19lb vs 25lb Fuel Injectors : 5.0L EFI

[jakester888]

For you EFI owners out there, here's a question.

I have a stock 93 Mustang 5.0L running EFI. I swapped out the OEM 19LB fuel injectors and put in 25LB. I left in the stock MAF & removed EGR. Question : is there a computer change I need to make? Especially for the fuel injector swap I did?

[jakester888]

Make that 24LB (not 25).

[frankeeski]

It's going to run dead rich. You will either need to get a new mass air sensor calibrated for 24 lbs./hr. or have your stock one re-calibrated here. http://www.promracing.com/meter-reca...er-brands.html

[Carlos C]

Exactly. Every time you change injectors to higher or lower specs, your mass air meter must be re-calibrated to match them. There are many companies that would do this for you, but Pro-M is the only one I use. They do a great job, and you get a quick turn-around, with a spec sheet.

Just remember that the Mustang's ECM is very limited regarding fuel tables. As long as you stick to mild improvements to the engine, you'll be fine with the 24 lb/hr injectors, a re-calibrated MAF sensor, and a stock computer. Once you start doing major engine work, you'll need to get bigger injectors, re-calibrate the MAF again, and may have to get a piggy-back chip for the computer, which adds a lot more fuel maps. As an example, I'm running a supercharged 358W, making 603 HP at the flywheel. I'm using 50 lb injectors, a Pro-M MAF sensor, and a TwEECer chip.

Carlos

[jakester888]

Thanks for the tips guys.

As an alternative, could I also simply upgrade the MAF + sensor?

http://www.americanmuscle.com/bbk-maf-24lbcai-8693.html

[Carlos C]

You have two choices. Either get your current MAF sensor re-calibrated, or buy a new one already set up for your injectors. Do a little research, but I believe that option 1 is still cheaper than buying a new one. If you buy a new one, opt for one that the company has a re-calibration program for their own products. Not only are those of better quality, but they are built to accept a wider variety of fuel maps, but they are also a little more expensive.

Carlos

[skullandbones]

You can save some money by getting a Summit MAF. The components are very good. I did a lot of research before getting that one (SUM-29051B). That supports the 24 lbers. If I had it to do over again I would get the 30# injectors/MAF (SUM-29052B). The 24# injectors support about 350 hp @90% Duty Cycle while the 30# will support up to 425 hp. If you have the matched components you will not run too rich. The MAF will compensate. The problem with this is that it pretty much is a dead end. If you want added performance you have to do something to change the mapping in the EEC-IV which can not be reflashed (at least, that's what I have read many many times in books and web based articles). Carlos eluded to some strategies but I can tell you from my discussions with people who have used the piggyback chips and other after market tuners, there is a "steep learning curve". That's the reoccurring phrase you hear. There is a product that is pretty much "Plug and Play" that replaces your PCM with a box that looks just like the old PCM (will fit in the old holder) and plugs into your stock harness. It's the Mega Squirt PiMP. I think that is the way I will eventually go when the funds are available. You also have to have a wide band A/F meter to use in conjunction with the MS. However, if you just want to leave the performance at the level you have now, get the matching MAF and a fuel pump that will support the whole thing (about a 155 l/h). If you don't have the pressure at higher demand levels such as WOT, you will not get the effect of the injector as rated). Also, there are some rules you should follow regarding set up of a cold air system so you don't mess up the flow of air across the MAF. Good luck, WEK.

[jakester888]

I just looked around and found the following part lying around the garage. Looks like I just need to find the sensor that goes with it. Is there a place that just sells stand alone sensors? This part is a 76mm MAF with no sensor but says it supports 24 lbs:

Maf2.jpg

[Carlos C]

I just looked around and found the following part lying around the garage. Looks like I just need to find the sensor that goes with it. Is there a place that just sells stand alone sensors? This part is a 76mm MAF with no sensor but says it supports 24 lbs:

Maf2.jpg

Late Model Restoration Supply and American Muscle sell the sensors separately. Call C&L, since they made that unit. You could also try Pro-M. Hopefully, you'll end up finding the one that came with your housing. Sensors cost about $80.

I didn't get too specific about the tuning chips because that's not really what you're concerned with at the moment. Some chips are easier to work with than others. Ten years ago, you needed a laptop, the computer program, and a dyno, to tune the chips. With the technology now, all you need to do is connect a hand-held module with a digital display, answer some basic questions, do a couple of steps with the engine, and you're done. The chip will keep learning and adjusting on its own. I also didn't mention the stand-alone PCM's, but that would set you back $1K and up. Edelbrock, FAST, and Holley, are a few of the companies that make their own systems. They are also plug-and-play. My piggy-back chip is old-school, but it worked great at extracting a lot of power out of my engine.

But I digress: all you need now is the sensor that goes to the housing, and you should be all good, so long as you have upgraded the fuel pump as well, if you plan to more alterations to the engine besides upgrading the injectors.

Carlos

[frankeeski]

Do some research. C&L is crap and has a terrible reputation for consistency. Even Pro M won't touch them for recalibration.
Here is a quote from the recalibration page on Pro M's webpage


"We will recalibrate any FORD, PMAS, BBK, Summit Racing, SCT and Sniper meter, new or old.
Please Note we will NOT recalibrate C&L, Granatelli or Vortec meters."

And for the record, the Summit brand is manufactured by Pro M and cost exactly the same price when you add in the fact that you need the meter calibrated not only for #24 but also for "cold air".

[jakester888]

This one looks to be a direct OEM replacement part of the a 1993 SVT Cobra MAF sensor. In that case, the 93 Cobra was a 24lb variety. Do you my EFI fellows agree with me that this part will work with the 76mm C&L MAF housing I found in the garage?

http://www.autopartswarehouse.com/sk.../SIMF5519.html

[Carlos C]

This one looks to be a direct OEM replacement part of the a 1993 SVT Cobra MAF sensor. In that case, the 93 Cobra was a 24lb variety. Do you my EFI fellows agree with me that this part will work with the 76mm C&L MAF housing I found in the garage?

http://www.autopartswarehouse.com/sk.../SIMF5519.html

Unfortunately, you don't have a core, so you'll be paying almost twice as much as you should for the sensor.

Although I understand WEK's concern that there are a few different sensor designs out there, and that some are more proficient than others, I've never seen a compatibility issue. Your best bet is calling the tech department at C&L, and ask them if they sell the sensor only. If they don't, ask them which stand-alone sensors they recommend and which ones to avoid, and go from there. Otherwise, go the safest route, and get a whole new unit, as WEK recommended.

Carlos

[skullandbones]

Did you see the notice of the core deposit? Also, you should have a screen in the housing that creates laminar flow across the sensor. Do you have that? In my limited experience with these, I have never seen one that was not a one piece unit. The air tube or sensor wires are precisely placed in the housing. If it is a no adjustment install then OK but I would not feel good about cobbling that together. Excuse my paranoia about dealing with unknown components. A one piece would be my choice. Sell the housing on ebay. WEK.

[Jeff Kleiner]

Jake,
Lots of issues here but in a nutshell, the '93 Cobra MAF works through the same ranges as your stock one from the '93. The Cobra used a different ECU (X3Z) that was mapped for 24# injectors. Coupling the Cobra MAF to your 19# tuned A9L ECU won't work any better with the 24s than your OEM meter, which means that it will be dumping too much fuel across the entire operating range and driving the oxygen sensors and computer berserk trying to compensate. Really though, putting 24# injectors in your otherwise stock '93 5.0 will gain you nothing power wise but if you are dead set on keeping them just take the easy and proven route and get a Pro-M tuned for 24s.

Good luck,
Jeff

[JJ'snakepit]

You could also go around to your local wrecking yard / pick your parts and find an old f-150 pick up that has 24lb injectors in an grab it. It may have the old style plug on it which is easily converted. JJ

[jakester888]

if you are dead set on keeping them [24# injectors] just take the easy and proven route and get a Pro-M tuned for 24s.

Questions:

1) Why wouldn't buying a completely new MAF & sensor calibrated to 24 solve my problem?
2) I think if I understand from Jeff's post that a new 24# MAF would only work if I also swapped out the ECU to the Cobra variety.
3) If a completely new MAF calibrated to 24# won't solve the problem, why would the Pro-M solution be better? Are they somehow "tricking" my ECU?

[Jeff Kleiner]

Questions:

1) Why wouldn't buying a completely new MAF & sensor calibrated to 24 solve my problem?
2) I think if I understand from Jeff's post that a new 24# MAF would only work if I also swapped out the ECU to the Cobra variety.
3) If a completely new MAF calibrated to 24# won't solve the problem, why would the Pro-M solution be better? Are they somehow "tricking" my ECU?

Yes, the Pro-M is indeed calibrated to "trick" the ECU that you currently have. They do this very well for 24s or 30s but start to get a little ragged beyond that point. A new COBRA 24# meter would have to be coupled with the COBRA X3Z ECU to function properly.

Jeff

[jakester888]

Thanks for the input guys.

Jeff : Understand Cobra MAF must use Cobra ECU. But hopefully if I don't use the Cobra MAF, just a 24# BBK, I can avoid the ECU change.

DECISION : I'm going to try a new BBK 24# calibrated MAF from Late Model Restoration with my current ECU (A9M which came with the 93 LX). If this doesn't work well with the new MAF, meaning - still running too rich, I'll look for the Cobra X3Z ECU as a replacement for the A9M. There was a similar thread on this topic at ffcars forum which suggested I'll be OK without X3Z.
http://www.ffcars.com/forums/17-fact...ctors-a9l.html - refer to response #8.

My reason for avoiding the Pro-M mod is that my current OEM 19# MAF has a warped mesh/screen which I inadvertently damaged during harvesting. Therefore, I'd rather go new with the MAF.

So : here's what I am going with for now:

- BBK 76mm 24# calibrated sensor (just ordered this)
- 24# injectors (already have)
- A9M ECU (already have)

bbk-8004_2722.jpgImage2.jpg

I'll follow-up and let you all know how it turns out

[frankeeski]

Thanks for the input guys.
My reason for avoiding the Pro-M mod is that my current OEM 19# MAF has a warped mesh/screen which I inadvertently damaged during harvesting. Therefore, I'd rather go new with the MAF.

Not sure I understand where you got the idea that Pro M only does re-calibration and does not sell new Mass Air Meters? They are about $30 less expensive than the one you just bought for a new meter and each new meter is calibrated to the specs you give them. The BBK just comes with a generic calibration. Not that it won't work but may not work as well as it could. Oh well.

[jakester888]

DECISION : I'm going to try a new BBK 24# calibrated MAF from Late Model Restoration with my current ECU (A9M which came with the 93 LX).

- BBK 76mm 24# calibrated sensor (just ordered this)
- 24# injectors (already have)
- A9M ECU (already have)

I'll follow-up and let you all know how it turns out

New MAF Installed as you can see from the picture below. Running less rich - not nearly as noxious. Timing dialed in by taking the spout out and setting to 10 BTDC. I put the spout back in, fired her up and the computer adjusted to between 10 & 14. This Rhonda-beast sounds so damn good & fires right up!

CONCLUSION : the 24# BBK MAF does make a big difference - not running rich. And timing without the spout to 10 BTDC is right. Thanks for the tips guys. Forum saves me yet again.

Img_1495.jpg 149736d1329888473-93-5-0-dies-when-you-remove-spout-timing_marks2.jpg

---------------------------

Next : need to figure out why the oil pressure gauge is stuck on "0" while both the oil temp & water temp are stuck on "250" - even when running cold.

[Carlos C]

In perspective, my donor ('88 Mustang converted to mass air) was running with 50# injectors, a 90 mm MAF unit calibrated for these injectors, and an A9L ECU. Before adding a S/C, the engine dyno'ed at 377 RWHP. With 12 lbs of boost, and a TwEECer chip, it dyno'ed at 603 RWHP. I've never had an issue with either set-up, where the engine was running rich. The only thing noticed on my car, was that it'd puff a little black smoke for a fraction of a second when I gunned it. I attribute that to the O2 sensors being too far away from the heads (about 30") on the aftermarket long-tube headers. Even the fuel/air ratio meter installed, would normally stay on "stoic", except during the aforementioned gunning.

You should be fine with your computer, and 24 lb injectors with MAF unit calibrated for them. Even Pro-M recommended for me to get the A9L computer for my set-up back 10 years ago. Just keep in mind that if you're planning to extract more power out of the engine, you may have to upgrade the rest of the fuel system (pump, filter, regulator, etc). For my set-up, I ran the external A-1 pump and matching filter, 1/2" supply and 3/8" return fuel hoses, billet fuel rail, and adjustable regulator. This is just an example, as my set-up was fairly radical.

Carlos

[Jeff Kleiner]

I'd be willing to bet that the BBK meter is a rebadged Pro-M.

Jeff

[jakester888]

The timing marker came in from Late Model Restoration. Bolted it down, fired her up and dialed it in. I'm still running rich due to mismatched MAF and injectors (I'll fix that this weekend). But after the dial-in with timing light, I centered it right around 14 degrees past TDC and wow, runs better and doesn't stall.

[Jeff Kleiner]

... with timing light, I centered it right around 14 degrees past TDC...

Hi Jake, hopefully what you really mean is 14 degrees BEFORE top dead center, not after. Just to be sure that you &/or others are aware---when setting the baseline timing on a Ford EEC-IV system you have to pull the SPOUT (SPark OUTput) connector , adjust the distributor to the desired timing mark and reinstall the connector. With it unplugged you are taking timing control away from the computer to set it's initial "starting point" so to speak. When it is plugged in the computer has control of spark timing and varies it based on conditions and information from the various sensors. If you adjusted the timing with it connected it will not be correct and you'll find that it runs even better when done properly!.

The SPOUT connector is a little rectangular box with two spade connections that is located on a pigtail off of the group of wires that go to the TFI module:



Cheers,
Jeff

[jakester888]

Hi Jake, hopefully what you really mean is 14 degrees BEFORE top dead center, not after.

Yes, you are correct. 14 degrees Before TDC. Type-o in previous post.

I will re-try with spout removed. Thanks for the tip.

[skullandbones]

Glad your engine is doing better! BTW: I noticed you have your conical filter mounted directly to the MAF. I read something interesting while installing my cold air system for EFI. They recommend having a straight air path leading in and going out of the MAF. Turbulence is not your friend for this sensor. So by having a more linear flow of air in and out, the sensor feeds better data to the computer. I think they recommend 6 to 8 inches on the lead in but not everybody has that luxury. You may notice a screen installed in the pathway of the MAF. That also helps to reduce turbulence in the tube. I just got rid of my donor rubber snorkel replacing it with a 3 inch aluminum tube. Can't hurt.

Good luck,

WEK.

[Carlos C]

Jeff:

Great catch on the SPOUT connector!

Jake:

WEK is correct about trying to have a linear path to the sensor, if possible. You'll probably never notice the difference, but it'll help the engine running stoic.

Also, now that you have the timing set, you can go for the 14 degrees BTDC. You should pick up a few horses, and even feel the difference in throttle response. Just remember to remove the SPOUT connector again. When you're done, reconnect the SPOUT, and check the timing at idle and timing advance at WOT. Timing advance should not be more than 32 - 34 degrees BTDC. Before you do all this, make sure that the engine is warmed up, and that the idle is at around 650 RPM for a manual tranny, or around 750 for automatic. That way, your changes will be more accurate.

Carlos