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Chevy Colorado and GMC Canyon Fuel System



  • citrius91citrius91 Posts: 2
    j/w if that fixed your problems? thanks jason
  • citrius91citrius91 Posts: 2
    05 chevy colorado
    thanks jason
  • akexakex Posts: 2
    I've had this vehicle for a year now. Its got about 70K on it and it hasnt been beaten. The problem im having is that I'm not getting the MPG's that its suppose to do, not even close its supposed to do 16 MPG for city driving and 21 MPG for hwy driving. I'm averaging in the summer around 13 MPG and less in the winter. All the things that I could do to help my fuel consumtion I did. Like add a new air filter, did a purge, flushed my oil a couple of times. I dont have big tires, I always try to keep my engine from reving over 2000 RPM. Is this normal? If not what is the solution? Thanks, Alex
  • gmcustsvcgmcustsvc Posts: 4,240
    The best fuel economy possible is the direct result of proper maintenance and good driving habits. Listed below are GM's recommendations to achieve the best mileage possible. The first group are things to consider for your vehicle, while the second are tips relating to your driving habits.

    One of the major contributors to poor fuel economy are under inflated tires. Tires low with pressure create drag that the vehicle’s powertrain must overcome, wasting dollars in fuel. Always keep your tires inflated to the proper pressure as shown on the vehicle placard. This not only serves to increase gas mileage but cuts down on tire wear, further decreasing your costs per mile.

    A vehicle that has a dirty air filter can’t efficiently draw air into the engine. This restriction forces the engine to expend energy to "breathe" wasting fuel in the process. Change recommendations are found in your vehicle Owner’s Manual.

    Always use the proper viscosity oil in your engine. Oil that has a higher than required viscosity will create more drag on the internal components of the engine causing more work for it, especially when cold. Each Owner’s Manual contains information on the proper type of oil for your vehicle. Look for the "starburst" symbol on the front of the bottle, and the SM rating on the API circle on the back label. If you are in doubt, stop by your dealer for an oil change, and any other services required. Most current GM vehicles are equipped with oil life monitors to further assist on the "when" to change your oil. (Aveo/Wave/Optra/Epica currently do not have oil life monitors).

    Note: GM Vehicles DO NOT require additional engine oil additives. Some additives may cause harmful effects to the internal seals and additionally void the terms of your vehicles New Car Warranty.
    Purchasing higher than required octane fuel is a waste of money. Using higher octane fuels in a vehicle that only required regular unleaded fuel will neither increase performance nor improve gas mileage. In all cases refer to your owner’s manual and ONLY use the octane rated fuel recommended for your vehicle.

    Even though current GM vehicles have 100,000 mi (160,000 km) service intervals for spark plugs if your vehicle is at that point in its life, have the spark plugs changed to assure proper running and continued efficient, trouble free operation.

    Avoid quick/full throttle acceleration from a standstill in town and high cruising speeds on the interstates. While the optimum MPG for highway cruising speed varies from vehicle to vehicle, faster is almost always worse. If your vehicle is equipped with a Driver Information Center that displays Instant Fuel Economy, select that readout and vary your cruising speed while on the highway. The display will change continuously with uphill and downhill sections but you should quickly be able to identify on level ground the speed range that your vehicle does the best in. Avoid leaving unnecessary items in your trunk. It takes power to move increased weight and that means more gasoline consumption and reduced performance. While the change may be slight, multiplied by thousands of miles, it all adds up. Your vehicle uses much more fuel when the engine is cold. This is especially true in the winter months when the engine will take the longest to warm up. Combine errands or trips so that the vehicle only needs to warm up once to encompass many different stops.

    If you still believe you have a concern please visit a dealer. They will be able to look into the situation.
    GM Customer Service
  • akexakex Posts: 2
    Hi Christina,

    Thanks for the reply, I appreciate your time. Everything mentioned above has been addressed and I've also brought it to the dealership and I keep getting the same response I just received from you. Has there been any issues with the fuel injectors, could they be sending too much gasoline then necessary? I'm running out of ideas... Does anyone else have any issues with their Canyon?
  • Hi All,

    I have a 2005 Colorado with 68K miles, the check engine light recently came on, it shows two codes, both P0442. Mine is an I5 engine 4WD, extended cab. I understand this indicates a leak in the evap ssytem, which the sensor checks by trying to hold vacuum. I replace the fuel cap to no avail. Does any one know of a way to defeat this sytem to make the Check engine light go off, like plug the line between the sensor and the tank?

    I bought this truck new, it has been a troublesome vehicle, tire wear that seems to unfixable, water leaks, multiple elctrical problems. I should get 150k miles or 10 years with zero problems, very disappointed in this truck.
  • Good morning,

    I understand your frustration, and can appreciate the fact that you are seeking to resolve these concerns on your own. If we could look and see if there are any open recalls or special coverages on your vehicle, we would be happy to do so if you were to email us the last 8 digits of your VIN.

    I realize that working with a dealership is not an option at times, whether due to technical expertise or other factors. If you do decide to work with a dealership in the future, though, I just wanted to let you know that we would like to make sure that things go well. Just let us know through an email (preferably, if you could include your name and contact info, last 8 digits of your VIN, the name of your dealership and appointment information) and we'd be sure to follow up on that.

    Happy Holidays,
    GM Customer Service
  • caoroncaoron Posts: 4
    I have 2004 Colorado Z71 Crew Cab With I5 engine and I'm experencing intermittent hesitation on acceleration, expecially when I first drive off after vehicle has been sitting for a while and cold. I have already experenced the Carbon Buildup in the Throttle body and I just cleaned that and I am still experencing the hesitation problem as if it is not getting fuel. After a few seconds it will continue acceleration. Anyone experenced this problem. P.S. Also the engine light comes on for a couple of days and then resets.
  • I have an 06 Chevy Colorado, bought it used with 50,000 miles. My husband and I have put about 10,000 miles on it and had no problems until a few months ago. We thought it was the fuses at first because the first time it wouldn't crank one of the fuses had come loose, it happened once more with the fuses so we replaced some of them. Have had issues where I couldn't get it to crank so my husband would drive home from work to only have it start up the first time he tries!! The probem has progressively gotten worse over the last few weeks, where it would happen every once in a while to where it was an everyday, nonstop thing. The last two weeks it has taken longer and longer to get the truck to start up with trying to start it in the ten minute intervals. This past week the time frame went to 15 to 30 minutes of trying to an hour and half sometimes two hours of trying till it would finally start. Three days ago my huband spent an hour and a half trying to get it to start doing the 10 min. of wait time, and it would start and then sputter out and die a few times before it finaly started up and ran just fine. Yesterday we tried it and after two hours of trying couldn't get it to start. So we had it towed to the dealership and it actually did the same thing there, it kept sputtering out and dying on them too! Mechanics are saying it is the fuel pump, that it isn't holding pressure, hooked it up to the machine and showed my husband the gauges and it really isn't! Has anyone else had the problem? I have scoured the forums and seen a lot of Colorados with starting issues but none that end like mine. Just wondering if it really is the fuel pump or should I still be worried about the Passlock system, we thought it was that at first too!
  • Oh the mechanics told us that the reason the fuel pump has gone bad is becaus its only driven around the city. I am a stay at home so only do around town driving. I had a Chrysler Mini Van for three years and thats all the driving it got exept for one trip to Florida, never had to replace anything on it!! Their reasonin just doesn't make any sense unless its a design flaw in the system!!
  • gmcustsvcgmcustsvc Posts: 4,240

    We're sorry to hear that you've encountered this starting issue with your Colorado. If you would like for us to follow up on this situation with your dealership, please email us at (include your name and contact information, a summary of the situation, the last 8 digits of your VIN and mileage, and the name of your involved dealership).

    Sarah, GM Customer Service
  • hi dick28540:

    i have a 04 Colorado, and the gas filter was very easy to change.
    (or run out of gas). then and only then UNHOOK fuel lines from filter, which IS OUTSIDE,of gas tank. my 04 cost me $15.00 to buy, and my time.
  • THANK YOU repairagain:
    i am having the same trouble with my 04 colorado, ck lite.
    i have a NEW gas cap, replaced it in 2011, fixed the lite on. but now and then the ck lite will come on and stay on. and the gas pump will shoot gas out tank
    if you stand too close. MUST BE THE BACK PRESSURE, I WILL ck my bleeder relay, on the canister. THANK YOU AGAIN.
  • ok you will love this problem,
    seems evap system is faulty, but i saw the gas beening put into my truck,
    and as the pump shut off automatic, i saw a gush of GAS behind the gas filler neck.
    So i took off the rear splash shield, to see the FILLER tube, i cked it all, and could NOT find anything loose, or cracked, missing. So i shall watch the next fill up. with the shield OFF, IT DID GUSH BEHIND THE GAS FILLER DOOR.

  • caoroncaoron Posts: 4
    I have experienced a similar problem with my 04 Colorado Z71 Crew Cab 3.5 I in the past couple of months. I have encountered a problem of not starting eventhough the engine turns over normally. After sitting for a few minutes and retrying, it started. The last time it took longer for it to start. I came on here to see if I could get some answers as to what was causing the problem. It is as though the ignition was turned off or fuel shut off. I was also concerned that it might be something to do with the security. Did replacing the fuel filter take care of your problem? If so, how expensive was it?
  • HappsterHappster Posts: 33
    The gas caps are a chronic problem..,.there is actually an NTSB bulletin...should've been a recall. But if you replace the gas cap and your problem persists, it is a problem in the Eval system. The primary suspect should be the vent solenoid. It is mounted on the charcoal canister in front of the spare tire. It is normally open, but closes for the system check. If it is stuck open or closed, it will trip a code. One person mentioned reversing the spring to keep it open...don't do that. That will just trip a code when the system check can't close it to pressurize the system and check for leaks. Put power to it and see if it opens and closes. If not, tap it and try again. If it starts working, exercise it 20-30 times and then reinstall. If that works, check the cannister - take the hoses off and try to blow through it. If you can't, it is might get away with smacking it around to loosen things up. There is also the purge solenoid up on the engine near the starter (accessed through the left wheelwell). This one is normally closed and opens to purge the canister at appropriate times. If all these things check out, it is either an electrical connector issue or a cracked hose/line. Here is a helpful cut-n-paste from the tech manual and a user's explanation of his fix:

    I seriously think your problem is the Canister vent solenoid / valve or the filter mounted on top of the solenoid. I just had mine out tonight. It took me forever to figure out how to remove it but once I figured it out it was a simple job. My solenoid / valve was sticking and I freed it up.

    First lets make sure you do not have an electrical problem.

    The vent valve is mounted to the charcoal canister. The canister is located just in front of the spare tire under the bed. Find the electrical connector on the vent valve and unplug it. Did you hear it click? If yes, try filling it up with gas and see if it is still hard to get the gas in it. I suspect you will still have a problem filling it but if you don't then you have an electrical problem which we can discuss in a followup posting.

    To get the valve out you do not need to remove the spare tire but doing so gives you a little more room to work. The choice is yours. There are two hard plastic hoses hooked to the canister. Squeeze them by hand to release the clips holding the hoses in place and pull the hoses off of the canister. Then unplug the electrical connector if it is still attached to the valve. If you want to test this canister and valve before removing it, take a piece of hose and slide it over the larger of the two nipples where you removed the hoses from. Put your finger over the small nipple and blow into the test hose you just installed. The air should move freely through the canister and out of the valve. If it does not, continue with the following:

    Laying on the ground look up on the driver's side of the plate the canister is sitting on. There will be a vertical bolt with the threads looking down at you. Undo the bolt from the top down. It is easily accessible with a ratchet or box end wrench. Once the single bolt is out the whole canister assembly will easily lift out of there and you can work on it outside of the truck.

    The vent solenoid is suppose to pass air freely with no power applied to it. You should be able to easily blow air in any port while holding the other port closed with your finger and get the air to come out of the solenoid / valve. I used my mouth to easily blow air through it.

    There is a filter mounted on top of the valve under the 2.5" diameter cap. Gently open the approximately 6 clips with a small screwdriver and the cap will come of. You can now see and clean the filter if necessary. Mine was barely dirty but I cleaned every thing anyway. You can also remove the hard plastic tube that goes between the canister and the valve. Remove it on the canister end by pushing out the white retaining clip until it is completely removed. Then pull of the hose. Now you can blow air through the canister or the valve to determine which one is causing the restriction. The valve also can be completely removed front the canister by lifting the little center tab on the mounting piece of metal and sliding it out of it's track.

    Once you determine which one is causing the problem you can try to free it up or you can replace the failing component. I have not found a good part number for the solenoid/valve yet, but the canister is around $250.00. If the canister is your problem, I would go to a junk yard for a used one.

    In my case it was the valve stuck closed. I was able to tap on it and to get it to open up. I then energized the solenoid 15 or 20 times with a battery to exercise it. It is now working again. Since I only did it tonight I have no idea how long this fix will work. If I can find another valve cheap I will replace it.
  • HappsterHappster Posts: 33
    Sorry, here is the clip from the manual:


    The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valveOFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.

    Large Leak Test
    This tests for large leaks and blockages in the evaporative emission (EVAP) system. The control module commands the EVAP vent solenoid valve ON and commands the EVAP purge solenoid valve ON, with the engine running, allowing engine vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. The control module then commands the EVAPpurge solenoid valve OFF, sealing the system, and monitors the vacuum level for decay. If the control module does not detect that the predetermined vacuum level was achieved, or the vacuum decay rate is more than a calibrated level on 2 consecutive tests, DTC P0455 will set.

    Small Leak Test
    The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.

    The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.

    The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in) . The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.

    Canister Vent Restriction Test
    If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.

    Purge Solenoid Valve Leak Test
    If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.

    The powertrain control module (PCM) sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when any of the following occur:

    A malfunction in the evaporative emission (EVAP) system and a large leak test fails
    A malfunction in the EVAP system and a small leak test fails
    The evaporative emission (EVAP) system consists of the following components:

    EVAP Canister
    The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.

    EVAP Purge Solenoid Valve
    The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.

    EVAP Vent Solenoid Valve
    The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.

    Fuel Tank Pressure Sensor
    The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts . A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.

    EVAP Service Port
    The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid valve and the EVAP canister. The service port is identified by a green colored cap.
  • HappsterHappster Posts: 33

    ok you will love this problem,
    seems evap system is faulty, but i saw the gas beening put into my truck,
    and as the pump shut off automatic, i saw a gush of GAS behind the gas filler neck.
    So i took off the rear splash shield, to see the FILLER tube, i cked it all, and could NOT find anything loose, or cracked, missing. So i shall watch the next fill up. with the shield OFF, IT DID GUSH BEHIND THE GAS FILLER DOOR.

    Late to the party, but figured I'd share my experience for those reading the blog these days. '04 Canyon, gas cap light and large leak code. Replaced the cap x 2, no change. I figured the cap wouldn't likely trip a large leak code, so I checked the next usual suspect on these trucks - the vent solenoid on the vapor canister. They are normally open, providing fresh air intake for the vapor canister purges, and close for system pressure checks. I put power to it and it clicked, which usually means they are fine, so I checked the canister and lines for leaks or obstructions. The large line coming from the canister goes to the gas tank and provides the excess vapors for the canister to store and eventually burn. Hard to check this for leaks, beyond smelling for gas vapors. The small line goes to the purge solenoid in the engine compartment (by the starter, left wheel well access I hear), and sends the vapors to the air intake for burning when the PCM sends a purge signal. The purge solenoid is normally closed so I blew into that small line and was unable to...that means the line and the purge solenoid was likely fine (unless it was not opening on command...which I thankfully never had to check). The other lines looked great, no cracks or obvious leaks and I smelled no gas coming from the fuel tank vapor supply line. So I dropped the canister and solenoid for closer inspection. The canister was not obstructed...often they are, but mine was fine. I knew this by blowing into the larger line of the canister while blocking off the vent solenoid line..air came out of the smaller purge line no problem. Then I put power to the vent solenoid while blowing through the intake of the solenoid. I should have been able to blow through it with no power and it should have closed up tight with power. It still clicked, but it was not closing internally...air passed the same whether it was powered up or not. Tough troubleshooting - usually if the solenoid clicks with power they are fine. But on mine, the actuator in the vent solenoid was fine as evidenced by the click, but the internal valve was jammed or otherwise faulty. $121 at Auto Zone and I'm good to go. I also had a problem with gas blowing out of the fill pipe when filling up and I had a P300 multiple misfire code. Hoping this fixes all...I if you don't hear from me again, it did.


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