Bypassing the FICM

curtis.sandidge

New member
Feb 11, 2025
1
1
1
Louisiana
Has anyone ever tried to bypass the FICM not having fuel go though it to cool it. I've been having trouble with my engine loosing prime. So far to date I've had the fuel filter housing replaced several times, replaced all the hoses and hard fuel lines from the tank to the filter housing. I've had the sending unit replaced, replaced the regulator above the CP3 pump. I just had all the injectors replaced. Now the mechanic is saying hes found the trouble to be the FICM leaking. He has it bypassed now and the truck is not losing prime and motor is not surging while running. So the question is can this be bypassed and not cause harm to the FICM. 2002 Chevy.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
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Larsen, Wisconsin
Yes, it is possible to bypass it but I personally think your mechanic may not have been completely accurate. It doesn't have the capability to leak unless the housing itself cracked into the fuel passage as it's a continuous cast area.

If it's leaking where the fuel connections are then it is as simple as replacing those crush washers and you're good to go.

I would ask him for some clarity as to where exactly it was leaking.
 

2004LB7

Super Moderator
Staff member
Dec 15, 2010
8,551
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Norcal
Moved to fuel and exhaust

The fuel running through the case does little if any cooling. On the LLY it's a straight line from one end to the other. Plus fuel is going to be pretty hot anyways

Most that bypass it also move the FICM off the engine. But those who keep it in the same location don't seem to have any more issues
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,781
355
83
Boise, ID, USA
I bypassed the fuel going through my FICM and left it on the engine with no I'll effects for 50k miles and counting. But I agree, the issue probably isn't the FICM leaking, but the fittings, which is easy to fix with new crush washers.

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N2BRK

Well-known member
Dec 31, 2009
2,377
712
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I followed Tony’s (Moonshine) advice in an old post here, and routed my FICM on the return side. I run about 15psi from the FASS 250 in it’s as-received setup, and my lb7 doesn’t care. I’m about 25k and 2 years on it.