I have a recurring p1457. Wondering if the fact that I have no vacuum in my gas tank (no sound when taking off cap) helps pinpoint which part it might be?

I've had a chance to pull the purge valve and it seemed ok - (held had power and vacuum) ran out of time to check activation of the solenoid and to get to the two-way valve. Will probably be tackling this again this weekend.

BTW - it seems to come on when I go over large bumps (like a railroad track) at speed that cause quick vertical motion for the car. Don't know if this helps or not.

Any advice is much appreciated!

Almost forgot, car is a 2001 LX 4dr

 

Could be a number of things. The troubleshooting procedure(s) can be up to 45 steps, which is .. a hell of a lot of typing. HAHA! So .. you are on the right track, though!

The next step (as you likely know) would be that Bypass Solenoid Valve, followed by EVAP Canister Vent Shut Valve testing, Canister System Leak testing, etc.
I would expect to have to replace the EVAP canister (so it's not an irritating 'surprise' if it happens) but hope that it doesn't actually come to that.

 

With proper knowledge of the system and the right tools it can be diagnosed in far less than 45 steps.

Pressurize the system, with a smoke machine designed for EVAP testing, at the vacuum line on the manifold with the PCS, BPS and CVS commanded ON.

Watch the FTP. It should rise to about 3.3 volts. Disconnect the PCS connector and monitor the FTP voltage. It should remain at 3.3 volts. This indicates that there is no system leak. If the voltage drops, you need to find the leak.

Next, change the status of solenoid command to, PCS on, BPS off and CVS on. Apply vacuum to the PCS line at the manifold. Monitor the FTP. The FTP voltage should not decrease. If the FTP voltage decreases this would indicate a leak at the 2 way valve or BPS.

The trick to diagnosing EVAP systems is to differentiate a system leak from a component malfunction.

 

Quick question - I head read that the canister purge valve (the one held to the passenger side of the canister by two Phillips-head screws) should be closed at rest. Is this correct for an '01 civic?

 

This would be great if I had access to such tools. Thanks for the input though!

 

This is getting pretty aggravating, but probably the heat here in VA!

Question: One of the steps in the troubleshooting procedure calls for checking the voltage at the EVAP canister purge valve connector terminal. This terminal has 2 wires, one is yellow w/ a blue strip (1), the other black w/ yellow stripe (2). The procedure indicates that w/ the ignition on, you should get 12v at (1). I didn't have voltage on (1), but had it on (2) - (2) had no continuity to ground but (1) had about 84 Kohms to ground. Dunno, but it seems opposite of the procedure so I'm a bit confused. Any suggestions? At least I've accomplished one thing, which was verifying that the two-way valve is working!

^
1 2

 

Check your Private Message inbox. We'll get this sorted out.