Delica Canada | Mitsubishi Van Club

Has anyone with an inline pump installed a fuel pressure gauge before/after the wvo filter to see how much psi is pushed to the IP? (too much can kill it/advance timing, too little will be ineffective)

VW related.
I was going to install a 7 psi inline pump on my VW. I asked a injection pump repair shop here on the island and they said it will not make a difference to the IP. they said any excess pressure will be bypassed to the return line through the bypass relief valve on the back top of the pump where the return line comes out of the pump. they said that is how they prime their pumps and the fuel just recirculates back to the return.

That's an interesting take.

Installing a higher than 7psi in line pump advanced my timing by 3*.

As per the shop, if it wouldn't make any difference, then the ip would have bled off the excess and the timing would remain the same.

Does your return line go back to the tank or is it plumbed into the inlet line like I've seen on some WVO conversions? if the return line is also pressurised by the inline pump, then the bypass relief valve will operate at a higher pressure.