Ask Bill about carbing a DeLorean and other K-Jet/Carb tangets

[Ashyukun]

There is a keyed 12v at the RPM relay already.

Yeah, this is how mine is set up- it's jumpered such that the the fuel pump is running whenever the key is turned to 'run'- I just have to remember to not just leave the key sitting there in 'run' when 'aux' would suffice.

[Farrar]

Bill mentioned keying the fuel pump to switched power on the old DMCTalk, to the accompaniment of much wailing and gnashing of teeth. Evidently, if you wire up your fuel pump to run with the key on, your car will explode in a fiery ball of gasoline if you're ever in an accident. You have been warned...

(FYI, I plan to make the same modification -- although I like the arrangement where the pump runs with a switch to fill the fuel bowl after sitting for a long time, I don't like the idea that I might hit the switch by accident.)

Farrar

[DCUK Martin]

If you run the fuel pump directly from the green wire at the RPM relay plug, you're loading the pump onto the wrong fuse. The RPM relay is there for a reason and that reason is primarily one of safety.

[Farrar]

If you run the fuel pump directly from the green wire at the RPM relay plug, you're loading the pump onto the wrong fuse.

I'm not sure if that's the wire Bill used; we'll have to wait for him to speak up.

Good evening, Martin!

Farrar

[stevedmc]

If you run the fuel pump directly from the green wire at the RPM relay plug, you're loading the pump onto the wrong fuse.

I know that. But our low pressure fuel pumps only use a few amps. My guess is it will pull from fuse #1 instead of fuse #7.

Fuse #1 - 10A fuse that powers, RPM Relay, distributor, vacuum solenoid, ignition ECU, and idle speed ECU
Fuse #7 - 20A fuse that powers lambda relay, lambda ECU, frequency valve, fuel pump, and control pressure regulator

The real question is can a 10A fuse power our low amp fuel pumps along with everything else on that circuit or will it blow?

[ramblinmike]

your car will explode in a fiery ball of gasoline if you're ever in an accident. You have been warned...

Isn't that what the inertia switch is for?

[stevedmc]

This afternoon I am planning to remove my old K-jet wiring since I no longer need it. I have been staring at a messy engine bay for about a year and I am ready to clean things up.

I have searched a little bit and I can't find any pictures of what the bulk head connections should look like after the K-jet wiring has been removed. Does anyone have any pictures of a cleaned up engine bay such as Bills?

Bill used to have pictures on the old forum but I can't find them anywhere on the new forum.

[content22207]

2508WiringBulkhead.jpg

Bulkhead2_2508.JPG Bulkhead1_2508.jpg

Bill Robertson
#5939

[content22207]

If you run the fuel pump directly from the green wire at the RPM relay plug, you're loading the pump onto the wrong fuse. The RPM relay is there for a reason and that reason is primarily one of safety.

Look closely at my empty RPM Relay socket:
Attachment 2519
Purple/White is driven by a Green wire attached to Fuse 7 (if you look real closely you can see insulation piercings where Purple/White and RPM Relay Green used to be scotch locked together). The quick connect allows me to disable the pump.

Airtex low PSI pumps only draw 1.4 amps -- you could tap them in pretty much anywhere. I moved mine to Fuse 7 for design consistency, not because of electrical load.

As far as safety is concerned: when the needle valve is open, fuel pressure plummets to 2-3 PSI. Fuel flow into a carburetor is extremely low (it has to be -- the only thing shutting it off is a foam float pressing against a piece of rubber). Very different from EFI pressures, which seems to be where DeLoreans are catching fire and burning up, thank you very much.

Bill Robertson
#5939

[stevedmc]

Thank you so much for the pictures and drawings. I was able to remove my old Kjet wiring this afternoon and I also rewired my ignition resistor and gapped my plugs to .50

I immediately noticed how much higher the car would idle. I assume this is because of the increased voltage and gap, although I might have managed to screw something up. Anyway, I set the idle down to 900 and everything seems to be fine.

Right now I am taking an AC break but I will try to go back out there before dark to snap some pictures.

I also made a jumper wire with connectors to jump my RPM relay wire. If I remember correctly I have a wire ran from the white/purple wire to the green one. I have another wire connected into my jumper that is supplying 12v to the electric choke on the carburetor.

Things are looking nice.


Edit: I forgot to mention but the picture of your RPM connector isn't loading for some reason.