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Hey David,

Saw this in another thread:

The low-pressure in-tank pump in the Ford CFI systems were rated 4 to 6 psi. With an old pump and those long lines to the front, I would test actual max psi at the engine before assuming anything. The flow was primary in the design (not the pressure) and has plenty for your application - if the psi is good. BTW - if you are looking for better power and mileage for up to 300hp, the CFI system is a good step-up from a carb if controlled with a cheap aftermarket ECM such as a Megasquirt-1 or 2, and tuned with a WBO2. Been there - done that. Good stuff.
David
PS: The replacement pumps are Airtex E2485 and Carter P74067 for reference examples.
I have a 1985 LTD LX 5.0 CFI that I plan to Megasquirt. Tell me all that you know on the subject.

Thanks! boway
 

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I have a 1985 LTD LX 5.0 CFI that I plan to Megasquirt. Tell me all that you know on the subject.

Thanks! boway
Boway, that would take a lot of typing. ;) Tell me why you want to do it, and a couple examples of things you want to know. From that I can gauge what else you'll need to know from there to do the job. CFI/TBI and MS is a simpler and very inexpensive first-step into custom EFI, whether a carb conversion or upgrading a factory setup. It's also a good option/alternative for many setups even if you've been doing EFI for years. :tup:

David

PS: If you haven't already, you can search the MS forums (especially MS-Extra) for lots about them. A couple thousand of my posts were lost in the server changes, but there are still many of my CFI/TBI posts there along with those of several other Gurus and Super Squirters.
 

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Boway, that would take a lot of typing. ;) Tell me why you want to do it, and a couple examples of things you want to know. From that I can gauge what else you'll need to know from there to do the job. CFI/TBI and MS is a simpler and very inexpensive first-step into custom EFI, whether a carb conversion or upgrading a factory setup. It's also a good option/alternative for many setups even if you've been doing EFI for years. :tup:

David

PS: If you haven't already, you can search the MS forums (especially MS-Extra) for lots about them. A couple thousand of my posts were lost in the server changes, but there are still many of my CFI/TBI posts there along with those of several other Gurus and Super Squirters.
Hey David,

It's nice to see that someone has something positive to say about the Ford CFI system. I have a bunch of questions but I will start with just a few. So was your CFI on a Ford? Was the engine stock? Did you modify the throttle body in any way?

Thanks! boway
 

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There is not much negative to say about them. Compared to the GM TBI, they fit standard 2-barrel manifolds, use common and inexpensive Bosch-style injectors, and have carb-style warm-up and idle air control. The GM TBI has larger throttle bores in some versions, and... well, that's about the only advantage, if it's even necessary. The funny thing is that the larger bores are great, except you can't flow more fuel for HP without very expensive injectors. Catch 22. Both have integrated throttle position sensors and fuel pressure regulators as well, so they are virtually self-contained EFI systems. Add an air and a coolant temp sensor, 40 psi fuel supply and a cheap ECM. Done.

The GM TBI is usually mentioned, because years ago it was the easiest ECM to hack. That is obviously irrelevant these days, and so that makes the CFI the more attractive option for carb conversions on mild to moderate street engines.

Yes, I've helped several guys with upgrading or carb-to-CFI conversions. Most folks prefer the HO units (Mustangs and Lincoln Marks) not only for their larger venturis, but their idle air control scheme. Reality is you can easily open the bores on V6 and lo-po 5.0 versions to HO specs, and remove the 'choke' if you like, but it works fine. So, if you have one of the smaller versions, you can port the venturis and swap the injectors for bigger ones. No need to hunt or pay high for an HO unit.

I've done stock and near-stock Fords and a Dodge with CFI. I've also modded a set of three for a 2x3 tri-power-style setup, though I did not do the final installation and tuning on that one. I've also had my hand in a bunch of custom TBI setups, and drive one of them regularly. That one was done with one of the first MS1s many years and approaching 100,000 miles ago, and still runs like a champ. It has saved it's cost several times over just in increased MPG, and the gravy is the added power.

So, I hope that answers some of your questions. Now I'll assume some questions and answer -

  • Yes, you can piggyback a MegaSquirt onto your existing setup, having it control the injectors and let the stock EEC control the rest. Super easy.
  • Yes, I would strongly recommend adding a wide band O2 like the Innovate LC-1 to the setup for easiest and most effective tuning.
  • Yes, you will see a bump in both performance and mileage on an '85 302 LTD (my daughter had one).
  • No, you do not want to take someone's tune and try it. Start from scratch. Seriously - it's easier and better in the long run.
  • An MS1 or MS2 is fine. Anything more advanced is a waste, as you dont have SEFI or an electronic transmission. A v3.0 board is preferred over the v2.2 as it has built-in control for any kind of injectors, including the low-ohm injectors in CFI/TBI.
  • Find some of my MS posts about tuning throttle body setups. There are a couple tricks that make it easier and more effective.
  • Software? The free MegaTune and a copy of Mega Log Viewer works well -or- a paid copy of Tuner Studio MS ($60).
  • Build your kit straight out of the manual (about 2 hours if you take your time), and set the ignition option for Ford TFI. Or, order it assembled for that.
  • If you're handy with wiring, make your own harness. It won't be complicated. If you're not into that, get the pre-made harness from DIYAutotune.
  • Ask questions. Skim (don't think too hard) the MegaManual. Ignore info that is not about your specific setup. Skim the manual again. The second time stuff will start to make sense. Ask questions.
  • When you install the MS hands-on, it will rapidly all start making sense. Don't wait until you think you understand it all. Just do it. After you get it going, you'll wonder why you didn't do it sooner.
David
 

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There is not much negative to say about them. Compared to the GM TBI, they fit standard 2-barrel manifolds, use common and inexpensive Bosch-style injectors, and have carb-style warm-up and idle air control. The GM TBI has larger throttle bores in some versions, and... well, that's about the only advantage, if it's even necessary. The funny thing is that the larger bores are great, except you can't flow more fuel for HP without very expensive injectors. Catch 22. Both have integrated throttle position sensors and fuel pressure regulators as well, so they are virtually self-contained EFI systems. Add an air and a coolant temp sensor, 40 psi fuel supply and a cheap ECM. Done.

The GM TBI is usually mentioned, because years ago it was the easiest ECM to hack. That is obviously irrelevant these days, and so that makes the CFI the more attractive option for carb conversions on mild to moderate street engines.

Yes, I've helped several guys with upgrading or carb-to-CFI conversions. Most folks prefer the HO units (Mustangs and Lincoln Marks) not only for their larger venturis, but their idle air control scheme. Reality is you can easily open the bores on V6 and lo-po 5.0 versions to HO specs, and remove the 'choke' if you like, but it works fine. So, if you have one of the smaller versions, you can port the venturis and swap the injectors for bigger ones. No need to hunt or pay high for an HO unit.

I've done stock and near-stock Fords and a Dodge with CFI. I've also modded a set of three for a 2x3 tri-power-style setup, though I did not do the final installation and tuning on that one. I've also had my hand in a bunch of custom TBI setups, and drive one of them regularly. That one was done with one of the first MS1s many years and approaching 100,000 miles ago, and still runs like a champ. It has saved it's cost several times over just in increased MPG, and the gravy is the added power.

So, I hope that answers some of your questions. Now I'll assume some questions and answer -

  • Yes, you can piggyback a MegaSquirt onto your existing setup, having it control the injectors and let the stock EEC control the rest. Super easy.
  • Yes, I would strongly recommend adding a wide band O2 like the Innovate LC-1 to the setup for easiest and most effective tuning.
  • Yes, you will see a bump in both performance and mileage on an '85 302 LTD (my daughter had one).
  • No, you do not want to take someone's tune and try it. Start from scratch. Seriously - it's easier and better in the long run.
  • An MS1 or MS2 is fine. Anything more advanced is a waste, as you dont have SEFI or an electronic transmission. A v3.0 board is preferred over the v2.2 as it has built-in control for any kind of injectors, including the low-ohm injectors in CFI/TBI.
  • Find some of my MS posts about tuning throttle body setups. There are a couple tricks that make it easier and more effective.
  • Software? The free MegaTune and a copy of Mega Log Viewer works well -or- a paid copy of Tuner Studio MS ($60).
  • Build your kit straight out of the manual (about 2 hours if you take your time), and set the ignition option for Ford TFI. Or, order it assembled for that.
  • If you're handy with wiring, make your own harness. It won't be complicated. If you're not into that, get the pre-made harness from DIYAutotune.
  • Ask questions. Skim (don't think too hard) the MegaManual. Ignore info that is not about your specific setup. Skim the manual again. The second time stuff will start to make sense. Ask questions.
  • When you install the MS hands-on, it will rapidly all start making sense. Don't wait until you think you understand it all. Just do it. After you get it going, you'll wonder why you didn't do it sooner.
David

Hey David,

Thanks for all the great info! I can remember way back when that MegaScott used CFI and MegaSquirt on his 68 Cougar and that he had an issue with the choke and fast idle not working. How did you address that problem?

Thanks, boway
 

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MegaScott - dang I haven't seen Scott for a few years now. I don't recall which CFI throttle body version he was using (there are several). The ones with the carb-style choke control work just like a carb with a throttle step for increased rpm, and are independent of the EFI system. Of course, they have no choke plate, as the extra fuel during start and warm-up is handled by the EFI system. They work fine as-is, though if you want to remove it you can substitute either a Bosch idle air bypass valve or an MS-controlled on/off air valve. Simple, cheap, and clean.

Some versions use a throttle-control motor, and that's probably what he had. As they are big and ugly where they sit stock, I never tried to use those and removed them. Instead I used the stock fixed idle screw along with ignition timing and fuel to make for a stable auto-recovery idle. In other words, if the set idle speed of perhaps 600 rpm was to drop (decel, AC on, PS load in a turn, etc.), then the ignition would increase timing below 600 rpm to increase idle speed to counteract. This is just one way to do it, and you can get all sexy with full warm-up and idle speed control using any of a variety of idle air control valves under the control of the MS.

This is a big reason I prefer generic aftermarket EFI systems like MS, as you can use virtually anything for parts that you want to or have on-hand, and tune them to work together like they were designed that way. Does that help?

David

[EDIT] BTW - these are all options if you replace the factory EEC. If you are just going to piggyback to try it out first (or permanently), then the factory EEC will control the idle speed just as before, and MS will control the injectors, or the injectors and timing. If you find my MS posts about piggybacking a GM TBI, that's the idea. Very simple as you only have to hook-up power and ground, tap the TPS, tach and coolant signals, and attach your WBO2 signal wire. At that point it is ready to control your injectors, so just put a connector on the two injector wires and you're in control. This way you can also swap between the factory ECM and the MS in a few seconds as often as you like to compare tunes and performance.
 
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