not getting enough gas

[grico777]

My 76 jeep was running fine except I had to replace the steering gear. I finally did that but then the jeep was not getting enough gas to the gas filter so I changed the filter, plugs and oil. Still not getting enough gas so I replaced the fuel pump. Still not getting enough gas. I could see through the gas filter and it seemed like the gas would push to the filter sporadically.
Any advice is appreciated.

 

[BusaDave9]

Maybe the in-tank filter.
What engine do you have? Fill out your profile http://www.jeep-cj.com/forums/profile/edit/
Sounds like you have a see-through filter. Not stock? Do you have a return on your filter?

 

[grico777]

The engine is a AMC 258 i6 / 4.2l six. The emision system has not been hooked up and it had this fuel filter for years and the engine ran great. I blocked off the vent lines but have now unblocked them but did not connect them to the check valve and it runs better but not enough to drive.

 

[BusaDave9]

If you have the OEM mechanical pump it is possible that you have a leak in the fuel line between the pump and the tank. A small leak will allow the pump to suck air but not leak out any fuel.

 

[lynch43]

I have the same issue with my 1979 CJ5 and it had a AMC 258 i6 / 4.2l in it but replaced it with a 360 v8 and have the inline see thru gas filter. i believe my AMC 258 i6 / 4.2l had the filter with the return line so i believe its a vapor lock issue as the fuel filter has no return line. how do i install this and can i just run a rubber line from a new filter to the gas tank? It runs fine until it gets heated up about 10 miles or so then just dies like its out of gas, the see thru filter looks like its not filling up and it wont start until it cools down again.

 

[grico777]

Thanks for all the responses. It was a small leak in the fuel line. I replaced the line and it runs great now.

 

[jasonmark1993]

I have the same issue with my 1979 CJ5 and it had a AMC 258 i6 / 4.2l in it but replaced it with a 360 v8 and have the inline see thru gas filter. i believe my AMC 258 i6 / 4.2l had the filter with the return line so i believe its a vapor lock issue as the fuel filter has no return line. how do i install this and can i just run a rubber line from a new filter to the gas tank? It runs fine until it gets heated up about 10 miles or so then just dies like its out of gas, the see thru filter looks like its not filling up and it wont start until it cools down again.

Removing the fuel cap should cure a vapor lock.

Running a new hose would probably be the easiest if a quick inspection doesn't reveal a hole in the line.

Never heard of having a filter on the return line but who knows.

 

[lynch43]

Thanks for the advice but i didnt mean a filter on the return line but my original AMC 258 i6 / 4.2l used a fuel filter that had a return line but the v8 has a fuel filter that has no return line. I mean i dont know shouldnt it have a return line to the fuel tank or is the inline filter all it needs?

 

[JR74CJ5]

My AMC 304 V8 has no return line. (or filter with 1 in 2 out.)

Every once in a while, it appears to not be getting enough gas, but it will run fine so I don't worry about it (too much )

I have the glass type as well.

I am thinking of a pressure regulator and possibly a electric pump to help keep the exact amount of fuel i want at any time at the carb...


~ JR

 

[JR74CJ5]

I have the same issue with my 1979 CJ5 and it had a AMC 258 i6 / 4.2l in it but replaced it with a 360 v8 and have the inline see thru gas filter. i believe my AMC 258 i6 / 4.2l had the filter with the return line so i believe its a vapor lock issue as the fuel filter has no return line. how do i install this and can i just run a rubber line from a new filter to the gas tank? It runs fine until it gets heated up about 10 miles or so then just dies like its out of gas, the see thru filter looks like its not filling up and it wont start until it cools down again.

I will try to find some of Dave's posts on Vapor lock (think it was Dave... ) and pop them up for you.

If you want them quicker, try the advanced google search at the top right of every page.

http://www.jeep-cj.com/forums/misc.php?do=page&template=advanced_search


~ JR

 

[jasonmark1993]

You're fine without a return line. It's "preferred" but my AMC 304 didn't have one and I don't have one now. Low pressure pumps are bypass type and the needle/seat in the carb are controlled by the float to keep the bowls full.

It is possible you got a bad pump, but pretty unlikely.

You may have a hole in the line or a problem in the tank where it can suck air. You're not low on fuel are you? Stupid question but I've actually had customers tow their cars in because they "wont run after you worked on it" and they ran it out of gas.

A real quick test would be to stuff a short hose off the pump into a gas can. That will eliminate anything downstream including a vapor lock problem.

 

[BusaDave9]

I have never heard of vapor lock after driving only 10 miles but then again you live in AZ.
I have had a major problem with vapor lock. I tried every trick in the book. I insulated my exhaust and fuel line. I vented my hood. I replaced the fuel pump. I tried removing the fuel cap. Nothing worked until I replaced the mechanical pump for an electric. That did it.
I am still not sure your problem is vapor lock.

I have had a AMC 258 i6 / 4.2l and now my present CJ has a AMC 304 V8. Both engines came from the factory with a fuel filter that had 3 connections. One line goes back to the tank.

You should have 2 lines at the fuel level sending unit. The big one goes to the pump. The small one comes back from the filter as the return line.

Mechanical OEM pumps need the return line. They don't slow down and need the gas to return to the tank. An electric pump only puts out so much pressure or they have an external pressure regulator. Either way they usually entail replacing the OEM 3 port filter with a 2 port filter.