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Hey guys, I have a 1998 Camaro Z28 and the SES light illuminated. Took it to Auto Zone and they pulled a P0440 code.
What is the common cause when that code comes up? The description is Evap emissions system. Not much to go on. Their computer suggested intake gaskets as the root cause, but I'm skeptical.
One thing I tired was, I disconnected the hose from the evap purge valve on the D.S. intake and blew threw it. It blows pretty freely, and I can hear the air escaping from under the car near the fuel tank. Is this suppose to flow freely? I figured the system would need to hold pressure until the purge valve was commanded to open.
Anyways, any suggestions before I bring it to a dealer?
BTW, my car is mostly stock with low miles and no rust. Not sure if that helps.
There are two solenoids as well. One on driver side near the TB and the other is near the front of the tank driver side. Essentially when the solenoid opens fumes are pulled from gas tank and are routed to the intake manifold by way of the throttle body. It's possible one for both might defective. There is a short intermediate harness that runs from the fuel hat on the fuel pump assembly that runs down to the solenoid near the front of the fuel tank on the driver's side. If that plug is disconnected you will get a code as well.
There is a quick connect fitting near the fuel filter on the end of a black 5/16 inch plastic line that runs up to the hat on the fuel pump assembly. It's end connects to the hard line that runs up to the intake. It might be loose there or broken.
Look for the quick connect fitting and black nylon line aft of this area in the pic. My fuel filter is relocated, but the black plastic line with the quick connect is just aft of two hard lines in the pic.
Don't remember which, but one of the plastic lines each with a quick connect fitting is the line that runs down to the the hard line near the fuel filter and then on to the intake. Doubtful, but you might have a leak at this connect point as well.
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P0440 Questions 
