I have a vortech MAF sensor with two sampling tubes- one with a larger opening and one with a smaller opening. I got the sensor practically new from my brother. He told me that one tube is for stock injectors and one is for 42 lb injectors, but he doesn't remember which is for which. Can you guys confirm which one I should be using? The engine has 42lb injectors in it.

It looks like this:
http://www.vortechsuperchargers.com/prod_imgs/img-27-0-xlarge.jpg

 

well a smaller tube will sample less air so will read a lower value reducing injector pulse, so the smaller tube should be for bigger injector than stock. But the tubes should have some markings or numbers on it that should be able to be referenced.

 

The smaller tube is for larger injectors.

The tubes were marked by colors in the past. A color matches to an injector size. Goole C&L meter and colors to find out.

 

thanks guys, the smaller tube is the one I have installed, just looking for clues as to why it runs so crappily (which I know is to be expected). It's a 302 with heads, cam, a blower, long tubes, and 42# injectors. I know it needs a professional tune badly, just trying to get it to at least idle before I take the car off jackstands. I have a tweecer but I'm new to using it and don't really know what I'm doing. any suggestions would be welcomed!

 

well is it blowthru maf or suck thru and do you have a bypass or blowoff?? have you tried clocking the maf(turning it) also do you have a adjustable fuel reg, try turning pressure up and down to see what car likes.

 

It is a draw-through MAF. I do not have an adjustable FPR, nor do I have a bypass valve on the blower (kenne bell 1.5) or even a boost gauge. I know it's in no condition to drive, much less tune, at the moment. I'm just trying to make the engine idle and run, (even if barely so) before I take it to a professional or make a legitimate attempt at tuning it myself.

For what it's worth, here are the engine stats:

stock 302 rotating assy
canfield heads
1.6 full roller rockers
F303 cam installed straight-up
gasket-matched 302 HO lower intake
BBK longtube headers
90mm throttle body
vortech MAF as listed above
MSD distributor, no MSD box (yet)
walbro 190 fuel pump
42# injectors


If anyone who knows their stuff would like to help me out with a starter tune, it would be welcomed. The last thing I want to do is damage this thing by being irresponsible with my tuning. The TWEECER was free so I figured I would try it before paying someone else to tune the car, but it looks like it's over my head. I'll be getting a fuel pressure gauge and a boost gauge soon.

 

FMS 42# injectors?

 

yeah, the green top injectors