318 5.2L Questions
 

Bought a 83 Dodge Xplorer with a 318 5.2L . and I have a few questions: It seems to be running rich and possibly missing so I'm going to start with plugs and wires, but I'm unsure on a few other things.

1.) I believe this is a 4 Barrel carb "Carter Thermo Quad", is that correct?
2.) From the first picture it looks like there is some type of vacuum line that might be missing right where the air filter goes.
3.) From the second picture coming out the front on the top it looks like there should be an air box or something attached here.
4.) The last picture there is a small box that also looks like it's missing a vacuum line but I can't figure out where it should run too.
5.) When I drive and I stop and put it in neutral it seems to idle high for a while. Any ideas on how to troubleshoot that or what the cause could be?

I drove it 4 and a half hours (300 miles) last weekend straight with no issues other than it seeming to run rich an guzzle fuel, which could be standard being that it's a pretty old engine. Trying to get this thing running like a champ so are there any other small fixes I can do myself without a ton of knowledge. I've never had a carbureted engine so I'm not sure how difficult it is to adjust it or if I should even try.

Thanks,
Bret

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Have you got a picture of the air cleaner? It's hard to tell just what your looking at with the pictures you have.

Bret -

Ah yeah, a more inclusive picture might help...

If it's a TQ (black body), while a good carb, on a stock 318, it's kinda on the big side.
A modified 318 would be a different story.

Basically, plug any holes or ports you can see (you can use tubing with a bolt in the other end if you don't have regular plugs) and see what happens.
Getting an air clearer sooner rather than later would be a good idea.

Archer

I ment the air cleaner assembly, I'm looking for the Leanburn box if it has one. I'm not sure what years they got used.

Sorry doesn't look like my pictures posted in my last reply. Here they are. I think this vac line with the stick in it, goes to the silver thing in the picture here that is inside the air filter although I have no clue what it could be for. The only other place I see a missing van line is the last pic from my original post. Added a few pictures of the vehicle for reference. Just finished changing out the plugs and wires and it seems to be running considerable smoother.

https://cimg8.ibsrv.net/gimg/moparfo...02468d274.jpeg
https://cimg9.ibsrv.net/gimg/moparfo...ad57a4919.jpeg



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So I looked up my engine and apparently it is a 360 with a Carter 4bbl thermoquad. I found the early specs. There are two, I'm not sure which one is correct as one is light duty and one is heavy duty?
https://cimg1.ibsrv.net/gimg/moparfo...ac97ff1151.gif
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Found my answer, apparently they come on the car. Surprised that this is still in such good condition. Hope I can still find some of these parts somewhere, I know I'm missing the delay valve and the heated air vacuum diaphragm,
https://cimg0.ibsrv.net/gimg/moparfo...299f1a750.jpeg

1st pic looks like a thermoquad great carbs fussy but good. the secondarys are vacumm. they really only up when needed.
the pot in the aircleaner there should be line connected from the underside.
2ndpic that opening is fresh air in, theres a tube from tha opening that should run to the core support. not really a big issue
3rd pic really cant tell where that goes.

Its kinda challenging to diagnose this things with missing information. All i can tell you it that you can go to this website (Mopar-central.com) and check out what you might need. The have diagrams and illustrations according to your VIN number. Dont stress about calling the dealerships and being on hold for minutes just to tell you they dont know what you need...

Check out.. Mopar-central.com
or https://gulfgate.moparestores.com/

A few additional question here. On the bottom rear of my carburetor is this cut off hose. I recently picked up a fuel filter for the 360 5.9 which has three connections coming off of it however, the filter on the engine now only has two. I am assuming this is some type of fuel line return and that it should hook to the additional connection on the fuel filter? If this is the case as the hose is the correct diameter would they have somehow plugged this from inside the carburetor or would it work in some other format, i.e. a valve opening from pressure if the hose were to be hooked up.

My remanned carburetor will no be here till mid may. I want to install the fuel filter in the mean time though. Should I just grab a length of hose and reconnect everything as I believe it should be, or should I grab one that is inline and keep it as is? The same goes for when I get the new carburetor, am I going to have to plug something in it? Pretty confused as to why there isn't just gas running out of that opening right now?d

https://cimg1.ibsrv.net/gimg/moparfo...454b0ea59.jpeg

https://cimg5.ibsrv.net/gimg/moparfo...d47387ccc.jpeg

That goes to your vacuum amplifier.
Its on your vacuum diagram.
Good luck

I think my original assumption might have been off base. Tried to get a better picture of this. Both of the line appear to be connected properly that go to the vacuum amplifier. After doing some more research I believe that both this port and the additional port actually should run to the vapor canister which I believe may have been removed as I can't locate it anywhere.


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Im trying to help u out the best i can..
Sorry that wasnt right what i posted. Sure looked right.
The vapor can should right behind the headlight on the drivers side. Its about the size of a coffee can.
If not the drivers side then passenger...

If that goes to the vapor and the can isnt there
There would be no harm plugging that vac port
If that vac port was open it would cause your engine to run very lean.

Just an update here, got the Carburetor installed and the engine miss completely went away. Turns right over every time. The mechanic said he had to set the timing to 20deg as opposed to the recommended 16deg and that it was that way from the beginning. The bog down when stomping on it is mostly gone as well. Will still do it a bit if you attempt to stomp on it at 15mph but if you're over 35mph it sounds pretty good and there is a lot more power there.

The only issue he came across was the the vacuum throttle positioner seems to be keeping the engine at 2000 rpm and not dropping off. I think I can just remove this altogether and plug the vacuum line as it only seems to be there for emissions. The EGR valve though could not be replaced as the OEM replacement part fits but was too tall and wouldn't fit under the carburetor itself. Not sure how to solve that one, but according to the mechanic the valve is good.

Apparently the port on the carb doesn't ever have vacuum so it must go to the missing vapor canister. The new carb just has a screen in it.

Thanks for the help here.