OK everyone...I finally have a little bit of money to spend on my car....have had the code 33 since I bought it(January 2001) and am now able to replace it....But I just want to be absolutely positively sure that the MAF is dead and that there is not an electrical problem of some sort....If someone could let me know of a good way to pinpoint all of the possibilities I would surely appreciate it....Not that I am against spending money on my baby but i simply want to put it where it will most effective.....Thank you all in advance....


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Scott Downs
85 Trans Am
305 tpi/700r4
3.73 w/255/60R15
plain firebird nose(for better engine cooling)
T-Tops, pwr everything
been to about 140mph

 

You can tap the MAF sensor with a screwdrive (car running) and if it stumbles, then it's probably bad. Make sure the TPS voltage is set at or right around .54v (There's an artical on this site on how to set it) and you can test current going to the MAF plug (one's supposed to have 5v with key on and another 12v with car running, can't remember which though ) I don't know if 85 had a MAF relay or not, but they can go bad, too.

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86 TPI 305 Iroc-Z
700R4 (rebuilt)
Accel HEI SuperCoil
Flowmaster
K&N Filters
Ported Plenum
Comp Cams H268 218@.050 454/454 110 LSA

 

With a code 33 set already you could beat that thing bloody with a screwdriver and it won't do anything because it's in limp-home already.

First inspect the wire inside the sensor for breaks.

Then swap the maf burn off relay with the maf power relay and see if you set a code 36 instead. Then you know it's just the relay.

Then probe the green wire near the maf with it hooked up (in the center) and see what you have. It should be .5 volts at idle. If it's 5V then check to make sure the plug on the sensor is making good contact. Sometimes the pins spread out and don't make contact or corosion....

If you have nothing on the green wire, there's an open in the wire.

If it's 5v and the plug is good, check both the black and black with white stripe wires and make sure you have 0 ohms to ground.

Then check the maf power wire (i think it's orange) and make sure there's 12 volts there. Swapping the relays should show this, but maybe the wire between the relay and the sensor is open, so double checking isn't a bad idea.

The blue wire is the burn off, but checking this isn't nessecary...

I actually had a spread out plug and wasted some cash on a maf, so checking it is always a good idea imo.

Hopefully it's something simple. Good luck!

 

I had almost the same problem you are having a few weeks ago. My car would chug back and forth hard while reving up from idle. If you unplug your MAF and your car runs just a tad bit better, then it is the MAF. My car has 140K miles on it and this is the first sensor I have ever had to replace on it. I dropped $150 at AutoZone for a remanf'd MAF by A1 CarDone. Swap it while you are in the parking lot or take yours off before you go in b/c it has a $80 core charge. Oh yeah, make sure they have it first and have them hold it for you. Once I replaced mine my code 33 went away and my car now runs good again.

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Poor college student(donations welcome ;0) with an all stock 1988 5.7L IROC-Z Hardtop, Auto. trans, white ext. w/gold accents (soon to be silver), black custom cloth interior, 4-wheel discs and G92 pkg. Car is dead stock. Has only standard Z28 power options and all the IROC performance stuff you could get. No pwr. seats, mirrors, or rear defrost.

Best run: 1/4 14.90 @ 92.7 MPH

See My Car here: http://zap.to/chevyguy1969

#3 Gone but shall never be forgotten. Long live the legacy of the man in black. RIP Dale Earnhardt "The Intimidator"

 

ok i tested wires and this is what i get....engine off ignition on MAF unplugged and checking voltage at the plug 5v, 12v, and 0 ohms....engine running and MAF plugged in this is it....4.7 v, 13.4v, and 0 ohms....is this showing everything but MAF operating properly??...by the way Joel....85 TPI has the odd computer....no burn off or power relays....thank for the other info tho....


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Scott Downs
85 Trans Am
305 tpi/700r4
3.73 w/255/60R15
plain firebird nose(for better engine cooling)
T-Tops, pwr everything
been to about 140mph

 

The 4.7 should be about .5v so the MAF's prolly toast.

Sorry, I think I posted this before and I should make sure it's not an 85.