Carburetor Help?

[Green Mesa XJ]

ok i see so i should get a carb with Vacuum Secondary since they are ideal for street vehicles with automatic transmission
and a 2 barrel carb is simple and easy to tune 
 
i have found the stamp that verifies its a Rochester Varajet II (i think the 2 stands for 2 barrels)

 
and i am not sure what this stamp is for but i was trying to figure out what exact model it is 

 
I found this website and clicked on "CK277" and it looks like the model i have 
http://www.carbkitsource.com/carbs/tech/Rochester/Varajet.htm
 
Also this looks like an electric choke so does that mean the the current carb is a
2 barrel / electric choke / Vacuum secondary 

 

Yep, you have the standard factory carburetor with electric choke or one of those flavors. 2se or e2se Rochester Varajet. Awful carburetor.
Here are a few pictures from my 32 year old XJ, your missing part of the factory set up, maybe even the valve covers cause the drivers side cover looks wrong, but it also may not be necessary for all these lines to exist.
Also remember I put the Weber carburetor in many years ago and this is how I set it up (following their instruction) some of these lines might be unnecessary.

Just uploading small pictures for now, if you need a bigger picture I can upload it later . It's a confusing mess of lines either way.

The picture for the firewall specs didn't come out, 700 rpm idle, 1200 rpm with vacuum advanced.











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[AMC86Kid]

i feel like its not getting enough gas when it dies 

maybe i can put up a video of what it sounds like so you guys can hear 

[Pete M]

did the previous owner complain of this from day one of the swap or is it a new problem?

 

[AMC86Kid]

the previous owner sold me the vehicle with the 3.4 rebuilt engine in the bed of the truck 

he did not install the engine because he had realized it was gonna be a lot of work and decided 

that he would rather work on his Studebaker so he offered to sell it to me at a price that i could not say no to 

and now I'm here putting it all together and trying to figure out all the problems 

[Eagle]

On 9/6/2017 at 2:22 AM, AMC86Kid said:

here's the info on the fuel pump 

its made specifically for carburetors 

http://www.autozone.com/external-engine/fuel-pump/spectra-premium-fuel-pump/191528_0_5752?&searchText=E8016S

 

Can you send me a link for the correct Webber and Holley carburetor 

I can't even find the official Webber site and the Holley one asks for engine's cubic inches (not sure how to figure that out)

and for maximum RPM I'm assuming around 4600 since i have a 3-speed A904 automatic tranny 

 

Also should i get an electrical choke since its easy and regulates the carb automatically 

and should it have Mechanical or Vacuum Secondaries

 

One liter is 61 cubic inches, so a 3.4 liter engine displaces (approximately) 207 cubic inches. Carb sizing isn't rocket science and you don't have to be accurate down to the third decimal place. Pick a carb for around 200 cubic inches if you'll never see high RPM, or pick one for 225 to 250 cubic inches if you drive with a lead foot.

[AMC86Kid]

ok so if my Cubic inches is around 207 and my max RPM is around 4600

then i need a carb around 225 - 250 CFMs

 

and i am currently taking apart the current carb and cleaning it out 

then i will put it back on and see how it performs if any better 

[Green Mesa XJ]

You might also check the fuel is reaching the carburetor and the line is clear while it's out.


Eagle what else would fit that intake?


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[AMC86Kid]

the carb is now cleaned and i made sure to secure it good so there are no leaks 

also the gaskets look good to 

but it still pretty much acts the same 

 

how strong should the fuel filter in the carb be 

cause mine is hard to blow air threw but its not dirty i cleaned it out 

 

i also get plenty of gas out the fuel line that connects to the carb (when the fuel pump is running)

but it seems like the carb has very little suction power to be able to pull gas out the fuel line when the fuel pump is not running 

that must explain why it runs when you step on it but not when you let it sit 

I'm assuming when you step on it the suction of gas is much stronger then when it sits 

[86FUBAR]

Your carb is an 2SE (the E2SE version is electricly controlled) there is a IIRC a mixture screw that requires a special tool located under the rectangular mesh screen on top of the carb that could be adjusted ! I remember doing it to mine when I swaped to a 3.4 , I'll see if I can dig up the info for ya and as for the tool I borrowed it from a friend who owned a shop. To me it sounds like it just needs to be adjusted ! That's a heck of a lot cheaper than buying a new carb , I know these ain't the best carbs but they do work .

 

Edit:

http://www.autozone.com/repairguides/Jeep-Wagoneer-Commando-Cherokee-1984-1998/CARBURETED-FUEL-SYSTEM/Rochester-2SE-E2SE-Carburetor/_/P-0900c152800a9cdb

found this !!! This is actually got an amazing amount of helpful info in it !  Near the bottom it talks about an external idle mixture screw that I totally forgot about. I would  start here.

[Eagle]

12 hours ago, AMC86Kid said:

i also get plenty of gas out the fuel line that connects to the carb (when the fuel pump is running)

but it seems like the carb has very little suction power to be able to pull gas out the fuel line when the fuel pump is not running 

that must explain why it runs when you step on it but not when you let it sit 

I'm assuming when you step on it the suction of gas is much stronger then when it sits 

 

Carburetors 101:  The carburetor doesn't take gas directly from the fuel pump into the intake manifold. The fuel pump pushes the fuel at around 5 to 7 psi. From the inlet line the fuel goes to a reservoir in the carb body called the float bowl. There's a float in there, that activates a needle valve. When the fuel rises to the upper limit, the needle valve closes and shuts off the flow of gas into the carb.

 

From the carb to the engine, the venturi (or venturis, if it's a 2-barrel or 4-barrel) such the fuel out of the float bowl. Gas in the float bowl is only under atmospheric pressure, it's not being pushed by the fuel pump, as it is in a fuel injection system. The faster air flows throiugh the throat and past the venturi, the more fuel gets sucked out of the float bowl. When you step on the throttle, the throttle plate opens wider, which actually causes the velocity nof the air through the carb throat to slow down -- which, in turn, reduces the suction effect on the venturi and starves the engine of fuel. So there is also a plunger deally called the accelerator pump, which gives a squirt of gas into the throttle bore when you step on the gas to copensate for the momentary leaning out when the throttle plate first opens.

 

If you can keep it running by working the throttle, you're getting enough gas. You have a problem with the idle circuit -- either that idle mix screw isn't adjusted correctly, or the idle air circuit is dirty and clogged.

[AMC86Kid]

ok i took off the rectangular mesh

and is that hole with the piece of metal inside the thing that 86FUBAR was saying to adjust 

 

 

[HOrnbrod]

http://www.autozone.com/repairguides/Jeep-Wagoneer-Commando-Cherokee-1984-1998/CARBURETED-FUEL-SYSTEM/Rochester-2SE-E2SE-Carburetor/_/P-0900c152800a9cdb

 

[AMC86Kid]

i was able to find a service manual 

http://c777913.r13.cf2.rackcdn.com/varajet_service_manual.pdf

it seems like it just explains how to take it all apart tho 

 

also i was wondering how the fuel pump is suppose to be working 

mine is just pumping gas for a few seconds before i start the engine and thats it 

it doesn't pump anymore gas as the engine is running 

is that correct or is it suppose to be wired so that its constantly pumping gas and the extra fuel 

goes back to the tank on the return line ?

[HOrnbrod]

http://www.s10forum.com/forum/f106/85-s10-2-8-gas-tank-and-electric-fuel-pump-question-454877/

 

2.8 / 3.4 fuel pumps

[AMC86Kid]

ok so in that forum they run it from the battery to a safety oil pressure switch then to a relay in which he has a switch to turn the terminals on the relay off and on 

so i get how its wired but i don't get if the fuel pump will be always running as the engine is running or if he just turns in on and then shuts it off after the engine starts ?

[Green Mesa XJ]

i was able to find a service manual 

http://c777913.r13.cf2.rackcdn.com/varajet_service_manual.pdf

it seems like it just explains how to take it all apart tho 

 

also i was wondering how the fuel pump is suppose to be working 

mine is just pumping gas for a few seconds before i start the engine and thats it 

it doesn't pump anymore gas as the engine is running 

is that correct or is it suppose to be wired so that its constantly pumping gas and the extra fuel 

goes back to the tank on the return line ?

It should stay pumping. You might need to check where it's drawing power from.

 

 

Edit: do you have a cut off switch? Maybe that's cutting it off?

 

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[AMC86Kid]

so you say its should be constantly pumping gas threw

and the excess gas should flow down the return lines and into the gas tank 

then i need to find out how to hook up my return line to the carb 

because currently it is not hooked up to anything and just plugged with a bolt 

 

anyone know where the return should be hooked up at so i can get a constant cycle of gas ?

[Green Mesa XJ]

The lines should still exist, hang on I'll get a picture.

This is where it comes out in the engine bay near the fender.



One line is already being used to pump the fuel I guess connect the return line to the correct line.
I was pretty sure that line with a bolt was vacuum. I don't remember a return line being on that carburetor, it was on the mechanical fuel pump, pretty sure I connected the fuel line to the new carburetor and sorted the vacuum lines out, no return line to cut out.
I think the regulator I installed had the option for connecting a return line, not sure it was so long ago.

I'm not sure what the electric pumps should do in this set up. some like to add a kill switch in case ending stalls or there's an accident. Some run power from the ignition or something that is only powered while the ignition is on run.


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[AMC86Kid]

yes the first line to the left is the gas coming from the tank 

the middle line is the return to the tank 

and the last line to the right is the gas tank emissions to the smog canister 

 

but I'm trying to figure out how to connect the return line 

does it connect to the carburetor or to something else thats connected the the fuel line 

[Eagle]

6 hours ago, AMC86Kid said:

so you say its should be constantly pumping gas threw

and the excess gas should flow down the return lines and into the gas tank 

then i need to find out how to hook up my return line to the carb 

because currently it is not hooked up to anything and just plugged with a bolt 

 

anyone know where the return should be hooked up at so i can get a constant cycle of gas ?

 

I'm not familiar with that piece of crap carburetor, but I've never heard of a carburetor with a return line. Remember, it was designed to operate off a mechanical fuel pump, and a mechanical fuel pump doesn't shut down if the pressure exceeds 7 psi. You are using an aftermarket fuel pump, so you need to take a look at how you wired it, and how the manufacturer says it works. My expectation is that it's supposed to run all the time. Fuel flow into the carburetor is controlled by the float and the needle valve.

 

But ... you originally posted that if you keep working the throttle, the engine stays running. Is that correct? If that's true - then you obviously don't have a fuel delivery problem.

[Jeep Driver]

I suspect the regulator is installed wrongly.

 

You have a gauge........it tells you what?

 

I suspect the gauge is plumbed on the inlet side and the fuel line is plumbed on the regulated return or gauge side. 

[Jeep Driver]

You've got a constant electric fuel pump, you must have a return at the regulator. 

 

Your regulator should be at the pump. 

[Green Mesa XJ]

I was digging though some saved files on doing a 3.4 swap, here are few of useful links I found.

 

 

Install instructions for Holley 12-803 fuel pressure regulator (there is a return port)

http://documents.holley.com/199r7914-3rev6.pdf

 

Thomas Hardman 2.8 Weber swap with good pictures of the lines and hoses, anyway better than I got.

http://www.thomashardman.com/tech/comanche/comanche-weber/

 

S10 forum has a guy by the name of Jimmykicker who has done the 3.4 swap on a 85 S10 which had the 2.8 w/carburetor, he has a few yourtube videos and s10 forum post about the swap.

 ericknight from the s10 forum had this summery on fuel supply

Quote

Here's what I used, AC Delco EP42S fuel pump, and mount it as close to the tank as possible, NOT under the hood, they push fuel better than they pull it. If you have an oil warning light, you can use Standard PS132 pressure switch (cuts power to fuel pump if oil pressure goes to zero) and AC Delco PT139 wiring pigtail for it. If you have an oil pressure gauge you'll have to figure something else out. Holley 12-803BP bypass style regulator with Marshall 0-15psi gauge (dry) from Ebay. You want to mount it close to the carb. Some will say you don't need a regulator, but your pump will last longer if you have one. Universal fuel pump relay from Jeg's. I spliced into the power wire to the coil for the fuel pump, hot in start and run key position, off in accessory key position. http://www.s10forum.com/forum/f106/2-8l-to-3-4l-600274/

 

 

Other links I think you've already found.

 

Also found two GM diagrams of the Vacuum Lines for the 2.8 carburetor from 1983 & 1984, that might help you sort the lines.

 

Before the swap did it run with that carburetor? Your getting fuel to the bowl, my guess is there is something wrong with it, blocking or clogged keeping the idle mixture off. Even with bad fuel pressure it should run until the bowl is empty.

[AMC86Kid]

so did the 2.8 mechanical fuel pump have a return on it ?

 

and is it possible to have a fuel pressure regulator set up to connect to my carb 

then have a bypass on it connected to my return line 

so then i will always have gas pumping to the carb and the excess fuel flowing back to the tank

[Green Mesa XJ]

Yes the mechanical pump had a return line built in.

Look at the instructions for the regulator, you can set up it up to return the fuel to the tank. I don't use that on my set up cause I still have the mechanical pump, but do have the pressure gauge and regulator set up near the carburetor which is where it has to go for this kind of set up.

Maybe as a kludge fix use the old 2.8 pump as a way to route the return line temporarily. Probably a bad idea, you need a regulator or at the very least a way to gauge the pressure . If you have this then you know if the electric fuel pump is working or not.

That carburetor calls for 4.5 to 5 psi fuel in the specs, but as long as the fuel bowl in the carb is full the engine should run.

You said the previous owner wanted that carburetor so he could tune it manually, was it electric computer controlled before?
And do you know for sure that carburetor worked on the 2.8?
Other things don't look right from the pictures but I'm not sure what you've actually got and what you actually need to make that carburetor work.

I think you've got two problems from what you say is happening, fuel supply and probably a bad carburetor.


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