Northeast_Nomad

Good Morning Gentleman,

long time lurker first time poster. To make a long story short I spend most of my time on Ih8mud with the land cruiser crowd. My problem is definitely outside of their expertise so I'm here trying to find some sort of solution

what brings me here is my engine swap. I have a 5.3 shoehorned into the FJ60 with a brand new Howell harness custom made for the truck.

What I can't seem to nail down is the MAF. The truck keeps rejecting the Mass Airflow Sensors

whats been done so far

New TPS
New Throttle Body
(2) new O2 sensors (yes these have been test)
(3) new mass airflow sensors, one was a dud out of the box
brand new exhaust gaskets and flanges
No exhaust leaks of any kind
New Air Filter - Cleaned ducts etc
No vacuum leaks of any kind
Relflashed the computer with Howell for good measure

what am I missing? I've replaced every sensor under the sun so I know I'm missing a few from that list.

truck is fine for a time when I swap the MAF out for a new one but the code appears anywhere from one hour to three days later. The truck drives just fine with the light on, no noticeable difference in performance, but I'd sleep easier without the idiot light on

JoeNova

Is it doing anything other than throwing the code?
Have you checked to make sure the MAF is still reading after the code appears?
Has anything been done to the tune?
Are the MAF sensors a direct replacement? There are a couple of different ones.
Is it blowing the fuse that powers the MAF?

Northeast_Nomad

its not doing anything other than throwing the code, and the replacement is a brand new Delphi unit. Direct replacement on all sensors

MAF is still reading after it appears to my knowledge but I'll plug a scanner in to check, and no fuses are blown.

its a stock silverado tune on the computer, so nothing wild there.

I've had several people look at it, so we've replaced everything that would affect it at this point. Completely baffled by what could be doing it

JoeNova

Have you plugged in an old MAF that was presumed bad to see if the code goes away and then comes back days later as the new ones do?

Even an intermittent interrupt will cause it to throw a code. So if the connector, wire, or pin in the PCM loses signal for even a very short period of time, it will throw the code.

Start by checking the pins inside of the connector, and any PCM grounds that might be loose.

Northeast_Nomad

Good line of thinking. When I kept getting the code I plugged in an old MAF out of a junker and the light didn't appear.

Then in the meantime I ordered a brand new delphi unit so I'd have a new one. Plugged that in, 40 minutes later, P0101.

Removed the new delphi and plugged in the old junker MAF and it lasted three days before the light went on, which brings me to now.

ill check the PCM pins, as well as the grounds.

I cant find it now but I was reading somewhere that if you went down a few MM on the intake it might remedy it? Probally BS though

JohnRodriguez

the problem you are having, and i'm sure other members are having with the MAF is that you are more than likely using a oiled air filter element. the oil will coat the sensor, which you can clean with a good electrical contact cleaner. I was running spectre cleaner and had this problem for about a year on my Jeep JK conversion. I still have spare sensor and can of cleaner in the back. the way I fixed it, is I switched to aFe dry type S cleaner. never had a problem again. been over 2 years now with no problem.


I'm not bashing spectre or advocating aFe, I'm just saying, oil type air filters will transfer oil to the sensor and you can use who ever's air filter is a non oil type filter to fix the P0101 problem. in my experience.

Northeast_Nomad

I run paper filters in the land cruiser, while not nearly as nice, and I have to replace them yearly, they work with my diesel air filter element that allows the use of a factory snorkel

im going to try and spray the sensor with a can of electrical cleaner regardless. Maybe some dirt got in there at some point, I didn't think of that

JohnRodriguez

check and see where your pcv intake inlet is hooked up. if it upstream of the MAF sensor, then this could be where you are getting a oil film on it.

pdsq98gt

Can you post a picture of your air intake/pcv setup? How many hertz or g/s is the maf reading at idle? It should be somewhere around 5g/s at idle. If it reads low, you have unmetered air entering the engine downstream of the maf. So if the clean air side of the pcv system isn't connected to somewhere between the maf and throttle body, it'll suck unmetered air in through the pcv valve.

If the pcv setup and idle g/s are good I would follow these steps. Hook some kind of scanner up and graph the Mass air flow in either hz or g/s. Wiggle the entire harness from the maf to the pcm. Also don't forget the power wire that goes to the fuse block. See if the signal drops out when you manipulate the harness. Also make sure you have good terminal tension on the maf connector and pcm terminals for the maf.

ryeguy2006a

iTrader: (27)

I'm very curious to find the outcome of this as my DD is having the same problem. It is a 2003 Silverado with a 5.3 and it seems that the code for me comes on only when I accelerate too quickly, but when I drive like a grandpa it goes away. I have a K&N intake system on it and I was leaning more towards the MAF curve in the ECU. I was thinking that due to the added flow of air that it was falling out of the normal curve.

ryeguy2006a

iTrader: (27)

1. the obvious one: clean the MAF grid with MAF approved cleaner. it is very likely - and I am guilty as charged - that oil got on it and causes havoc. I have my opinion on other posts and what your dealer says about K&N, but it is irrelevant. one thing I do know is that overoiling and not letting oil dry enough, WILL suck it onto sensors anywhere downstream from the filter.
2. P0101 OBD-II Trouble Code
Technical Description

Mass Air Flow (MAF) Circuit Range/Performance Problem
What does that mean?

Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds.


Symptoms

You will likely not notice any serious drivability problems, although there may be symptoms.
Possible Solutions

The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:

* Inspect for the following conditions:
An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.
* When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
* A high resistance on the ground circuit of the MAP sensor can cause this DTC to set.
* Any loss of vacuum to the MAP sensor can cause this DTC to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.:rules:

Copied this from a GMC truck forum: http://www.gmtruckclub.com/forum/thr...e-p0101.21136/