General Tech External Fuel Pump Heat Sink Cover

[Jay5.9L]

I'm running an external fuel pump on my CJ 4.0L swap and its time to address what I think its vapor lock issue. It starts and runs great but does not like to restart when the weather is hot. Given some time it starts just fine again.

I'm assuming the external pump is causing vapor lock. I'd like to upgrade to a in-tank set up but until then a heat sink on the pump may help. Anyone know where I can get one? Did a little googling and did not find much for an existing pump. Looking for something like:

 

[thenag]

Have you tried running fuel without ethanol?

I have a "heat soak" issue that I have heard that will go away with "real fuel". One is opening up near me, so I am looking forward to summer to try it out. There are a few stations around that have ethanol free fuel, you can google them.

Nathan

 

[Jay5.9L]

Never heard that ethanol would make a difference. A Murphy's Express just opened near me and they have a non-ethanol pump. I'll give it a shot.

 

[thenag]

A Murphy's Express just opened by me as well, I am in Kearns though...

I don't know it will help your issue, but with the "heat sink" (or "heat soak") issue of 2000 and 2001 xj's it is supposed to. basically the fuel in the fuel rail gets really hot when the motor shuts down, since all cooling shuts off it just sits there and when it starts back up it runs like crap for a while. the 2000,2001 xj have a perfect situation of way too small engine compartment, return-less fuel system, and pre-cats right under the intake manifold. (my xj is a 99, I have 2 of the 3 issues of the 2000,2001 xj, but added some displacement to the motor and a self induced exhaust restriction on a 2000+ manifold... now I am rambling on my issues... Sorry)


I guess there is a station in Moab that has non-ethanol fuel, but you can only get it M-F 8-5 or something...


another shot in the dark, if you suspect your pump is running hot and it is near any exhaust, a simple piece of metal shield will make a ton of difference, like a beer can, seriously. You can test this with an IR temp gun.

Nathan

 

[Jay5.9L]

My pump is on the passenger gram rail while my exhaust is on the driver side. Maybe it's the fuel rail in mine. We will see if my cooling upgrades help out this summer

 

[Gravy]

If you have a 7 I would look into swapping the entire pump and tank assembly from a YJ. You ought to be able to find one rather cheap I threw away a YJ tank a few years ago

 

[B2-Bomber]

I've seen this so many times. . .so many times. Usually customers who retrofit EFI to older vehicles. And don't have an in-tank pump

Electric pumps aren't suited to "suck". They are suited to "push.

They still can "suck" to some extent. And siphoning effect helps too.

The pump will wear to some indeterminate point,and then have trouble "sucking".

Every time, moving the pump to in-tank has solved it once and for all.

 

[Jay5.9L]

The end goal is to put the pump in the tank when the budjet allows. Is a YJ tank a direct swap or is the filler on the wrong side like a TJ?

 

[N-Smooth]

I've never had an issue with the external pump on my '93 4.0. What year is your engine?

 

[B2-Bomber]

The end goal is to put the pump in the tank when the budjet allows. Is a YJ tank a direct swap or is the filler on the wrong side like a TJ?

It's not difficult to retrofit a pump to inside a tank that didn't already have one.

I literally did it for a customer with an '83 CJ7 this month even.

 

[Jay5.9L]

I believe it's out of a '97 XJ. Does not have a return line.

Bomber: that's cool what did it entail and what was the cost?

 

[B2-Bomber]

The cost is the cost of whatever pump/ strainer you use. Plus $10-ish, some 3/8" hose, clamps, wire etc.

I took the original sending unit, cut the pickup tube shorter to fit the in- tank pump. Clamped a 1" or so piece of rubber line to connect the pump to the pickup tube.

I then tacked a thin piece of steel to the hanger next to the pump that i could then use a hose-clamp around the pump to anchor it to.

I have a roll of fuel safe wire, drilled a small hole in the top of the access cover for the positive wire. And globbed fuel safe sealant (NOT SILICONE) to seal it up. The pump's negative wire i tapped into the existing in-tank ground for the sender.

That was about it

 

[B2-Bomber]

I forgot to mention the pickup tube was a little bigger (like 7/16") than the fuel pump's end (which was Like 5/16"), so i had to get crafty to connect the two together. As i recall i split the difference, and used 3/8" hose. I then heated the hose, and massaged it to fit onto the bigger steel line. And the clamp was able to clamp the 3/8" hose onto the pump's 5/16" fitting just fine

 

[Kirk]

I have had similar issues with my 5.7 tbi. running bad - especially when hot, puking gas out the vents, last summer it got hot, was at high altitude, and it wouldn't start for 20 mins - I thought I could hear boiling gas up by the motor. Theory is exhaust is getting fuel hot as it goes by the exhaust - ethanol supposedly is the variable thats changed things..... I have an external pump mounted on front of the tank. My brother has had similar issues with his TPI 350 - he actually went back to an in the tank pump, and it didn't help. i am going to try to add some type of expansion tank - not sure if it will help. I have a scanner, and have recorded all the reading to my phone while I know was running bad - but according to a mechanic - none of the readings are indicating that anything is wrong......

 

[B2-Bomber]

In theory, ethanol has a much higher boiling point than gasoline.

So again in theory, it's possible the effects of one portion being boiled/vaporized. While another portion remains unboiled might cause all sorts of gremlins because the fuel is separating.

But, these would only be a problem in fuel systems poorly laid out. I.e. external pumps, routed poorly (near heat sources), with improper venting (without a proper evap system) etc.

Ethanol sucks, no argument there. All I'm saying is that a proper fuel system would be far less vulnerable to ethanol's sucking