There shouldn't be at all. The GSL392 Pumps have built in Check Valves so fuel can't go backwards into the tank. I called Walboro's Tech line and I was referred to TI Automotive who is the one who actually makes this pump. I sent an email and picture of my set up to Kelly Christians who is the Head of the After Market for the GSL392 Pumps at TI Automotive, his response is here..........
To: Christians, Kelly
Subject: Walbro GSL392 Pumps Quick Question
Do these pumps have a built in Check Valve so fuel does not go back into the tank when the fuel pump is not in use?
I am using 3 of these pumps for my Twin Turbo Application. 1 pump will be the main and the other 2 will be activated at 2 PSI of Boost. They are sharing a common Fuel Rail, see the picture below.
Thanks in advance!
Hi Louis,
Thank you for your request. Yes, the GSL392 does have a built in check valve so you should be okay…interesting set up, I’m jealous!
Best of luck,
Kelly Christians
Account Manager - Aftermarket
TI Automotive
630 Columbia St., Caro, MI 48723
t: +1 989 672 8260
e: [email protected]
