According to the second gear pulls I performed, my 5.0/AFR 165 heads/Comp 266XE cam/ stock EEC-IV/19lb injectors was asking for around 13.7 AFR at just over 4000 RPM in Open Loop and was and was delivering 14.7 +-.  Thats at 6000 foot elevation so I know it was running out of injector.  Back in November I took it to the mini-bash in Waco and discovered that it wanted to seriously detonate  as soon as it went into Open Loop...again at +- 4K RPM.  That was at around 4000 feet in New Mexico.  I didn't have the AFR gauge at the time so I'm not sure where the AFR was going but it was going very lean.
After the test runs back up here I went to Seimens DEKA 60lb injectors and adjusted the calibration via Moates QH to accommodate.  After a couple of tweaks the demanded and actual AFR were very close.  
I was running an Explorer TB and a stock 5.0 MAF at that time and will probably change to a 93 Cobra MAF and change the calibration via the Moates to accommodate it. 
That's when I get the new engine installed.
My suggestion would be to install a good AFR gauge and keep the MAF you have as the ECM is calibrated to run that.  Do some research before you pop for bigger injectors and a "calibrated" MAF.  There is a lot of info out there that indicates that they don't work all that well.  For about the same bux...or less...you can have the Moates QH and TunerPro softwear which will allow you to change the calibration in you A9L for any change you make.  The learning curve was a bit vertical for me but I'm a lot older than you, Dan.
With your nearly stock engine I don't think you will exceed the capability of the 19lb. injectors.  I went to the 60lb DEKAs even though they are way more than I'll ever need but they have a great reputation for linearity and the price was the same as most other new injectors.   For normal driving I couldn't notice any difference but at WOT it was not going lean.

Good luck, BB1

Last edited by Bullet Bob (7/08/2020 1:22 PM)

Calibrated MAFs are straight up BS.  You're fooling the system trying to get it to act a certain way.  Works fine a WOT, but basically nowhere else.  We ran them for years and thought the issues were just part of life with a modified car.  Then we learned how to tune and found out its not.  Get the MAF transfer function right and you'll be amazed at how well even a highly modified engine runs everywhere, not just at WOT. 

In my experience on a 302 you want to move beyond 19s at 300-325HP.  24s will carry you to 350-400.  Keep in mind these power numbers are for an NA engine.  The requirements for forced induction are different.  5.8s got away with 19s because they turned low RPM.  The '93-'95 Cobras used 24s stock. You also need to make sure that your fuel pump can support the additional demand as power levels rise.

The current EFI will run a 351.  It may not be optimum, but it will start, idle, and run.  The intakes are a good deal different though, and EFI 351 intakes are not cheap. 

I'd posit that the stock MAF is fine, but your TB is way too big for a stock cam/head engine.  The problem you get into is how much the area changes on a 70mm TB as it opens vs. a stock one.  Without the ability to tune the TPS based enrichment functions are not going to be right.  My advice would be to go back to a stock TB, or a 65mm TB.  I'm running a 70mm TB on my 331 that will make 425-450 HP for point of reference. 

You have to keep the combination in mind as you swap parts.  There's no magic bullet part that's going to turn that 250HP engine into a 450HP engine, well, except for nitrous.  At this point your limiting factor is the stock cam, followed by the stock heads.  The MAF is a distant 3rd in hindering power production. 

I'd advise leaving the combo alone and picking up a tuning package and learning to tune before dropping a lot more coin on hard parts.  I'm partial to the Moates Quarter Horse. 

For highly modified engines the Lightning MAF and 42 lb/hr injectors are a good choice, especially for a forced induction application, but for a stock or close to stock application the injectors are WAY too big.  Injectors are another area where you want to match power golas to parts.  The ideal is that at max demand the injectors should be in the 90% duty cycle range.  Running more than  that risks failure and under fueling, but less means the injector isn't being optimized, and you can have issues at low pulsewidth situations like idle because rthe injectors are so big that they have trouble metering very tiny amounts of fuel accurately.  A good friend runs this setup on his '95 Cobra on a blown stroker and it works great.  That's kind of the ideal application though.  This would be a bad fit for say a 300HP NA engine, especially with a novice tuner. 

Last edited by TKOPerformance (7/09/2020 5:40 AM)

All sounds like good advice.

Are we all talking about EEC IV?

Don’t recall SCT having anything working with factory efi...especially recently, like today.

Many chip companies have dropped any new sales for this old technology with the glamour of the Coyote.

And in my neck of the woods, there ain’t squat for racing or tuning of any kind.  I sure as 7734 don’t believe everything I read online either.

I haven’t played with any of the tuning software at all...did some reading in the past to try to comprehend EEC IV.
I’m no computer techie either, I am fortunate I can use my phone.😂

As stated earlier, I still have the 60 mm MAF so my ecm is still monitoring the same information for calculating “stuff”.

Is there a larger MAF that will play nicely?
I was thinking along the lines of OEM.

Ya know, break down on side of road and just get a replacement at local auto parts store. Not have to modify parameters just to get home kinda of thing.

This is a street and highway cruiser type car.

You can bolt on a "calibrated" MAF and go.  It will work.  Water will also work in your hydraulic clutch if you're stranded in the middle of nowhere and don't have any brake fluid.  The results are about the same.  Will it physically work?  Yes.  Will it run the car, and allow you to run larger injectors if you choose?  Yes.  Is it going to be optimum?  No.  Are you likely to have odd driveability issues because of it?  Yes.  How severe will they be?  Depends on how good a job they did with the "calibration".  Like I said, we ran them for years.  But, we ran them for years because it was all that we had.  If you absolutely must go this route I'd suggest Pro M. 

You don't need larger injectors.  There's a lot to know about injectors, and its hard to cram it all in here in a paragraph.  90% duty cycle is when you are maxed out at WOT, and yes, if that's where you are or beyond its time  for larger injectors.  Most of the time you are well below that.  You can make larger injectors run on an engine that in no way needs them, but it begs the question why?  If the engine is going to make 300HP you're fine with 19s.  There's no reason to put an injector in it that will support 550HP, and it makes tuning harder for a novice.  I can get a 750cfm carb to work on a stock 289, but I'd choose to run a 500 because it makes my life easier. 

Ah, the Moates vs. TwEECer debate.  Both have their merits.  IMO Moats and its software pack are more user friendly for people who aren't programmers.  The battery on the Moates is no longer soldered to the board like it once was.  Now its just replaceable.  Carry a spare, its never been an issue.  The TwEECer is also a solid option.  My buddy with a blown '95 Cobra uses it.  He does have two masters degrees though in electrical engineering and programming.  I'm just a gearhead that's good at figuring stuff out. 

I'd avoid the chip burning route.  Did that with GM vehicles for years.  Not a fan.  One of the EECIV's biggest advantages is that service port that allows you to use an interface to tune.  It'll work, but its even more to learn. 

Nos681 wrote:

Thanks for advice guys.
I really appreciate the info.

FYI, wasn’t slamming Techies.
I probably know enough to be dangerous for my own good.

I will definitely have to do more learning and perhaps next Bash can see what’s involved on your cars.

So far I haven’t veered off stock by much.
Just haven’t plunged deeply into the ecm...yet.
Running stock calibration A9L

Good luck and have fun, never thought you were bashing techies at all! For some folks it's just not their cup of tea, that's all I meant