Wiring in a high pressure fuel pump

db9146 · db9146's Garage

I have a 1970 914-6 and am swapping in a larger, fuel injected -6 for driveability and performance. Since the car originally came with carbs, it has a single fuel line system and a low pressure fuel pump. To prep for the new engine, I am replacing the fuel lines with SS lines and high-pressure SAE30R9 hose throughout. I also need to wire in the high pressure fuel pump and am thinking through the best way to wire the pump - there is already a relay tied into the engine oil pressure but I'm wondering about a relay and higher amperage fused line to power the pump.

Any ideas or recommendations? Anyone done this before for a FI engine retrofit?

sixbanger · 08-02-2016, 08:29 AM

12V is 12V. Are you talking the DME relay?

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I believe that the 914-6 had a return line in the tunnel, just like the four-cylinder cars did. It sounds like someone may have made some changes after the factory. The pump running on the oil pressure switch makes that sound much more likely.

If you are swapping in an injected Six, you will want to replicate the setup that the donor 911 had. The 3.2 and later cars ran DME, and have a "DME relay" (which I think is like the dual relay that the 1.8 liter 914s used) that powers the injection and the pump. You will need to figure out where you want to put it, but it is definitely what you should use.

--DD

BoxsterGT · 08-04-2016, 06:27 AM

Yes, the 914/6 has a return line through the tunnel and the original pump is in the engine compartment.

Its best to mount your new pump up front. I am happy to help you with hoses if needed, as they most likely will be custom.

Please email me for info.

Len at Autosportengineering dot com

db9146 · db9146's Garage

Thanks for the replies.

The engine I'm installing is a 2.7 running ITB EFI and MS3 as the ECU. There is an output from the MS3 for the relay for the pump it turns out. So once I get the new fuel lines in, and the specs from the MS3 unit, hopefully it will be more clear to me. And yes, the pump was moved to the front some time in the past so the new one will stay in that location.