Converting TBI to carb 360 Ramcharger
#2672092
06/30/19 08:30 PM
06/30/19 08:30 PM
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tt76400
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1990 Ramcharger 360 TBI with A518, we are converting this to a carb, making a hot rod street truck, can we just replace the in-tank pump with an older Ramcharger sending unit and use a mechanical fuel pump? We didn't know if the tank changed when they went to throttle body, if we can do that, how do we get the factory fuel gauge to work? The bigger issue will be what can we eliminate wire wise from the computer? We will be going to a standard Chrysler electronic ignition setup, we are just not sure what the factory computer all controls in these vehicles, don't want to eliminate any circuits/wires that we have to retain, and would like all the factory gauges to work as well, this is just for a street toy that will be getting a cam, intake, Holley 600, and good exhaust, I can find tons of info on GM TBI to carb swaps, but nothing on the Mopar swap, I know someone has had to do this before, I just want to do it correctly. Thanks!
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Re: Converting TBI to carb 360 Ramcharger
[Re: tt76400]
#2672107
06/30/19 08:54 PM
06/30/19 08:54 PM
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Sniper
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It has been years since I fooled with the old LA TBI setup and it was on a stick truck. That said, what I remember, and it's been decades so take a grain of salt, the computer used it's own sensors and the gauges used the normal old school setup. IOW the gauges don't need the computer to function. I do want to say the computer has some control over the auto trans though. Lockup and OD I suspect there are workarounds for that. Such as this setup.As for the fuel pickup, I would pull the pump out and replace it with a bit of tube and a sock. But to be honest I think the mechanical pump will pull thru it anyway. Fuel gauge will still work as the sender is separate. Fuel tanks for this vehicle are virtually nonexistent anymore so be careful. You will need to wire in the older voltage regulator as that is one thing the computer does control, you can keep the existing alternator. Will need a new intake. That's all I remember for now
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Re: Converting TBI to carb 360 Ramcharger
[Re: tt76400]
#2672122
06/30/19 09:17 PM
06/30/19 09:17 PM
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Sniper
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Yes, the tanks are different, but that shouldn;t be an issue going from TBI to carb, would be the other way.
You don't need to fool with the fuel gauge sending unit at all, it is separate from the pump module. In the picture, number 8 is the fuel pump module, number 9 is the gauge sending unit. they go into separate holes in the top of the tank.
All I would go is pull the fuel pump relay, plumb in a mechanical pump and see if it will draw through the in tank pump and feed the carb. One thing that did pop into my mind, your engine may, or may not, have the fuel pump eccentric bolted to the front of the cam, it probably does. If it does not you will need to add it. If you want to try to regulate down the in tank pump instead, the computer is what turns that pump on and off via the fuel pump relay. You would need to address that.
Ramcharger tank drawing
Last edited by Sniper; 06/30/19 09:20 PM. Reason: more info
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Re: Converting TBI to carb 360 Ramcharger
[Re: Sniper]
#2672126
06/30/19 09:23 PM
06/30/19 09:23 PM
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tt76400
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Thank you! That helps clarify things! I assumed the electric pump and sending unit were one unit, I should be able to just use my brand new old style fuel pickup/sending unit in the hole where the current electric pump goes then and just not worry about the carb-style sending unit wire on it, we will be using an LA roller cam with the long snout for the fuel pump eccentric
Last edited by tt76400; 06/30/19 09:24 PM.
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Re: Converting TBI to carb 360 Ramcharger
[Re: tt76400]
#2672135
06/30/19 09:29 PM
06/30/19 09:29 PM
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tt76400
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That is assuming the old style pickup/sending unit assembly goes into the same hole as the electric pump? If we were to regulate the pressure down, it would be with a mechanical fuel pressure regulator and use the factory return line, then we would need to keep the fuel pump relay hooked up and keep the computer, not remove it entirely?
Last edited by tt76400; 06/30/19 09:31 PM.
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Re: Converting TBI to carb 360 Ramcharger
[Re: 500ciDuster]
#2672148
06/30/19 09:43 PM
06/30/19 09:43 PM
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tt76400
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what adapter are you talking about?, you used the in-tank pump with just a return line with a carb?
I had a brain fart, you used an adapter to put a Carter BBD 2bbl from a 318 on your TBI intake and then used a regulator to get the pressure down, correct?
Last edited by tt76400; 06/30/19 10:30 PM.
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Re: Converting TBI to carb 360 Ramcharger
[Re: tt76400]
#2672170
06/30/19 10:48 PM
06/30/19 10:48 PM
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Montclaire
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All 360 TBI motors kept the eccentric on the cam for the mechanical fuel pump. What cam are you swapping to? Keep in mind that the stock valve springs will not accommodate a lot of lift. Your real problem is compression, stock should be around 8:1. Don't forget to plug the air ports if you change the exhaust. There's an old Mopar Action article about installing a switch to trigger the lockup feature on the trans, or you could you just swap to a non-lock up converter? You'd be looking at something like a CR20 probably. I don't know about the computer but I do have a TBI wiring diagram saved somewhere if you need it. AFAIK the computer controls the engine and trans only. There may be a cab computer, too.
Last edited by Montclaire; 07/01/19 12:28 AM.
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Re: Converting TBI to carb 360 Ramcharger
[Re: rbkt65]
#2672751
07/01/19 09:04 PM
07/01/19 09:04 PM
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tt76400
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