P0440 Code
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From: Livonia, NY
P0440 Code
I got a check engine light and found a P0440 code had posted checking with an ODBII scan tool.I searched the other P0440 related posts, but no one had the additional symptom I have.
I occasionally hear a muffled sound when I start the car that sorta sounds like the engine may be backfiring into the intake manifold or through the throttle body. I only notice it if the car has been running a while, gets shut off for 5-10 minutes and is restarted. I had the fuel pressure regulator replaced under the recall last year. I also pulled the vacuum line to the new regulator while the car was running, but I didn't see any gas or smell any gas fumes (thinking maybe the regulator was replaced with a faulty one).
Does this point more clearly to the gas cap, evap canister or something else? Thanks for any help.
I occasionally hear a muffled sound when I start the car that sorta sounds like the engine may be backfiring into the intake manifold or through the throttle body. I only notice it if the car has been running a while, gets shut off for 5-10 minutes and is restarted. I had the fuel pressure regulator replaced under the recall last year. I also pulled the vacuum line to the new regulator while the car was running, but I didn't see any gas or smell any gas fumes (thinking maybe the regulator was replaced with a faulty one).
Does this point more clearly to the gas cap, evap canister or something else? Thanks for any help.
DINOSAURUS BOOSTUS
Expert Gearhead
Joined: Mar 2005
Posts: 41,391
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From: Enfield, CT
Start with the basics. Sounds like checking the gas cap and double checking for vacuum leaks. If possible test the vacuum with an actual vacuum meter to see if you have enough. It is possible that since your car is 6 years old one of the vacuum lines has cracked or rotted and is causing the code. And probably causing you to be too lean for a moment until the engine gets up and running.
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Joined: May 2005
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From: _Phoenix, AZ_ _WCBF '05, '06, '07 Survivor_ ____NEBF '07 Remnant___
Trace/Check ALL vacuum lines for cracking/deteriorization from the evap canister to the evap purge solinoid and evap vacuum switch. Flex the lines to see if any show signs of cracking.
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Joined: Feb 2004
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From: Livonia, NY
Just a follow up. Looks like the problem was caused by a faulty gas cap.
When I loosened the cap last week to fill the tank, I found it somewhat snug but noticed it didn't take anywhere near as much effort to open as it did after I tried tightening it first and then immediately trying to open it.
Since I never tried to tighten the cap first when filling the tank, I never noticed the lack of effort required to open it. Probably has been vibrating to a loose position for a while.
I replaced it, reset the computer and the problem hasn't returned. Also seemed to have cured the muffled internal "backfire" as well that occurred after sitting a short time before a restart.
Thanks again for your help.
When I loosened the cap last week to fill the tank, I found it somewhat snug but noticed it didn't take anywhere near as much effort to open as it did after I tried tightening it first and then immediately trying to open it.
Since I never tried to tighten the cap first when filling the tank, I never noticed the lack of effort required to open it. Probably has been vibrating to a loose position for a while.
I replaced it, reset the computer and the problem hasn't returned. Also seemed to have cured the muffled internal "backfire" as well that occurred after sitting a short time before a restart.
Thanks again for your help.
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