2001 LB7 P0102 code

[Napco4WD]

Hello to all. Ive come here looking for advice. My truck is a 2001 LB7, it has been down due to head gasket job. Ended up rebuilding the complete engine. Has taken a year!. So got it running Saturday night. Now getting an error code P0102. Had some mods done, cold air intake, high flow up pipes, down pipe, headers, rebuilt turbo (stock), CP3 pump and all the ARP hardware. A friend had his truck down for 2 years but we decided to try his MAF sensor to see if it was a wiring problem or the sensor. His did the same thing. His truck is a few years newer but the sensor appeared the same as mine. Has anyone got a schematic of the wiring for the sensor and what wires do what? I need to diagnose the harness.
Any help would be MUCH appreciated!

[More Power]

P0102 - MAF sensor signal is less than the possible range of a normal sensor or less than 16 grams/sec air flow.

MAF (Mass Air Flow) sensor not properly installed? Unplugged? Broken wire?

A decent code reader should be able to read the MAF signal. That'll let you know if it's processing a signal.

I forgot to plug in the MAF in my Lil Red truck following a head gasket replacement. Of course it illuminated the truck's SES lamp. Even after plugging in the sensor, the SES continued to be lit. It took a number of successful key-start-cycles for the SES to remain out. A reader can reset the codes.

Jim

[Napco4WD]

The latest, and thanks for the reply. I went ahead and purchased $140.00 Hitachi MAF sensor. Cleared code, installed and drove it and no issue with MAF. BUT! still problem with what I now believe is a transmission communication issue with the engine?
You get on it, shifts good until you get up to about 40-55 mph and it like it goes into limp mode? Throttle cut in half. Put in neutral and throttle pedal very responsive, full range, no lagging which leads me to believe its a trans communication issue now? And appears to be stuck in a lower gear waiting for a signal to shift up? Does all this make sense?
Thanks!

[DmaxMaverick]

Limp mode can be caused by several conditions, but the trans and throttle behavior will be similar. The SES lamp should be on, and there should be DTC's to indicate what may be the problem, or a direction to a problem system. If one of the codes is P0700 (simply means a TCM request that the PCM light SES lamp), you will need a scanner/reader capable of reading TCM data. TCM communication errors or absence usually cause the PRNDL lamp to flash. Further TCM codes will be stored in the TCM, but most common, inexpensive code readers can't reach them. The same applies to most of the other module codes, which can also cause limp mode and irregular behavior.

[Napco4WD]

Thank you Maverick. You are correct I get no codes on my cheap reader, and when this happens I don't get a check engine light? I have a friend who is bringing a good scanner to see what there is if any.

[DmaxMaverick]

If something is amiss with the tranny, it should set the MIL (Malfunction Indicator Lamp, AKA: SES), and P0700. If it isn't shifting correctly, or doesn't seem to, and isn't complaining, something else is not right, and the MIL should be on. About the only thing I can think of at the moment that cold cause poor shifts and/or low power and no DTC's (yet) is fuel contamination or interruption. Low power, such as caused by a plugged fuel filter or contaminated fuel (bio/water/gasoline/air), messes with the throttle position and power correlation, which delays shifts and limits power and RPM under load. If it continues, expect a P--93 code to appear (HP pump unable to produce desired pressure), among other red herrings.

If it's been down for a year, fuel quality may be suspect, especially if stored outdoors. Diesel fuel doesn't "go bad" like gasoline (I've used 60+ year old fuel in tractor restores with no issues), but can become contaminated, and even grow biological contamination (algae). Water can collect from condensation, compounding the problems, including bio growth. Also, don't rule out mischief, such as someone dumping something into the tank that doesn't belong there.