OK WTF!!?? MAF or NOT??

[gmrulz4u]

Simple question:

 

Does my 89 Supreme, 2.8L, have a MAF(Mass Air Flow) Sensor, OR not??

 

Because my Haynes book says cars that do not have a MAF, have a MAP instead, but carparts.com has a MAF listed for my car!!??

 

So WTF??

 

THANKS:)!

[Gearhead43]

What shape is the air cleaner? Round , or regtanular?

[gmrulz4u]

The air cleaner housing is Rectangular...

[Gearhead43]

Then you have a MAP system... look at the top of the intake on the back side next to the firewall... You'lll see a Black regtangular box attached by a clip to the intake thats the MAP

[MARK 91 Z34]

all w bodies til 1993 have MAP, 1994 on.... they are MAF..

[Gearhead43]

MARk... no no.. some of the 88-89 2.8's that used a round air cleaner assembly had MAF

[91GranSport]

All right, now what's the difference between a MAP and a MAF? Also, is it something you need to maintain on a regular basis?

[Gearhead43]

MAP = Mainfold Air Presure

 

MAF = Mass Air Flow

 

Both systems are used to help the ECM calulate the pulse width of the fuel injectors. MAF uses Air Flow to determine the fuel delivery While MAP uses mainfold presure to determine fuel delivery.

 

A failure of either system usually sets off the SES light and stores the pertaining code into the ECM memory

[ctx46]

actually every W-body will have a map sensor, But in the later years they added a maf with sequential port feul injection (instead of the 3 and 3 fire setup), I just wanted to add that little tid bit of info......

[RedZMonte]

MAP = Mainfold Air Presure

 

MAF = Mass Air Flow

 

Both systems are used to help the ECM calulate the pulse width of the fuel injectors. MAF uses Air Flow to determine the fuel delivery While MAP uses mainfold presure to determine fuel delivery.

 

A failure of either system usually sets off the SES light and stores the pertaining code into the ECM memory

MAP = Mainfold Absolute Presure

 

just thought i would point that out.

 

RedZ

[gimp19]

I know for a fact my 88' cutlass has a MAF "mass air flow sensor" it has the round air filter box. I had to replace it this past summer because it was making my car jump around going at steady 30-55+ speeds with cruise on.

My sister's 94 grand prix 3.1 has the square box w/out the MAF sensor.

[Guest TurboSedan]

this is taken from my book "TPI Fuel Injection Swappers Guide" by John Baechtel:

 

"Port Fuel Injection uses two different types of air flow calibration: Speed Density (aka MAP system) & mass flow (aka MAF). it is further characterized by two types of injection: batch or group fire (in our case the 2.8/3.1 MPFI GEN-2 engine), and sequential fire (the 3100/3400 GEN-3 engine) . speed density systems calculate air flow based on input from MAP (vacuum), MAT (air temp), TPS (% open), CTS (water temp), O2 sensor, and Battery Voltage. Mass flow fuel injection actually means measuring air flow instead of calculating it. this allows the fuel injection to compensate for moderate engine content changes (cam, heads, etc.). wheras the speed density system cannot because its fuel map hasn't been programmed to understand or acknowledge fuel requirements that exceed its range. Mass flow sensors would include MAF (air flow), MAT, TPS, CTS, O2, and Battery Voltage."

 

i love this stuff! this book is about the '85-'92 Tuned Port LB9/L98 305/350ci Camaro/Corvette, Firebird/TA engine but alot of the stuff pertains to the 2.8/3.1 MPFI as well. i got the book on ebay but it can be found at Daltons or Barnes & Noble or Hastings or something for $10. i see the 3.1 MPFI as the 60' V6 version of the L98 350, and the 2.8 as the 60' V6 version of the 305 TPI engine.

hth

joshua

[88Intl]

My 1988 2.8 Cutlass has a "SPEED DENSITY UPDATE" sticker on the shock tower:

 

http://www.sts.sae.org/membersonly/techinfo/articles/article6.htm

The 2.8 and 3.1 liter, Generation II V6

--------------------------------------------------------------------------------

 

by Kevin Carpenter

The 2.8 and 3.1 liter, Generation II V6 engines produced by Chevrolet were used by Chevrolet, Pontiac, Buick, Oldsmobile, and Cadillac in certain front wheel drive models between 1987 and 1993. These engines may use a unique air/fuel ratio calculation strategy at throttle openings of 2% or less (i.e., idle). Systems that use this type of fuel calculation strategy include those used on 1987 and 1988 engines which have had a “speed-density update†by means of a mem-cal replacement. This is a change which effectively bypasses the system’s use of the mass airflow sensor as an input to the ECM. When the airflow sensor output is ignored, the MAP sensor’s output is used for the speed-density calculation.However, these systems only operate in speed-density mode at throttle openings of greater than 2%.

[Guest TurboSedan]

so did a dealership convert your MAF system to MAP? interesting.

joshua