engine bay fuel line routing

[Eric in GA]

I'm going through a recently purchased '78 CJ5 with a 258 and Weber carb. The PO routed the rubber fuel line (from the mechanical fuel pump to the carb.) across the valve cover of the engine. The fuel line literally lays across the valve cover. I assume this is incorrect. Can anyone tell/show me how this line was routed from the factory?

Thanks!
Eric

 

[huntnCJfool]

I'm going through a recently purchased '78 CJ5 with a 258 and Weber carb. The PO routed the rubber fuel line (from the mechanical fuel pump to the carb.) across the valve cover of the engine. The fuel line literally lays across the valve cover. I assume this is incorrect. Can anyone tell/show me how this line was routed from the factory?

Thanks!
Eric

I just rerouted mine when I installed a weber carb. From the factory, there is a metal line from the fuel pump around the front of the valve cover, where it goes to the fuel filter then to the carb.

The problem with this route is that it puts the fuel filter connections right over the exhaust manifold which has caused fires. I actually had a leaky hose one day but luckily smelled gas when I stopped and was only on a short drive.

You can see how I routed mine in the photos. The weber requires a pressure regulator, so I used a bracket on the valve cover and that also holds the fuel filter in place with the return line at 12 o'clock and the line to the carb 6 o'clock and above the carb. This keeps my fuel line further from that exhaust manifold while also moving connections away from that side of the engine bay. You may just need to put a bracket so the hose is not just laying there.

 

[Eric in GA]

Thank you - that looks really nice - I'll give that a go. Now, you said the Weber requires a pressure regulator(UH-OH). I'm certain I don't have a regulator between the pump and the carb. If you don't mind, can you expand on that a little? I'm not a carb guy but it looks like I may have to begin learning...the Jeep doesn't always love to crank and when it's at idle it doesn't always love it when you give it throttle...The cover is missing off of the choke and and the PO said "the choke needs some work". I need to find a link to "all things Weber" I suppose.

Thanks again!

 

[huntnCJfool]

The 258 has a mechanical fuel pump that increases pressure with RPM, the webers only like a 3.5 psi or less fuel pressure. I guess the carter bbd was made to handle the higher pressures. Now, you will see folks out there that argue the 1 in 2 out fuel filter acts as a pressure regulator, which I am sure it does to an extent. However, every weber installation instruction I have read says run a pressure regulator set between 2-3.5 PSI or it can screw up your tuning. I went with the Holley and it also allowed me to change the fuel line routing which had been on the list. As a side not, I had my pressure turned up too high and it was also suffering fuel economy and had a bad gas fume, so those could be indications of fuel pressure issues.

As for the tuning, the instructions are pretty simple and I think I have mine just about dialed in, just want to see how the fuel economy is. Here are instructions: Weber CARBURETOR SET UP AND LEAN BEST IDLE ADJUSTMENT

I had to change some jetting, but I am also at 6200 feet. That choke will definitely cause you some issues, especially on cooler mornings. I got a manual choked weber, but they make a kit as well. Hope this helps. I did a lot of reading in the weeks prior to my install. I had no real experience with carbs and it has mostly gone off without a hitch. Lots of good info out there.

 

[Lumpy Grits]

That's a lot of rubber hose that can heat soak, and that leads to vapor lock.
With the return line-Your line PSI to the carb ain't much at all.
LG

 

[Eric in GA]

Good information. Thank you very much.

Eric

 

[JeeperChris]

Eric, I just did the weber carb on my 258 in my '79 CJ5. I went with an electric choke that is only hot when the engine is running. You can hook it to any hot wire so it has juice when the key is turned on, I just went one little step farther.

If you're interested in this I can post some more specs for you. Here's what it looks like:

https://images-wixmp-ed30a86b8c4ca8...Q.yTo-uRNvpigRd8h42rRkkwPrvKcysUsyoMsPV7UqUpo

 

[Scout1067]

I have the Weber 32/36 on my 258. I know for a fact I don't have a pressure regulator on my fuel line as I just replaced my fuel tank and all lines a few weeks ago. I also have a manual choke on mine as I had issues with the previous factory "new" electric choke staying open regardless. Once I got my idle adjustment dialed in all my starting problems were related to the choke and of course the PO had the incorrect fuel filter on it when I bought it. One thing I have not yet done is reroute my fuel lines although I did replace the rubber over the valve cover with a metal line.

My dad, has been an invaluable help in relearning and learning things about carbs since he has forgotten more about carbureted engines than I will probably ever know.

 

[huntnCJfool]

That's a lot of rubber hose that can heat soak, and that leads to vapor lock.

With the return line-Your line PSI to the carb ain't much at all.

LG

That's something I did not consider. It should be easy enough to add steel line back in. Cross one thing off the list and the list still always grows!

Sent from my SM-G950U using Tapatalk

 

[Eric in GA]

Thanks Chris - I am interested in more specs...I'm a dry sponge right now.

Huntncjfool - My buddies 7 has the factory style steel line around the front of the engine that is then spliced to a rubber line with the filter then back to the steel line for entrance to the carb; a Holly in his case. I'll see if I can get a pic to post...

 

[Lumpy Grits]

Thanks Chris - I am interested in more specs...I'm a dry sponge right now.

Huntncjfool - My buddies 7 has the factory style steel line around the front of the engine that is then spliced to a rubber line with the filter then back to the steel line for entrance to the carb; a Holly in his case. I'll see if I can get a pic to post...

That fuel filter location, is an engine fire waiting to happen.
Get that plastic filter away from the exhaust.
LG

 

[Eric in GA]

Thanks LG - I'll pass that info. along to my buddy. That would be the opposite of good.

Eric

 

[Lumpy Grits]

Back in the day-That was the factory location for the metal OEM fuel filter.
Many engine bay fires were linked to the filter leaking, then dripping onto the exhaust.
Even the NTSB had opened an investigation into this.
Had a friend lose his CJ7 to this--
Tell your friend, to get a metal filter.......
LG

 

[huntnCJfool]

Thanks Chris - I am interested in more specs...I'm a dry sponge right now.

Huntncjfool - My buddies 7 has the factory style steel line around the front of the engine that is then spliced to a rubber line with the filter then back to the steel line for entrance to the carb; a Holly in his case. I'll see if I can get a pic to post...

I deleted that steel line for the fire reason LG stated. I just reused my steel line to run from the pressure regulator to the carb to get rid of some of my rubber hose.

 

[JeeperChris]

Hey Eric, didn't mean to leave you hangin....

For the electric choke, here's what I did and it's working great for me even though it's only been two weeks.

Just went to my local auto parts store and bought a Standard brand oil pressure switch. Part number is PS135. This has the correct threads for the engine block.

My CJ came with a mechanical oil pressure indicator so when you look at this picture, that's what's coming off the brass T. I told the parts guy that I needed a T to run the switch and the oil line from the block. He asked me what thread size and I said "The same as on this Switch". They had the block and one threaded adapter behind the counter so he picked them out. The threads matched so that's all I needed. That's everything you see in the picture.

The white wire is coming from the choke. The red wire: On my firewall coming out of the top center area of the wiring loom is an empty connector. My CJ has a few of those, they are for things I don't have like A/C. I checked that it was hot when the key is in the "on" position, they crimped a spade to the other end of that red wire and plugged it in. Now it's all connected.

The switch only lets the current pass to the choke when there is oil pressure, which is only when the engine is running. Now I can sit and use any electrical stuff I want and the choke will not be getting hot and opening. To me this means that when I start the motor the choke will work as expected. No more cold motor and open choke.

I also used liquid pipe thread sealant on all the oil fitting threads so there's no leaks.

Did I really need this? Maybe not, it's just a nice touch that's simple to do.

Hope that helps, and here's that pic again:

https://images-wixmp-ed30a86b8c4ca8...Q.yTo-uRNvpigRd8h42rRkkwPrvKcysUsyoMsPV7UqUpo

 

[Eric in GA]

Thanks Chris - no worries - that's a neat set-up. I'm going to try and come up with the parts and duplicate it. When you say "wiring loom", do you mean the plugs that are on the engine side of the firewall the mate with the fuse panel on the cabin side of the firewall?

 

[JeeperChris]

It's actually the plastic sheath that all the wires are inside of as they go along the firewall and over the engine. That bunch of wires had a wire sticking out of it just over the valve cover area and that's the one I plugged into for the hot. From there it went to the oil pressure switch then switch back to the carb.

 

[Eric in GA]

Gotcha - I found one in the same spot. This is a big help - Thanks again,
Eric