Ray Khan

here's the story. I had a home made intake setup for a while and was running a brand new MAF for the last 2 months. So one day I'm messing with some stuff in the engine and I re-orient the way the MAF sits so that the connector does not face all the way up. I get a CEL shortly after, low MAF signal DTC. So I hear from a few trusted people that the MAFs don't like to be orientated like that. That the sensor wants to face straight up and down so that the connector faces stright up as it is in the stock airbox. Ok, I'll accept that. I get another MAF from a junkyard and decide to reinstall the stock airbox a week ago. Car is running well all week especially last night after a fuel filter change recently. Today the CEL is on again and the same low input signal code is there. So it's possible I have bad luck and my junkyard MAF wasn't up to the task, but I don't want to drop more $$$ on another before I take some steps to try to see if there is something killing my MAFs. I'm starting to wonder if my connector to the MAF might be the culprit. Just trying to figure out how to troubleshoot that. At this point te connector has been on and off the MAFs often and taken a beating. It doesn't seem to click going on, but it doesn't come right off and has the tab has to be released to remove it. So possibly there is a connectivity issue. If this is the case, not sure if it's going to be easy to get parts and a crimp tool to redo a new connector. The other thing I should probably check is the connector itslf. I'm pretty sure the Bentley has some diagnostic check for the cable/connector, but my Bentley is not cooperating with me right now. I would appreciate any suggestions for troubleshooting. Thanks.

Yippers®

I gave you a 'paste' of the Bentley's in your thread on Ed's place.

Stratocaster1422

for us not cool enough for Ed's website and not paying the $4K entrance fee

I'd like to see what part of the Bentley you are talking about...

Yippers®

Here:

Here is the information: (beginning from the curved end of the connector up to the square end)
Pin 1 unused
Pin 2 (green/yellow) is ground
Pin 3 (yellow wire) to pin 27 on the J220 (ECU)
Pin 4 (white/green wire) to pin 53 on the J220
Pin 5 (green wire) to pin 29 on the J220

"Voltage supply for Mass Air Flow (MAF) sensor, checking
Test requirements:

Fuse for Mass Air Flow (MAF) sensor OK
Electrical Wiring Diagrams, Troubleshooting & Component Locations
Fuel Pump (FP) relay OK; checking Page 24-53 .
Note:
Voltage is supplied to Mass Air Flow (MAF) sensor from Fuel Pump (FP) relay.
- Disconnect connector from Mass Air Flow (MAF) sensor."

{Terminal 2 to Engine Ground (GND) (Terminal 1 is at the round end, 2 is second terminal from the round end, 3 is 3rd etc ..) }

"- Operate starter briefly (engine can also start).
Specification: approx. battery voltage

Connect multimeter for voltage measurement as follows.
Harness connector
Connect multimeter to terminal 3 and terminal 4 of connector for voltage measurement.
Specification: about 5 V "

When using a Vag tool or Vag Com to check block outputs:
"Display field: 3
less than 1.0 ms Smaller values are only possible when driving in deceleration mode


larger than 4.0 ms Engine under load due to power accessories.
- Reduce load (A/C system/power steering/generator)

Poor idle (does not run on all cylinders)
- Check spark plugs.
- Check fuel injectors Page 24-38 .

Throttle valve control module - J338- faulty
- Check throttle valve control module Page 24-120

Display field: 4

smaller than 2.0 g/s large false air mass between intake manifold and Mass Air Flow (MAF) sensor
Voltage supply of Mass Air Flow (MAF) sensor or wire connections to Engine Control Module (ECM)
- Check intake system for leaks (false air) Page 24-68 .
- Check voltage supply and wire connections Page 24-64

larger than 4.5 g/s Engine under load due to power accessories.
- Reduce load (A/C system/power steering/generator)
Voltage supply of Mass Air Flow (MAF) sensor or wire connections to Engine Control Module (ECM)
- Check voltage supply and wire connections Page 24-64 "

Stratocaster1422

thanks

Yippers®

Welcome

Liam in Montreal

it was pretty stretched (almost 90 degree angle between wires and the connector).

Ray Khan

I am wondering about this now. I see 5v pretty steady on pins 3 and 4, but the pin 2 voltage is a bit flaky. It might be my contacts, but I seemed to get the 5v from 3 and 4 with no flakyness. Makes me wonder....does having iffy gournd kill a MAF or just not let it
power up"? I am thinking to run wires from MAF pins to the connctor pins, but run from the ground pin right to the battery to see what happens.

Liam in Montreal

try disconnecting the maf connector completely, does it drive smoother (albeit slower) ? (dont go WOT with the connector off )

Ray Khan

I think the MAP sensor in DBW helps us out a bit when the MAF is gone. I have my boost controller turned down for now until I solve this problem. The car is running smooth (off boost or low boost)but a little down on power. When I get into boost, the car has this feeling of surging. Needless to say I don't get into boost unless I reall have to. I have ordered a new connector. In the meantime I'm not risking a new MAF until I rewire the connector. I have an old one which is most likely shot, but I've sires a wire to it I will run straight to the battery ground and test with it. My gorund voltage measurement seemed to be flaky, but it just might have been bad contact. I have no idea.