Fine Tuning after installing Pro-M & 24lbs

[mikeys5.0]

Well the breakin period is over and I trust her again to take me to Cali and back if I wanted too!

A few months back I had to upgrade to 24lbs and I also went with the 75mm PRO-M. I am also using it with a Mac CAI. Over all the car runs great but I am still trying to fine tune it. So far the car seems to run best at 40PSI fuel Pressure with Vaccum on and the MAF slighty tilted in. This is once the car warms up. Ever since the MAF and 24s the car is very cold natured. If I step into even just a little before it warms all the way up it backfires in the intake. As long as I drive real easy and let it warm up it drives perfect. I have played with the Fuel pressure and position of the MAF all I can and cannot cure this. This never happened before I installed PRO-M. I was using a 73mm C&L before with 19lb injectors and the car ran strong but was too lean. By the way the MAF is brand new. Also when I drive it cold the check engine light comes on and my idle likes to stick. If I turn the car off and turn it back on once it warms up the light goes out and the idle quits sticking.

So my question is, is are these common problems when you trick the computer with MAF calibrated for diff. than stock injectors? Also would a custom dyno tune help these issues? Can anything be done until I have it tuned with new chip?

Thanks,

 

[forrealb50]

Go get a dyno tune where they can adjust the air/fuel ratio. You will get it perfect on a dyno by adjusting the fuel pressure and timing. You will also probably pick up some horsepower. You wont get it perfect until you get to the dyno...

 

[forrealb50]

Oh yeah, you don't need a chip just a good dyno tune...

 

[FordRangerFan17]

i'm guessing something is wrong somewhere. First off, you are not "tricking" the computer by using an MAF calibrated for different injectors. The MAF tells the computer how much fuel to put into the air:fuel mixture after it measures the incoming air charges temperature/volume.

*The new MAF is calibrated for the 24lb injectors, correct?

*Are you positive there are no small leaks in the intake system anwhere??

*rotate the maf sensor 90*, sometimes the intake setup just needs a better angle to get a better sample of incoming air.

I dont know what else, I dyno tune may help I guess, but just a simple swap of maf and injectors shouldn't be causing these kinds of problems.