Concerned whether I have M.A.F. or Speed Density in my '91XLT.
I checked the air tubes and did not find a sensor.So I'm assuming it's S.D. I only checked the tubes near the air box.Would they be closer to the throttle body?Could not find any info in the owner's manual or the Haynes manual.The reason I'd like to know is I've been reading over some old threads concerning K&N's drop in air filter,and how the treating oil contaminates the fine wires of the sensor,causing performance problems.
I have not seen any oil deposits in the tubes.

Thanks

 

MAF wasn't a stock feature on the Bronco unitl the late 95-96 model year. The Speed Density engines can be converted to MAF. The stock mass air setup combined the twin air intake hoses into one larger hose with the sensor near the airbox. The larger hose split into twin hoses at each end....presumably so Ford didn't have to redesign the throttle body and airbox that utilized the twin hose setup. In short, unless someone did the swap, your 91 is speed density.

 

Thanks greystreak92.Just wanted to be sure.

 

'94-95 California trucks were EEC-IV MAF - all others were EEC-IV MAP. All '96-up trucks were OBD-II MAF.

 

Ok.So I have the s.d. with tha MAP(which stands for?) sensor.
Could someone enlighten me as to where this sensor is and how
this unit functions?If I remember from previous threads,the maf
measures air intake and adjusts engine conditions accordingly?
And the s.d. is already programmed to encompass a wide range of engine characteristics?
Thanks

 

If i remember correctly MAP stands for manifold absoute pressure. It measures the vacuum of the engine. fuel delivery is based on the map and TPS primarily. That is why any change that affects the engine vacuum (i.e. cams) screws the computer up. Hope that helps.

 

Yep - jeep is right. The early ones were voltage-varying and were mounted to the R inner fender near the starter relay. But the vast majority of MAPs are frequency-varying and are mounted to the top firewall stud for the evaporator cover. You can see both locations in the GP Pics in my signature.

 

Thanks.The only mod. I have plans to do are headers and 'y' pipe
to a hi-flow cat.Will this set-up any future problems?

 

Not if you mount the HEGO properly and keep the smog pump hooked up.