Do I need a new MAF and injectors?

Rad Racer · Sep 15, 2006

Ok everyone, here's the setup:

87 LX coupe
96 Explorer motor (used the stock bottom end and GT-40P heads)
E303 cam
1.7 ratio Cobra rocker arms
Trick Flow Street Heat intake
Ford Motorsports 65mm throttle body w/EGR
19lb/hr injectors
stock 55mm MAF
stock airbox w/K&N no silencer
A9L computer
MSD 6A, Accel coil and TFI module base timing at 10*
Ford Racing GT-40P shorty headers
Bassani X-pipe
Mac 2.5" catback
T-5
3.27 gears

I think that should be all the pertinant info. The engine seems to be a bit flat at WOT. The car almost feels faster at 75-80% pedal travel than it does wide open. I thought I would ask you for some advice. Do you think that I am in need of a new MAF and injectors to cure the problem, or do I only need an adjustable fuel pressure regulator? Or would you look to something else as the likely cause? Thanks for any help/info you can give me to point me in the right direction.

71swing · Sep 15, 2006

You haven't out grown the stock injectors yet, but a larger thottlebody and MAF sensor wouldn't hurt. Only thing is if you purchase a new maf sensor now i would go ahead and get the proper injector for it. unless you want to go with a C&L maf sensor,and just change out the airtubes as needed.

You will want the adjustable regulator some day.
3:73 or 4:10 gears would help also.

JChalfan · Sep 15, 2006

I agree with 71swing, you should still be fine with the 19lb injectors.

It sounds like maybe you have another problem causing power to feel flat at WOT. Have you checked the codes yet? You can have codes stored in the computer even if the check engine light isn't on.

Your stock MAF is definitely an airflow limitation, but I'm not sure that would cause it to "feels faster at 75-80% pedal travel than it does wide open". Definitely about time to upgrade the MAF though.

I would recommend a Pro-M MAF since I have had good luck with the one I have. The Pro-M's can only be recalibrated by the factory, so like 71swing said, it might be a good idea to buy the MAF and 24lb injectors at the same time, to save the trouble of sending the MAF back later and getting it recalibrated for the bigger injectors.

I don't see the need for a larger throttle body, I think 65mm is plenty.

An adjustable fuel pressure regulator wouldn't hurt. Have you checked your fuel pressure? Do you still have the stock fuel pump? I suppose if the stock pump is getting tired, it could be running out of pressure at the top end WOT, but I don't know how realistic that is.

Jeff

ninety15.0 · Sep 15, 2006

you will be fine with 24's...im running them with my current setup and a 75mm pro-m. You will need an adj FP regulator becuase the 24's will be a little big and you might need to trim down the pressure! good luck man

Rad Racer · Sep 15, 2006

I have checked the codes, I only get two: the fuel pump not working code and low VSS reading. I never sent the wire to the computer for the fuel pump since everyone said it would not make a functional difference and I never installed a VSS because I don't have cruise anyway.

I have a 190LPH fuel pump in the car, so I doubt that it is the probem. I also played with the timing just to see if I got anything, but it did not seem to make a difference.

Sounds like I am on the border for injectors and the MAF is a good idea. I can probably get by with the 19's, but 24's might be good for later.

I do intend before next spring to put a March ram air and underdrive pulleys on. Does that put me in 24lb/hr injector territory? Will the 24lb/hr injectors work with my setup now and with a little(6psi) of boost?

Thanks for the help.

Rad Racer · Sep 15, 2006

I forgot to ask in the last post, which do you like better, the Pro-M or C&L MAF?

BlownFiveLiter · Sep 16, 2006

The stock MAF should still work, but it's a restriction in your intake since it's only 55mm. Personally, I'd jump up to the 24lb injectors now, as the 96 Explorer engine has the same GT40 heads (GT40P heads weren't until mid-97) as the Cobra, and you wouldn't be pushing your injectors so close to their useful limit. There's a possibility that you're starting to lean out up top with the 19lb injectors without a bump in fuel pressure, so that could explain the flat feeling at WOT. I like the Pro-M MAF personally, but either one is a quality piece. Some members here swear by each one, giving reasons they're better over the other, but you really can't go wrong with either one on a mild N/A build.

sweet03cobra · Sep 26, 2006

When you all talk about the Pro-M Maf, do you refer to the "bullet" one.

gcwh02 · Sep 26, 2006

you can easily get away with 19's and a 75-76mm MAF. I would get a adjustable fuel pressure reg. either way if you go 24's or 19's. Stay with the 19's, bump up the FP a little, get a 76mm C&L and when you need 24's, swap out the tube. Just my opinion

vristang · Sep 26, 2006

Rad Racer said:
I have checked the codes, I only get two: the fuel pump not working code and low VSS reading. I never sent the wire to the computer for the fuel pump since everyone said it would not make a functional difference and I never installed a VSS because I don't have cruise anyway.

Thanks for the help.

The VSS also controls the engine speed when coasting to a stop.
Go ahead and install that, just so you don't have issues in the future.

Personally, I would get sick of seeing the fuel pump code come up every time I pulled the codes, so I would fix that too.
It doesn't need to be fancy, just functional.

jason

sweet03cobra · Sep 27, 2006

I'm assuming though with that setup that 24's would be ideal because ford using the same parts put in 24s from the factory in the 94-95 cobras?

Rad Racer · Oct 10, 2006

I went out and looked at the heads on the car and I have P heads. So I am thinking it is a 97 engine as it had an EGR Explorer/GT-40 intake on it when I got the engine.

I was also thinking that 24's would be a good idea since the 93 Cobras had them and I would think this engine is every bit as wild as the Cobra motors where.

I have access to an LM-1 A/F monitor so I think I am going to go with an adjustable pressure regulator, 76mm C&L MAF and C&L inlet tube. Hopefully I can adjust it out. If it don't work, I can go back in with the 24's and grab a new sample tube.

I've been driving with the VSS missing for over a year and its not given me any probems. When it does, I'll get in there and hack it in. And as far as the fuel pump, isn't not pretty but funcional what I have now?

Thanks for the help everyone. It is so nice to have a place to get so much info.

stang&2Birds · Oct 11, 2006

Rad Racer said:
so I think I am going to go with an adjustable pressure regulator, 76mm C&L MAF and C&L inlet tube. Hopefully I can adjust it out.

Sigh. Have fun.

IMHO, go
a) with a 94/95 Mustang MAF and 70mm square mount to round adapter
b) A **NEW** PMAS-style MAF.

And, DO NOT USE A CONE FILTER IN THE ENGINE BAY.

C)
For 24's do:
24's
93 Cobra MAF
93 Cobra ECC

If you use a stupid POS C&L, pressure regulator, or cone filter, then good luck. I told you MY suggestions. I have better things to do then to get into p****ing contests with people that don't know about control theory, electronics, EFI theory, the EEC strategies, etc.

Tmoss, and others, have been nice and have pulled together a bunch of stuff, check out
Mustang EEC IV 5.0 HO Information. Note: Some of this may be A9L Specific!
http://www.veryuseful.com/mustang/tech/engine#EEC

Here's a *quick* overview of the EEC-IV: A Quick Overview of the Inner Workings of the EEC (Mustang Fuel Injection Computer), by TMoss:
HTML/web version: http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings/
PDF version: http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings.pdf

BTW: My policy now is to post the info and then forget about the thread. YOU choose. Hey, before, I was just ignoring many of these threads because of the p******ing contests.
Good luck!

Rad Racer · Oct 12, 2006

WTF crawled up your ass and died?

rfedd · Oct 12, 2006

Why not take it to a Dyno facility where they can look at Injector duty cycle's and MAF voltages. Only way to know for sure if you need to invest in new parts.

RF

Rad Racer · Oct 12, 2006

The more I read about the EEC the more it sounds like tuning the computer is the only good way of doing it. No matter what stuff you bolt on the outside they are all stop-gap bandaide style fixes. The only way for it to really be right is to tune the EEC directly.

vristang · Oct 12, 2006

Rad Racer said:
WTF crawled up your ass and died?

LOL
Don't take it too personal,
I think I am one of the guys that started to piss him off

Joe (stang&2birds) is right though.

Rad Racer said:
The more I read about the EEC the more it sounds like tuning the computer is the only good way of doing it. No matter what stuff you bolt on the outside they are all stop-gap bandaide style fixes. The only way for it to really be right is to tune the EEC directly.

You are on the right path with that thinking.

The MAF signal is used quite extensively by the eec.
The more accurate the MAF signal is, the better the car will run.

If you need 24's then it would be best to get a custom tune

If you can stay with 19's, then running a 94-95 Mustang MAF may be the quickest AND BEST solution.

jason

stang&2Birds · Oct 12, 2006

Rad Racer said:
WTF crawled up your ass and died?

You're clueless. People like you and your stupid attitude get what you deserve.

Have fun. BTW: Guess what I do for a living.

stang&2Birds · Oct 12, 2006

vristang said:
LOL
Don't take it too personal,
I think I am one of the guys that started to piss him off

Other than the C&L issue, you and I agree on most things.

I realize that you're looking at the C&L issue from the information that you have. I have 10+ years of experience working with this type of stuff. However, I think that you're more involved with the trying out different Tweecer mods. I got tired of that *many* years ago (with the EEC tuner, etc).

Rad Racer · Oct 13, 2006

stang&2Birds said:
You're clueless. People like you and your stupid attitude get what you deserve.

Have fun. BTW: Guess what I do for a living.

BTW: Guess who doesn't give a damn. Since you've been exactly no help with your piss-poor attitude. Jackass.

Do I need a new MAF and injectors?

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