98 Pathfinder EVAP Canister repeat problems !

[andruet]

98 PF SE:
It has 127K on it now but the problem started around 60K.
Every time my SES light comes on it turns out to be a problem in the EVAP system. So far: 1 canister replaced under warranty, then 1 more at my cost, 1 Purge valve (dealer said they have to replace the whole canister with that), then a 3rd canister, along with blowing out the whole system ($800 !)
Now, the light is back on again, same problem code.

So, what the H_LL is this all about ?
The dealer insists I'm overfilling the fuel tank. WRONG !!!
I know better by now.
Any hints, advice, suggestions, etc., etc. ?
This is getting costly.

[lewisnc100]

Can you post the actual EVAP error code you are getting? None of them specifically say the canister has to be replaced unless its cracked, leaking charcoal or the vent control valve needs to be replaced. The error probably has other causes as well such as the purge control value, pressure sensor etc.

[andruet]

Originally Posted by lewisnc100

Can you post the actual EVAP error code you are getting? None of them specifically say the canister has to be replaced unless its cracked, leaking charcoal or the vent control valve needs to be replaced. The error probably has other causes as well such as the purge control value, pressure sensor etc.

Thanks for the reply.
I don't have the code for this particular time, I still have to retrieve it (and I don't have an OBD reader).
The codes I got the first couple of times are as follows: P1442, P1440, then P1442 again. The first time the can was cracked, the second it was the vent valve. The most recent indicated the purge valve was stuck open, the mechanic said the system had charcoal throughout, so they had to blow it out.

My question isn't so much about diagnosing the specific problem, but why there are so many failures involving the same system. Could it be the location of the canister, or charcoal containment issues ?
I work in an engineering environment, so getting to the "root cause" is of particular interest.
I'm well aware of "poisoning" of the canister from overfilling the fuel tank. That was known from the early days of emission control systems.

Are there any "engineering types" out there that could lend perspective on the subject ?

Thanks, in advance !

[lewisnc100]

The vent control valve and canister were redesigned on models manufactured after 4/97 so yours should have come with the redesign. I think the location has a lot to do with the vent control valve going bad and the canister getting cracked, but can't think of any good reasons for the charcoal leakage problems Nissan has had.

I replaced my canister and valve over a year ago, luckily I haven't had any errors since. I think they had it right in the 96 year, the canister was in the engine bay and I don't think they have had as many problems.

[CT18fireman]

Does anyone have the part number and approxiamate price for the canister for the 98? I like to go to my dealer with the numbers.

[andruet]

Sorry, wish I had that info at hand. The last time I replaced the canister, I think that part alone was around $400.00, roughly. Best to get a price from someone who's authorized to work on emission systems.

Just curious, what is your specific problem ?

[CT18fireman]

I originally got a check engine light, scanned the car and found I had a bad emissions valve (located just behind the throttle body) Took it off and found it and hose back to canister clogged with charcol. had to disassemble hose at few points to blow all the charcol out. Cleared valve and it works fine. I plugged the line at the canister to prevent the clogging again but need a canister to get it back so that I can clear engine light (comes on after resetting and driving but engine running fine).

I replied to another thread with similiar problem and they said a late 97 canister was only $50-60 last summer. Hoping it is the same one.

[coombsboy]

I've had problems with my EVAP system on my 98
pathfinder, I know this is nothing new. I'm trying to
figure this out? When my vehicle is cold, it runs like a top
then 15-20 minutes later its bumping and stuttering with
no power. I'm about to replace cannister and VC valve
but I'm open to suggestion etc....