Another "fuel in the valley" thread..worth pulling lower intake?

[K5_489]

'96 K2500 4x4 auto trans, 202K miles...stock as far as I know, other than my DIY Turbo-Master. Noticed a minor, intermittent, fuel leak starting last year, which recently became a major fuel leak. Like many others, is dripping from the weep hole in the trans inspection cover, and I have verified that fuel is pooling in the valley under the intake after cleaning the valley out.

I have already read dozens of threads from multiple forums saying that the FFM or the hoses under the intake are the common culprits. It is NOT coming from the FFM, nor is it from the hoses from the FFM to bleed valve, FFM to IP, or either of the rubber feed and return hoses near the firewall and behind the motor/under the FFM. I had already raised the FFM above the intake and replaced all of those hoses previously, along with deleting the fuel heater (gutted the heater element out, then welded the base hole closed) and installing new o-rings on the bottom and behind the WIF sensor. It's also not leaking under the fuel filter plastic cap/top seal.

None of the injectors or return lines are leaking, including the ones under the turbo/heat shields...(though I can't see how those leaking would cause fuel to end up in the valley..but I saw it mentioned in many threads...). It's not leaking at the fuel inlet on the IP, or the return fitting. Not leaking at either end of the return hose on the IP, or at the other return junction hose at the passenger front of the motor.

I jumpered the fuel pump relay to keep the lift pump running with the key off/engine off. Leak started after about 3 minutes of running the lift pump. Found the optical sensor o-ring was leaking, and replaced that today, along with fully cleaning/drying the valley near the drain hole. Now, it doesn't leak at all with just the lift pump running, but will start leaking almost immediately after starting the engine. I watched fuel flow down the valley to the drain hole on top, and then out of the trans inspection cover again.

It doesn't appear to be leaking at all from anywhere on top of, or the sides of, the IP. But fuel is definitely running down the valley to the drain hole. At this point I'm assuming the IP itself is leaking, presumably from the weep hole? Would it be worth my time to yank the lower intake manifold for further inspection, or is it pretty much a guarantee that the IP is in need of replacement? I'm not putting $800+ into this truck, so if it's IP time, I'm either selling it as is or parting it out.

[sctrailrider]

Sounds like it would be better to find the leak in stead of throwing money/parts at it, the lower is easy to remove, and you could clean under it and also run the motor with the intake off, just make sure nothing gets sucked into the intake runners...

[Robyn]

Definitely keep stuff away from the intake ports.

A buddy of mine had a loose rag laying somewhere and goosed the engine and the fan got the rag airborne and it went in a port.

Engine was NEW....FIRST RUN UP.

Rag filled the cylinder and held the valve open.
Piston hit the valve.
Bent the rod, blew the side out of the cylinder and generally spoiled a fresh engine....

MAKE DAMNED SURE THERE IS NOTHING LOOSE THAT CAN GET INTO A PORT.

GM SPECIAL TOOLS ACTUALLY SHOW A SET OF SCREENS THAT COVER THE PORTS FOR DOING THIS TYPE OF WORK.
Very fine screen that will keep out even small screws...1/16" mesh