.56gm/sec for one reading. Even at 1200 rpm when the MAF reads 105gm/sec, it will still drop to 2.56gm/sec for one reading every 20 secs or so. The engine runs fine, but the MIL will set because of this.

The sensor was brand new (GM, not aftermarket) about 60 hrs of running ago.

We do not have the pulsation dampener on the intake. Is this important?

Any help would be appreciated.

[DmaxMaverick]

The resonator chamber shouldn't effect MAF function.

Sounds like the MAF is bad or contaminated. Have you tried cleaning it with electrical contact cleaner or alcohol? Give that a try. If it's contaminated, you may consider a close look at your intake and filtration system. If it's in a salt water boat, it could have some corosion building up. Oil type foam or gauze air filters can cause contamination issues if too much oil is used. If it's an open intake, you may have a bug or something jamming it up. Excessive vibration can cause them to fail prematurely, so that's something else to look at. Also check that the sensor is in the clean airflow path of the intake air. If something is diverting airflow, the inputs will be skewed, but shouldn't show a constant 2.56.

[More Power]

Electrical gremlins can sometimes creep into the picture if all of the powertrain grounds aren't what/where they ought to be. The various wiring harnesses have several ground connections, as does the engine and so on.

Post some pictures of your marine conversion. I'm sure others would be interested in what you're done..... :)

Jim