"convertable" fuel system ideas

SVO42

Active member
No, I don't mean a fuel system for open topped-vehicles, either. :P

I'm thinking of swapping a 300 into my '94 Explorer within a year or two. I want it to be EFI for off-roading and general drivability. I have seen pics of 300s installed into 2 Rangers, so it is do-able. One problem with fitment is the stock EFI intake interfering with the heater box.

I'm considering using an EFI 300 with a carb intake. I'm hoping that the carb intake won't interfere with the heater box as much. The intake would just have to have fuel injector bungs installed.

I'd like to use Megasquirt and also set it up as a flex-fuel vehicle (which MS II allows). Now, since I'm using a carbureted intake, could I just use a carburetor for a throttle body? I don't see why not. Just don't connect any fuel lines to it.

This leads to an idea: if the engine has a carburetor on it anyway, I could easily switch between using EFI OR a carb for fuel delivery.

Other considerations: MS allows for any distributor/ignition type, so why not just use an old points distributor and lock everything out and let MS handle spark duty? Cool. Spark is done, how about fuel? Port EFI needs a high-pressure pump which my Explorer already has. Would there be any problem with leaving a mechanical fuel pump hanging off the block as long as no fuel lines were connected? I can't think of anything.

So, what I would have is a fuel-delivery setup that could be easily switched between EFI and carburetion. If I ever had any sensor or electrical gremlins with the EFI, I would just have to make a few quick changes and let and old carburetor and set of points make the engine run.

Note that all of this would also be beneficial in the unfortunate event of an EMP. :shock: What do you guys think?
 
The nice thing about TPSs is that they can be mounted anywhere you want as long as you have a proper input and output voltages for the computer. You could mount one somewhere on the carburetor/throttle body or somewhere along the throttle linkage.
 
Any EMP that might take out the ECU will probably take out your ignition system and charging system too. :?

Not sure what the advantage of all the added complexity would be. EFI simply doesn't fail that often and is probably more reliable than a carb.

If you really wanted a swappable system I think a dedicated EFI throttle body on an adapter would be better, along with a carb and non-computer dizzy in a box to do the low-tech fuel mixing.
 
MustangSix":25u20zs2 said:
Any EMP that might take out the ECU will probably take out your ignition system and charging system too. :?

Not sure what the advantage of all the added complexity would be. EFI simply doesn't fail that often and is probably more reliable than a carb.

If you really wanted a swappable system I think a dedicated EFI throttle body on an adapter would be better, along with a carb and non-computer dizzy in a box to do the low-tech fuel mixing.

word. There is an abbriviation for making things complicated for the sake of being complicated.

It's called being dumb. If you cannot identify a clear and present benifit to your suggestion, then it's just a solution looking for a problem...
 
Bort62":3r2pj01m said:
MustangSix":3r2pj01m said:
Any EMP that might take out the ECU will probably take out your ignition system and charging system too. :?

Not sure what the advantage of all the added complexity would be. EFI simply doesn't fail that often and is probably more reliable than a carb.

If you really wanted a swappable system I think a dedicated EFI throttle body on an adapter would be better, along with a carb and non-computer dizzy in a box to do the low-tech fuel mixing.

word. There is an abbriviation for making things complicated for the sake of being complicated.

It's called being dumb. If you cannot identify a clear and present benifit to your suggestion, then it's just a solution looking for a problem...

LOL@truth
 
I guess I should have phrased my intentions and thought process better initially. I do plan on having a port EFI 300 swapped into my Explorer, possibly running MS. The heater box vs. stock EFI intake had me thinking about using the carbureted intake instead (if it would actually provide better clearance).

Then, I would have to figure out a throttle body mounted on the carb intake, but that would be fairly easy. I would likely conider using something like the Clifford 300 intake with the optional 2- or 4-bbl mounts.

"Easy" swappability came to mind after getting to that point. That was more of a thought problem. :hmmm: I also don't like making things unnecessarily complicated, believe me. I got my fill of that sorting out the vacuum lines and emissions system on my old '87 Jeep Grand Wagoneer. Talk about a bowl of spaghetti under the hood! :bang:

Sooo, is anyone using a carb intake with EFI? :mrgreen:
 
The Holley Projection system comes to mind as an example. There are two versions. The low end version uses a throttle body injector which can be mounted on a 4bbl carb manifold. The other version uses an EFI throttle body and port injectors.

You could do the same. Add the injector bungs to the 4bbl manifold, mount an EFI TB on the carb opening (a Mustang or GM TPI would work nicely), and power it all with a Megasquirt. Use the Ms to control ignition, too.
 
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