ok this confuses me. What effects the calibration of the mass air meter for the injerctors?? The Electronics or the size of the small airflow tube where the electronic wires go?

i have 24# injectors on my car and im not positive what size or calibrationmass air is on there now but it runs ok with it... i went and bought a pro flow 73mm that was supposed to be for 24# injectors and it included the electronics.. when i put it on the car barely ran . it would sputter then backfire like crazy when driving. whats going on?

 

not an expert w/ this but I'm gonna say it's because you didn't buy a larger TB w/ the MAF, mayB someone can back me on this?

 

True, im not sure if that is the case. But yeah i thought about that. although i just bought a 70mm throttle body, so i guess ill spend another $100 on a mass air and try it again. im hopefully going to match it with a 70mm 93 cobra mass air and put the 24# sample tube in. cuz guys say they dont trust the aftermarket companies because of faulty calibration! its so tedious damnit.

 

The sample tube is what they change for injector calibration. If your sure the correct sample tube is in there disconect you batt for about ten minutes and then try it again. You shouldnt have to change the TB when you do the mam. Although it does help.

 

What computer are you using?
since your car was converted to MAF, you may have to pull the computer to find the catch code.
Most likely it will be an A9L or A9P, but it is possible that the MAF conversion was done with a X3Z (93 Cobra) computer.

The Throttle Body size won't have an impact on the calibration of the MAF.

Ford did not calibrate any of the MAF meters to suit an injector size. Instead Ford created a setting in the computer for the MAF, and a seperate setting for the Injector size.

Only aftermarket air meters are calibrated to an injector size AND COMPUTER.
You may be getting hosed on the computer part.

There are 2 ways to re-calibrate a MAF meter.
1. Change the diameter of the sample tube, which will affect how much air flows over the sensor. C&L is the only manufacturer that does it this way. Generally speaking this is less accurate than method 2.
2. Modify the output scale of the MAS (the little black sensor box). This is how PMAS calibrates its meters. Generally speaking this is more accurate than the sample tube method.

C&L meters work fairly well in most applications, as do PMAS. But once in a while both cause problems with a specific car.



Pull the computer and check for the catch code.
Once you know the catch code you can select the appropriate MAF for your injectors.


jason

PS-
Assuming you have a C&L...
Check my site for some of the sample tube diameters. C&L has been known to sell the wrong tube, or mis-color the tube.

 

HAHA, yeah thanks for the info. very helpful. and i do beleive that to be true about C&L. it seemed thats what happend with the last one i bought.

Its messed up though. I bought one 76mm Pro-Flow and that Did the same thing as the 73mm C&L. both were suppsed to be calibrated for my injectors but i had no idea about the computer matching part.

Either way, will a Chip anda tune correct the MAF reading if it is off at all??




also how do i calibrate the TPS sensor. my car is modded as you can see and the current TPS is drilled out but for the new one i do not know how to tell what is the right calibration

 

A custom tune will correct any MAF problems you have.
This can be pricey though, as doing it right requires dyno time. Probably 500 to 800 range
None of the mail order chips will do anything to help you.

The tps should be between .6 to 1.2v at closed throttle.
Setting exactly to .998v is a waste of time. The computer only looks at the tps for...
1. Rate of throttle change
2. How far fromidle the throttle is.

Rate of throttle change is how quickly the throttle blade is opening or closing. The values don't matter, the computer only sees the delta between the previous and the current.
The tps rate is used for fuel and timing calculations, to improve accel/decel performance.

The idle or base tps voltage is constantly being checked by the computer. The lowest value the computer has seen, can be thought of as the 'base idle voltage'.
The computer adds 2.8v to that to determine when to enter Open Loop/WOT.

The only reason to keep the tps voltage between .6 and 1.2 is that the computer will register anything outside this range as a defective TPS. A code will register.

Pull the computer from the kick panel and see what your catch code is. Since 2 MAF meters performed the same way, I suspect you have an X3Z (or possibly a custom chip?).

jason