manladypig
manladypig Reader
7/14/24 3:05 p.m.

I got a 1986 Dodge Ram B350, Its had running problems for a while now. I installed a brand new fuel pump thinking that was the problem, it also has brand new spark plugs, wires, and distributor.  But it continued to run weird, shutting down frequently, lacking in power. Both of those replacements temporarily improved things but it declined again later on. But it did keep running, it never fully stopped. 

Anyways after struggling with it chug chugging along all summer in Mammoth I had to drive it home 8 hours to San Diego, and it made it home fine! And then one day after getting home it shut off and now refuses to stay running for even 5 seconds. At least it got back before E36 M3ting the bed completely. One thing to keep in mind is throughout all of this, it has always and still will start instantly on starting fluid and run fine. I used starting fluid to drive it up a long driveway after it stopped running on its own completely. So considering that im thinking it has to just be a fueling problem right? if that sounds correct than i just need help finding a new Carburetor, if it sounds like something else let me know

So Ive called several Carb shops and they've either told me I'm SOL or offered a very expensive rebuild price along with a long wait time. Are there really no replacements that I can just bolt on out of the box? After owning 10 different vehicles, this is my first Carbureted and first American so I'm out of my realm here. There are so many different options and fitments and I'm lost. So can anyone confidently say what a good option could be? Just anything that will get this thing running right again. Its the 5.9 V8 Automatic. the Carb is some kind of 4 barrel thing, here it is pictured below

ShawnG
ShawnG MegaDork
7/14/24 3:08 p.m.

Thermoquad probably. 

Get the number off the carburetor. Get a rebuild kit, a clean place to work and rebuild it yourself.

 

Cousin_Eddie (Forum Supporter)
Cousin_Eddie (Forum Supporter) SuperDork
7/14/24 4:01 p.m.

That is not a Thermoquad. That is a Quadrajet. Commonly used on GM vehicles. less commonly on Chrysler stuff.

I have no affiliation with this company. But they have what you need (Quadrajet for 85-88 Dodge 360)

https://i-5automotive.com/products/rochester-quadrajet-carburetor

But, my money says you have a fuel delivery problem, and not a carburetor problem. I know you said you put a new pump on. I'd verify strong fuel pump spurt before I shot the parts cannon at it.

ShawnG
ShawnG MegaDork
7/14/24 4:10 p.m.

In reply to Cousin_Eddie (Forum Supporter) :

Didn't know they used Q-jets on Mopars. The choke horn looks different than a GM Quadrajet.

I'm not a Dodge guy though.

Could be a plugged fuel filter. Quadrajet filters are tiny and lots of people don't even know there's a filter behind the fuel inlet fitting.

APEowner
APEowner UltraDork
7/14/24 4:17 p.m.

That's a Rochester Quadrajet.  Depending on mileage it may need to have the throttle shafts replaced and/or bushed to get perfect which might make a rebuild impractical for DIY.  I can't vouch for this vendor but here's at least one source for a rebuilt unit-> i-5automotive

Russian Warship, Go Berkeley Yourself
Russian Warship, Go Berkeley Yourself PowerDork
7/14/24 4:21 p.m.

In reply to ShawnG :

Thermoquad has a plastic fuel bowl/ main body.




Carter went out of business in 1984, so there weren't any T-quads anymore.

That's a Rochester Quadrajet on the van.

ShawnG
ShawnG MegaDork
7/14/24 4:27 p.m.

In reply to Russian Warship, Go Berkeley Yourself :

Didn't realize they were all plastic bodies.

I've rebuilt a ton of carburetors but never managed to work on a Thermoquad.

Stampie
Stampie MegaDork
7/14/24 4:44 p.m.
manladypig
manladypig Reader
7/14/24 4:53 p.m.

In reply to Stampie :

Ooh I like that price

manladypig
manladypig Reader
7/14/24 4:54 p.m.

In reply to Cousin_Eddie (Forum Supporter) :

Im gonna do one more test of just directly filling the bowl to see if it will stay running before i do pull the trigger on a new carb

DarkMonohue
DarkMonohue SuperDork
7/14/24 5:08 p.m.
manladypig said:

I got a 1986 Dodge Ram B350... I installed a brand new fuel pump thinking that was the problem, it also has brand new spark plugs, wires, and distributor.  But it continued to run weird, shutting down frequently, lacking in power. Both of those replacements temporarily improved things but it declined again later on. But it did keep running, it never fully stopped. 

Just because the fuel pump is new is no guarantee it's good - or that it ever was.  DOA and failure rates on new aftermarket parts are both pretty terrible sometimes.  What sort of diagnosis have you done before or since replacing the fuel pump?  At that age, everything you've replaced was probably at or near the end of its life, but still, you really want to know what is causing the problem before you start chucking more parts at it.

 

manladypig said:

Anyways after struggling with it chug chugging along all summer in Mammoth I had to drive it home 8 hours to San Diego, and it made it home fine! And then one day after getting home it shut off and now refuses to stay running for even 5 seconds. At least it got back before E36 M3ting the bed completely. One thing to keep in mind is throughout all of this, it has always and still will start instantly on starting fluid and run fine. I used starting fluid to drive it up a long driveway after it stopped running on its own completely. So considering that im thinking it has to just be a fueling problem right? if that sounds correct than i just need help finding a new Carburetor, if it sounds like something else let me know

New/reman carbs are listed at Rock Auto.  They break them down by light or heavy duty, with or without feedback, and match their listings to your OEM carburetor number.  But let's not go that far yet.  Your statement that it runs on starting fluid but not on its own certainly suggests a fueling problem, but that does not automatically mean that you need a new carburetor.  They aren't disposable, and they aren't cheap.  Rebuilding it is certainly an option, depending on your skill/comfort level and patience.  Replacing it because the engine seems to not be getting fuel under certain conditions is jumping to a very expensive conclusion.

 

manladypig said:

So Ive called several Carb shops and they've either told me I'm SOL or offered a very expensive rebuild price along with a long wait time. Are there really no replacements that I can just bolt on out of the box? After owning 10 different vehicles, this is my first Carbureted and first American so I'm out of my realm here. There are so many different options and fitments and I'm lost. So can anyone confidently say what a good option could be? Just anything that will get this thing running right again. Its the 5.9 V8 Automatic. the Carb is some kind of 4 barrel thing, here it is pictured below

 That's a Rochester Quadrajet.  They are incredibly common on OEM applications (mostly GM, but Chrysler and Ford also used them).  Maybe yours is a little different, being a Mopar application, but by no means is this exotic machinery; should it come down to a rebuild, there are several Quadrajet specialists in the world.  Or, as Shawn said, do it yourself.

Try this: crank the engine on the starter for ten or fifteen seconds, then put the keys in your pocket and remove the top of the carburetor (there are many videos on YouTube to walk you through disassembly) and see how much fuel is in the float bowl.  If there's no fuel, then find out why the fuel in the tank is not making it to the float bowl.  Is the pump working?  Is the inline filter clogged?  What about the little filter in the carburetor fuel inlet - is it clogged?  Is the float moving freely, and when it drops, does the needle move freely away from the seat to allow fuel into the bowl?

You got this!

EDIT: Ah, hell.  Looks like I am the slowest typist in the room.  

ShawnG
ShawnG MegaDork
7/14/24 5:09 p.m.

In reply to manladypig :

Check the filter.

Check your fuel pressure.

Whack the bowl near the fuel inlet with a screwdriver handle. If the float is sticking, this will help to jar it loose.

 

warpedredneck
warpedredneck Reader
7/14/24 5:16 p.m.

Way, way back,  I looked after a fleet of Ambulances, all dodge 3/4 ton or 1 ton's with the 360/ quadrajet carb,

All of them had the "sock" in the fuel tank slide up the pickup, blocking it.

Not saying this is your problem, but I would sure check/replace it

Streetwiseguy
Streetwiseguy MegaDork
7/14/24 5:19 p.m.

Don't buy some unknown piece of rebuilt crap.  The one on the engine has the right jets, the right needles and so on.

Remove the fuel line between the carb and fuel pump, which ever end is convenient, find a can to catch the fuel, and get someone to crank the engine.  Fuel should spurt-spurt-spurt as the engine cranks.  If not, find the problem there.  

Good fuel, grab your 1" wrench and pull the inlet fitting. Check the little filter.

FIRST, DO NOT TWIST THE STEEL LINE INTO A PRETZEL BY LETTING THE FITTING IN THE CARB LOOSEN OFF BEFORE THE FLARE NUT LOOSENS!

SECOND, DO NOT CROSS THREAD THE INLET FITTING WHEN YOU SCREW IT BACK INTO THE CARB!

I can't count how many times I've seen that.

Then, if it still won't run, go find a mechanic who is at minimum 60 years old, and pay him to fix it.

I don't think it's an internal carb problem, based on your story.

Stampie
Stampie MegaDork
7/14/24 5:34 p.m.

In reply to Streetwiseguy :

National Carb isn't an unknown piece of crap.  They rebuild their own in house and can even customize them.  If they advertise for that year/make/model then it'll be jetted for that year/make/model.  I've been very happy with them over the years.

manladypig
manladypig Reader
7/14/24 7:41 p.m.

In reply to Streetwiseguy :

I should be more specific, the van stopped running 6 months ago, I replaced the fuel pump all rubber lines and i know about the little filter that was also replaced. Those replacements fixed the problem, the van ran again. But now Its dead again. But you're probably right that I should do that test again just to see, I dont think the pump would fail in 6 months, but I do beleive that the filter may have clogged. I'll do some checks and report back later

Noddaz
Noddaz PowerDork
7/14/24 8:48 p.m.

As others have said, that is a Quadrajet.  And as others have said, it IS the right carb for your van.

While this won't make it stop running, what is going on here?  (Circled in red)  It looks like a big vacuum leak.  I am guessing this was supposed to be connected to the PCV valve or the brake booster.  Most times a vacuum leak that bad won't cause the engine not to run, but it will run really bad.

And then go back to the basics.  Use a fuel pressure gauge to check fuel pressure.  There are many videos on You Tube on how to do this.  A gauge is available here from Harbor Freight.  It looks very similar to the gauge I bought off of a tool truck 35 years ago.  If you buy the fuel pressure gauge, hook the rubber adapter with the brass nipple to the hose on the gauge and plug it onto the metal nipple under the broken hose circled in red.  Then try to start the engine.  Maybe you will be lucky and that is all it is.

 

 

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
7/14/24 9:45 p.m.

Qjets are my bag, but my bag is getting a little old and crusty.

Qjets are the single most accurately-metering carb on the planet.  Better than any factory carb, and better than any aftermarket carb.  Most carburetors take three stabs at mixtures; idle, primary, secondary, and they do a little bit to make it adapt to other vacuums/loads, but the Qjet can be almost like EFI when tuned right.  The downside is that they're a little complex with a lot of parts.  The first time you rebuild it, you'll be left with a check ball on the bench and swear a bit, but you'll be fine.

I also agree with others.  Carbs are remarkably reliable things.  It is quite possible you got junk in it and clogged a jet, or that your float sunk or got stuck, but carbs don't really change... the engine changes as it wears out, but there isn't much about a carb that "goes bad."

First things first.  Verify that you're getting fuel pumped.  Fuel pump diaphragms are a rubber-y material and they will last almost indefinitely unless they sit and get dry.  You can have a perfectly-operating mechanical pump on a 250k engine, but the first time you let it sit for a couple months and that diaphragm gets dry, it's a goner.  One way you can verify is the messy way (take the line off the carb and crank to see if you drench things in gasoline) or crank it for a bit and then look down in the primaries while opening the throttle with your hand.  You should see a pretty instant squirt of fuel from two holes just under the choke plate.

Also verify that you have the correct pump.  Over the years, the 360/5.9L came with at least three different cam snouts and different fuel pump lobes.  If the parts store gave you a random 360 pump, it's possible it sheared the pin in the pump.  Ask me how I know.

A clogged or missing sock in the tank is a good thing to check.  They are a steel mesh tube thing pinched at the end.  They rust, fall off, get clogged, etc.  While you have lines exposed and pulled, use compressed air to blow through them and make sure you don't have a clog of gunk that got past the sock.

Qjets are known for wearing out the throttle shaft bores.  The shafts are steel or brass, and the throttle body is aluminum.  Every time you push the pedal, it pulls and rubs the shaft against the back of the bores and opens them up.  Jet Performance has a super-easy fix.  They send you a reamer and a bunch of brass sleeves to return them back to the right size/shape.

Double check your timing.  I know it seems like a fuel issue, but starting fluid burns way different (and ignites way easier) than gasoline, so the fact that it runs on starting fluid but not gasoline could be giving you a false conclusion that it's fuel.

If you eliminate everything else, THEN assume it's carburetion.  You should be able to pull it apart and just clean everything out using a rebuild kit.  Pro tip, buy a set of welding tip files.  It looks like the picture below.  Find the right size to clean out the jets and passages.  Blast carb cleaner or brake cleaner through every hole, and wear eye protection because some of the holes are not the whole way through to anything.

Welding tip files:  Just tiny filing "pins."  The secret is to rod out the jets but not file them.  Tiny changes to the jet size will throw things off.  You're just looking to make sure there isn't anything crusty in them.

DarkMonohue
DarkMonohue SuperDork
7/14/24 9:47 p.m.

Given the age of this van and the assumption that it sat for many years before OP bought it, that fuel tank is probably nasty. If there's crap in the tank then it's going to keep sucking it up, clogging the pickup in the tank as well as both filters with tedious regularity. 

How hard would it be to drop the tank and give it a good internal scrub, or at least a good inspection? At the very least, you're going to want to pull the pickup tube and make sure it's clean, inside and out, and that's another opportunity to peek inside the tank. 

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
7/14/24 9:55 p.m.

Oh, and buy yourself a Haynes or Chilton's manual on Qjets.  For more advanced Qjet stuff, Cliff Ruggles has a couple books on them.  Your rebuild kit will come with a complete set of specs, but may not have actual instructions.  There are a few hundred different Qjets, but only about 20-30 rebuilt kits that include gaskets and parts to cover a few dozen carbs in the lineup.  There might be 5 different horn gaskets and 4 different TB gaskets in the kit, so make sure you line up the old with the correct new.

There might be slight differences between the old and new gaskets, but don't stress.  For instance, if your base gasket is a 4-hole, but the ones they send are a big open gasket, it really doesn't matter much.  If your old TB gasket has a triangular hole and the new one has a round hole around something exposed to manifold vacuum, it won't matter.  You just need to make sure that whatever was covered (or uncovered) before is the same on the new gasket as the old.

Do take the time to properly set the float level.  Qjets have relatively small fuel bowls.  Too high and they'll overflow.  Too low and they'll not have enough reserve to handle higher throttle positions.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
7/14/24 10:03 p.m.

Dangit, I keep forgetting things.

Look on the side of the main body for a stamped number.  It should start with "170"  That's your carb model/serial.  There are websites that can decode it, but honestly.... they suck.  Yours might decode to a Buick with a manual transmission.  That's not important.  It's just important that you have that number so you can get the right parts.

Tony Sestito
Tony Sestito UltimaDork
7/15/24 10:47 a.m.

Your issues sound A LOT like the issues I had with my Power Wagon when it still had a carb. I would have odd fueling issues, and I went through 2 fuel pumps and had the carb off a bunch of times to look for issues. While some of the issues were due to improper vacuum routing, a bad base gasket, and things like that, the main cause was the fuel sender sock disintegrating in the tank and its remnants making their way into the fuel system. Some of those chunks somehow got through the fuel filter and into the pump and carb. I would make absolutely sure you have unblocked fuel lines to start. 

And like others said, that's a Rochester Quadrajet. They are great carbs if things aren't all gunked up. They do have an inlet filter where the fuel line attaches to the carb; make sure that's free and clear as well. 

manladypig
manladypig Reader
7/26/24 6:18 p.m.

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