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I've been driving my 02' c5z with code P0442 which doesn't bother me too much but with spare time, I decided to tackle this. I removed the purge valve and tested with a vacuum gauge. The side that points towards the gas tank could not hold vacuum. The side that points to the throttle body, does hold vacuum. I went to the auto parts store and tested the new purge valve. Bothe sides did not hold vacuum.
Both my current and new purge valves were tested out of the car. I'm confused, is the current one faulty or is the new one faulty?
The side with the long vacuum connection holds vacuum and the side where the electrical also resides does not hold vacuum (the original purge valve). Hope I explained it correctly. I included a few photos.
First off how did you determine it was the purge valve ??...you can have a bad gas cap, EVAP canister, vent valve, or any of the EVAP lines..the 0442 is a “small leak”...this can be difficult to diagnose properly... You really need a smoke machine and a bi directional scan tool to properly diagnose this...suggest you take it to a shop that has this equipment !!...oh, the end going to the intake manifold should hold vacuum and best to test with a Mityvac !!...good videos !!
First off how did you determine it was the purge valve ??...you can have a bad gas cap, EVAP canister, vent valve, or any of the EVAP lines..the 0442 is a “small leak”...this can be difficult to diagnose properly... You really need a smoke machine and a bi directional scan tool to properly diagnose this...suggest you take it to a shop that has this equipment !!...oh, the end going to the intake manifold should hold vacuum and best to test with a Mityvac !!...good videos !!
Thanks for the links. I have some spare time and the "Mityvac" so I decided to tackle this. I will also do the fuel cap next.
I took two separate videos:
One video will show that the valve does not hold vacuum at either end (strange; it only happened this one time out of 10 or so). The red tape is a point of reference......this connection points towards the back of the car. The other end points towards the front of the car.
In the other video, it shows that the end pointing towards the front of car holds vacuum while the other remains the same as always. Again, the purge valve I tested at the auto store did not hold vacuum at either end.
If I understand correctly, the end to to the intake is the one with the red tape. Does this mean it's not functioning property?
The end without the electrical connector is the end that goes towards the intake manifold...in the video it looks like it held vacuum...in that case the valve is good !!...the red tape end goes towards the canister !!
p0442 is a small leak code, often the gas cap. The code is tossed when the system is tested and it won’t pressurize or hold a vacuum. There are other possible small leak sources, and sometimes the fuel tank pressure sensor can cause this as it goes bad. The pressure/vacuum report from this sensor will cause the pcm to toss this code.
If you had the intake off, did you push the plumbing connectors on the purge solenoid? That “snake” hose can be hard to seat at the back connection
The end without the electrical connector is the end that goes towards the intake manifold...in the video it looks like it held vacuum...in that case the valve is good !!...the red tape end goes towards the canister !!
The end where the electrical connection is (where I also put the red tape) doesn’t hold vacuum. Is this correct?
The end where the electrical connection is (where I also put the red tape) doesn’t hold vacuum. Is this correct?
correct !!...the intake side is the end we are worried about !!...if you did have a leaking purge valve after you fill the gas tank the intake would be pulling in gas fumes from the EVAP canister...the engine would be a little more difficult to start...engine will run a little rough (running rich) and then the engine will run lean because you now have a vacuum leak once all the gas fumes are burned !!...if you have a scan tool your fuel trims will be negative and then go positive once the engine leans out !!
Purge valve testing - 02' c5z
