TJ is peak. Anyone tried to de-modernize theirs?


freedom_in_4low

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Would it be difficult or impossible to put a carb into a 4.0?
Probably not very difficult, really. Just need an intake manifold set up to bolt a carburetor on top of it. I don't know enough about 4.0 history to know whether an early YJ or CJ manifold would bolt up to the head (my power steering pump I believe bolts to the manifold as well). If it didn't, you could probably have someone skilled at aluminum welding fabricate one for you. Then you'd need the mods to the fuel system to get fuel to it at the right pressure. and if you're converting and ditching the PCM altogether, you'd need a standalone ignition and new gauges, since the instrument panel is PCM-driven.

I don't know that much about the 32RH, but I thought the H stood for hydraulic, meaning it was not computer controlled except for the torque converter lockup.

If you did the toggle thing, you could keep your instrument panel but you'd need 2 fuel systems, and you'd have to get used to having a check engine light whenever you had that toggle switch in "carb mode", 'cause the PCM isn't going to like not having control over the fuel mixture. I'd put a shutoff valve in the carb fuel system, not just a pump that shuts off, or else you'd probably get codes for an evap leak. I also don't know what all it uses to determine spark advance and if it would do anything undesirable based on those inputs when it doesn't have control over the fuel. Going back into EFI mode after being in carb mode would probably take some relearning of the long term fuel trims and it'll run richer than crap, if not die entirely, until the bowl is empty.

Nothing seems too insurmountable if you really wanted to do it....no more complicated than a motor swap anyway.
 
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J
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Guys let's focus. We all love our TJs. I think we can all agree that there is one or two things we wish the factory did differently. Anyone ever wanted an inline fuel filter? Or how about an auxilliary fuel pump? Maybe that's just me. For example I built an fuel feedback filter system that draws fuel from the tank through a copper tube in the vent hose, runs it through a 10 micron filter/water separator, then pumps it back into the vent hose and into the tank. Perhaps it's overkill but it floods here in TX and small-town gas stations don't always have the cleanest fuel. At least I don't assume they do. I'm also putting on an auxiliary inline fuel pump because if your pump goes out you're stuck. I also have a screw-on transmission filter and a screw-on power steering filter. The fact that Chrysler didn't want to spend the money doesn't mean something shouldn't be there.

We all mod our Jeeps. I personally favor redundancy. Sure some things 'rarely happen', but engineers for the military and aerospace industry don't say silly things like "f**k it I have AAA". The whole point of our Jeeps is to be out in the middle of nowhere in terrain that would cripple other vehicles.

So, seat belts aside, I think it would be advantageous to 1) have an auxilliary computer you could switch over to, like a second battery; or 2) an auxilliary fuel/spark system to run in an emergency. It's not like we don't have the room under the hood.
 
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J
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Probably not very difficult, really. Just need an intake manifold set up to bolt a carburetor on top of it. I don't know enough about 4.0 history to know whether an early YJ or CJ manifold would bolt up to the head (my power steering pump I believe bolts to the manifold as well). If it didn't, you could probably have someone skilled at aluminum welding fabricate one for you. Then you'd need the mods to the fuel system to get fuel to it at the right pressure. and if you're converting and ditching the PCM altogether, you'd need a standalone ignition and new gauges, since the instrument panel is PCM-driven.

I don't know that much about the 32RH, but I thought the H stood for hydraulic, meaning it was not computer controlled except for the torque converter lockup.

If you did the toggle thing, you could keep your instrument panel but you'd need 2 fuel systems, and you'd have to get used to having a check engine light whenever you had that toggle switch in "carb mode", 'cause the PCM isn't going to like not having control over the fuel mixture. I'd put a shutoff valve in the carb fuel system, not just a pump that shuts off, or else you'd probably get codes for an evap leak. I also don't know what all it uses to determine spark advance and if it would do anything undesirable based on those inputs when it doesn't have control over the fuel. Going back into EFI mode after being in carb mode would probably take some relearning of the long term fuel trims and it'll run richer than crap, if not die entirely, until the bowl is empty.

Nothing seems too insurmountable if you really wanted to do it....no more complicated than a motor swap anyway.
Absolutely bad ass. Sounds like you've put a lot of thought into this. You've saved me some reading.
 

bedhed

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You're saying you got an external voltage regulator? So you're bypassing the one in the PCM? Interesting
Right. I intended on posting a single link for you to check out, but it will be more helpful and informative to simply do a search for ERCKFRM voltage regulator kit. The regulator's voltage output is adjustable on this particular regulator, although it's not a one-off, so you can find the same one in other places. "The alternator man" on eBay sells individual parts there.
 
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Right. I intended on posting a single link for you to check out, but it will be more helpful and informative to simply do a search for ERCKFRM voltage regulator kit. The regulator's voltage output is adjustable on this particular regulator, although it's not a one-off, so you can find the same one in other places. "The alternator man" on eBay sells individual parts there.
Thank you, sir. Never would've known.
 
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bedhed

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If/when you dive into this, don't leave us hanging. I like where your thinking is with this. Heck, start a thread for it. I'm really interested in seeing what you come up with.
 
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One of the main attraction I see in a diesel swap is the simplicity and lack of computer control. Nothing wrong with how mine works - but it’s a great backup for when mine eventually fails.
That's an interesting addition to the conversation. Hadn't thought of that.
 

Jerry Bransford

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I would like to switch to a carb also if needed. I can work on carbs....not computers...
I grew up with carburetors before FI was common in cars and 30 years before Jeep introduced FI. I synchronized pairs of carbs and rebuilt/adjusted them... lots of carb experience because they needed lots of TLC. And they suck on steep climbs where they starve the engine of gas which causes engine stalls.

You guys who want to go back to carburetors either have little experience with them, poor memories, or are just plain nuts.

Would I run an old Chevy with a carb? If course but I'd only do it for purism and nostalgia.

Would I convert any of my fuel injected cars or my Jeep to carbs? Not on your fucking life. I may be old but I'm not nuts.
 
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I grew up with carburetors before FI was common in cars and 30 years before Jeep introduced FI. I synchronized pairs of carbs and rebuilt/adjusted them... lots of carb experience because they needed lots of TLC. And they suck on steep climbs where they starve the engine of gas which causes engine stalls.

You guys who want to go back to carburetors either have little experience with them, poor memories, or are just plain nuts.

Would I run an old Chevy with a carb? If course but I'd only do it for purism and nostalgia.

Would I convert any of my fuel injected cars or my Jeep to carbs? Not on your fucking life. I may be old but I'm not nuts.
No one's arguing with its downsides Jerry. I think the conversation has evolved to having both so that in an emergency you can toggle over to a carb. I'm over simplifying it but that's what I think the concession is.
 

Jerry Bransford

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No one's arguing with its downsides Jerry. I think the conversation has evolved to having both so that in an emergency you can toggle over to a carb. I'm over simplifying it but that's what I think the concession is.
In an emergency toggle over to a carb? Are you shitting us? OK I'm done wasting any more time in this thread.
 
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In an emergency toggle over to a carb? OK I'm done wasting any more time in this thread.
Hold on Jerry, we're trying to expand our knowledge. Obviously you aren't personally interested but if you're taking the time to comment please enlighten those of us who are less knowledgeable as to why it is implausible, for those of us who are interested.
 

Rubi04

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With Jerry on this, those who have ran both (I have) would never go back to a carb setup after having good, dependable FI the TJ offers. If your worried about emp and other doomsday stuff, put extra PCM and electronics in a foil bag for spares. Jesus. That the least of my concern with a emp strike but you do you. 😂