Little advise for fuel problem

[Pxxcmd]

Hi im having a little trouble with my fuel problem for my cj7 1981 4 cylinder engine. I dont have a fuel pump but the carp would suck up the fuel on its own. I cant start the engine without having to poor a little bit of gas into the carp to get her started up. Also the carp would stop sucking up the fuel when its half full. Is it hard installing a new pump thanks

 

[69jeepcj]

Your fuel pump should be on the side of the engine block (passenger side). If for some reason the PO took it out and blocked it off with a plate to run a electric fuel pump instead but never installed it before you got the jeep would be the ONLY reason that your jeep shouldnt have one. The mechanical pump (which you should have) or electric pump are easy to instal or replace. follow your fuel line and it should go the the pump on the side of the engine block. Just undo your fuel lines and unbolt the pump, pull it out and slip the new one in, hook the lines back up is about all there is to it. There is no high presure on the fuel lines like the newer cars have.
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I will look something like this, the

 

[Pxxcmd]

No i dont see a part like this anywhere on my jeep. Just tubbing from the gas tank to the fuel filter then to carb. I may have missed it. Lets see i have a Rochester 2se carburetor to be more acute on the model. And to give you a idea on the of the carb i have

 

[Pxxcmd]

Wait i found it.

 

[69jeepcj]

thats it! I cant believe you were able to start it let alone drive it with out the pump. Your engine must have awsome vacuum. Your are lucky it never left you stranded. After you get the new pump on, you will have to crank the engine over and over before it will start because you have to suck the gas back up from the tank to the pump. I have drained a few batteries doing it that way, you can pour some gas in the carb to start it and the engine will suck the gas up to the pump. much easier that way.

 

[Pxxcmd]

Thanks it probably needs a new filter. I dropped the gas tank and the air filter was black so was the fuel filter was black. So im pretty sure of i replace filter in the pump it should start working again. Or should i just get a new one?

 

[superj]

change the filter and try it. if it works, you're good. if it still down't work then you got the hard part done already so changing the pump is easy

 

[Pxxcmd]

Ummm i just pulled the pump? I have no clue on how to open it? No screws no nothing.

 

[Pxxcmd]

Any one know this type of pump?

 

[Utah_jeepster]

Mechanical fuel pumps are a non-servicable. Just replace. There is no fuel filter inside it by the way.

Sent from my PG86100 using Jeepz

 

[Pxxcmd]

O i didt know that.

 

[69jeepcj]

Yeah, you have to replace it. They are not very expensive. If follow your gas line back to the tank you should find your fuel filter somewhere along the way probably along the frame rail. It will probably look like a small can. Any of your local parts stores should have the pump and filter.

 

[Pxxcmd]

Yea i already changed that. Still didt fix the problem

 

[69jeepcj]

You changed the pump and filter and it didnt fix it? Could you have put the lines on the pump backwards? Your filter may (some do, and some don't) have three places for hoses on it, one is just a return line back to the tank and if you put the main line on the return your fuel pump cant pump anything.

 

[SteelHeadz]

This sounds more like that the problem is not in the fuel pump but in the tank itself. If the fuel pump creates vacuum at the smallest amount with fuel in the lines, it should deliver the fuel in the carburator. If the fuel drains out of the fuel lines back into the tank and have no prime for the fuel pump to create enough suction to pull the fluid out of the tank back up, then i would suspect that there is a leak internal or external to the fuel line from the tank. The smallest amount of leak in the fuel line between the tank and the pump could easily create this symptom as the pump is made to pump fluid not air and the pump would just keep suctioning the air from the leak source instead of the fluid in the tank which is the farthest away from the pump. Another thought on this matter is the fuel cap. It has to be a vented fuel cap so the fuel tank does not create negative pressure as the fluid is evacuated from the tank thru the fuel lines. If the fuel stops delivery to the carburator at half a tank but ok at a full tank, so much more reason to suspect that the pick up tube in the tank could be the problem.

 

[Pxxcmd]

Ahh i think ik the problem now. The hose from the tank to the fuel cap is cracking and does leak when i pour gas in il replace that as soon as i can

 

[SteelHeadz]

That wouldn't be the problem on fuel delivery , however it does need to be fixed eventually. The lines you need to look at are from the fuel tank to the fuel pump. Inspect the internal part of the fuel sending unit module as well. If there is a hole on the upper section of the metal tube going down to the bottom of the fuel tank, it wil suck in air instaed of fuel unless the fuel level in the tank goes above that hole. Think of it as sucking a fluid from a glass of water with a straw. If you puncture a hole in the middle part of the straw above the water then suck on the top end, all you'll get is air and not the water in the glass. Does that make sense?. I'm working on your problem from the symptoms you describe and all these possible causes are in theory. It's up to you to verify if the thoery fits.

Ahh i think ik the problem now. The hose from the tank to the fuel cap is cracking and does leak when i pour gas in il replace that as soon as i can