i keep getting these codes 33 and 36, both of them point to something with my mass air flow sensor. does anyone know what they mean exactly? i've tried 3 different sensors, and i keep getting the codes. the sensors havent been new ones, but still i figured one of them would be bound to work. i've reset the computer every time i change it. do you guys think maybe i have an electrical problem on that wire that plugs into the sensor? if so, how do i check that the voltage is correct?? also, do you have to calibrate your mass air flow sensor if you change your motor from a 305 to a 350, or if you change your injectors, etc... thanks

 

You will set the 33 error code when:
1) under 2000RPM,
2) over 45 gms/sec, and
3) less than 25% throotle.

Do you have an auto or manual tranny? If auto, try resetting the ECM to clear the codes, and then drive in D not OD, and see if the code shows up agian. The purpose of this is to get above 2,000 RPM before qualifying on items 2 and 3 above.

Also, do you feel the engine booble a bit just before the check engine light comes on? And with the 33 error code, you should be in "limp home mode".

The TPS has to do with the third item above, so by setting the TPS voltage at closed throotle to something different (or setting it to spec) may prevent the 33 error code coming back.

And also, a bent pin in the MAF connector, broken wire, or a non-functioning MAF burn-off relay can also lead to the 33 and 34 error codes.

 

After swapping the MAFs you cleared the codes yes? If so I'd be swapping in relays now.

 

Same problem happening here!
Haven't checked the codes yet, but it "bobbles" slightly, then the light comes on for about 10 seconds.
I had switched my MAF out to one of those new Granatelli ones a 2 months ago. I think I forgot to reset the ECM before doing so and haven't since the codes either. Should I just try that or adjust the TPS as well?
I've also been driving in OD for the past month for fuel economy and have been at lower rpm's when it occurs.

 

yeahh exactly... is it the same problem as mine? i get the code sometimes, and sometimes i dont... it'll also come on sometimes a few minutes after i start it, then it'll go off after a while of idling.

 

i'm pretty much always driving in OD, so it usually happens during a normal steady speed with rpm's below 2000.

 

Replace MAF and MAF burnoff relay or atleast swap them around to see if the code will change from a 33/34 to a 36.

 

Same problem here with the 33. Changed MAF, relays, new TPS (adjusted correctly) and even have custom chip with parameters set far out as to not trip the 33... still get it all day. Going to check wiring next or get a sledge hammer and start smashing the motor. $7000 under hood this year and the car boggs with code 33, damn gremlins...

 

I put about $4,000 into my 350 TPI back in 1995 and I kept coming up with the 33 error code. I changed all this stuff listed above and still got the 33 error code.

Then from this board and my factory service manual found out the 3 conditions that will set the 33 code while you are driving, they are listed above.

I tried several settings for the TPS but with limited success. Finally a ordered a custom chip from a guy near Detroit and the problem was gone forever.

Couple years later, I learned to "burn" my own chips on this board, and learned how this guy fixed my 33 error code.

Getting a custom chip is the only for sure way to get rid of the 33 error code. I have said this many times on here over the last 5 years. Last year, a student at Kent State posted about this problem. He came up to see me and I fixed him up.

 

sweetness man... i might do the same. give me your info, and ill contact you about a chip. my screen name on aim is balkey312 or bigguschiefus. email is skycamefalling@optonline.net im in long island ny. thanks again

 

Will getting rid of the code via chip stop the surging "bobble" I get as well?
Is it harming the engine whatsoever driving in OD all the time in that 25% throttle range?
What exactly is modified in a custom chip to prevent it from coming on?

 

i really have no idea, but im sure its not hurting the engine... i just checked my codes again, im getting 33, 36, and 45...... im not sure if they are all linked together... 33 and 36 are both MAF sensor codes, but 45 is a rich exhaust code, so im thinking they are all linked to the maf sensor maybe not being calibrated right, or the computer not doing the right thing. anyone w/ some info? thanks

 

There are two things I alter in the Eprom, 1) un 'x' the code and invrease the flow level to set off the code to 255 in place of the current 45 gms/sec.

I think that increasing the flow rate to set the code would most likely be sufficient.

I strongly urge you goes to learn how to program your own Eproms. This capability opens up a whole new world for you and MODS.

 

Chief, I had the same issue as you after I built a new 350 TPI for my '89 Firebird. The MAF had the correct output and the sensors were fine. Turned out I had a bad computer. Keep in mind a few things should you find this is the problem after replacing all the sensors. If it is your computer, make sure the company you buy a new on from replaces all 4 quad drivers which control the fuel injector pulse. If they do not you could experience the issues you are. 9 out of 10 times, if a computer goes bad, it is a quad driver issue. What the rebuild companies do is replace only the non-functioning drivers. Keep in mind if one driver goes damage to the rest usually occurs. However in a bench test the damaged driver may appear working well, but under driving conditions it is not working. In serve cases the problem can cause your exhaust cat to heat up and turn red. Also the computers in these cars can only diagnose problems in an engine to a limited capacity. The computer cannot diagnose a problem with itself. If it has a problem with itself, it thows a code for the most likely problem, even though it is the wrong one. Hopefully I haven't lost you too much. As for the computer make sure you talk to a remanufacturing company and request all 4 quad driers are replaced, it may cost a little more, but will save ya a lot of headaches in the long run!! Just something for you to keep in mind should your problem not be a simple sensor change!!!

Wayne Donovan

 

you know... that sounds like the best reason for it b/c i've looked at the computer in the car, and im pretty sure its a junk yard computer cuz it says like 4cyl 5spd on it lol.... i mean it works, but its giving me those codes. i've been driving the car for a year now, and i've put about 2k miles on the new engine... ill look into a new computer thanks man

*also do you know how much it would be?

 

Chief,

Honestly I do not know. Before I did the research I did and found out about the computer issues, I bought one for about $100.00 with exchange. Fortunately for me, I have a great mechanic that helped me out with this, and took a chance, one he said he hopes to never do again, and opened the computer, found the bad quad drivers and replaced them with some he knew were working correctly. Keep in mind that on a lot of these computers they are interchangable. I bought the computer for mine from a local (shhh....) Corvette parts company. The only difference between these 2 cars is the Eprom (computer chip) that is used. The best advice, talk to whoever you want to buy from, explain to them what you know, and see if they can sell you a computer with 4 new quad drivers, not one that is benched tested fine! You may pay a little more, but the headache you save will be worth all the expense! Best of luck!

Wayne


"..do the reaseach, pay a little more, save the headache for something else":

 

yeahh thats true. ill try and find out if they are bad. thanks man

 

Well I just changed my computer 6 months ago, so I'm sure it's not that.

I tried driving in D instead of OD and it still came up 1 time then goes away after about 10 seconds. I normally go easy on the throttle in general so I don't know.
It still has that bobble, weird surging every once in awhile as well even if the light doesn't always come on.
Other than that she drives great.
It's probably something with that adjustable MAF I have now. hmm.. .

 

yeah man, sounds exactly like my problem. hopefully we can work them both out... anooyingggg