I have pullin my hair out trying for weeks now to round up information from ford-trucks.com on the MAP sensor mod and they havent gotten back to me yet, so im sayin forget 'em! Ok so does anybody out there know how to preform this mod correctly? has anyone preformed this mod on there own rig? if so any power gains? worth it? any info would be greatly appreciated as i have no more hair left to pull out. Thanks

 

the only map sensor mod i have heard of is a boost control valve. if you mod your truck to produce more than 24 psi you will not get all the performance you can unless you do something to the map sensor. what happens is if the map sensor sees more than 24psi boost it will send a voltage signal to the pcm which activates the ses light and sends a signal to the fuel system to defuel the engine. a boost control valve goes in line from the manifold to the map sensor and will bleed off anything over 24psi thus keeping fuel flowing when the turbo makes more than 24psi. some chip manufactures use electronics to fool the map sensor

 

OK, here's the deal.

If your MAP sensor sees more than around 24 lbs of boost, it will tell the ECU to start defueling your engine- to limit any further boost increase. If the pressure rise continues, it'll set your check engine light. IF this applies to you or you have a chip or any other mod(s) that will raise your boost to that point, read on. Otherwise, the mod will do nothing for you.

There are two ways of preventing this defuling which limits your maximum power. One way is electronic. A zener diode is connected to one of the wires coming out of the MAP sensor, which fools the ECU into thinking there is no excess boost occurring by limiting the electronic signal from the MAP sensor. Search the truck sites or google using the terms zener diode and MPA sensor and you'll find many places where the mod is described. The zener diode is only a dollar or two.

The other way to fool the MAP sensor is to install a little pressure regulator in the 3/8" rubber hose that runs between the intake manifold and the MAP pressure sensor. I use a little adjustable 1/8" NPT regulator, 30 PSI gauge and barbed brass fittings (from Grainger) and a small air bleed hole on the downstream (MAP sensor) side. This little air regulator is a miniature version of what's on a tire air compressor. Mine is set to about 23 PSI, that means that the air pressure on the sensor side is limited to 23 PSI, regardless of what it really is in the manifold. Some performance shops on the web sell a setup like mine, or you can build yourself for maybe $25. Search and you'll find the instructions here and there on the web.

 

Hey Paarothead, If i remember correctly, the MAP sensor tube from the y pipe is 1/4 inch isn't it?? Just want the guy to get the right parts the first time.