MAF Voltage/Wiring

[kevinbowe2000 10]

I have been chasing a cold start issue for a while now and think I might have found the issue but looking for some advice.

 

I used this:

http://s2central.net/ds_G70.html

to test the MAF and wiring.

While testing the MAF (Part 1), I found that all was fine except for pin 3.

It says that it should be like this:

 

Connecting the harness plug back onto the MAF, again teasing back the insulation hood enough to get the DMM probes onto the pins entering the connector, measure DC VOLTAGE across pins #1 (one) and #3 (three).

 

With the ignition ON and engine OFF, a value of 1.2 - 1.5 V should be measured

With the engine idling a value of approx 2.5 - 2.6 V should be seen

With brief blip of the throttle, the reading should be seen in the range of 3 - 5 V.

 

However, the voltage on mine is 0.02V constantly, no matter what the rpm etc.

 

With the connector remove, the resistance between pin 1 and 3 on the MAF (Ra) is 3 ohms as per the post, and voltage thru connector is 0.02V. With the connector replaced, the resistance between 1 and 3 is 13 ohms an voltage is the same at 0.02V.

 

It is a relatively new MAF (but not bosch), so dont think that the MAF is the issue. Was thinking of replacing th wire for pin 3 back to the ECU (if that is possible and where it goes), or would it be more likely to be a different issue?

 

Any thoughts/ideas would be most appreciated.

[sankysvr6 0]

Not sure what would be the cause of the MAF readings your getting, but before you start tearing up the wiring loom.

 

I would defiantly start a post for the cold start issue you having and see if some the resident experts on the forum can help.

 

Have you had the car on Vagcom, to see if it shows up any errors?

[kevinbowe2000 10]

Thanks for the reply. Wasnt planning on ripping up the loom just yet.

Was going to just put in a temporary length of wire to see if it got the correct voltage but amnt really sure where the red wire (pin 3) ends. I believe it goes into the ECU but have never done any work on the ECU yet etc. and not really sure what I'd need to be doing.

I have done a number of things to try get to the bottom of this cold start:

cleaned ISV (tried two different ones), put on a known working black box behind ISV (thanks easypops), totally removed the black box, checked for air leaks, replaced blue temp sensor, new MAF, ecu reset and basic settings a few times, replaced coilpack (was cracked), new battery (needed it but dont think it would have any effect on the cold start really), replaced intake air temp sensor (had come up on vagcom).

 

Have vagcomed it a couple of times and these keep coming up:

 

00525 - Oxygen (Lambda) Sensor (G39)

03-10 - No Signal - Intermittent

00537 - Lambda (Oxygen Sensor) Regulation

11-00 - Control Limit Not Reached

 

Also did a log of when the engine was nice an warm (attached).

[kevinbowe2000 10]

Also get this vag error sometimes but only after I go for an italian tune up.

00281 - Vehicle Speed Sensor (G68 )

27-00 - Implausible Signal

 

Not sure if that would have anything to do with the strange voltage?