How can I tell if I have Mass Air Flow or Speed Density? I want to get a K&N FIPK but I don't know which I have. I drive a 1995 F150 4.9L I6 fuel injected.

 

Right after the air box the should be a mass air meter. It has a plug and 4 wires coming out of it.

If it aint there, its speed density.

 

Look at the intake. If you have 2 separate hoses leading from the throttle body to the air box it's S/D if you have a single hose which is bifurcated at the throttle body end and which leads to an aluminum clyinder mounted on the end of the air box it's MAF. The aluminum cylinder is the mass-air meter.

If you're expecting any real HP gains out of the K&N save your money. The gains from the less restrictive airflow are largely offset by the higher air temperatures. Thry work well on some other models where they provide a high flow cold air intake but on our generation of F150, they mostly add intake noise.

 

Thanks for the info from both of you!

 

'96 was the only year of MAF with the 4.9L...I've heard rumors some '95's did but I have yet to see one.

 

The 95 CA trucks were allegedlly MAF. Living in CO he could have one since Ford may have lumped the "high altitude" spec tuning inwith the CARB spec,

 

That's made life very frustrating for me because every factory service manual lists specs for a MAF 4.9 for '95 California trucks, but I am yet to see one either. I have to presume that the '94 4.9 California trucks were exactly the same as the '95's because there are no factory manuals for a '95 California 4.9. My '95 4.9 is a California truck, it says so right on the emission label, but it's SD, and was built the end of May, 1995. If any '95 4.9's had MAF, you'd think mine would be one of them, being so far into the production run.

Go figure.

 

Well, since you guys are on this topic. Which one is more emission friendly, in that which one over the long haul is better for the emissions that are coming out of the truck? I would have thought that the MAF would be since it is more adaptive to the operation of the engine compared to the speed density that only has specific fuel curves that it follows. If there was something wrong with the engine's operation, I thought the MAF would be better able to correct that problem than the S.D. would. I was rather surprised that California has S.D. instead of MAF, but maybe I am thinking backwards on this.

PRKWUD: Glad to see ya back, how are you doing these days ????

Have Fun & Keep on Truckin'
Dean

 

The MAF system may be slightly more emissions friendly on a stock engine but it's unlikely to be significant. TheS/D lookup tables actually allow a fairly wide range of variance from expected values before they puke. The biggest reason for converting to MAF in 96 was probably the requirement for OBD-II. Start modifying things and the range of allowable variance gets progressively smaller as you move closer and closer to the edge of the table.