1965 Fuel Pump Question

[skinny_tom]

Short story:

Why would my 1965 Eldorado with air conditioning have this fuel pump:


and not this pump?


I'm asking because I'm having vapor lock over 85 degrees ambient outside temperature. The pump I pulled only put out about half of the expected volume as described in the shop manual. It also doesn't look like the proper pump according to the shop manual and every online retailer that has replacement fuel pumps for 1965 Cadillacs.

I'm also asking because the "correct" pump worked for about 30 seconds then stopped working. By working, I mean, "it kept the engine running." Now it doesn't.  I have yet to troubleshoot... that comes this afternoon... but I have oh-so-many questions about why there's a 66 pump on my 65 eldo.

For the record, I have checked all the fuel lines (from/to), tank vent, fuel filter, etc. All new rubber hoses last fall etc.

[fishnjim]

These pumps that are "crimped"(no screws holding it together) were made to be less expensive options, so has been changed at some point.  They're not made to be rebuilt.
I'd have to look up the right number but take your picture.

[skinny_tom]

The crimped pump required the rubber intake hose to make a funny bend around the sway bar...

FWIW, the replacement "correct" pump failed. The pump shaft had come off the lever... Rather than repairing a brand new item, I sent it back for replacement. I'll spend some time testing the new, new pump when it comes in so hopefully I won't have this issue again.

[66 Eldorado Fan]

Hello sir - had the same issue. I got a pump from Amazon seller that when it showed up, looked just like your photo. Caddy Daddy was gonna sell me the same, but took longer. Its the wrong pump for our cars. I got mine (trying to replace it now), from OPGI, and it is a perfectly identical replacement for OEM. It's just difficult for me to get it back in

The pump you pulled out, I believe, is correct for the car, but others here may correct me.

Good luck sir

[skinny_tom]

The crimped pump required the rubber intake hose to make a funny bend around the sway bar...

FWIW, the replacement "correct" pump failed. The pump shaft had come off the lever... Rather than repairing a brand new item, I sent it back for replacement. I'll spend some time testing the new, new pump when it comes in so hopefully I won't have this issue again.

As a follow up. I got finally got to installing the new, new pump. However, before I installed it, I decided to hand cycle it a number of times and SURPRISE! It failed in the same manner. So this time I took the finger lever out to have a look. It turns out that the lever half that catches the pump shaft has a shape that prevents it from coming out of the shaft catch. To assemble it correctly, the lever half has to be inserted before the top and bottom pump case halves are screwed together. Since this has happened twice, I figure it's an assembly procedure issue at the factory.

Once I fixed it, I cycled it by hand a bunch of times and was satisfied. After installation I drove it for 10 miles. So far so good.

[skinny_tom]

More follow up...

The new pump has solved the vapor lock issue I was having. Whether the last (crimped) pump was not capable of providing enough fuel volume to overcome the hot environment or just worn is not known.

I've driven in 110 plus degree heat with no drivability issues and left it to rest for 30 minutes in the sun on those days as well. It takes a bit longer of a crank to start it when it's that hot, but it starts and runs nicely- even in 110 degree heat.