jthorn9

You're running about par with where you should be. 14.5 is a little lean, but get a tuner, and change the fuel load settings to run the car richer. The ideal/sweat spot is 12.8-13.2. But 14.5 isn't bad, my 5.0 hit an astounding 18.X before I did the first engine build, something was screwed up, think it was my pressure regulator, but in any since, I went from one extreme to the other of running a 10.5 after words, so yea, rich as hell lol. Have no idea where I'm at now.

Synyster06Gates

I plan on keeping it N/A, for a long time anyway. How hard is it to swap injectors? All I know is it's running about 14.5:1 when it should be around 13:1. Everyone was commenting on how I need to fix it... (Mustang dyno day...)

And damn... I was not wanting to hear "get a tuner" because I don't have that kinda cash! haha oh well, we'll see..

jthorn9

Well FYI, you just don't "swap" injectors, your ecu has to be calibrated to the new size, aka, tuner, so you'll need it anyways. Only other way is to get an adjustable fuel pressure regulator and make sure the fuel pressure is set properly (if your stocker is faulty or something), to get it a little richer, but a tuner is the best/easiest way.

Synyster06Gates

Damn...guess I'm just used to working on carburetors where all ya have to do is unscrew the jets, haha. Looks like a tuner is in my near future. But when I put my intake system on (when I finish it), won't I be even MORE lean?

jthorn9

Maybe, maybe not, if you make the proper adjustments with the tuner, the ECU should correct itself. Remember how the fuel system on a fuel injected car works:

The compression of the pistons creates a vacuum, this vacuum draws air into the heads/plenum/intake/MAF/air filter. As the air enters the mass air meter it's sampled/read by a sensor. Think of the MAF as the screw in the carb that controls the fuel flow. The MAF then sends the signal to the ECU which tells the ecu how much fuel to dump into each cylinder based off of how much air is coming into the intake. So if you draw in more air, then then MAF will sense that and the ecu will make the proper adjustment until such time comes that your fuel injectors are no longer able to support the amount of incoming air. Now a fuel injected car running lean when stock/near stock can be caused by a dirty MAF sensor, faulty/failed fuel pressure regulator, faulty/failed fuel pump, faulty/failed fuel injector(s).

Now with that being said, see why you just can't drop in new injectors and be fine, that MAF is "set" to the size injectors your car is running, put larger injectors in and the MAF will not know any better and will still think you're running stock, so in short, you won't be able to use the entire range of the injector, or a more sever problem could come in and the car could run rich if the injectors are much larger than stock.

Synyster06Gates

Ahh got ya. But without the tuner, should I just leave the intake off? Seems like more air will be coming in, not to mention I'll have no box covering the filter, just a large cone...

NeoTokyo

Dang, I assumed you had a tuner. You really need to have one, use whichever your dyno tuner uses, but SCT is well liked and having both SCT and DiabloSport I prefer SCT.

Injectors are easy to swap out, changing the MAF is easy and changing the fuel pump is an afternoons work.

If you purchase your tuner from VMP, Justin will wright you a custom tune for the new injectors and work with you if it doesnt run correctly.

Justin may have been getting a lot of magazine time over the past couple years but he still treats his customers with the individuality that we have all come to enjoy.

He is in Florida so you will have to work through e-mails and over the phone, but thats what I have done with him without a hitch.

You can upgrade your fuel system from used 24lb injectors and Cobra/Mach 1 MAF to pump and get a tuner from VMP for under $650. Its a lot, and you arent really going to feel much of a gain for all of that money but it is needed if you plan to continue to upgrade.

jthorn9

It's your call, but honestly, I'd be looking into why you're running so lean on a near stock motor. The new intake isn't going to make a huge difference though, at worst you'll raise to 14.6, maybe 14.7 and that's a huge maybe because you're still bottle necked in at the heads and especially the lift allowed by the cam. I'd put it on and see what happens, but really you need to get a tuner and go back to the dyno and do a dyno tune, with the intake on, that way all the bugs are worked out at once. Also, by intake do you mean air intake or intake manifold/plenum, an air intake isn't going to allow a huge difference in a/f ratio on your year, it probably won't effect a thing. Ported intake manifold will make a hair difference, but not huge cause of the heads/cam.

Synyster06Gates

That's true. I am talking about air intake. What would cause me being so lean on an all stock motor w/ just dual exhaust?

NeoTokyo

Its cheap and easy to clean your MAF, you should do that anyways while you save for the upgrade.

J is correct though, you should try to figure out why you are running lean on a near stock setup.

How about just getting the tuner first, your tuner will be able to either fix the problem or tell you more about it.