changing my injectors and mass air meter, what fuel pressure?

cenok is family

15 Year Member
Jun 25, 2003
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Norman, Ok
for anyone that doesn't know whats going on, with the mods in my sig, my car dynoed 228rwhp and 278rwtq. well, Brian (the guy who tuned/dynoed my car) leaned my car out as much as he safely could to achieve those numbers and my a/f is STILL 10.0:1. so the way i see it, my options were to either get a chip burnt and installed for $300 to fix my problem, or by a 70mm '93 cobra' mass air meter calibrated for 19#er's for $60 and rebuild one of my sets of 19# fuel injectors for $25 (for the rebuild kit). i decided to go with the latter seeing as i'm a broke 23 year old. SO...i just got done rebuilding my injectors and the mass air meter came in the mail yesterday, so i'm going to be changing them out when i get a chance sometime in the next couple days. what would be a good starting point for the fuel pressure? thanks for any input. :SNSign:
 
for anyone that doesn't know whats going on, with the mods in my sig, my car dynoed 228rwhp and 278rwtq. well, Brian (the guy who tuned/dynoed my car) leaned my car out as much as he safely could to achieve those numbers and my a/f is STILL 10.0:1. so the way i see it, my options were to either get a chip burnt and installed for $300 to fix my problem, or by a 70mm '93 cobra' mass air meter calibrated for 19#er's for $60 and rebuild one of my sets of 19# fuel injectors for $25 (for the rebuild kit). i decided to go with the latter seeing as i'm a broke 23 year old. SO...i just got done rebuilding my injectors and the mass air meter came in the mail yesterday, so i'm going to be changing them out when i get a chance sometime in the next couple days. what would be a good starting point for the fuel pressure? thanks for any input. :SNSign:

It sounds like either you have something fubar'd in your system or your tuner doesn't know his a55 from a hole in the ground.

The 93 cobra meter is not going to work for you at all, as it's made for the cobra computer running 24lb injectors and is not calibrated to the injectors directly.

If you injectors are that bad, I'd look into a set of low mileage ebay replacements. I had used explorer 19lb injectors previously and they worked great.

Your fuel pressure should be set to the stock 39psi with the vacuum line off and your computer should take care of the rest.
 
Some guys have reported the Cobra meter working, but I still don't trust it...
Let us know how it works for you.

Keep fuel pressure at stock range 38-41psi-ish...
At least to start with,

jason
 
thank for the input so far guys. it's not an actual 93 cobra mass air, its one of those "like the 93 cobra" mass air meters that is calibrated for 19# injectors. it has a Ford sensor on it. and the injectors i just rebuilt are the 19#er's that were originally on my car. I did the same thing to these as i did to my 24# injectors when i rebuilt them. i take them completely apart and let them soak in B12 chemtool for 24 hours, then i hook each on up to a test circuit i made out of a 6v lantern battery and 2 jumper wires and sprayed some carb cleaner through each one until the spray pattern was correct and the carb cleaner was clear. then i repainted the metal body of each injector with black rustoleum and put new filters, seals and o-rings on.

here's a link the the meter i just got. i got it on ebay.

**NOT an active ebay link**
http://cgi.ebay.com/ebaymotors/ws/e...STRK:MEWN:IT&viewitem=&item=280166543067&rd=1
 
I looked at your mods in your sig and I must say: Im really confused as to what your trying to do, talking about going back down to 19 pound injectors. Are you missing some other supporting mods to compliment all that stuff in your sig or something. Those numbers look really low for your mods.
 
I looked at your mods in your sig and I must say: Im really confused as to what your trying to do, talking about going back down to 19 pound injectors. Are you missing some other supporting mods to compliment all that stuff in your sig or something. Those numbers look really low for your mods.

well thats kinda the thing, i have all supporting mods on my car but nothing really to support. lol. i still have the stock heads and cam. hopefully after my get the 19# injectors and mass air meter on, i'll have my a/f in check and my numbers will go up a little. somewhere around 240ish rwhp and 290ish rwtq is what i'm hoping for.
 
oh. I was gonna ask that question about what heads you have to man. Thats a shame That beast doesnt have a cam and some heads. Time will come soon enough for you though as long as you dont sell the car
 
oh. I was gonna ask that question about what heads you have to man. Thats a shame That beast doesnt have a cam and some heads. Time will come soon enough for you though as long as you dont sell the car

oh yeah, i've got plans for a tfs top end kit with an afm cam and a turbo. but that's not gonna happen for atleast a year or more. i've got too many bills and debts that i'm working off right now. so much i've gotta work two jobs. :( it's okay though, i've got all the time in the world because i'm never going to sell this car, ever. it's got way too much sentimental value to me. i was thinking about throwing on some thumpers until then though.
 
I'd put the 19 pounders back in with a 94/95 Mustang GT MAF. Do as others have said and set the fuel pressure to the stock settings (@39 psi). With the stock cam and heads you pretty much have the stock engine and you don't really need those larger injectors. Your A9L should easily bring the A/F ratio back into specs.