I have a 1974 Porsche 914 1.8 L I recently put a new fuel pump in, along with new stainless lines, filters, strainer, hoses etc. The car had been parked due to a fuel related issue about 4-5 years ago. I think the issue was the double relay which had been replaced. . That has been corrected but now when I start the car it fires right up and runs. However, the fuel pump never shuts off even when the key is in the complete off position. Anybody have any ideas where to start looking? I’ve already checked the airflow meter by unplugging it, no change there. Would next be the ignition wiring? Thanks, Mike

I have been meaning to get back to you on this. Life has been busy the last few days.

We need to check the wiring to the fuel pump. Is the fuel pump in the stock location?

Clay

Try something simple: replace the fuel pump relay. You can use one from the headlights if you don't have any spares (shame on you! ).

If pulling the relay stops the pump, but replacing it does not, then you have a good general idea of what half the of the car to look at (focus on the control circuit).

or....the power to the fuelpump does not come from the relayboard but from the battery directly, so 12V all the time. But you will know if you pull the relay.....
Since the car had pump issues before, you mention this, maybe they did a fix and got the power somewhere else as workaround or test.....

There were two dual relays and one of them is not correct, so that may be the culprit. The fact that you pulled the air flow meter lead and it still runs means that the dual relay has hot wired itself in some way and the only thing I can immediately think of is the wrong dual relay. First thing I would do is substitute it

I would agree. If it is the wrong dual relay, then the fuel pump would run all the time.

If you can get me the part number off the dual relay, I can compare it with the one off Betty's car and see if it is the same.


Clay

Guys, This is not D-Jet, this is L-Jet. The L-Jet system does not use the relays on the relay board. It has a separate, double relay mounted on the battery tray support. You can run an L-Jet car with NO relays in the relay board.

Clay

I just fixed this exact same issue on a 74 1.8.

make sure your relay board only has the one (working) round relay in it (in the second from rear position)

and make sure the single yellow wire is connected to one of the rear 2 leads in that 4 pin section.

This worked for me anyway.

(ignore the red circles):

Click to view attachment

1.8 have just one in the very rear for the heater blower. The very front one is for rear window defroster. The two middle slots are for d jetronic 1.7 and 2.0 fuel injection only

It appears I have the wrong double relay (by part number) in my car. New one ordered, will keep you posted as to if this corrects my issue.

Thanks to a few members on this site was able to find and correct my starting issues. Seems my double relay was bad and after purchasing what was thought to be the correct one Youmust verify the correct part number. On the 914 you must have the Bosch double relay that ends with 120 as the part number. Nothing else works correctly. Now on to the clutch cable adjustment and I should be able to put my car through an initial break-in on the road. Getting close!

congratulations !!! how long have you had the car? oh and where in iowa are you? Spent 4 years in Davenport in grad school and 3.5 in the southwest end of the state(Red Oak) before moving to SC 28 years ago, still have friends and family up there, dont get back much to their or my original home in MN... either too hot or too cold anyway i dont think i every saw a 914 when i lived in Iowa, i did have another aircooled ride, a '74 BMW R90/6 which i rode all the time before moving. there area few fun roads to run near the Mississippi river bluffs in east, hope you can get her out on the road soon!

Phil

Yep; mine's just like that. Was confused at first but George's 914 troubleshooting book straightened me out.