Hard start, think it might be the Purge Valve but...

[Liaztraht]

I had a couple hard starts, I think it might be the Purge Valve but the valve seems to have "fixed" itself.

I got the typical hard starts. Crank, no start, then crank starts and stalls, then crank and starts. After that, if its been sitting, it will either fire right up, or have one crank no start. A little rough idle before it warms up.

Last night, I popped the hood, and started it. No problem. Then I shut it off, and as I went to unplug the power and gas side of the valve, it made a loud whining fart-like sound before I could detach anything. It came directly from the valve. I could feel it vibrate while making the sound. Once unplugged, I fired up the engine and put my finger over the gas side hole. No vaccum. I think the sound was the valve forcing itself closed.

I think it's an intermittent stuck valve. I am going to replace it regardless, but figured I would ask what the community thinks? It could also be bad gas, but I also filled my Mazda at the same pump a couple days prior, and haven't had issues in it. The station gets their gas on Tuesdays, I filled the Jeep on Sunday, Mazda on the prior Thursday, so it is the same batch.

Its a 2011 KK. 101,000 miles. Only recent change was adding a locking gas cap.

 

[LibertyTC]

Hopefully the new mopar purge valve fixes this issue for you. Did you get a locking mopar gas cap?
Ya every once in a while lately my KJ also makes rude purge noises, but it hasn't failed to start.

 

[Liaztraht]

Hopefully the new mopar purge valve fixes this issue for you. Did you get a locking mopar gas cap?
Ya every once in a while lately my KJ also makes rude purge noises, but it hasn't failed to start.

My wife ordered a Stant gas cap. I told her to order OEM parts but... I was fine without a locking cap. I doubt a non OEM gas cap would cause this, but I've seen weirder things happen.

The issue is more of a nuisance. It always starts up, it's just odd to have it happen 3 days after getting gas and 2 days after a gas cap.

If I understand right, the Purge valve should be closed until its warmed up. It made the noise on a cold engine that I ran for about 10 seconds before hand.

 

[LibertyTC]

Gas cap should be a Mopar. I had no luck with stant stuff. I've had a mopar lock cap on for years, no issues, no codes.
It's about the seal & then pressurization too. If the cap seal allows any air into the system, it will not function correctly.
It may seem a bit confusing but here is how the purge valve works.

During the cold start warm-up period and the hot start time delay, the PCM does not energize the solenoid.
When de-energized, no vapors are purged. PCM de-energizes the solenoid during open loop operation.
The engine enters closed loop operation after it reaches a specified temperature and the time delay ends.
During closed loop operation, the PCM cycles(energizes and de-energizes) the solenoid 5 or 10 times per second, depending upon operating conditions.
The PCM varies the vapor flow rate by changing solenoid pulse width. Pulse width is the amount of time that the solenoid is energized.
The PCM adjusts solenoid pulse width based on engine operating condition.

 

[Liaztraht]

I will swap the stock one back on and see if it solves the issue.