Author Topic: 3.8 Persistent codes for evap emissions leaks? Check this first  (Read 646 times)

PajEvo

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3.8 Persistent codes for evap emissions leaks? Check this first
« on: October 11, 2017, 06:32:02 AM »
So your gen3 is throwing a cel for a small or large evap emissions leak. You've reminded your wife (or she's reminded you more like) to fully tighten the gas cap. You've cleared the code, only for it to come back on, usually while your father in law is borrowing the truck. You've checked all the vaccum lines under the hood. You're almost ready to do the "smoke test" at the dealership (whatever that is? You haven't smoked since that time you got sick from the cigars at that wedding...)

Hold on. Before you do anything else, pull the passenger side (assuming your wheel is on the LHS) rear wheel - okay, after you've jacked up the truck, secured it etc. Pull down the plastic shield that covers that network of fuel filler pipes, returns, vent lines, etc. After you've washed/blown all the trapped dirt and sand out, how does it look? If if it is pristine, then go ahead and book that smoke test, but if it was like mine, you have an oxidized network of pipes and hoses that would look more at home in the bottom of San Francisco Bay holding your boat's position. I actually had giant pieces missing!

Rockauto (and many other places) sell this assembly as a unit. In other markets, this assembly is responsible for taking out the lovely 4m41's injection pump, by introducing rust into the diesel. Luckily with the 3.8, a simple swap of the pipe work is usually enough to restore everything to working order. After I had swapped in the new assembly, I left the splash shield off, and now include this area in my cleaning regimen.

I'll follow up with a pic of the offender. But its not for the faint of heart!