Having a problem with my newly aquired 87 811 turbo. It runs great but will but out occasionally and usually starts right back up. Replaced the fuel pump relay and it was still doing the cutout thing. Now it just wont start unless I jumper over the fuel pump relay and then it fires right up. But the relay does not appear to be the issue. Has anyone had this issue with a previous car? Thanks.

 

Check the overboost switch. It is a white wire. They are known for going bad. Make sure the car is not over boosting first. If not then ground the wire down. If the problem stops then replace the switch.

 

You see the problem is you bought an 811 turbo, you really should have gotten a 911 turbo!

 

good luck fixing it.

 

Check the fuse box. I had the same problem. There are 2 fuses that run the system. They have a tendency to overheat. I had the fuse box rewired which cured the problem

Arnie

 

I am not an expert but remember my dad's 86 with a similar sounding problem (ten years ago). I remember him jumping the relays as well to just get things going. It came down to replacing BOTH fuel pumps. I believe there is one at the front and one at the rear.