i need to know whats up with this...

i bought a 75mm maf to replace the 55mm one i had.. i have an 88 and it is converted to mass air

i have 24# injectors so i upgraded to a 75mm calibrated for 24#

the maf may have bad elctronics because the car will not idle right and it made my car develop a top end knock and my brakes would fail while comming to a rolling stop.

my question is..... will the bigger mm. mass air reduce my vacumme?

i am planning on upgrading to a 70mm throttle body and getting a matching 70mm maf

i have my mods in my profile if necessary

 

i don't know about the knock but a friend of mine had a set up clost to yours Performer rpm intake 24lbs injectors matching mass air and a 75mm tb when he put the injectors mass air and tb on the car wouldn't idle he ended up swaping the maf internals for the old on and the car began to run perfect. i don't really under stand why but it did.

 

what brand mass air?

 

MAF meter size will not impact engine vacuum. Most likely the low vacuum is due to not idling high enough. Make sure the harness is properly connected to the MAF. Make sure the TPS wire is connected. If not either of those, Try adjusting the idle speed and the TPS

 

its a pro-m mass air , i bought it from some guy who replied to a post in the wanted ads i placed.


well i know i need a new tps cuz the scanner reads tps out of range, but i am waiting to get a 70mm throttle body.

i put the stock 55mm calibrated for 19lb injectors back on and the car ran fine again.... out of curiosity i took the computer from the pro-m maf suppsedly calibrated for my 24 injectors and the car ran exactly like it did while it was on the 75mm unit.

im assuming its just bad electronics or something.

why would i need to raise the idle? just because the injector calibration was right finally?

 

go find somebody that has the same mass air as you swap it and see what it does..
if it runs the same then the computer isn't accepting it.
if it runs fine go kick that guy's butt for selling junk that he knew was bad..

 

Sometimes when you change injectors/electronics you need the air at idle to be set a little different to get the same idle speed. If you adjust the idle stop, you have to adjust the TPS.