GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Page 1 of 2 12 Last Post byLast Post by
Results 1 to 10 of 17
  1. #1
    Master Mechanic
    KyleZ71's Avatar
    Join Date
    Jun 2010
    Location
    York and Wilkes Barre, PA
    Posts
    868

    Default Won't Start after Changing wires HELP

    I put on a set of pro form valve covers today, and since the coils get moved away, I had to get longer wires (MSD) for they are mounted on top. After getting everything mounted and plugged in, the truck will not fire. It turns over but simply will not fire. To me it seems like the wires are too taught, and that could be preventing the spark. I also thought that the coil packs are out of order but I thought the packs themselves don't have a order. What do you guys think?
    Objects in mirror are losing

    2003 Chevy Silverado Z71, 5.3L, K&N 57 series, 2.5'' Flowmaster Super 10 series dual exhaust , Corvette Servo, McNew Automotive Dyno tune, SS gauge cluster, Extang Trifecta Tonneau, Pacesetter shorty headers, Goodmark cowl hood, Sony Xplod speakers, Kenwood DDX-470 exhaust tips, 16" Ultra Badlands polished wheels, Pirelli Scorpion ATR .

  2. #2

    Default

    wires too taught would not cause the issue, unless the ends are not making proper contact. coil packs can not be out of order. I would look for a disconnected harness somewhere, like the harness for the coils

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. Likes KyleZ71 liked this post
  4. #3
    Master Mechanic
    KyleZ71's Avatar
    Join Date
    Jun 2010
    Location
    York and Wilkes Barre, PA
    Posts
    868

    Default

    I know the harnesses are connected but not the ends... now I'm gonna plug a wire in to each wire and see if they spark

  5. #4

    Default

    if the connectors are not getting down into the coil holes then you will not have spark. Well, you might have spark, it just will not travel thru your wires. Most the time you hear a significant click noise when you push the wires into the coil. You might melt a standard wire if you plug it into the plug wire. I do not suggest doing that. I would pull a spark plug out, plug it into a wire and set it against the engine block and crank it to check for spark.

  6. #5
    Master Mechanic
    KyleZ71's Avatar
    Join Date
    Jun 2010
    Location
    York and Wilkes Barre, PA
    Posts
    868

    Default

    Quote Originally Posted by Pikey View Post
    if the connectors are not getting down into the coil holes then you will not have spark. Well, you might have spark, it just will not travel thru your wires. Most the time you hear a significant click noise when you push the wires into the coil. You might melt a standard wire if you plug it into the plug wire. I do not suggest doing that. I would pull a spark plug out, plug it into a wire and set it against the engine block and crank it to check for spark.
    Got spark, got fuel (can smell) but still no start. Everything is hooked up, and grounded.

    - - - Updated - - -

    Guess ill bite the bullet, again, and take it to the garage.

  7. #6

    Default

    You relocated the coils, are they properly grounded where their mounted at?

  8. #7
    Master Mechanic
    KyleZ71's Avatar
    Join Date
    Jun 2010
    Location
    York and Wilkes Barre, PA
    Posts
    868

    Default

    Yes, I have one bolt fastening them to the bracket that sits on the top side of the valve cover. Didn't think this would be so frustrating

  9. #8
    Master Mechanic
    KyleZ71's Avatar
    Join Date
    Jun 2010
    Location
    York and Wilkes Barre, PA
    Posts
    868

    Default

    Ok it has been one week since the truck was picked up and taken to a local repair shop. The mechanic said that the wires were not long enough and the accel wires were not the correct ones. SO after ordering a custom set of MSD LS wires, the mechanic said the truck STILL will not start. He said when hooking it up to his computer it reads misfire but won't say where. He said it could be too much fuel in the engine, bad coils, or bad ECM. So frustrated right now because I do not want to try to lets replace and see what works game. Do you guys think it would better to get it towed to the GM dealer as they're computers are better and mechanics are better trained?? Please help

  10. #9

    Default

    I still think that for it not to start something has to be disconnected. Maybe a knock sensor. If you don't feel comfortable with the place it is at then by all means take it somewhere else. If it ran before you did the valve covers then I highly doubt that the ECM happened to go bad at the exact same time. I also don't think that all your coils went bad at the same time. did the coils have more than one bolt holding them down before you changed the covers? Are the covers painted? I am leaning toward your coils not being grounded well. You could always take 8 pieces of wire with alligator clips on the ends, clip them to the coils and then clip the other end to a good ground point. If it works then you found your issue.

  11. #10
    Master Mechanic
    KyleZ71's Avatar
    Join Date
    Jun 2010
    Location
    York and Wilkes Barre, PA
    Posts
    868

    Default

    Thanks for the response Pikey. I know for a fact the knock sensor were hooked up because that was my project only days before. The packs did have two bolts holding them on but the remount kit would only allow me to use one bolt. Maybe that's the problem. When changing the valve covers and gasket I read that it is not uncommon for oil to get on the plugs themselves. I did not pull the plugs, only putting a spare on each wire itself to ensure a spark. Hoping just oilly plugs. I too agree that all 8 packs shouldnt go bad at once and the same with the computer.

Page 1 of 2 12 Last Post byLast Post by

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •