So i got the code 33 in my 87 Camaro 305 TPI. It only kicks on when the car in warm. So if i start it up in the morning take it to work 15 or so miles it is fine. shut it off and back on and the light come on. If i then drive it is has lost power and seems to idle funny. I changed the MAF but still does the same thing. Check the TPS and it is set fine. Also changed the Manifold Air Temp sensor cuz it was black. still no luck. Also the car gets really hot quick. I changed the thermo and it was a 87 degree day but i went on a 1hr ride came back to the park camaro and it was still hot. The radiator was flowing fluid and i aint really worry about that just a side note. But any other ideas on the MAF code 33 issue?

 

The MAF burn-off circuit will not throw a code till the next start, because it is only used for a hot sec at power shut down (key off). Check the relay.

 

Pandin is right, check the relay. I had the same issue before. I think I paid something like 6 or 7 bucks.

What was strange with my situation was, if I put the key in and prime the fuel system before starting(like I always do), it would set the code almost every time and the check engine light would come on. But if I would start the car right away without priming the fuel system, the light wouldn’t come on. I ended up replacing both the power and burn off replays.

 

they are both new and same issue. Also this does it all day once the car is hot and it runs like crap. I am getting the code 33 not a burnoff problem code. Any ideas?

 

As posted here at TGO:

"There is a code 33 troubleshooting chart here:

https://www.thirdgen.org/techbb2/show...hreadid=245300 (Source of MAF code 33?)

in short: Code 33 indicates:


ECM has seen flow in excess of 45 grams per second (above 2.2 volts) for one second when:

* Engine is first started
OR
*TPS < 50% AND RPM < 2000"

Per DOC:

"FYI: the 33 error code is set when the following 3 conditions are true at the same time:
1) engine under 2000 RPM,
2) MAF reading over 45 gms/sec, and
3) less than 25% throttle."

I would check/change TPS, MAF, and Ref pulse components, wiring, and connectors. Don't just buy new, find somebody with a known non code 33 set up, like yours, and swap parts one at a time till trouble moves. Also data log, then graph the area's of interest looking for spikes or opens. Remember that the best data logs only sample once every 1/10 of a sec, so a lot can be happening that can't be seen.


HTH

 

connector to the mafs

 

It is a new harness from TPIParts.net but i haven't checked that. The connector seems tight. new wires and everything. How can i check it?

 

At idle: what is the TPS voltage? What is the RPM? And what is the static timing? Also, can you scan the ECM while driving around?

Do you know how to reset the ECM to clear error codes?

 

i don't remember the voltage but i believe it was 6 something. rpm is 876 and static timing? no idea? i can scan it but i will have to borrow it again from him. and you reset the ecm by disconnecting the neg term on the batt.
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I do want to state that i change the intake air temp sensor because it looked rusty sure enough it was black when i pulled it out. I put the new one in. the motor idled up and down when i reset the ecm and the light stayed off for about 30 mins. i drove it around the block shifted through all gears. shut it off and on. 4 times or so in a row no light. then the 5 time i started it. it shut right off. turn it again same thing. i had to hold down the peddle to get it to idle after 2 mins it would idle on its own. now it is missing real bad and the 33 code is back? what do you think happened there? also i check the maf and it was only reading 6gr at idle? when i gave it gas it went up so that seemed off to me?

 

Maybe this pic from the GM manual will help find the issue.

 

Yeah i just figured out how to read those charts. I have the tpi swapper guide and it has the same thing. I just need to find my test light to do the test. My last post about the mis, I unplugged the maf and intake temp sensor and it still does the same thing? Any ideas?

 

Check/replace TPS

 

when i had the car on the scanner yesterday it seemed pretty steady (TPS) so idk whats up with it. The 1 cyl plug looked clean.

 

What are you setting your TPS at?

A bunch of cars that have a code 33 issue is the fault of GM and setting the diagnostic threshold too low. If you modify the car it just makes things worse. Stock chip?

 

TPS is at 6 i beleive and everything is stock except. K&N Air filters, air foil, 3in exhaust catco cat, headers, and msd ignition.

 

If you used too much of the oil for the K+N's it could have coated the wire in the MAF and screwed it up. Do you have the thin wire style MAF?

 

just to confirm with everyone. I just tested system with the flow chart in the tpi swappers book and it said bad maf. I just bought a new one and still same issue. Also tps is set at 6.04 at idle and if i rev it, it goes down. I didn't put any oil on the filters as they are new. So if there is to much it would be k & n fault. I did get the light to go out after i disconnected the batt but it still had the miss. i check the first 4 plugs and they looked fine. Anything else i can check i am stumped. still

 

6.04 what?
TPS should be around 0.5V at idle and 4.5V+/- at WOT. If the voltage is high and goes down, the TPS is bad or you're checking it wrong. No way should it be 6 volts.

 

i had the meter on volts 20 range.

 

You measured from power to sweep, try gnd to sweep.

Pay attention to the red and black leads, the red lead on power, black lead on gnd, gives a plus reading (it won't change when moving the throttle, key on, engine off).

Then move the red lead to the wire that moves when the throttle is moved (this wire is the sweeping one). The reading will then be low at idle position and high at wot position.

 

I will check that out tomorrow after work and let everyone know. However i did a IAC reset and it seems to help but i had to run somewhere and couldn't check it out fully but i didn't have a light and it idle much better.

 

ok so i checked the tps and that is reading .55 and 4.75 wot. Good bad?

I checked out the IAC and when i did the reset it would click which i knew it should be doing but it wasn't steady. I put a new one in and the new one was steady clicking. I reset that one and started the car. no problems. i ran it for awhile drove it for 15mins so the computer could reset. shut it off and back on and then the light came on. 33 again. Any ideas guys? I am confused haha

 

As I have said before, the only way that I could get rid of the dreaded 33 code was to burn a chip. I am surprised that you are getting the code with a 305. What have you changed in the entire intake system, airlid, air filters (K&N), intake manifold, porting work, runners, plenum, cyl heads?

You might try setting the TPS voltage at closed throotle to 0.64V. Doing this may nullify one of the three conditions that someone posted above. To the best of my knowledge, the 33 error code will only be set when all three conditions are true at the same instant in time.

 

Have you ever had a radio with a volume control that would get static when turned but be okay when set. Your TPS is the same as a radio Vol control, they get used the most in that favorite spot. Think about your car being run on cruise, how long and many times is it used in the same little area.

You are quick checking your parts and then asking what else, swap your TPS with a "known good one" (non code 33).

Then try a different (non code 33 ECM), something is causing the three things Doc pointed out to cause your code 33.

A bad/intermittent connection will cause this kind of trouble and is very hard the find, it could be heat or vibration related (mice like to live in the dash wiring, it chews wells).

These are 20 year old cars that sometimes have set for years in damp conditions, do you see what the problem is now.

 

to doc. The only mods i did to the car are listed above. Air foil. k&n filter in the stock housing. msd ignition wires hooker headers and exhaust.

to pandin i ran the car hot with the meter plugged in and no change for 15 mins.
.55 and 4.75 wot. i am going to set the tps up a little and see if that helps and the only tps i have is a new one i purchased and having installed yet since i believe that mine it ok. but if it is nessary i might just use it.

Also when i reset the iac switch i folled the direction up until it said unplug the iac connect and start the car. when i did that with the new one it ran perfect and no code. when i adjusted the throttle and replugged it in. i got the code and it idle rough. i then tried to douplicate the good result with the iac unplugged again without success. so the car is all over. Also one thing i remembered is everytime i start the car or adjust the idle. if i shut it off at 1,000 rpms when i restart it it goes up to 1300 if i set it low like 800 and have it idling then restart it it will not run unless you give it peddle.

Thanks again to everyone keeping this thread going. I am trying to fix the code to sell the car. I had a buyer give a deposit but it didn't go through so i am using he money to fixed the code error and get rid of the horrible mis when that code is on.

 

I got the miss to go away. silly me it was the spark plug wire loose. errrrr Well it ran excellent but i got the code to come up when hot. (cold no 33 code.) I checked the tps again cold compared to hot and there is a difference. Cold (.55 to 4.75 wot) Hot .43 to 4.65 wot. Would this kick the code? is this normal of the TPS?