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maf sensor

3K views 7 replies 5 participants last post by  thumper 
#1 ·
I looked through the forums and didn't see much on maf sensors. I have been trying to figure out what is wrong with truck since I was able to get back to it after surgery and it doesn't make sense. Replaced fuel pump again (Edelbock external), installed new relay, circuit breaker and reset the ecu. Starts and idles without the maf sensor plugged in but as soon as I plug the maf sensor in it dies. Also while it's idling I push on the throttle just a little bit and it kills it. What am I missing here? 95 pickup 2.3l
 
#2 ·
The MAF is the Mass Air Flow sensor
The MAP is the Manifold Absolute Pressure sensor

I am looking a 95 2.3L engine schematic and I see the MAP sensor connection to the ECM but there is no MAF sensor. Does your engine have both a MAP and MAF sensor?
 
#4 ·
So I just figured out that the schematic I am looking at is for a 2.3L carburetor engine and the 95 2WD pickup with 2.3L was upgraded to a fuel injected engine.

At startup, the MAP measures the barometric pressure so the initial air/fuel ratio is calculated correctly for the elevation of the truck. The MAF is measuring the airflow into the engine so the ECM can adjust the fuel injector duration to produce the correct air/fuel ratio.

There is very little air flow into the engine at idle so the engine will start with the MAF disconnected, but as soon as the throttle is opened there is too much air for the amount of fuel being delivered so the engine stalls.
 
#6 ·
I never had trouble with any of my MAF sensors. I did have a problem with the MAP sensor on my 91 V-6 Trooper (all GM fuel injection). I found then, that all or almost all GM MAP sensors of that vintage were the same (including the ones on ISUZU 3.2 V-6 Rodeos and Troopers). The $3.00 replacement from the boneyard took care of my problem (I think the counter guy pocketed the money). If there is a boneyard near you, this is worth a try (they're usually under 10.00 anyway). I know that some with the 2.6 EFI have had drivability issues because of a hole worn in the intake tube that runs across the valve cover. The hole allows unmeasured air into the intake and a lean condition. This, or an MAF problem shouldn't affect IDLE as there really is very little air flow through the MAF when the engine is idling. Dennis
 
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