Can the 4.0 be modified to run Holley Avenger off-road carburetor?

[jungletrek74]

Debating about doing an off-road modification for fuel use that would be used in South America where fuel isn't the best quality.

Can the engine be modified intake, etc to run a Holley Avenger off-road carburetor with a fuel pressure regulator installed to lower pressure inbound? In addition, would be eliminating the catalytic converter and o2 sensors so as to run dirty blend or leaded fuel, too.

Ideas, success in this, as I like the engine and also plan on installing the Edelbrock exhaust manifold to eliminate leaks, too.

 

[Chris]

Running a carb on the 4.0? That's going to take some serious work. At that point you're better off dumping the 4.0 and putting in an older engine that has carbs from the start.

To run carbs on the 4.0, you're essentially going to need to get rid of the computer altogether, which is going to cause a plethora of other issues.

Like I said, at that point, I would rip the engine out and put in a small block 350 or an older carbureted 4.2 from a YJ.

 

[wraith1516]

fuck that chevy shit if you want a carbed engine find an older 4.2 liter Chrysler/jeep engine. it should mate right to trans no need to buy adapters or change EVERYTHING behind the engine

 

[L0jik]

Wasn't the most eloquent explanation, but Wraith is right, swapping in a Chevy small-block would introduce things like adapters or changing the transmission. However, theres plenty of benefits as well.

Either way, the big difference though, is a 350 swap (or similar) is MUCH more charted territory than turning a injected engine into a carbureted engine.

While it certainly would go much smoother to simply swap in a different engine instead of reinventing the wheel on a 4.0, if you are going to go through the work of swapping in a different engine, you might as well swap in one that will get you more power, like the 350, instead of an engine like the 4.2 out of the YJs which I believe is slightly less powerful than the 4.0.

However, if you really want to stay with the 4.0 and change to a carb, you are gonna be in uncharted territory I'd say.

Not to hijack your thread, but if you have any Jeep pics of the front from straight on, i'd love to see them. I have the same bumper and have been considering getting the winch adapter plate and wanted to see how it would look.

 

[JoshNZ]

To run carbs on the 4.0, you're essentially going to need to get rid of the computer altogether, which is going to cause a plethora of other issues.

Not disagreeing, but curious as to why?

Pulling the Cats/O2 sensor will give a CEL and mess up fuel tables, but with no injectors, who cares?
Pulling the injectors/injection fuel system will give all sorts of codes, but will it stop the computer from functioning?
Do our TJs have a "limp mode"

As long as the computer doesn't mess with the timing and ignition, I'd assume it would still function?

This thought comes from the "TDI swapped trucks" (I'm gathering parts and info for mine) where the end result is both the Jeep ECM (for body module and gauges etc) and TDI ECM (for engine control), both in tact and both looking after their respective parts only.

 

[BuildBreakRepeat]

I’d swap a Chevy 350 - more power and one of the most supported engines in the aftermarket world.

 

[Chris]

Not disagreeing, but curious as to why?

Pulling the Cats/O2 sensor will give a CEL and mess up fuel tables, but with no injectors, who cares?
Pulling the injectors/injection fuel system will give all sorts of codes, but will it stop the computer from functioning?
Do our TJs have a "limp mode"

As long as the computer doesn't mess with the timing and ignition, I'd assume it would still function?

This thought comes from the "TDI swapped trucks" (I'm gathering parts and info for mine) where the end result is both the Jeep ECM (for body module and gauges etc) and TDI ECM (for engine control), both in tact and both looking after their respective parts only.

If you rip out all the cats, O2 sensors, and everything, then what happens to the computer? You'll have to rip it out too. But then what's controlling your fuel pump? What's controlling your gauge cluster? What about feedback for all the sensors on the engine such as the camshaft position sensor, crankshaft position sensor, throttle position sensor, etc.

The computer is needed to run all of this stuff, but it's not going to function with missing sensors and fuel injectors. Could someone figure it out? Sure, I wouldn't doubt it. Would it be worth it? I highly doubt it.

Maybe someone has better advice than I do, but to me this seems like a very large undertaking.

 

[Chris]

I’d swap a Chevy 350 - more power and one of the most supported engines in the aftermarket world.

My thoughts exactly. Wraith gets pissy about anything Chevy, but I don't really care what he says. Parts for older Chevy 350s are far more common than they would be for most alternatives.

Yes, it would be a lot of work, but it's a documented swap that has been done before.

 

[freedom_in_4low]

As long as the computer doesn't mess with the timing and ignition, I'd assume it would still function?

I'm not certain what all parameters the computer looks at to determine the timing advance. It could very well do something undesirable if it think's something is wrong.

the solution would be replacing the ignition with something like MSD. Probably easier on an early TJ with a distributor but I still think it would be easier than an engine swap.

 

[Goatman]

One of those Sunday morning shows (engine power?) Did a whole show to put EFI on a 4.2. Ran like a turd, so they threw on a carb and got it pulling pretty good on the dino.
It was on the same channel as 'truck tech', 'extreme 4×4' if I got the names wrong, I'm close. Still on the U Tube and their group website containing all the episodes.