Hello all,

I have a 2000 us xj8 base model 4.0 model. I had a p0433 code both my valves seem to be functioning correctly, I made a make shift smoke machine and I noticed some smoke under the car near the charcoal cannisters. Haven't pinpointed yet since the wind was pretty strong today. But I noticed the hoses and the vapor pipe connecting canisters look brittle and bad so wanna replace those. Can I use any hose to change those? Also is there a specific part number for the vapor pipe connecting cannisters? Or is there a specific search term for it? I recently purchased this car and had a bad fuel pump and I fixed that but now I have the EVAP code that I am trying to clear so I can register it.

Thanks in advance.

 

I found this diagram helpful.

 

I would check the 'O'rings to the plastic canister case.
I worked on a brand new car with a check engine light that turned out to be a leaking EVAP system.
Smoke machine revealed a defective (torn) 'O'ring from the factory.
I went to the parts dept and ordered the 'O'ring.

A few days later, a GIANT box showed up with the plastic pipe from the canister to the engine bulkhead. (like 10 feet long)
I ONLY needed the 'O'ring but the parts dept. said that was the only way to get the part as it was NSS. (Not Sold or Serviced Separately)

I pulled the 'O'ring off the new pipe assy and installed it on the car, sent the old 'O'ring and new pipe back to the parts dept. for warranty return.

Sometimes you just shake your head!

 

Ditto. Mine was leaking at the o-rings. I just took the old o-ring to my Ace Hardware and matched the size to their stock.

 

Sometimes you can find a large assortment of O rings in a nice plastic box
for not much money and it is handy to have them available when needed.

 

The interior of your car looks new! Nice! Let us know if the new O-rings fix the code. One of my 2000VDPs is not running right...maybe it's a similar problem?

 

So I ended up buying a cheap smoke machine and found I did have a leak in the hose from the vapor pipe to the canister. I replaced that and smoked again and could not see any smoke coming out of anywhere under the car or in the engine bay. I even pulled one of the hose's from the solenoid behind the throttle bottle and was indeed getting smoke all the way to the motor.

I cleared the P0433 code and pulled the negative lead from my battery overnight. First drive was good no pending codes, then second drive cycle I got the p0433 pending again.

I did verify voltage at the cannisters valve close. I pulled it and tested it with a battery and seems to operate correctly, no voltage normally open and with voltage applied valve close.
At the EVAP purge cannisters valve in the motor I verified I was getting voltage to the unit and pulled hoses and verified It had some suction (just with my finger)

I am at a complete loss now at this point, is there any other thing I should be looking at? Trying to clear this p0433 so I can smog.

 

I’ve hunted down this same code a lot before finally solving it. Mine turned out to be debris from the fuel egal line clogging the EVAP purge valve so it wouldn’t open / close properly.

You can carefully pry the evap purge valve apart with screw drivers and clean the bladder inside. See if that helps.

Keep smoke testing the engine bay. Good luck

 

Is this one near the throttle body or the one under the car attached to the charcoal canister? I original replaced the one near the throttle bottle hoping that was the issue in the begining.

 

Near the throttle body. I replaced all the vacuum lines and the EVAP purge valve and the problem went away for a while and then came back. It gets gunk in there from cars that have sat.

 

I’ll share with you an experience I had with a customers 2003 XJ8 about 6ish weeks ago. His car had the same P0443 purge valve code (behind the throttle body on the firewall). I did all the usual checks like you did. Power and ground present at the purge valve (firewall) and the vent valve (on the P/S canister). I went to the purge valve in the engine bay, ohm checked it (very little resistance), applied power and ground and the solenoid clicked. I used a hand held vacuum pump with gauge and applied 15” of vacuum to the solenoid. The solenoid held vacuum and didn’t leak down. When I applied the +/- to it the vacuum went away. Keep in mind this customer couldn’t leave the car as he lived kinda far away so he was waiting. Anyways, I wanted to further test the purge valve by taking it off the car and bench test it but I was told not to spend anymore time on it. Besides, I have broken a few of those nipples off the purge valve trying to remove the short fat hose that attaches to the part load breather tube on it and I wasn’t in the mood to break another one. I cleared the code, told my boss and the customer that off hand I couldn’t find the issue but I thought it was the purge valve behind the throttle body possibly sticking (???) and went on to my next job. The following week the customer returned with another cel on and verified that it was the same code. I told them that it was likely the purge valve but I would need to remove it to bench test it to confirm it (because there was no lean codes like a part load breather tube leak) and next thing I know the purge valve was on order. I replaced it later that week and I haven’t seen or heard from him since so I have to assume that it took care of the cel. I did carefully open up the old one out of curiosity and there was a fair amount of rust dust in the diaphram where it comes from the evap system in the back of the car. My recommendation to you is the get the engine up to full operating temperature, turn the car off and go straight to the 2 large hoses on the purge valve and *carefully* remove those hoses. They’re way easier to remove when the engine bay is hot vs when it’s cold. Those rubber hoses come off a lot easier when they’re hot as they’re more flexible. They’re held in by barbed tubes. There’s a mini air filter on top of the solenoid that can be checked and if you’re patient, you can take the main body of that off and inspect the diaphragm and ports for any clogging. I’d also blow through the hoses that attach to it to make sure they’re also clear. I’m not going to suggest tossing a purge valve at it because it’s kinda pricey but it’s likely the issue.

 

That was the first thing I ordered when the code first popped up. So maybe for giggles I will toss in my old one and see if that one works a little better. It did seem like it was functioning but was trying to be quick and dirty and get it going quick.
So back story on the car I bought it from a friend for 1300. It was her father's that passed. Her husband didn't fit in it to well, so she knew I needed a car. It was running and everything was fine with it as far as they could tell.
It sat for like 2 years before I was able to get it from them. Lots of complications on their end and was during covid. When I went to get it, it would not start. The fuel pump went bad, so I towed it and changed the fuel pump and drained all the old gas. The tank looked clean and immaculate inside. Started first try, and drove it a little then that's when the p0433 code popped up. It was never present when they got the car.

 

If the FP was changed, perhaps hold off putting the old purge valve back in as to not risk breaking it due to those barbed fittings. Instead why don’t you spend time double checking the hose connections on top of the fuel tank lid. Smoke check the fuel tank to make sure everything’s copacetic since you already smoke checked the canisters and engine bay. You may have to carefully pinch that large hose to the left of the tank so it’ll build pressure on the smoke machine gauge (if it has one).

 

Thanks for the advice. I originally smoked the tank area with a small make shift smoker I made but I guess it did not build enough pressure. That large hose to the left of the tank actually started to leak a little smoke once I built enough pressure. Which was weird since that hose looks fairly new.
I have driven 3 days now when I can and no p0433 code. All I got left to pass on my im readiness is the ccm and the cat. So hopefully I can clear those tomorrow. Thanks everyone for their advice.