I'm All MAF'd out - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


General GM Chat When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made. Chat about all things GM (and related cars). Off-topic stuff should be in the Lounge, and all Model specific mechanical problems should be posted in the proper forum.

Reply
 
 
 
Thread Tools Search this Thread
Old 12-29-2010, 09:41 PM   #1
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Dec 2010
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
gamarines2 is on a distinguished road
Default I'm All MAF'd out

Folks,

My daughter'* grandma car had a check engine light since I bought it at an auction. It had a code 34, but ran fine so since the sensor was so darned expensive, she just kept running it. On several trips, she has some major power loss issues, but was always able to limp home. About a month ago, it didn't have enough power to get out of the driveway, so there it sits. I convinced her to buy an aftermarket sensor for big $$ (for a student anyway). Now the car will not run unless I manually open the throttle while she starts, and then it will idle OK but die immediately under load,even with this new sensor on it. And the ECM is still throwing a code 34 at us.

I bought and replaced the connection pigtail, thinking maybe it was bad.....no help.

I have checked for vacuum leaks and have found none, any suggestions where I might concentrate my search?

I have checked the circuit diagram and don't see a relay; only a connection to PCM (yellow wire) and Fuse panel (pink/black), and of course ground (black).

WHAT AM I MISSING?
gamarines2 is offline   Reply With Quote
Old 12-29-2010, 10:47 PM   #2
Senior Member

True Car Nut
 
sseidriver97's Avatar
 
Join Date: Mar 2010
Location: Portage mi
Posts: 7,124
Thanked 3 Times in 3 Posts
sseidriver97 is on a distinguished road
Default

first off welcome to the forum it would help greatly ifwe knew what year make and model and trim this vehicle is..i would test Fuel pressure first and foremost..sounds similar to symptoms of bubba when his fuel pump died
sseidriver97 is offline   Reply With Quote
Old 12-29-2010, 11:27 PM   #3
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Dec 2010
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
gamarines2 is on a distinguished road
Default

Sorry. Buick Century Custom 1989 3.3 liter. Fuel pressure checked out. It seems when I do get it running that it is running extremely rich.
gamarines2 is offline   Reply With Quote
Old 12-29-2010, 11:33 PM   #4
Senior Member

True Car Nut
 
sseidriver97's Avatar
 
Join Date: Mar 2010
Location: Portage mi
Posts: 7,124
Thanked 3 Times in 3 Posts
sseidriver97 is on a distinguished road
Default

have you tested coil voltage
sseidriver97 is offline   Reply With Quote
Old 12-30-2010, 01:31 AM   #5
Retired Senior Admin

Expert Gearhead
 
Danthurs's Avatar
 
Join Date: May 2006
Location: Sheboygan Wisconsin
Posts: 29,661
Thanks: 0
Thanked 16 Times in 13 Posts
Danthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to allDanthurs is a name known to all
Default

Code 34 is your MAP sensor, not your MAF, big difference. With a bad MAP the car will run very badly, no power, may not shift right, incorrect AFR. Also easy to change, and far less expensive then a MAF.
Danthurs is offline   Reply With Quote
Old 12-30-2010, 07:43 PM   #6
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Dec 2010
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
gamarines2 is on a distinguished road
Default

I am not so sure this car has a MAP sensor. Aren't MAP sensors on throttle body injected machines?
gamarines2 is offline   Reply With Quote
Old 12-30-2010, 07:49 PM   #7
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Dec 2010
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
gamarines2 is on a distinguished road
Default

I will test the coil voltage as suggested.
gamarines2 is offline   Reply With Quote
Old 12-30-2010, 08:26 PM   #8
Administratus Emeritus
Certified Car Nut
 
GXP Venom's Avatar
 
Join Date: Jan 2006
Location: Purgatory, Pennsylvania
Posts: 16,538
Thanked 7 Times in 4 Posts
GXP Venom is on a distinguished road
Default

Quote:
Originally Posted by gamarines2 View Post
I am not so sure this car has a MAP sensor. Aren't MAP sensors on throttle body injected machines?
RockAuto says your engine has one ( http://www.rockauto.com ) Always best to first attack what the cars computer is telling you the "fault" is.

Related Parts1989 BUICK CENTURY CUSTOM 3.3L 204cid V6 MFI (N) OHV : Fuel/Air : Manifold Pressure (MAP) Sensor WikiPriceORIGINAL ENGINE MANAGEMENT Part # MS21 **#16017460, 16137039, 21020103, 33000153, 8161370390, 8161580550, 8933000273}
(Only 1 Remaining)
$29.79Add
GXP Venom is offline   Reply With Quote
Old 12-30-2010, 09:11 PM   #9
Junior Member
Posts like a Ricer Type-R
Thread Starter
 
Join Date: Dec 2010
Posts: 13
Thanks: 0
Thanked 0 Times in 0 Posts
gamarines2 is on a distinguished road
Default

well, my code reader not only gives the code, it spells out the fault, and it clearly says MAF or MAF circuit problem. Please don't be condescending...it is not helpful. I have been around cars; just new to this forum. The Haynes manual for this car doesn't show a MAP sensor in the wire diagram for engine controls, nor in the location photos of various emissions/engine controls. A MAP is shown for 2.2, 2.8, and 3.1'* but not for the 3.3. So based on your advice, I checked the engine compartment over very carefully. I traced each vacuum line coming from the manifold area,and cannot find a sensor that has both wires and a vacuum line attached. If there is a MAP sensor, I have not found it.
gamarines2 is offline   Reply With Quote
Old 12-30-2010, 09:18 PM   #10
Administratus Emeritus
Certified Car Nut
 
GXP Venom's Avatar
 
Join Date: Jan 2006
Location: Purgatory, Pennsylvania
Posts: 16,538
Thanked 7 Times in 4 Posts
GXP Venom is on a distinguished road
Default

Didn't mean it to sound condescending. I just checked with Rockauto whose database I've used alot and found it pretty faithful. And the statement about trusting the cars computer was pointed at another poster who'* advice steps around that. I'll look into it here a bit more.
GXP Venom is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
All of you MAF guru's out there....(fixed) forest20 Pontiac 7 01-13-2012 12:14 PM
All Out of Amour All Maymybonnieliveforevr Detailing & Appearance 14 09-07-2006 01:45 PM
turns out i've had an engine all this time after all.. gbrl21 Your Ride: GM Pictures & Videos 7 07-23-2006 02:46 PM


Tags
34, maf

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 03:20 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.