Nissan EVAP System

Lurch830

Lurch830

messin' with sasquatch
Joined
Mar 1, 2007
Location
Wilton & Albemarle, NC
Anybody know anything about EVAP systems? Even better yet, EVAP systems on a Nissan hardbody?

Got an error code for the EVAP purge valve on my 97 Hardbody(inspection month of all things). Closest thing I can find in the service manual is an EVAP purge canister valve (vacuum part that deals w/ smog regulations and is therefore killing my MPG). Neither AutoZone or Advance carry the part or can special order it for me. So it looks like if I can't do a DIY I'm gonna have to take it to a garage/dealership.

Speaking of garages, anyone know of any in the Concord/University area that are good for this type of stuff? I've heard the dealerships aren't that good about maintenance.

Thanks,
Brandon
 
What's the code #?

EVAP canister controls fuel vapor. It has a valve that opens/closes and releases the fuel vapor into the intake. The opening/closing of the valve is controlled by the ECU. When the vehicle is not running it remains closed, keeping fumes from getting into the air.

I have the FSM for the 97 HB. If you need I can copy some of the pages on that topic and e-mail them to you.
 
Before I forget.. After the problem is fixed the truck will need to go though approx. 12 cold/hot cylces before the computer will clear the code and have enough information stored to be inspected.
 
Check your gas cap to see of it's loose/missing. Also check to see if you've got a vacuum hose cracked or off at the charcoal canister. (Might look like a coffee can or other can type shape. The evap canister stores fuel vapor and the purge valve lets that vapor into the engine at part throttle, so it actually helps you get BETTER gas mileage since that vapor would otherwise be wasted into the atmosphere and doesn't hurt any horsepower either since it only opens at part throttle.
 
rbo1577186 said:
What's the code #?

I have the FSM for the 97 HB. If you need I can copy some of the pages on that topic and e-mail them to you.
Click to expand...

I can't remember the code #, but will get it next time I'm working on the truck. If you don't have a need for the 97 HB FSM and its a good one that covers only that year model and not all the HB models, I'd be more than happy to buy it off of ya!

rattlecanpaint said:
Check your gas cap to see of it's loose/missing. Also check to see if you've got a vacuum hose cracked or off at the charcoal canister.....it actually helps you get BETTER gas mileage since that vapor would otherwise be wasted into the atmosphere and doesn't hurt any horsepower either since it only opens at part throttle.
Click to expand...

I've got a locking gas cap on it, but the 'Service Engine Soon' light was on before I put the gas cap on. I've checked to see if there are any cracked hoses (sprayed WD-40 and looked for bubbles) and haven't seen anything indicating cracks/holes....MPG is going down though was 19-21 now its 11-15.
 
Damn, I got nuthin'
 
rattlecanpaint said:
Damn, I got nuthin'
Click to expand...

Now you're in the spot I was about a month ago. Its crunch time now and if I can't find a junk yard with an EVAP purge valve for sale or a garage that knows how to fix it, I'll be paying an arm and leg for a Nissan dealership to fix it which is gonna suck.
 
knowing the code would help me greatly, first of all there is a purge control valve, a purge control solenoid valve, a canister purge control valve, a vapor pressure sensor, an evap shut valve, a system pressure sensor and a vacuum bypass check valve. So there is alot to go wrong in the EVAP system. But the good news is that there is ways to bench check almost all of those.

First I'd start with the purge control valve, To test the purge control valve plug the bottom right port and apply approx 11psi to the top port and it should hold that pressure for 15 sec, then test the bottom left port the same way with the bottom right port plugged off. That test can rule out the purge control valve.

Then i would test the control solenoid, apply 12 volts to the solenoid and check for flow change between the three ports, you should also hear/feel the solenoid click.

The purge volume control valve is alittle more in depth to check and would require you to have the schematics. Let me know what happens with those tests and what the DTC is
 
So finally got to tinker with it for a minute or two.....the code # is 0807 and I tested the EVAP canister purge control valve and it seems like its working. And thanks to rbo1577186 I have copies of the FSM for this code so I'm gonna try to detect/fix the problem this weekend. I'm thinking that its either the solenoid valve or a broken hose....anybody else got any ideas?
 
reset the codes, leave the gas under a 1/4 of tank drive 30 miles under 50 mph most of you readiness test will reset EVAP will not reset b/c there is not enough fuel to run the test, you can get a 97 inspected with 2 not reset. allthough i have had a nissan reset evap w/out a 1/4 a tank they are a breed of there own. if a line is leaking a smoke machine would be helpfull.
 
well did some DIY with the help of the FSM rbo1577186 sent me and detected it was a broken wire from the ECM to the solenoid valve. Drove it a while to re-cycle the system and checked for any codes to display again....there were none. Took it to AutoZone for one last check before inspection and their little tool threw up P1441 & P0443 which correspond to codes 0801 & 0807. So its back to trouble shooting for the day. If I can't get it figured out by this weekend I'm gonna try Cperry's idea and if that falls through I'll have to take it to a garage/dealership.
 
Don't know about those codes but it takes a few hot/cold cylces to purge the codes from memory. Give it some time if you're confident you fixed the problem.
 
Tested the solenoid valve mentioned above and it was bad, then according the the Nissan dealership, I had some bad grounding issues and a fried computer. So now that its fixed I'm gonna be able to start lifting and wheeling it. Thanks for everybody's help!
 
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