Where is the baro sencor

[Justifyedbyfaith]

Hey guys got a 89 firebird and well when i scanned the computer it spit out code 33 and 34 map sencor high and low. well my car dont have a map sencor it has a baro sencor. i can fix just about anything i can find. so if yall got any idea where its at please let me know. P.S> its not on the firewall and the only thing that resembles it is the egr possision sencor.

[Christopherrr]

wow...let me read that again.

If I'm right and I'm pretty sure I am...you do have a MAP sensor. And I'm assuming "baro" is bar...if that's the case you have a 2 bar map sensor.

[Benm109]

What engine do you have?

[Christopherrr]

he said firebird, so I assume the 2.8

[Justifyedbyfaith]

yeh i have the 2.8 . and my repair book states that the 89 and earlier does not have a map sensor. and the parts store sells a barametric sencor or baro for short. and i still cant find it.

[Z Ya Later]

Hmmmm, never heard of that before. If you can, go to the parts store and look at the sensor they have. Using that, take a look at your motor. My guess would be its either on the intake manifold or along the air intake ducting. What repair book do you have? Usually the Haynes and Chiltons manuals have illustrations of this stuff.

[Dave M]

I remember this problem from when I had my 88 GTA, but I can't remember what the earlier cars had instead of the MAP sensor. The MAP sensor, for those cars that have it, is on the manifold. For some reason, I'm thinking the MAP sensor was only on the speed density cars and that the MAF cars went without the sensor because the Mass Airflow Sensor (MAF) did that job. And I was thinking they switched to speed density (with MAP sensor) in 89 (at least on the V8's), so if your computer is saying MAP sensor then you should have one. It should be a rectangular black plastic box, like the size of a business card or smaller, on the manifold somewhere. Should easily be visible from the top. Your manual may be a misprint on what years had the MAP sensor. I'm not sure on this info, I'm going off memory and it's been several years since I messed with the thirdgens.

Do you have a MAF sensor in the intake ducting? Are you sure it's not saying the codes mean MAF sensor high/low? Where are you getting the info that the codes mean MAP high/low? From the same manual that says you don't have a MAP sensor? I'm confused... please elaborate on some of these points and I can probably help.

[Injuneer]

Where did you get you "code" definitions? DTC 33 means a MAP sensor problem in the speed-density cars, and a MAF problem in the MAF cars. Same with DTC 34. My Chiltons shows the 88-89 2.8L fuel injected engines are MAF engines. And the list of sensors for them only shows an MAF, no MAP or BAR sensor.

[Justifyedbyfaith]

The manual that i have is a haynes and where i got the code from is directly from the tester. I put in the fifth vin # and it tells what the code means. Now i have started noticing that who ever had this car before me has swaped some things around from year to year. it seems that they have put on many parts from a 90 and between 89 and 90 they made some major changes like a map sencor. And when i got the car they kid said that someone had put in a 3.1 liter cam in it and he could never get the timing right. so i am wondering if they also put the 3.1 computer in it too. i do believe that the 3.1 has a map sencor. my parts car is 88 bird and i am contimplating pulling the cpu out of my parts car and seeing if it is the same as the one in my 89. they both have the same motor so i think it should. the motor on my parts car ran fine and did not have the service light. (but it did have gas in the oil so im not wanting to jack with pulling it out.) I just need this motor to last till january cause when i get my taxes back i am putting in a carburated 350. no more computer bs.

[Dave M]

The 89 2.8 is an MAF car. They switched to speed density in 90. That means, if the car is stock, you shouldn't have a MAP sensor, but you should have an MAF sensor. It's located in the intake ducting. It would be a black plastic tube about 4" long right up near the radiator and would have part of the wiring harness leading to it. Chances are your MAF is bad. Do you have any driveability problems like stumbling or stalling?

[Justifyedbyfaith]

yeh it stimbles and stalls and when ever i stop. The parts car that i picked up had has the mass air flow replaced 2 months befor i got it so i already have changed it. Along with my stumbles and stalls i also get tapping when i first start it up and when i am excelorating from a stop. I put the factory cam back in it fixed the intake leak new lifters pushrods and valve cover gaskets. so im not sure what else would cause the tapping and stalling

[Dave M]

Stumbling and stalling at idle is a symptom of a bad MAF, and since you've got the code 33 and 34 I'd say there is still a problem in that area. The relay for the MAF may be bad. Happened to me on my 88 5.7. The relay should be on the firewall... check your manual. It's a cheap and easy fix if that's the problem, so it's worth a shot.

[bru333]

I agree with Dave, check the relay. The 2.8 has the relay next to the radiator, passenger side (V8 engines it's on the firewall). Also check over the wires, could have a "backyard" repair done that is making intermittant contact.

VIN S, engine wiring and sensors

Sounds like this car has Previous Owner Syndrome real bad!

Good luck with it!

[Justifyedbyfaith]

hey where getting close. i changed out the relay out of my parts car and cleared the code by leaving the neg bat cable off for a couple minutes. When i started my car up i bout did the jig when the service light went off and then it flickerd and came back on steady . so i tryed it again with another realay(seems to be a comon relay) thinking maybe that one was falty but the other one did the same. its dark now and i do all my work in the gravel drive so im thinking that i will put my old maf sencor back in tomorrow and see if it makes any changes. but im happy that it went off for at least a second that means im on the right track. any more ideas would be greatly appreciated. (the ole ladys b-day sunday so i gotta fix it tomorrow)

[Justifyedbyfaith]

hey hey yall are my heros. went out this mornin and low and behold there was a bad conection. started her back up and no service light. but i still have a bit of a knock. am wondering if when i set the timming if i was just defeating my purpose with the maf not reading. its kinda a pain in the rump to get to the distributor so will wait to mess with that. also i noticed a sencor that was broke off on the passenger side back of the block i changed it with my parts car not sure what it was but it was in the water jacket. well gunna go test her out.

Thanks bunches.

Richard