Our Community is 940,000 Strong. Join Us.


Is P0440 code only an enviornmental issue?


nosefirst
08-15-2005, 03:46 PM
Does a small evap leak affect any other systems? Does it affect the way my engine runs? Do I really need to run and get a smoke test?

Come on Merlin....

Maybe no one knows, maybe the nose knows.

Austin8214
08-15-2005, 04:08 PM
Does a small evap leak affect any other systems? Does it affect the way my engine runs? It could Do I really need to run and get a smoke test? NO

Come on Merlin....

Maybe no one knows, maybe the nose knows.


Small evap leak may be as simple as repalceing or tightening your gas cap.

nosefirst
08-15-2005, 04:26 PM
Thanks Austin.......I know that.

Doesn't come close to answering my Q. Maybe I'm not being co-herent, lucid, clear, ...........again.

ctesla
08-15-2005, 05:00 PM
P0440 and 0442:
Evaporative emissions sense a fault when there is a leak(it reads negative atmospheric pressure from the fuel tank pressure sensor), when it senses a leak it will set the engine light.
this indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

:2cents: I have never seen any driveability problems arise with this code.

that said, with the light on you cannot see if the ECM eventually trips for something else, and naturally, if you have emissions/inspections in your state or area, it would have to be corrected prior.
this being a truck, the Vent Solenoid is the most potential culprit (educated guess), as an over filled tank, under filled, loose fuel cap, etc.
could cause excessive fuel vapor/moisture into the vent and/or canister.
plus, being mounted usually under the vehicle, moisture, humidity, road grime can assist in bringing this one to an earlier death than the Purge Solenoid which doesn't usually fail (I say again, usually).

if you are a four wheeler (or at least drive like me) or have had the fuel tank over filled, this might be the area to inspect: the filler tube from cap to tank, as sometimes weight and or mileage and shock, can pull the worm drive clamp or the neck (if one solid plastic type) away from the tank or fuel cap side; or the canister, solenoid, and hoses under carriage are another possibility.
if these are not your culprits, a smoke test is pretty much the only way of identifying this leak, unless many components are pulled and swapped,
but, the engine will not drop into a closed loop, rough idle, misfire, etc.

hope this helps,
chris
nrt racing

nosefirst
08-15-2005, 08:00 PM
Chris


tHANK YOU...tHANK YOU...tHANK YOU!!!

GMMerlin
08-15-2005, 08:12 PM
Usually EVAP codes ( those pertaining to leaks) do not cause other driveability issues..BUT..
An EVAP leak code could indicate a leak in the fuel tank...so there is the possibility of a fuel leak (Sender, sender seal, cracked tank)..so now you start getting into a safety issue.
Depending on the EVAP code, there could be a sticking purge solenoid which could cause a driveability issue due to a vacum leak or a rich code by the fuel vapors being pulled into the intake.
So to answer your question...yes and no

nosefirst
08-16-2005, 08:59 AM
Thank you Merlin,

I erased the code right after I filled up the tank and it hasn't reapeared. There wasn't a lean code , and I assume a vacume leak would cause a code too. A carefull visual inspection hasn't revealed any obvious leaks (gasoline). For now I'm not going to worry about it. Too many other things to worry about.

Thanks again.

Add your comment to this topic!