Eldebrock fuel return

[sweetpeet]

So, I have an AMC 360 4bbl eldebrock carb. Does anyone know how the fuel return is suppose to work on my set up? I know that most set ups like mine don't have a return but I recently had pressure build while only the pump was going and had a fuel seal bust. So if y'all got any other ideas besides a fuel return let me know.

Here's a pic of my carb I think that other nipple with the cap might be a vacuum. Would it help attaching that?

 

[steady.foot]

Do you have an inline fuel filter like the older 6 cylinders have just before the fuel line goes into the carb? If not maybe it's a good time to install one, And the earlier 6 cylinder fuel filters have two outlets. One for the carb and one for fuel return. Like this one Omix-Ada Part 17718.02 - In-Line Fuel Filter Kit

 

[PoliceMonkey161]

Do you have a fuel return line? Depending on the year of your CJ5, likely not. You may need to run one back to the tank. It's not hard to do, but to do it properly, you'll need to drop the fuel cell and install a bulkhead on the tank.


Regardless of how you get the return line, Holley makes a great little pressure return valve for about $80.00. If you need the part number, just let me know.

 

[jps4jeep]

There should not be a return line. That looks like a 1406 electric choke carb. The small ports on the front are vacuum ports (EGR and distributor.)
Also looking at the picture, generally the distributor vacuum line goes to the timed (pass side of carburetor) port. This is mandatory on emission controlled applications, if so applies to you.

 

[jps4jeep]

Disregard that, I am an idiot, you have it on the correct side, I had a massive brain fart.

 

[69jeepcj]

You can use a fuel regulator. holley, eldelbrock, both make them and others im sure. I have seen them a advanced auto before. As to the ported or full vac debate, I like running the full vac all the time, other like the ported vac, but jps4jeeps is correct that the timed port is more for the smog engines of the 70,s and 80,s. which is you.

 

[sweetpeet]

I have a Holley pressure reg. I don't have a pic but its got one inlet and two outlet. Is one of the outlets suppose to be a return? Cuz I've got a gauge on that second one.

 

[PoliceMonkey161]

Yes, it can be a return line. I would re-mount my gauge in a tee after the regulator on the inlet side of the carb.

 

[69jeepcj]

thats odd. I am using a cheap mr.gasket pump on my chev 327 and no regulator with no problems. If you have a presure gauge or vac gauge (most vac gauges can be used as a presure gauge too) I would put it on your fuel line and see how much presure you are running. It should be between 5-7 psi. If not then turn your regulator all the way down and recheck. If your regulator is not regulating the fuel presure then I would get a new regulator. newer cars are running around 55psi so your regulator may be turned way up.

 

[PoliceMonkey161]

So....After re-reading your orginial post, How did the pressure build up "while only the pump was going"? So the pump was running without the engine firing? Do you have the OEM style mech. pump or an electric pump?


Just curious.....

 

[jps4jeep]

Kinda what is being said, do you need the regulator?

Here is my brainless way to determine if you need a regulator.

run the fuel from the pump directly to the carb, and fire it up. If the carb is flooding out and/or fuel is dripping from the carb booster at idle, you need a regulator, your fuel pressure is too high. If it is just running rich, this is not a pressure issue but rather a carb tuning issue.

If you want to be dead nuts on and run that carb right out of the box with out tuning, put a fuel pressure gauge right at the fuel inlet for the carb. start the motor and see what you have for fuel pressure. as previously stated you want between 5-7 psi. If you determine you need a regulator, install between the pump and carb and tune down to 6.5 psi. The regulator is fairly static and will fluxuate under different idle/throttle condition, 6.5 tends to be ideal for the small edelbrocks and holley's. I find this the easiest, fool proof way to get a carb on a motor and have it running.

 

[sweetpeet]

So....After re-reading your orginial post, How did the pressure build up "while only the pump was going"? So the pump was running without the engine firing? Do you have the OEM style mech. pump or an electric pump?

Just curious.....

Electric pump wich is at the tank. The pressure build up was at the gauge which is in the second outlet of the reg.

 

[sweetpeet]

Kinda what is being said, do you need the regulator?

Here is my brainless way to determine if you need a regulator.

run the fuel from the pump directly to the carb, and fire it up. If the carb is flooding out and/or fuel is dripping from the carb booster at idle, you need a regulator, your fuel pressure is too high. If it is just running rich, this is not a pressure issue but rather a carb tuning issue.

If you want to be dead nuts on and run that carb right out of the box with out tuning, put a fuel pressure gauge right at the fuel inlet for the carb. start the motor and see what you have for fuel pressure. as previously stated you want between 5-7 psi. If you determine you need a regulator, install between the pump and carb and tune down to 6.5 psi. The regulator is fairly static and will fluxuate under different idle/throttle condition, 6.5 tends to be ideal for the small edelbrocks and holley's. I find this the easiest, fool proof way to get a carb on a motor and have it running.

When I run it with no reg the carb will tend to flood especially on inclines or will run so rich that it gets bogged down

 

[PoliceMonkey161]

Ok….Now we are getting somewhere. What is the fuel pressure? Which fuel pump did you use? Part of the problem sounds as if you have your pump wired wrong. The pump should only run while the key is turned to the start position and/or once your oil pressure registirs. Do you have an oil pressure switch wired in?

 

[sweetpeet]

Ok….Now we are getting somewhere. What is the fuel pressure? Which fuel pump did you use? Part of the problem sounds as if you have your pump wired wrong. The pump should only run while the key is turned to the start position and/or once your oil pressure registirs. Do you have an oil pressure switch wired in?

No oil pressure switch i don't think, I know for a fact that its a manual oil gauge that I got. I've got the pump set to turn on when I turn the key to the first notch when all the electronics go on. I've got a Nappa brand pump not sure exactly what brand ill have to check later. But the psi is rated at something like 5-7 psi.

 

[PoliceMonkey161]

No problem....... You may want to consider installing a oil pressure switch and relay. This way you will have a N.O. circuit that will run the pump with oil pressure and another N.C. circuit that only works during starter turn over.

I will send you a schematic when I get home.

 

[sweetpeet]

No problem....... You may want to consider installing a oil pressure switch and relay. This way you will have a N.O. circuit that will run the pump with oil pressure and another N.C. circuit that only works during starter turn over.

I will send you a schematic when I get home.

<img src="http://www.jeepz.com/forum/attachment.php?attachmentid=14986"/>

<img src="http://www.jeepz.com/forum/attachment.php?attachmentid=14987"/>

<img src="http://www.jeepz.com/forum/attachment.php?attachmentid=14988"/>

Looks like you got the same reg as me. Where'd you set the reg psi at? Cuz I almost always have a low reading.

As far as the oil pressure switch, I'm assuming that it will replace the oil to gauge set up by relaying electrical signals instead of physical oil. I prefer the mechanical cuz it's less likely to fail.

So if you got another alternative to the oil switch I'd be interested to hear about it.

 

[PoliceMonkey161]

Mine is set for 4 psi. because I run a Weber. You would keep the mech. gauge, you would just plumb in a 1/4" tee at the engine block. Sorry I don't have better photos with me, I'll see what I have at home later.

 

[sweetpeet]

Mine is set for 4 psi. because I run a Weber. You would keep the mech. gauge, you would just plumb in a 1/4" tee at the engine block. Sorry I don't have better photos with me, I'll see what I have at home later.

Haha man, me and tee taps have never got along well. They always break in whatever I'm drilling in

 

[PoliceMonkey161]

Your current oil psi gauge should be threaded into the block, so you'll remove that and install a (1/8th inch) nipple into the block where your current tie in is, then a tee (1/8th inch) and re-connect the oil line going to the dash. On the branch of the tee you'll install a oil pressure switch (i.e. Holley # 12-810).