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Old 08-14-2016, 03:28 PM   #1
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Unhappy AMC 4.9 304 Carb Swap

Hey. This is my first post for my first Jeep. I need to replace the carburetor in my '86 CJ7 because the dealer who sold it to me and his mechanic were idiots and melted the carb in it by pouring gas down it. At some point, the CJ was lifted 3" and had the engine swapped for a 4.9L 304. The carb they melted was a Rochester TBI. I'm wondering what I should swap it out with. I'd like to take the CJ out for moderate off roading, but also be able to run it around town. From what I've read, I'm 90% leaning toward the MC2100. Is this the right choice, and are there considerations for switching from the TBI to this carb? I live in northern NY and hope to run the Jeep year 'round.

P.S. The dealer gave me $1500 off the price for the replacement and inconvenience, so I'd rather buy new than look for a used one.
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Old 08-14-2016, 05:34 PM   #2
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More info

I forgot to say I'm learning as I go. I would prefer a new carb, but I took off the Rochester and discovered it has electronics to it. Are these specific to the Rochester, or will they work with other carbs? I also noticed the Rochester is a two bore they slapped on without a converter. Was this regular practice at one point? The carb itself doesn't seem to be in too bad of shape. It's the wires and plastic plugs that were fried. Any advice would be helpful. I have mechanic friends willing to help, but they aren't Jeep specific either.

Thanks!

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Old 08-14-2016, 05:58 PM   #3
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Question Carb or EFI

Reading is a dangerous thing. I just read about FI. Is this the direction I should be headed? Will it work in this Jeep? Again, I'm only looking to get the part and will have help on the install. Just looking for advice.
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Old 08-14-2016, 07:12 PM   #4
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Ok. Now I'm confused. The TBI is an injected fuel system, I assume, because when I leave the battery hooked up - it has a flip switch attached to the positive terminal- the gas jets out of a hose to where the carburetor USED to be. I'll still take advice on a good solution to having no carburetor attached. Since it's the electronics that were fried, do I do a carb or pull all the wires and start new with EFI?
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Old 08-15-2016, 06:33 AM   #5
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Ok. Coming to my own conclusions. I'm keeping the TBI for now. It looks like only the plastic casing on the wires melted a bit - I'll try to attach pics. The Jeep starts and idles roughly. I'll clean the carb and look into timing adjustment. I know there's more that will need to be done, but it looks like I'm going to have to wait a while for responses in this forum.
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Old 08-15-2016, 10:56 PM   #6
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Quote:
Originally Posted by Brahmb View Post
Ok. Coming to my own conclusions. I'm keeping the TBI for now. It looks like only the plastic casing on the wires melted a bit - I'll try to attach pics. The Jeep starts and idles roughly. I'll clean the carb and look into timing adjustment. I know there's more that will need to be done, but it looks like I'm going to have to wait a while for responses in this forum.
Hey,
Well I guess you're just having a little confusion over terminology. You have a throttle body, not a carburetor, look like to me. I'd keep the throttle body, maybe go to a junk yard and pick up those plastic clips. Clean it out with a spray can of throttle body cleaner. You can even get a new injector for the throttle body from Napa or advance or oreillys I do believe. It's a good system and should serve you well. Now, if it's running but rough, I'd start by replacing plugs, wires, cap and rotor (if it has those). Then see what you have as far as its running. If it has a new injector and all the tune up items and still runs rough, check the compression. That's how I'd start any way.
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Old 08-15-2016, 11:01 PM   #7
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Also, the last time they made a Chrysler 304 in a jeep was 1981. They did put 360 in jeeps up until 1991 I think. So, has yours been upgraded to fuel injection, or do you have another brand of engine, like a Ford? Or? It's possible you have a Chevy Tbi sitting on top of a 304 AMC. That would be an easier modification than many others.
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Old 08-17-2016, 10:39 PM   #8
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I have a Rochester TBI 220. I haven't found the engine stamp yet, but dealer said it was AMC304. It has a spread bore manifold with the funky pattern, so I'm guessing it's the AMC.
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Old 08-17-2016, 10:57 PM   #9
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Quote:
Originally Posted by Brahmb View Post
I have a Rochester TBI 220. I haven't found the engine stamp yet, but dealer said it was AMC304. It has a spread bore manifold with the funky pattern, so I'm guessing it's the AMC.
The AMC 304 is a great engine. I had one with a carb in my 72 cj-5. Anyway, I'd say keep the TBI, and get the parts necessary, get a tuneup done and see how she runs.
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Old 08-19-2016, 07:57 AM   #10
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Unfortunately, I am having no luck finding the electric part that I showed in the picture. It might help if I knew what to call it. Injector electric connector?
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Old 08-19-2016, 10:18 AM   #11
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Unfortunately, I am having no luck finding the electric part that I showed in the picture. It might help if I knew what to call it. Injector electric connector?
Here's a link. It's probably from a mid 90's gm. Also, you could Walk in to a parts store and show them a picture. I honestly think your best bet tho, is a junk yard. Look for a Chevy 350. Get the whole unit, and put it on. That way you know that it hasn't been in a fire.

https://arduino-info.wikispaces.com/GM-TBI-220

I just googled Rochester 220 it and found that
Read that whole article carefully. He shows how to change injectors and also, the symptoms, and also, the spray patterns for the injectors when engine is running.
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Old 08-19-2016, 11:45 AM   #12
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Thanks! I had just found that article this morning. The trouble is that I live in an area where there don't seem to be the parts in the junk yards. I'll keep looking, though.
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Old 08-19-2016, 06:07 PM   #13
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Go on eBay, type in gm Tbi connector. You'll see some...

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