Where is the MAP sensor on 85, Code 34.
Thread Starter
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
Where is the MAP sensor on 85, Code 34.
I have a Code 34 problem since long time but have no driveability issue, Code 34= Low manifold air pressure. Where this little critter located at?. anyone have clue where to look for and how to get rid of this code 34. Thanks in advance. sami
Race Director
Joined: May 2006
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From: Phoenix Arizona
To quote from the GOOD BOOK.........."A low, rough, or unstable idle could result in a code 34. Also be sure the air ducts are tight and not cracked. Check ckt 998 for a potential short to ground. Code 34 could also result from a dirty or misadjusted throttle body."
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
You shouldve listened to Pete, you dont have a MAP.
Its a MAF code, either the MAF sensor or the Burnoff Module which is buried inside your passenger side dash.
Its a MAF code, either the MAF sensor or the Burnoff Module which is buried inside your passenger side dash.
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Melting Slicks
Joined: Oct 2004
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From: Austin Texas
MAF (Mass Air Flow):
In a "mass air" engine control system, as used in the 94 and later F-bodies, the PCM only needs a few pieces of information to manage the air and fuel mixture. The most important is the amount of air entering the engine, to be used for combustion with the correct amount of gasoline. More specifically, it needs to know the "mass" of air, or the number of pounds or grams of air that entered the engine to be used to burn the gasoline.
The MAF sensor works by internally measuring the temperature of the air coming into the system. It then uses the wires to heat the small amount of air that is actually touching the wires, a fixed number of degrees above the incoming air. By measuring the electrical power required to heat the air, and knowing the specific heat of air, the MAF sensor can calculate the "mass" (or roughly "pounds") of air entering the engine. It then converts this signal to a variable frequency output. Inside the PCM, there is a calibration table that converts the frequency to a "mass air flow" rate.
In a "mass air" engine control system, as used in the 94 and later F-bodies, the PCM only needs a few pieces of information to manage the air and fuel mixture. The most important is the amount of air entering the engine, to be used for combustion with the correct amount of gasoline. More specifically, it needs to know the "mass" of air, or the number of pounds or grams of air that entered the engine to be used to burn the gasoline.
The MAF sensor works by internally measuring the temperature of the air coming into the system. It then uses the wires to heat the small amount of air that is actually touching the wires, a fixed number of degrees above the incoming air. By measuring the electrical power required to heat the air, and knowing the specific heat of air, the MAF sensor can calculate the "mass" (or roughly "pounds") of air entering the engine. It then converts this signal to a variable frequency output. Inside the PCM, there is a calibration table that converts the frequency to a "mass air flow" rate.
Pro
Joined: Feb 2005
Posts: 560
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From: Hamilton New Jersey
So anyway about your problem, obviously you need to diagnose a code 34 for a MAF system and not a MAP system, here is a link to a flowchat for a code 34 on a mass air flow system http://www.chevythunder.com/maf_code_34.htm if I were to venture a guess I'd say you need a new MAF sensor, it's either that, a short, or a ECM.
Racer
Joined: Jul 2004
Posts: 434
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From: Santa Barbara Minnesota
I believe the correct code is 24 .. MAP
I just recently had this very same problem after getting my new motor running. My car is an 86, but built dec. 85 .. Over 10 years I never had this code .. but when we started the new engine .. code 24. I eventually brought the car to Larry at Camarrillo performance, he dyno'd and chipped it before. He said it needed the MAP sensor .. which it did not have. It is located underneathe the TPI. at the rear .. So the whole Fk'g TPI. has to come off to get at it. He ran a new wire from the ECM. to the new sensor, and code gone .. also put in new 24lbs. injectors while it was appart, and the idle control motor. ??? Code 33 and 34 are MAf issues .. I was never able to resolve my code 33 issue, I hav 3 maf's everything replaced .. we just programmed code 33 out of the chip .. weird stuff?
Race Director
Joined: May 2006
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From: Phoenix Arizona
I think that was the MAT (manifold air temp) sensor. code 23. The only tuneport vettes with MAP were the 90 & 91 L-98. I believe code 24 is vehicle speed sensor.
Last edited by zr1fred; Dec 30, 2006 at 10:04 PM.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Sami, you have no MAP, and that's why you are lost.
Your code is for a low MAF voltage, either from a bad signal wire, connector, MAF, or burnoff circuit.
Your code is for a low MAF voltage, either from a bad signal wire, connector, MAF, or burnoff circuit.
Racer
Joined: Jul 2004
Posts: 434
Likes: 0
From: Santa Barbara Minnesota
I stand corrected .. code 23
yup, that's it 23 .. I wasn't sure, it's been about 2 mo.'s now .. anyway, my old motor didn't hav it .. there was a plug where it was supposed to be? But that is correct, code 33 and 34 are maf. issues .. like I said I was never able to resolve my code 33 issue, and I replaced the MAF. ECM and relays.
Thread Starter
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
I got a used maf burnoff module, will plug in lets see what it does, actually i wanted to hear the members who have gone through this code, and what they did. I sure hear ya, i know what u said long time ago about it. Dont be disappointed pete.
