I have had a code 33 on my GTA for about a week or so, and the SES light stays on. I checked all wiring between the MAF, the computer, and the relays. Everything is OK and there are no grounds or open wires. I have checked the voltage to the MAF and got 12V. Also checked the signal voltage from the MAF and got between 1.4V - 1.6V no change regardless of airflow. The relays are good, and the wire in the sensor is still intact.
So assuming the MAF was bad I bought a new one and still got a code 33. The guys at Auto Zone let me have the old one back so now I'm back to ground zero again.
So what gives, was the new sensor bad too, or am I missing something.
Another thing I noticed was that when I started the car and the SES light did not come on, the car would run as if it had no power at all and would not accelerate like it should.
Any ideas?

 

The MAF itself may not be bad but something connected to the MAF is if you're getting code 33!! I don't know a lot about what else is "connected" to the MAF so there's not much more help I can give you!!

Sounds like maybe air isn't flowing properly through the MAF too!!

 

The only thing that I can think of is that the sensor's internal electronics are bad. Maybe a short that by-passes the resitor wire therefore the voltage is high. The output voltage from the signal wire is suppoed to be between .5V (idle)and 4V (WOT).
I also put the stock PROM back on to see if it made any difference but it doesn't.
Vacuum leaks are irrelevant since the signal is constant regardless of airflow through the sensor when the throttle is opened.
I'm thinking about getting another sensor and see what happens again.

[This message has been edited by Ozzy88GTA (edited April 13, 2001).]

 

Ozzy,

Your '88 should have the Bosch analog MAF. The voltage signal should vary depending on engine load (throttle opening and RPM. Normal readings at a 900RPM idle are around 0.800 to 0.850 VDC. The voltage should increase almost linearly with throttle position and engine speed.

Vacuum leaks will make a difference, but usually for a 34 DTC, not a 33. Your MAF error is for TOO MUCH air flow, not too little. This is commonly a problem with TPS being set too high or ignition timing problems. Make sure the TPS is set correctly (0.54VDC at idle position).

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Vader
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Had the same problem with '33' where everything checked out fine, but I still had 5v on the green wire. Changed the MAF and the same thing. Here the plug was bad (Pins spread out) and it wasn't making connection. Now I have an xtra maf.

 

Thanks for your replies. I will go ahead and check the connector thoroughly, and verify the TPS.
Again, thanks for the help.
Ozzy

 

It is finally fixed. Apparently I had a bad reading when testing the voltage supply to the sensor. It should have been 12V, and after rechecking it I had nothing. So the problem was the supply to the sensor which is the MAF Power Relay. Since I knew the Burn-off Relay was good for sure, I swapped them to see what happenned. Sure enough the sensor now had power but the burn-off did not occur after shuting the engine off. I then replaced the relay and everything is working good with no codes.
A final word about those relays, just because you can hear the coil activate does not mean the contacts are good. It only takes a small pit on the contact and you no longer have a connection.
I used the burn-off circuit to verify the relay by running the engine and having someone shut it off. Before doing so, remove the duct between the air filter and the MAF sensor, then observe the sensing wire in the sensor. It should glow briefly after the engine is shut down. The relay should also be heard when the wire is being heated.
Thanks for everything.
Ozzy

[This message has been edited by Ozzy88GTA (edited April 17, 2001).]