mebirkle

Hi!

I have a 90' LX 5.0 5SP and I would like to list the recent top end additions to my stock bottom end.

New Edelbrock Performer Heads 90379 (60cc Chamber, 170cc Intake Runner)

Cobra upper/lower intake with throttle body to match 75mm

BBK fuel pressure regulator (pressure is at 30 pounds)

cold air intake

Ford Racing e-cam

30lb injectors (they were all the guy had that did the work and mine fell apart off the rail)

Shorty Headers (used... maybe headman.. no name stamped on them)

gutted cats (for now and going x-pipe)

I am currently running the stock fuel pump and airflow meter with stock ECU.


The car's idle like to bounce between 800 and 1200 when the A/C is on and sometime when it's off. This causes a stall for me when it drops as I just can't seem to catch it when it drops. Is this just an idle adjustment or should I be looking somewhere else?

Also, the check engine light is on. The stock O2 sensor(s) are connected. I know the fuel air mix is quite different from the past. I'm pretty sure that I need to get a mass air setup to match the new air needs and probably need to up the anti on my fuel pump.

My questions:
How should I attack the idel issue?
Do I need to upgrade to mass air? Why?
Do I need a bigger fuel pump because of the new injectors or because of another part that was bolted on?

Thanks so much!! The care really woke up with the build. I want to dyno it, but I think there are still some missing parts in my build.

mjr46

you need a mass air that is "calibrated" for 30 lb inj otherwise it will run to rich and you'll have issues like you have, fix that first, and I'd upgrade the fuel pump to compliment the current mods , but like I said, fix the mass air issue then worry about the other two issues, after mass air is resolved, do a base idle reset

tinman

Not sure but I don't think 30 PSI for fuel is right, should be more like 40PSI......

mebirkle

Sounds good.... will do! 1 return question, if I go a lower sized injector / mass air, will that help with fuel economy? I'm getting 180 miles a tank; down form 240.

I'm also rechecking fuel pressure this weekend. I guess I need driving pressure so I know what I'm dealing with. I probably need to add a fule/air gauge thing-a-ma-gigger with the bung.

Deeper and deeper I go... where i stop, nobody knows.

pedalhappy

I think you should drop down to some 24lb injectors. No need for 30 with an E cam and smaller mods. Would run much better with 24's which is still an upgrade from your stock and would fit about perfect with your mods and would lose alot of your problem but a maf would work as well... kinda your choice between the 2

drhoward

You could just get it tuned for what you have, I know the fox computers aren't as bad but I would always get a tune after messing around with the cam

reldla1996

Going to smaller injectors or MA should not change fuel economy, but getting the injectors calibrated to the MA may well change it. 30# injectors are a little big for your combo, but I wouldn't change them since you already have them in place. Just get the MA changed to match, as MJR stated above. Factory fuel pressure is 39 psi, and you should be close to that; 30 psi is definitely low. The only reason for you to get a tune, in my opinion, is if you wanted to get around your issue of having the wrong MA for your injectors, but it would be smarter to just get a MA tuned for your 30# injectors (in the 73-80mm size range). I would think when you're done, your gas mileage should be around 20 mpg around town for "normal" driving, which is roughly the same as factory stock - mine always did with mods similar to yours.

mebirkle

Thanks everyone....

The person who helped me has a bunch of tricks up his sleeve. He does stuff that isn't even googleable.

He used a 4 cylinder starter on the car (with some minor mods to avoid heat soak from the new headers.

His planned workaround to my Mass Air issue is to use an MA from a 94 town car which is much bigger than the stock one. It's somewhere in the 85mm range and it will match my throttle body on the cobra intake. I will then give this a shot at the tuners. If this doesn't work, I will address with an after market setup (BBK or something similar) for the MA with 30pound tune and similar MA.

Anyone have opinions? I'm not sure what injectors are in the town car so I don't know what it's tuned to, but it's much much bigger.

Thanks again.... I'm hoping a $10 fix may do it. Fat chance...

wydopnthrtl

Any MAF body can be tuned. Just need the MAF sensor in a decent stream of clean air. You'll have to pay tuner time for mapping a new transfer function.

I'd suggest getting a MAF assy that makes sense for expected power, overall cost, & ease of replacability. Something like a ford 80mm out of 99-00 Lightning

mebirkle

Interesting about that can Ve programmed. Is ther a rule it has to Mactch the AF! Diameter.m I believe the one for the cobra intake is 85.