Ok, so I have a 94 f-150 with a 393 stroker,f303 cam yada yada. I bought a set of 24# injectors the other day and people keep telling me that I have to get it tuned for the new injectors when I put them in but my question is do I have to get the truck computer tuned, the actual mass air meter itself, or do I have to buy a mass air meter thats made for 24# injectors? I don't know that much about it so any input is helpful thanks
who knows about mass air?
- Thread starter strokedf-150
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SpartaPerformance
10 Year Member
Pick up a Ford Racing catalog they always have formulas on how to properly select injector size and MAF size.
2BADSTANGS
Member
You can compinsate for the 24lb by using a meter calibrated for the 24lb and "trick" the computer, but when the computer ignores the maf signal (cold start) you'll have hiccups. The other option (better IMO) is to have a chip burned to change the computers programming. I'm currently running the "trick" MAF and a stock A9L on my '93 and on cold starts, it idles like crap (I've tried all the tricks in the surging idle checklist) When it warms up, she runs beautifully, so when I win the lottery, I'd like to buy a Moates Quarterhoarse or a Tweecer. Think Delta force makes a setup for these too.
Maryland Stang
Active Member
Not with the stock untouched intake and heads. 24 pounders will supply more fuel than those parts could ever need. The stock parts are only going to flow but so much no matter how big the engine is.
You probably already know this but you're leaving a couple hundred horsepower on the table by using the stock intake and heads. A good cam, intake and heads are what you need. Seriously. Now.
Tanus
New Member
yeah gotta get a 24lbs maf meter, I have a mustang one I'll sell/trade, not sure if its the same as f150 though.
Hey guy - With a tuner, you'll be able to fix that cold startup issue by adjusting the "Cranking pulsewidth vs ECT". Basically, it adjusts your pulsewidth as a function of Engine coolant temperature.
In the old days, we called this a: Choke
In the old days, we called this a: Choke
With my limited experience so far...
Your least expensive & partial solution, using thost 24lb injectors, is to get a MAF which is calibrated for those injectors. The engine will start and run, but you're going to leave horsepower on paper and not on the ground
For even when you have a calibrated MAF to work with the 24# injectors, and given the change in stroke and cam, the EEC and it's interpretation of the HEGO inputs will only go so far.
In short, your MAF mapping will not change and your Air-fuel ratio is going to be jacked up lean or rich)...in either case, if you need to pass emission inspections, you could very well have problems.
I don't know what type of heads or induction system you're using, but those 24's do sound small for the engine. Sure, they'll work up to a certain point, but you'll reach a point where they cannot keep up...even "if" you had the ability to alter the injector high/low slopes and breakpoints... which you currently do not.
My limited experience comes from using a stock A9L with a 347 stroker. I've used Tweecer and I now have Moates. If you want more information on performing your own tuning, write me.
If you don't want to go through that expense, learning curve, and you don't plan to make any more substantial changes to your setup, then I would recommend a dyno tuner & chip burn...and then enjoy the car/truck.
Cheers !
-D
Your least expensive & partial solution, using thost 24lb injectors, is to get a MAF which is calibrated for those injectors. The engine will start and run, but you're going to leave horsepower on paper and not on the ground
For even when you have a calibrated MAF to work with the 24# injectors, and given the change in stroke and cam, the EEC and it's interpretation of the HEGO inputs will only go so far.
In short, your MAF mapping will not change and your Air-fuel ratio is going to be jacked up lean or rich)...in either case, if you need to pass emission inspections, you could very well have problems.
I don't know what type of heads or induction system you're using, but those 24's do sound small for the engine. Sure, they'll work up to a certain point, but you'll reach a point where they cannot keep up...even "if" you had the ability to alter the injector high/low slopes and breakpoints... which you currently do not.
My limited experience comes from using a stock A9L with a 347 stroker. I've used Tweecer and I now have Moates. If you want more information on performing your own tuning, write me.
If you don't want to go through that expense, learning curve, and you don't plan to make any more substantial changes to your setup, then I would recommend a dyno tuner & chip burn...and then enjoy the car/truck.
Cheers !
-D
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