Fuel Pump Wiring Issue

[baltimucho]

86 SVO just up and died on me.
The relay clicked, so I dropped the tank. Pump works fine. Replaced the relay, nothing. Jumped the inertia switch, nothing.

9421

I am not getting ANY power to this solid yellow wire. Everything I read said I should be. When I jump power to this yellow wire from the yellow wire from the harness on the ignition, then the pump comes on. Are there other fusable links somewhere in the line? Just wondering if someone has had this same problem and determined if it was the ignition switch or the ECU?

[MikeFleming]

We have seen this before.

https://www.svocop.com/forum/showthread.php?3246-fuel-pump-wiring

There is a crimp of four large yellow wires near the EEC relay, inside the EEC harness (probably impossible to get to without removing the dash!). It starts at the positive terminal (hot at all times) lug on the starter solenoid as a brown wire with a 18ga/15A fuse link, then changes to yellow as it enters the EEC harness near the EEC Self-Test connector. From there it is crimped/joined to three other yellow wires - EEC relay power, fuel pump relay power & EEC Keep-Alive power. There is no solder in this crimp, hence one of the reasons it fails.

If too much current (over time) passes through that crimp, it will start to loose connectivity (increase in resistance), and things like high fuel pressure on a 255 lpr pump will draw woo much current (18+ Amps).

Some pics.

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Best to run a separate (20A fused) 10 or 12ga wire from the starter solenoid power terminal directly to the fuel pump power wire at the relay. Check always-on power at the KAP pin (Pin 1) on the EEC 60-pin and also at the EEC relay. Repair as needed.

[baltimucho]

THANK YOU! That is pure baddassssery!