'84 Carrera no start after loooong project :-(

[sus911]

I've finally got it all back together after 2 years of dismantling, cleaning, re-plating, powder coating, & some painting.

The engine was out for new clutch and a good tidy up. It has great compression and leakdown tested good.

Anyway, a lot more work was done but I'm stuck at fuel pump issues. As per Bentley, the DME relay socket has all the power/switched power and earths as per the recommended tests. However, the fuel pump will not run whilst cranking and it won't run when I jump terminal 30 & 87b on the relay socket.

I hot wired the fuel pump with a spare battery and it spun up nicely so it does work.

I checked that the pump fuse is good at the fuse box and it has continuity. What is puzzling me though is that I get power at the pump fuse terminal whether I jump the 30 & 87b terminals on the relay socket or not.

Power is not available at the pump connections regardless

I've cleaned all connections and the transmission earth strap connection.

I'm stumped at this point.

[sus911]

I forgot to mention that I did replace a crank sensor and made sure both were gapped properly.

Also, the earth wires have been connected to the the front of the intake runner position.

All the injectors were serviced and tested to be ok.

After all the reading I have done on the subject it seems alarm systems, especially after-market ones seem to end up being the culprit. My car did have one but I removed it years ago but some of the wiring remains. I'd love to completely get rid of all of it but I'm a little scared I might pull out some factory wiring

[gtc]

Sounds like something got miswired by accident, if there's always power at the fuse but none at the fuel pump connection.
Similar but different situation:
Fuel pump runs with engine off AND relay disconnected

[sus911]

SOLVED!!!!!

I was a bit concerned that when I reinstalled the fuel tank that a connection may have been damaged. It’s quite tight at the filler neck next to the fuse box. So I popped the tank up an inch or so and noticed a red/black wire suspended right next to the earthing point on the LSF inner wheel well area. I noticed that one of the earths had the remains of a broken wire from a splice on it but a bit strange that it was red/black as all the other earths are brown.

Anyway I connected it and jumpered the fuel pump again and voila, pump spun up! At this stage I was getting pretty excited and reconnected everything and it wasn’t very long before she was spluttering back to life.

What a relief! She sounds amazing with the 993 HE’s and the M&K muffler. Time to finish assembly and off for a wheel alignment.

The moral? Take care reinstalling your fuel tank and don’t always expect a Porsche earth to be brown....