trex

why do people notice power gains when the map sensor is unplugged? I notice that i can puff some smoke when i want to and it seems to have more low end. It also runs really rough, why is that. My next step is some injectors but it will take some saving gotta slow down on the scotch for a while. but i can do it!

oestreich84

Since there is no manifold pressure signal going to the ecm, the truck gives more fuel. Most of the gain is in the way the truck responds at low rpm. Somebody dynoed with it unplugged and gained, I think, about 10hp. The only box that I know it works good with is the comp, other seem to run like crap with it unplugged. When I still had my Van Aaken box, I unplugged the MAP sensor and it gave a good boost in low end response, but I had a check engine light.

trex

thanks that makes sense now. i noticed that you have the holley blue inline pump what kind of fittings did you have to get to make it work? can you get what you need at a advance auto or something similiar?

b.t.w. noticed 36 psi without map sensor 33-34 connected.

oestreich84

I used two 3/8" compression fittings. I measured the width of the pump, and subtracted 2 and a half inches. I cut out the section of line, put the Holley in, connected the lines, and hooked up the wiring. Total price was about $80, and fuel pressure will not drop below 18-19psi. I got all the parts, except the pump, at Napa. Any parts store should carry the all the parts that you would need though.

BigBlue

The only difference when I ran mine unplugged was smoke and a noticeable increase in the bottom end. Other than that it ran like the day I bought it.