I'm going to replace the original '74 3 port fuel pump with a '75-76 2 port model in the original stock location on the body under the R/S engine tin. As long as the flow rate and the operating pressure are sufficient, are there any operational problems putting it there?? How about mounting??

I know these pumps "push" fuel better than suction, but I don't want to relocate it to the front trunk. (I'm also trying to avoid buying a China rebuilt 3 port.)

All help appreciated.

Paul

I think the reason that Porsche moved the fuel pump up front in the first place was to fix a persistent problem with vapor lock.

I maintain a '74 914 that has the 3 port pump up front, mounted next to the steering rack. The relocation was done by a PO, but it seems to work fine as far as I can tell.

I've heard the vapor lock claim, and have yet to see/hear anyone complaining of a rear mounted pump vapor locking. I also see a lot of very old 3-port pumps working just fine. If I were shopping for a replacement pump, I would get a used 3-port before I retrofitted a 2-port into the back.

If your redoing all your lines, then put it in the front. If your only replaceing the pump, in the rear should be fine. Don't forget your step hose. You have 9mm and 7mm.

I disagree with the contention that there was/is a persistent problem with vapor lock. I have lived in So Cal almost all my life, and have worked professionally on 914s there for 36 years. I have yet to see a case of "vapor lock". If I were to take an educated guess, I'd say they moved the pump in favor of a MUCH cheaper model, and the location because there is room, the pump is a "pusher", and they could eliminate come parts. They changed size and material of the pressure line, too.

Now, on to the question. Yes, you can put the pump there. Yes, there is a difference in the plumbing, which is pretty easily overcome. You remove the "Y" fitting and the 2 pieces of return hose. You then replace all 3 with a single piece of 7 or 7.5mm HP fuel hose. You're done ................ While you're in there, check the condition of the reducer hose from the plastic supply tube to the filter (which you have to change, too). If it's at all shaky, replace it. Part number 914 356 525 00, available from Porsche. DO NOT attempt to use a 3/8 hose and squeeze it down with a hose clamp!!!!!!!!!!! We like you, and we don't want to see your car become a training mission for your local fire department ................

The Cap'n

Actually had a '73 completely shut down at 60 mph on a hot summer afternoon some years back. Pulled to the side of the road and it just cranked. Got towed to a shop and a few hours later (cooled down), it started right up. Vapor lock??? Who knows.

Anyway, any particular reason why you would stay with a 3 port instead of going to a 2 port?

Paul

Nope, no reason at all to stay with the early pump, IMO. While using a used 3 port pump is OK, IF you can find a good one, there are lots of 75 and up VW bugs and busses still on their original 2 port pump. The Cap'n

I've had my pump get overheated in the stock location, cooled it down with ice cubes to get back on the road, this happened several time to me. Never with a four, everytime was with the six. I moved it up to the hell hole area and eliminated the problem.

What size is the two port pump inlet hoses?
I recall one of them is some huge size like 12mm or something...I cant remember, but I recall it was not an easy hose to bend without kinking, so It had to be cut the right length.

all that blather wont apply to this setup, but the hose size and the need for some adapter would apply...

I found a delco pump that was half the price of the Bosch (sorry Capn) pump and it fit perfectly and was at the same specs.

The pump, from what I recall, needs to produce 65PSI...that is the original spec. I cant remember the GPH number, but its not small.

I went to my local FLAPS and he pulled out the pump book. We looked up the Bosch pump and read the specs, then looked around for others.
Volvo, mercedes, and several others used this type of pump.

Rich

The 12 mm line goes from the filter to the pump. The filter uses the same adapter/reducer hose as the earlier filter. The pump outlet is the same size as the outlet of the early 3 port pump. The brackets are the same, too, but you have to remove the push-on electrical connectors from their plug in order to plug in the pump. Where's the difficulty? Yes, there are Delco and other brands of pumps that'll work, and that's OK with me. I just choose to go the easy route, one that I have to do NO research, no shopping, and very little adaptation. The Volvo and Mercedes D jet systems used a similar, if not the same, 3 port pump, and they're equally unavailable. I don't believe either maker used L-jet.

The Cap'n

The volvo pump is a two port pump like the 75/76 pump.

The delco one is a replacement for that 2 port pump.
Not alot of research, I just waited while they looked up a comparable pump...pretty simple.

Rich

It would be interesting to know what Volvo used that pump, because I've never seen one that did ........... The Cap'n

1973 p1800 ES wagon.
I have two.

Interesting. The Bosch D-Jet book shows a 3 port pump for all Volvo D-jet cars, and the '72 car here has a 3 port pump, as does the car I just put a pump in. However, when you put the part number from the equipment list into Worldpac, you get a roll-over to a pump with an off center 9mm outlet on one end, and a smaller inlet port on the side at the other end, and a plastic electrical socket like the one on a 914 pump. So we have your experience, my experience, the Bosch manual, and Worldpac's parts catalog, all without a clear majority agreement ............... Makes my job fun ....................

The Cap'n

I used no book.
I removed the Original pump, covered in undercoating, cleaned that off and took the part number to the store.
Its a two port pump (Its a 73 ES Wagon) that is used on Djet....
The volvo, as you know, is djet..alot of the parts are the same, yet different.

I have two here, and a friend has one also..all have the same pump. They all seemed to die within about 12 months....odd but true. They lasted 35 years.

I replaced that volvo pump with the delco...no issues.
I then used the same delco on a 914...everything fit.

Rich