MAF is going **** up right?

 

The only true fix for this is a custom Eprom chip. I did one for a guy who drove to my place in Michigan. He was at his wits end on the matter. Now he loves to drive his car.

GM set a few parameters which can be easily exceeded and this will set the 33 error code. You will set the code if three condition are met, one is under 2000RPM, the second is over 45gms/sec flow thru the MAF, third and less than 1/4 throotle.

After a few mods, I could set this at will on the Xway running in OD with my 700R4. I did all the usual stuff, replacing the burn off and power switches, play with the TPS, even bought a new MAF. It all was just a waste of my time and money.

BTW: The Hypertech chips and the other power chips do not take care of this code.

 

My engine is bone stock really. When it set the code it wouldn't idle and when the engine is warm it feels flat at anything but WOT. You can be at a 60 MPH cruise in OD add some throttle and it looses power. Something is definately wrong here and it's surely in a sensor. I just want to be sure I know what it is thats bad before I throw good money at it.

 

85 huh?

My condolences.

The MAF itself is probably fine. Its probably the MAF burnoff module. Those are prone to failure on 85's (the only year F-bod with it).

Try to find someone that has a good MAF, and see if it fixes your car. I bet it doesnt. Its better than shelling out $100+ for something that isnt going to solve your problem though.

 

Yep, probably the MAS module, not a good thing, very expensive part unless you can find a working used one.

Oh, and BTW, your cam is NOT the peanut cam. In 85 you got the "good" cam.

 

The MAF burn-off module is about $9 (I think). So go ahead and change that out with the your battery disconnected. Disconnecting the battery will also reset the SES codes.

But, you stated that you can set the 33 code at 60mph,, this leads me to believe that you are satisfing the three condition that I listed above. I feel very strong that changing the burn-off module will not get rid of the 33 code long term.

 

He has a 1985 TPI system, the power and burn-off functions were handled by a MAS module (not relays) piggybacked on the ECM, they cost on the order of $500-$800 from GM.

 

below is what you are looking for on the ECM and it lists for $753.79

 

here is the MAS module for 1985

 

I'm guessing that it's time to consider swapping out to the faster 86-90 ECM?

And I'm a she, just because I know my car don't let it fool ya

 

First try to isolate it down to what is bad, if it is the MAS. unless you can find one for cheap (used and working) then yes it may be time to swap to the 86-89 165 ECM, takes a few hours and less than $100 to do it.

Sorry, didn't read the name, he is kinda "generic" on the internet.

 

MAN!!!!!!!!!!! (and that is generic also), I cant believe that cost. I had no idea the '85 MAF cars were like that.

Morley,
But, if those three conditions (the ones I listed above) are present at the same time, do you think the '85 ECM would set the 33 code?

I know for a fact that my '87 car will, in fact, I can go out a set the 33 code at will!!!!! I very proud of that, HA HA HA.

 

When I set the code I was coming to a stop for a redlight. I have a 2200 rpm stall converter that if it means anything in this instance. As I was just about stopped it tried to die, I was able to keep it lit but everytime I let it drop to idle it woulddrop well below 500 rpm. I got stopped in a parking space down the street, shut it off, pulled the code, restarted and drove home (30 miles). The last 5 miles if I added any throttle it seemed to lose power unless I went WOT in which case it would run normally.

6 months ago I was having similiar probs. The codes were pulled then (33, 34, 43) and the ECM was reset. Nothing since then until yesterday. I even had it on a chassis dyno over the weekend for a club event and no issues except my BF who drove it down there for me said it was having the same loss of power when adding throttle.

I've had the car for over 12 years, 2 divorces and 3 BF's. I gotta get her fixed fellas.....

 

Check the TPS. I know that sounds weird, but... trust me. Make sure the voltage isnt too high with the throttle closed, and make sure it moves steadily upward as you open the throttle. Should read from .45v-4.2v, or thereabouts. I have never had good luck setting the TPS higher than about .45-.5v, and with the throttle all the way open it should hit at least 4v, if not more. Might get all the way up to 5, seen it happen.

 

I see a code 34 mentioned there. Do you have the updated PROM chip in that car or is it running the factory original? If it isn't the updated prom, then that is your first thing to do. There was a TSB released many years ago on the 85 TPI cars for corrupt proms and false code 34 is one of the major things it fixed.

 

i have an 85, i replaced the maf about 7 months ago now im getting a code 33 once in a while, by reading this post i never changed the maf burn off or the maf power relay. whats so special about 85 and this code 33 ? and i dont know if this 33 code problem has to do with another problem ive been haven incunjuction with this code 33, like high rpm struggleing past 3000 rpm

 

There are no power or burnoff relays on the 85 TPI, both functions are supplied by the $800 MAS module.

 

so why iam i getting this code? it it becasue of the ported plenum? or gutted air box ?

 

You need to adjust TPS to .54 at idle (throttle blades closed), then burn a custom PROM chip with a correction to the MAF Threshold (error 33) constant. The stock value in the stock PROM is 45 gm/sec. You need to change it to 55 gm/sec and re-burn the chip. This will probably take care of your code 33 for good (provided the burn-off relay is in good shape).

Just my $.02

 

Well, if you get a custom chip, set the flow rate at 255 gms/sec. I guarantee that you will not set a 33 error code again.

As I said before, the for sure way to get rid of the 33 error code is a custom chip. I did one for a guy from Cleveland area. He was as fustrated with it as I was several years ago. He came up to my house, I read his Hypertech chip, editted the right stuff, and burned a new chip for him. He went away happy and a recently checked with himw, the 33 error code never came back and its been about one year.

85 IROCZ Lady:

I know what you are going thru. My advice to you is to go over to the EPROM message board on thirdgen here and see if anyone knows how to fix this problem. Do not ask someone to burn a chip directly. If someone over there lives near you, send him/her a private message about burning a chip for you.

 

i got the code again,when i get my code my car starts idleing crazy going from 500-1500rpms back and forth, then when i went home to check things out , i was trying to rev it up and u can hear the air sucking in but the tpi like rejected it and wanted to stall every time i try to rev it this never happen to me b4