Guys on my GTA I keep getting codes 33 & 34 which in my manual is Mass Air sensor.My car is a 88 with the 5.7 TPI.I borrowed a MAS sensor off my buddie who is currently rebuilding the motor in his Iroc same 5.7 TPI. I get the same codes 33 & 34.His sensor is a Bosch mines not. his is like the ones that I'm use to. Screen on each end with the element in plain view inside.Mines totally different ,screen on one end only and the screen is not a wire mesh like the other one it's thicker,also the element inside looks like a circut board. They both have the same female plugs on them,Can anybody PLEASE HELP!!!

 

I Forgot to add,His car is the same year as mine and he just bought his sensor two months ago.

 

Try the MAF Relay .... Under $15 at the Local Dealer. Solved the same problem takes like under 5 minutes to change and was located the most outboard of the three at the firewall.

 

Thanks,I'm a carb guy. When it comes to TPI I'm just learning.

 

I replaced the relay,I guess you ment by the most outboard of the three,the one closest to the fender,the one farthest to the
rite.anyway I replaced it and I've got the same problem,check engine light,codes 33,34 Mass Air.Any other suggestions?

 

You have to clear your codes first by unhooking the battery at the negitive terminal and let it sit for 20 mins. Then take a wire brush while ur waiting for the codes to clear and brush clean the conecter which goes into the MAF (Not the one on the MAF but the plug that comes off the harness). then hook up your friends MAF to ur car, and reattach your battery and fire it up...all codes should be gone. If they gone then hook up ur MAF and see what happens...I had this same problem and what I just described worked for me. Hope this helps

Jason

 

All my connectors are spotless.I checked for cracked wires,corrosion,etc. I also cleared codes by unplugging the power wire to the computer.
You don't need to disconnect the batt. neg. cable to clear codes just the computer power lead for 30 sec.I've done all this several times without any changes.I start the car after clearing the codes and it runs for about 15sec. and then the check engine light comes back on,and I get the same codes 33,34.

 

All three relays are the same you may have changed a good one because someone else switched the position.Try swaping the relay you removed with one of the other two.The one in the middle is supposed to be the Fuel Pump Relay try that one first.If the car wont run (and it does now right) you have your bad relay.If it does run go to the next one.

 

I don't have 3 that are the same.Starting at the fender going left I have two that are the same then two totally different ones stacked in front of one another.

 

Well I dont know what to tell you.All the cars with a MAf Sensor I have ever seen have 3.They are not exactly all in a row,but they are next to each other.Maybe someone has added something extra in your case.Perhaps switching just the two I dont know what else to tell you.I do know this is a very common problem with MAF cars.

 

Thanks for all the suggestions.I'll mess around with it tomorrow and see if I can come up with something.

 

Those 2 outer most relays should be your headlight relays (you are talking firebird right?) They are on my 91 bird anyway. GM liked to move these things it seems.

 

Have a lookie here. And be sure to Thank Vader for posting this pic every time someone had a relay ?? He has the best collection of under hood shots...

 

One picture worth a thousand words. Thanks for posting it.

 

THANKS for posting the pic. I printed it out and I'm going to go see if I can make sense of the mess under my hood.Oh and yes
we are talking about a firbird,GTA.

 

OK I've only got 3 relays Electronic Spark Control 1.MAF Relay and two relays that look like the headlight relay.Today I replaced the relay that looks like the MAF relay.First only unhooked ECM power for 5 min. then checked got codes. Second unhooked neg. batt. cable 5 min. got codes.Third unhooked pos batt cable for 5 min. once again the check engine light came on and so I said **** on it and left the car turned off and left it alone for the next 4 hours.
Then I hop in the car to go get some grub and start her up, and
NO Check Engine Light.I even went out and made a easy pass and still no light.So I'll see how long this lasts.Thanks guys for all the help.Bill

 

Will it was nice while it lasted.My SES Lights Back but this time it comes and go's. For example,I drive to the store no SES light,then when I come out to leave,I fire up the car and it's back,
the d*mn SES light.I pull codes and only get 34 this time no 33 so I'm on the rite track.Any other suggestions aside from me shooting my car.Thanks guys for all the help.Bill

 

Had to bring this back up. Car is still doing the same thing.
I've had it parked thru the winter and just recently painted it and I'm now wanting to drive it but I've got to get this problem figured out first.Most of the time the ses light will come on a few seconds after starting the car. If I drive the car the light usually go's off a half an hour or so later but as soon as I shut it off and go and start it back up the ses light comes back on. I'm only getting code 34. Code 33 has yet to come back so I must of did something rite.I don't know if it's related but in the mornings when I first start the car it fires rite up but say I go for a 15 min. drive and shut the car off for a couple minutes it will start rite back up just fine but if I leave it off for more than 5 minutes and try to start it,it will turn over a bunch before it fires up.
Any suggestions?

 

Check your grounds, especially the ones on the back of the heads.

 

The grounds are fine. Any other suggestions?

 

is that picture accurate for camaros?

 

No idea, but I would think it would be the same.

 

ta bill i sent u an email hopefully u got it if not here we go. splice a wire into 1 of the grounds( i dont remember which 1 i would have to go look @ mycar)@ the back of the maf sensor and ground it directly 2 the body this will take care of that bright light and and performance problems, i was plauged w/ a 33 34 since i bought the car i thought it was fast then but i cant even believe the performance and milage increse since. also the three relays r not the same maf power and fuel pump r but the burnoff is different. some service books and stores refect incorrect usage. i work 4 gm and have held the original service bulliten in my hand if you need part #'s or any more info email me

mmacedo@stumail.jccc.net

 

I'm not really sure which wire to ground.Also do I just run a jumper wire from the ground wire going from the harness to the MAF sensor or do I cut a wire going to the MAF and ground it,if so which one. The code 34 went away and 33 just pops up every once in a while but tonight the car acted like it was loading up and then just died. It fired rite back up but with the SES light shineing bright and now I'm getting both 33,34 again. I appreciate any help you can give me.No I didn't get your e-mail.
I'm very frustrated and would like to get this thing fixed once and for all. Thanks

 

What is your TPS voltage?

Also when is the last time you set min-idle?

 

Being that it comes and goes and being that you don't have Voltage/wiring problems, I would have to say that the ECM or Memcal is bad. Borrow your buddies Ecm, Hook it up and see if this still happens. If this cures it take the Memcal out of yours and put it in his and see if this still happens.

Just my .02

 

I've never checked the TPS voltage but I will. I've never touched the min- idle but I know it idels between 550-600 when at operateing temp.I have a extra ECM with prom from another car.
Same year, same size motor that I can try switching around if you actually think it will do any good.I'm just learning on this FI stuff so bear with me.

 

it would only take 5 min to try it and it could possiably be something that simple. Then you know their are no electrical problems since you check every thing else. If it works Great if not you need to start Some where else. like the control module in the distributor. Fuel Problem. Low voltage from altenator ect. Go one step at a time. you will find it just keep on testing away.

make sure to start at the simplest point forward. Fuse, Wireing Ground out, Coroded conectors ECT.

One day my car would start and Die instantly, I worked on it for about 1:30 checking spark, fuel, Wires. and then it hit me I didn't Check the fuses. I 20 amp fuse later It was fixed the fuse blew due to a wire that had melted and shorted on the block. Man did that sucke

just my .02

 

there are 5 wires comin out of the back of your maf sensor there are 2 grounds (system ground, analog ground) splice a wire directly into the black and black/white wires and ground your spliced wire to the body of the car. make shure that that you leave no wires open. it isnt your prom or ecu it its your grounds i have now fixed 2 cars with this problem.

 

i just noticed that morleys pic is wrong fuel pump and burn off are switched and the gm part #'s r 10067925 for the burn-off relay and 10094701 for maf power and the fuel pump. ta bill e mail me and we'll swap phone #'s and i'll walk u through the repair i know exactly what is wrong, cause u cant have low and high signal voltage at the same time(33&34).

 

hey Mike, I went to the dealership tonight to get the MAF burn off relay and i used the p/n you gave but it came up as the power relay and the burn off relay was listed as someithing different. I don't have the p/n it was listed under but they said it should come in on thurs. so i will post it up then.

 

I took Mike's advice and grounded the black and Black w/white stripe. Code 33 went away but still have 34.I really cant tell any difference when the ses is on. It idels fine and smooth just like when it's not on. I'm going to try the sensor hokey pokey again and see if I can get somewhere with this.

 

hey i really have no helpful info to contribute, but i encourage you to keep workin on it. last summer my camaro would run rough, stumble and slobber off idle, and it would occasionally pop through the intake on light acceleration, but once the engine warmed up a bit it ran real strong. i have no idea what the deal was. sometimes this MAF stuff is like chasing ghosts. good luck

 

Stan

 

i got my burn off relay today and the p/n is 10094701 which is what mike stated was the power and fueld pump relay

 

Installed the Burn off relay and no 36 switched a new power relay with an original relay and no more 34. so i know i have a good burn off relay and MAF power relay. But now i have a code 54. which i think is caused by me swithcing the power relays. so my previously bad maf power relay is on my fuel pump relay?

 

OK, I've now replaced all 3 of the relays that are on the firewall.
But my relays are shaped different. In comparaison to the pic above,the one that hangs in front of my Electronic Spark Control looks just like that one as do the others in the pic but my outter 2 are more round than rectangular like those in the pic,they have 5 wires comming out of them and the numbers printed on them are printed out like this.
__8098__
14089936 If anyone can decifer this?

Anyway got around 50 miles on it and no SES light yet but I'm not holding my breath.

 

WOW ,I just noticed this dam problem has been going on for nearly 7 months.

 

Here is what I found in TPI book:
"Code 33 indicates: ECM has seen flow excess of 45 grams per second (above 2.2 volts) for one second when:
Engine is first started
OR
TPS is less than 1/4 throttle. RPM is less than 2000."

"Code 34 indicates: ECM has seen low air flow for less than 2.5 grams per second (low voltage) for one second when:
Engine is first started
OR
RPM is above 600. TPS is above 6%. To obtain 6%, the engine has to be running at about 2300 rpm in neutral."

Sence you see both codes I would guess you have flaky TPS that makes the ECM hard to figure out what the RPM to airflow relationship is. It also might be TPS harness too.

 

Any comments on the "ground solution" from Mike Macedo?
I mean, it just sounds to simple just grounding those two wires permanentely.
Are there any side effects by doing so?
I have code 36 (mass burn of ) for years now, sometimes the relay clickes twice after shut of, no ses light, but most of the time it doesn't click, or clicks barely, and the ses light (code 36) comes on.
Will grounding those two wires cure my problem?

 

This "fix" essencially provides another path to the ECM ground rather than fixing the wires to the ECM. Problems with this "fix"? The noise from all electric components (A/C clutch, alternator, etc.) will couple to the sensor signals at ECM potentially causing it to mulfunction (other codes intermittently). That is exactly why GM did not provide "Ground drop" right at the fast responce sensors (such as MAF, TPS, etc). Slow responce sensors such as temperature sensors are different because the signal can be filtered out at ECM.

The right way to fix it is to fix a harness. It should be easy to probe the wire resistance from ECM to the MAF sensor to detect which one is a problem.

 

When I can find the time this weekend I'm going to check my TPS and see where it's set at,check the wireing,etc.
All Mike's suggesting is to increase the ground going to the MAF.
The ground wires from the factory are marginal at doing there job.
So basically all your doing is strengthning a weak ground.

I dont see how any damage could result. It's kinda like where you have your battery ground wire going from the block to the battery then you have a smaller wire jump off close to the battery going to the fender. Do you need that extra ground? probably not but when it comes to your car you can't really have to many grounds.

Will the extra grounds help your problem, maybe and it doesn't hurt anything to try it.

 

Well, here we go again, two different opinions...who's next??
Did anyone besides Mike Mekado did the ground sollution, results??

 

Yeah here we go another thread derail.

Ok from what the choices are I would Probe the wires to and check the resistance and see if this problem persists.

Please Lets not derail This because alot of people have the code 33,34 Problem. Lets Work the problem, test,check and find out the solution. If there is a problem with a ground, Probing the harness like formula350_87 Suggested, That will tell you if there is a grounding problem in the harness, try it, post results, then we will know what or what not to try next.

 

Actually it's easy to check if these ground wires are bad. With ignition off measure the resistance between each wire and the chassis. It should read something close to 0. I think 1-2 Ohms is OK since the impedance of the sensor is much higher.

If it is higher than that check the ground wire resistance between MAF and ECM.

 

YES Dutch-Bird I tried the ground thing Mike suggested. I now only have code 34. Please read the thred before posting questions that are already answered in the thred.

 

OK TA Bill, but wil it cure my code 36 as well?
I'm sure it's a ground problem too!

 

Grounding the two wires was a suggestion Mike made. I stated in the thred that I tried it and my results. Will It work for you,who knows,Do a search for code 36. It's probably the fact that you have a cutted maf and no t-tops.

 

Hey Bill,
It didn't help you much, still code 34 right???

 

Not Lately