i recently bought a blow through MAF sensor calibrated for 50lbs injectors.
idles at .45v then it will spike to .65v and the engine stalls and dies. other than that it responds and runs great. anyone ever have or heard of this issue?

 

You need to tune for it. The maf transfer function is off.

 

exactly, Paul you should know better than to try and change MAF's without tuning for it, you've been playing with these trucks long enough

now go get 'er tuned and lets see how much boost the ol' 4.6 will handle so you can get the motor swap done

 

its has. been tuned for it. Neil is working on the Tune. it picked up 20more RWHP in just 2nd with the new MAF sensor. he changed my plugs out this morning and hes going to look at the MAF transfer function tomorrow.

 

20 hp is great, maybe more on the table yet.
It is still not "tuned" until the mtf is adjusted to the base fuel table. The spike you are seeing could be the iac duty cycle in need of adjustment as the maf is much closer to the throttle body now??

 

yep its about 24" from the throttle body now.

 

got tired of waiting on Sniper to fix the file. so we cranked the idle set screw up and it doesnt die anymore. with the new MAF sensor is picked up 25rwhp on a mustang dyno through 2nd gear with adding 4 timing and taking half a point of fuel out in mid and full throttle. also to fix the idle surge he increased the Pre pot table that pre positions the IAC open when it see's the TPS drop below a certain voltage. but total gains with the retune and new MAF was 35-40rwhp through 2nd gear on a mustang dyno, through a 3200stall.

 

Nice results!

 

208 in first 320 in 2nd. still no 3rd gear pull. this is on a mustang dyno 4500lb load. on 9psi 16 timing 94F ambient temp.

 

the PMAS blow through is on the left.