73 fuel pump mounting question, It has been too long !!!!!!! Options

[David_S]

SWL ...not a problem. I know what hibernation mode is like!! I will go look at mine later on, and see what I can find for sure! I was mainly curious as to whether it mounted to the engine tin, the engine shelf, or the frame rail. I guess if it comes down to it, I will just have to drill and tap new holes !!! Thanks for your time !!!

[swl]

Here is the (shitty) pic of the mounts. I'm really curious as to what that piece actually is. If it is part of the boxed in frame then those mounts must be just tapped in.

[KELTY360]

In a properly maintained car you should not experience vapor lock. I suspect that Porsche relocated the fuel pump because they couldn't count on people properly maintaining their cars. In the back it is close to a source of heat and possible ignition for those cars that owners maintain poorly.

At the pressure in an EFI system vapor lock shouldn't occur with a properly maintained vehicle. It is easy enough to relocate if you have the proper mount but a pain to replace it and the fuel filter.

That said, mine is up front. But it came that way...

My brand new (~1000 miles) '73 1.7 had serious vapor lock problems in 80 degree weather in the mountains of Colorado. When I finally got it back to the dealer they said, "yeah, we know about this, we'll fix it up." Unfortunately, I don't know what the remedy was, but it worked - never had a problem again.

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[stephestrad]

In a properly maintained car you should not experience vapor lock. I suspect that Porsche relocated the fuel pump because they couldn't count on people properly maintaining their cars. In the back it is close to a source of heat and possible ignition for those cars that owners maintain poorly.

At the pressure in an EFI system vapor lock shouldn't occur with a properly maintained vehicle. It is easy enough to relocate if you have the proper mount but a pain to replace it and the fuel filter.

Apologies for reviving an old thread, but this quote about "properly maintained" cars was interesting. I'm experiencing what appears to be classic vapor lock on my '74 2.0. For instance, the other evening after 30 minutes of driving up in the Berkeley hills, I pulled over and spent about 15 minutes watching the sunset. I'm new to the 914 experience, so I'm still learning the sounds, but when I tried to restart the car, it appeared that the starter cranked the engine over, but the engine wouldn't catch. I let the car cool down for an additional 40 minutes, then she fired up. The engine ran a bit roughly for a few minutes -- by this, I mean each time I came to a stop sign, the idle dropped so low that the rpms were barely registering on the tach and the car vibrated enough that I thought she might die out again -- but, by the time I was home, she was purring as normal.

My car has been pretty well maintained (and generally runs well), so I'm curious, if the original fuel pump placement were not the problem, are there specific parts of the car that should I check? Are there maintenance elements that I may have overlooked, but would result in the same symptoms as vapor lock?

Btw, I'm going to try and test the concept of this being vapor lock this weekend. My plan is replicate the problem, then pull the fuel hoses off the injectors and see if I have liquid fuel, or just vapors. Are there any other recommendations for testing vapor lock?

[JawjaPorsche]

I moved my pump to firewall twenty years ago and have never had vapor lock problems since. The old location was just too hot. This new location makes changing the fuel filter much easier too.

[914_teener]

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I moved mine exactly as it appears above and have had my car in the desert and in traffic in 100+ temps...I have never had vapor lock.

I don't think that your problem is vapor lock though. 80 degrees. You might want to start another thread.

Sounds like a different problem to me.

[stephestrad]

Thanks to you both for the feedback and the location pointer. The firewall sounds easier than moving it all the way up front.

I'll see how the test goes this weekend, then open another thread.

[Shindog1961]

I have heard that this pump location requires you to keep your fuel level up. What is your experience?

[914_teener]

No problem with the fuel pump mounted on the firewall if that is what you mean.

I have run my fuel level down to the reserve level all the time.

I have cleaned my tank btw.

[Shindog1961]

No problem with the fuel pump mounted on the firewall if that is what you mean.

I have run my fuel level down to the reserve level all the time.

I have cleaned my tank btw.

That's exactly what I meant. Glad to know. I agree that sounds preferable to under the fuel tank.

[Dtjaden]

In 1973 I had a new 914. I was in Minnesota at that time. It would vapor lock frequently whenever the temp went above 85. My solution at the time was to install a second low pressure pump in the front trunk. So it was not just maintenance issues that caused the problem.

Never a problem with my new 1976. I would put the pump in the front as I am going to do when I convert my current 73 back to FI.

In a properly maintained car you should not experience vapor lock. I suspect that Porsche relocated the fuel pump because they couldn't count on people properly maintaining their cars. In the back it is close to a source of heat and possible ignition for those cars that owners maintain poorly.

At the pressure in an EFI system vapor lock shouldn't occur with a properly maintained vehicle. It is easy enough to relocate if you have the proper mount but a pain to replace it and the fuel filter.

That said, mine is up front. But it came that way...

[KELTY360]

In 1973 I had a new 914. I was in Minnesota at that time. It would vapor lock frequently whenever the temp went above 85. My solution at the time was to install a second low pressure pump in the front trunk. So it was not just maintenance issues that caused the problem.

Never a problem with my new 1976. I would put the pump in the front as I am going to do when I convert my current 73 back to FI.

In a properly maintained car you should not experience vapor lock. I suspect that Porsche relocated the fuel pump because they couldn't count on people properly maintaining their cars. In the back it is close to a source of heat and possible ignition for those cars that owners maintain poorly.

At the pressure in an EFI system vapor lock shouldn't occur with a properly maintained vehicle. It is easy enough to relocate if you have the proper mount but a pain to replace it and the fuel filter.

That said, mine is up front. But it came that way...

I bought a new '73 1.7 in July of 1973. I drove about 600 miles, took it back for the initial dealer maintenance service and then left from SoCal on a trip to Colorado. Over the course of that amazing trip with my new Porsche I experienced numerous occasions of vapor lock, stranding me in random places for about 30 minutes before it would run again. When I got home and called the dealer, they said, "oh yeah, we know exactly the problem. Bring it in and we'll fix it up." I'm not sure what they did, but I now suspect they relocated the pump under the tank. Never had a vapor lock problem again. My problems had nothing to do with owner maintenance, just a design flaw that the dealer was well aware of and easily corrected.