I recently started to get code 33 so i tried to troubleshoot after doing my homework.

The only thing that does not check out is the voltage at the dark green wire.

With ignition on, MAF connection plugged in i get 2.5v at that wire and same at the b12 terminal at the ECM.

Then when i unplug the MAF, i get 5.0v at that wire and same at b12? WTF.

What would that indicate??

 

i had the same problem. all the relays and ecm were fine. the maf itself was bad.

the filiment wire was glowing red on and off.

 

Have you done your checks using the code 33 trouble shooting chart that has been posted on the board numerous times? Just a thought. BTW, that dark green wire goes to pin "B12" on the ECM and is the 5 volt MAF signal.

 

I haven't found the chart yet. The b12 is reading 2.5v with MAF connection in and 5v when unplagged?? WTF.

 

I have it posted in this link danielek, you will to scroll down several posts in it but it's there.

https://www.thirdgen.org/techbb2/sho...ght=maf+sensor

 

Update:

I tried troubleshooting using Trickster's chart and all pointed out to a faulty MAF..

I ended up buying a used MAF and plugged it in.. Before i started the car i did this:

- ignition on
- MAF connection plugged in

I then checked the voltage at the B12 terminal to see if it is what it should be and it is STILL showing 2.5V.

Car started good, no codes, run for 2 hours, no codes.

My question is should i be getting 5v at the b12 terminal when MAF connection is plugged in??

I am getting 5v when i unplug the MAF connection..

Could somebody check that on their car. I don't want to worry anymore...

 

This is another question about the MAF. I've noticed my car produces much more power when I unplug it - WTF? It dosn't idle as good but when I mash the throttle when its unplug I get two nice black stripes behind me. When plugged in I get a hug hesitation.

Regards,
G

 

Are you running a modified prom??

In my case is the other way around. When unplugged it runs OK, when plugged in it runs like a charm...

 

The prom is a Hypertech thermomaster chip.

 

That is your problem right there.. It tells you how good those aftermarket chips are...


Can somebody please test the voltage at the
- b12 terminal with
- key On and
- MAF connection plugged in???

What should the voltage be??


I did more testing today with a scanner plugged in and it the showing WITH KEY ON,

- maf reading of 23 gps which should equal to 1.5v (based on the maf table). When i ckeck the voltage at the b12 I get 2.5 volts and not 1.5v?

When i start the car the signal wire voltage corresponds with the MAF table readings.