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Doug_Scott

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About Doug_Scott

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    Senior Enthusiast
  • Birthday 04/11/1959

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  • Name
    Doug Scott
  • Location
    Ajax, ON
  • Gender
    Male
  • Drives
    2010 GMC SL Ext Cab 4.8

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  1. 1996 C1500 5.7l P0300 code

    This may sound stupid, but you never mentioned it, did you change fuel filter? You may want try unplugging the brake booster vacuum line and plugging it. Take truck for drive to see if the light still comes on. Before driving it on road, try to stop to make yourself aware of how hard it is to stop without vacuum assist. This is best done without traffic around. That will test the booster for vacuum leak. A partially plugged exhaust can create issues as well. When pump was replaced was the inside of the tank checked for crap sitting on the bottom of the tank? You have replaced everything right up to the wiring harness. The first error code is random misfire and that usually means the error is in a global system. Like gross vacuum leak, fuel supply issue, exhaust issue etc. Something that impacts all cylinders. Check all vacuum lines for decay or oil damage. I would think replacing the engine would find those though. Do you have a relative in another state that can buy your truck, then forget to take the truck home with them? After 6 months take a trip to Vegas, spend the night, then have your relative come for a visit again. You know, wash, rinse, repeat.
  2. Wiring Harness Connector Location Map

    Trouble codes for some things are not set right away. Some will wait until x number of faults. Same for being cleared. Some will clear the CEL after x number of restarts with the fault not present. From your description of how the door locks cycle after some jarring kind of bumps sounds like a poor/loose connection. Chances are it will be one made by the installer of the alarm. Without knowing how the installer works, I would first look for the easiest access to the wires he had to connect to. If you still have the install manual it would make it easier for you. For example, if instructions say to connect purple wire to pwr door lock switch signal wire, the easiest place to do that would be in the door. Take a look at the wire bundle that goes from body to the door and see if it appears to have been messed with. By that I mean the ribbed rubber cover. The example I gave is completely made up just to help explain what I meant. Jsdirt is right though, find the controller and follow the wires to remove, or if you have instructions use them to assist in locating any of the connections and follow them back to locate controller. Good luck, I always dreaded trying to repair others accessories installs. Back when I was working at Plymouth/Chrysler dealership I got a warranty electrical problem on a Sapporo that the interior lights would come on as soon as the headlights were turned on and the dash lights were always on bright, they could not be dimmed. I inherited the job from another mechanic who gave up after changing the dash light rheostat. Warranty paid straight time for wiring issues, that mechanic would refuse straight time flat rate, he could make more on customer pay jobs. I spent 4 hours on that car before I finally found the issue was caused by the shop that did the dealerships stereo upgrades and warranty work on sound system issues. These guys figured all green wires are ground wires on Plymouth, so they connected to the first green wire they saw thinking it was a ground. On Sapporos the green wire on the dash lights socket was for interior light and Max bright dash lights. Those 4 hours included morning break and lunch, I figured straight time meant how long the car took up my work stall. Guess they were lucky I got the job at 9am and not 4pm.
  3. 2008 suburban fm radio issue

    The quickest and easiest way to check the antenna is to take a simple fixed length antenna from any vehicle, as long as the connecter is the same as what the radio wants. If you can swap the antenna while the radio is giving crap reception you will instantly know if the antenna is the issue. Is the current antenna extended about 30 inches? FM likes 31 inch antenna if I remember correctly.
  4. TCM calibration update, service fast learn.

    Did a quick search for 8l90 fast learn and got this as second return http://sandyblogs.com/techlink/?p=4478 According to this link the fast learn has been a requirement since the 6 speed was introduced, albeit to a much lesser amount. The 8l90 needs the fast learn done after any repair or update. The tech should know this, and unless your truck was his first hands on repair of either the 6 speed or 8l90 it should have been second nature. The above link gives a basic description of the fast learn. The way I understand it the fast learn is what I thought it was. Chances are your transmission is getting better each mile you drive and by the time you get back to the dealer, having the fast learn performed will be a step backwards. I would still get it done, but would also insist it being done while you wait. Should only take 10 minutes maximum.
  5. TCM calibration update, service fast learn.

    Does your owners manual suggest you do that prior to checking fluid level if transmission is cold? Back when I was doing transmission work(decades ago) the first thing I did was a road test. That will warm up the fluid, and confirm that the issue I am looking for is actually what customer thought it was. I can understand running the truck with parking brake applied idling in gear with drive wheels off ground if road test is not allowed, but would be afraid of something unforeseen happening while doing what they suggest. Having a foot slip can create a good size dent in your toolbox that warranty won't pay for. I think what you are describing fits my thoughts on pre-loading an "enhanced" set of parameters. GM tech line may get a copy of settings from all 8l90 transmissions and create a average initial settings that replicates what you may generate yourself halfway through a complete relearn from basic default settings. If that's the case it would be helpful if service manager knew and told you at the time.
  6. TCM calibration update, service fast learn.

    If the service bulletin had instructions for the tech to follow then it cannot be marked completed until all the steps are performed. I wouldn't have accepted the truck back until they actually completed the job that GM paid them to do. The manager should have had the tech perform the parts of the job that he was paid to perform without you having to make another appointment and take time out of your day to allow them to finish something they should never of let go out incomplete. That being said, I can not believe any trained tech would bring a transmission up to temp by the way you suggest. It does not take long for the transmission to come to operating temperature. Simply idling in gear will bring it up to temp pretty quickly provided ambient temps are over 60F. If this fast learn is nothing more than disconnecting battery for x amount of time then reconnecting battery, having you go through the trouble of making appointment to have it done later would pissed me off to no end. To me the fast learn sounds like it is a preset set of parameters that are closer to final auto-learn calibration than the default settings you get from disconnecting battery. If that is correct, you are likely past that point now with the auto-learn so taking it back in will actually be a step backwards.
  7. I do not know about what vin number can do to the ECM, and would imagine dealers will not reprogram it is fear of being accused of "vin washing". Do you have access to the original engine or original ecm/tcm? Really have to wonder why they did not just change the engine itself and swap sensors over from the 03 engine. I wonder if the transfer case is the original one or if it is the automatic transfer case and if it is the required wiring may not be present. If you can locate an ecm at the wreckers, perhaps you could reprogram the vin into it to see if it changes anything. You would still have the current one in case it screws up the wrecker one. You will have to go through the security relearn sequence though. The speedo difference can't be just a gearing issue. Mathematically the truck would need to have a 2.80 gear. 72 to 55 is a huge jump. You could try contacting Justin at blackbear regarding updating vin and what it may impact. You have your hands full with this one, I would just do one thing at a time. Can you contact the owner that did the work?
  8. Truck was originally a 6.6 Duramax with Allison 5sd, 3.73 rear axle, manual transfer case, 9800 or 9900(cant recall off hand) lb towing, and came with the standard 245-16 tire size. With the vin from the ECM you could ask a dealer to run the vin to see what that 05 came with stock.
  9. What engine did this truck originally come with? Was the entire drivetrain swapped? What gears are in the rear end? You should be able to get all the RPO numbers from glove box door to find out what this trucked started life with. Speedo readings can be altered by transmission, rear axle gears, and/or tire size. To be off as much as it is is not going to be tire size, and if it's gears, it must be programmed for 4.10 gears but has 3.08 gears. You are going to need do a complete survey of what you currently have and what is expected to be there by the ecm/bcm/tcm.
  10. Vibration

    Contact GM customer service. One thing that I see in your post that is just plain wrong, wheel alignment will not cause vibrations. The only thing close to a vibration that can be created by wheel alignment is excessive positive castor, and that may cause a "shimmy". A shimmy caused by castor is a violent shaking of the entire front steering components as both front wheels try to flip around. Think of a shopping cart with the flapping front wheel. This is not happening to your truck.
  11. 2017 sierra denali/ oil leak

    Wouldn't change the oil until you have the dealer look at the leak. Let them handle the oil change under warranty if the pan needs to dropped. The leak could also be the pan gasket at the rear.
  12. Start at the bundle of wires that goes from the body to the tailgate. Also follow the wires from the left rear light to the body of the truck. There is likely a spot where the power wire to that light is being shorted to ground when the gate is opened.
  13. There are some people that for a variety of reasons simply cannot physically get into a car, and cannot come up with the coin for the SUV. If the nice ride bothers you so much, get a HD truck. Or, swap out the P tires for LT tires.
  14. Cooling problems 2000 GMC 2500 5.7

    Very likely an air lock. Usually in the heater core. Sometimes you can simply disconnect one heater hose with the engine running(don't do it on a hot engine) to get the coolant to push the air out. Make sure you have the heater control set to hot. Double check the fan is pulling air through the rad, not pushing. If it's pushing you have the belt routed properly and the water pump is also running backwards. You may want to verify you have the correct pump as well. Not sure why you went with Dex cool, I would have switched to Evans Waterless coolant that does not expand when heated, never needs changing, and does not contain any corrosive properties.
  15. Unplug the pwr window motor, connect one terminal to the ground clip of a test light, and connect the probe to the other terminal. Use the window switch and see if the light comes on. That will validate both power and ground circuits. Move the switch in both directions, light should come on in both positions. If it does not come on, move the clip end of test light to a good ground and check for power on both terminals for each switch position. Do not use a volt meter for this. You are replacing a 12v motor with the test light. A volt meter may show 12v, but, an open circuit with high resistance will not show the effects of the resistance, so it will always show input voltage.
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