Fuel pump location and vapor lock?

I'm having a vapor lock problem. Drive the jeep for about 20 min and the electric pump stops working. Let it sit for about 20 min and it starts working again. Done this two times in a row, like clockwork.

My question is, is this pump in a terrible location, or is it possible that the pump is going bad? I would immediately think its too close to the exhaust, but the stock pump was closer to the manifold and I'm sure it worked fine from yhe factory. I hate to go through the hassle of moving this one, only to find out it does the same thing elsewhere...

 

The set up looks like it may be kinda close. The lines and filter may be more the culprits than the pump itself. I would think if the electric pump were failing, it would just quit and, that would be that. Make up a cheap heat shield to help diagnose if it is in fact vapor lock.

 

Do you mean it stops pushing gas, or it stops having any mechanical action? If it was vapor locking I think you would still hear the pump trying to work.

Checked the gas cap vent?

 

It stops pumping completely. Normally, you can hear it as soon as you turn the key to the ACC position. When it stops, there is no sound coming from the pump and no fuel going into the carb.

I had the same thought - that with vapor lock, the fuel boils and cavitates in the pump. At that point, it would still be making a noise as if it was working, but nothing would be coming through.

I don't know... I'm puzzled.

 

move the electric pump from where you have it to back in the frame rail just in front of the tank. This puts the pump lower than the fuel supply,(which makes it not have to work as hard) and keeps it cooler. If mounted in the C <-- of the frame rail it will also be out of the way from all the moving debri you may encounter.

On the other hand, mine is mounted on the firewall side of the fenderwell, which keeps it and the two fuel filters I use (one before, and one after the pump) cool enough not to vapor-lock. No problems in this position.
We are currently experiencing 110 and above temperatures, and the 5 is my transportation while everyone else is at work.

But, then, I LIKE driving my JEEP!

 

Most electrical pumps are good pushers but lousy pullers. I'd move it back towards the tank and certainly away from the manifold. Befor doing anything though Id do a pressure and volume test to make sure it is not failing. Stock V-6 Jeeps had a heat shield to protect the mechanical pump......


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Good point Billy. And if this pump is bad, I'll replace it with a mechanical pump. But I think I'll try moving it to the frame rail first. I lean towards thinking its a heat issue because it works perfect at all other times.