fuel pump relay

[sculler2x]

This year I put in a new regulator and the voltage is now consistently 14V.  Previously, the first 40Kmiles, it had been about 12.5.  I never had a problem with the fuel pump relay. I replaced the factory ones with the recommended Omron units a long time ago. This year I have had to replace the Omron one twice.  The third time I rewired it to a much larger Omron G8JN-1C6T unit.  Of course this solved the problem but it seams to have fixed another as well.

 

The beast has always stumbled at part throttle below 3K RPM. From the schematic it looks like the relay also sends power to the coils. No doubt the contact resistance is lower on the new part but I don't think that would explain the improvement. Any ideas?

[docc]

The best OMRON High Current "micro" relay is G8HE.

 

http://www.v11lemans.com/forums/index.php?showtopic=19755&p=216605

[sculler2x]

I have had 3 G8HE relays fail.  The specs for the G8HE and the G8JN are almost identical.  The JN is a much larger package and it is vibration rated as well as rated for 100 amp inrush.  People have have commented about how hot the HE get.  The JN runs cool, it does have a lower power density in terms of coil watts per CC.

[docc]

The "J" are physically larger, but still fit in the relay rack?

Three high current OMRON failed in the same position (#5)?

[docc]

So, the improved running with a reliable relay in Position #5 is not new. This relay feeds the coils, injectors and fuel pump.

 

The current is through the NO contact rated at 35 amps on the G8HE, so it is of concern that yours were failing there. I wonder why?

[Kiwi_Roy]

Could it be the relay socket needs to be tightened up, I posted a sketch how to get them out.

Another possibility is the contacts aren't clicked into place properly and not making reliable contact.