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
Results 1 to 3 of 3
  1. #1

    Default 00 Denali Misfiring after MFI spider upgrade

    *just noticed I posted in wrong section, excuse my mistake* Whats up fella's I have a 00 Denail 178k on the clock I am the original owner. I have been at battle with the random misfire code (forget exact code and cyl) but its the same code everyone blows after a while. I have replaced the Cap, Coil, Rotor, Plugs, Wires and Fuel Filter and replaced a faulty O2 about 8k miles ago and the truck would still heavily misfire once you got a good load on it, sometimes so bad it would feel like the motor is going to break free from the mounts and drop out the bottom! lol

    So today I replaced the stock spider assembly with the Delphi MFI unit, replaced all the gaskets with a Fel-Pro Kit, reassembled fired the truck up and took it for a test drive and its still doing the same damn thing. I didnt unhook the battery so I did that thinking maybe it needs to reset and it got a little better but still misfires under mid/high load and when going into overdrive.

    With all of that being said, my fuel pump is louder than the 2 external inline Walbro 255hp's I have on my race car.... assuming I should replace the pump next? Does anyone know what the fuel pressure should be on the truck and do I check it running or with just the key on?

    If the pump doesnt fix it I am yanking the motor, swapping in a Cummins and going emissions exempt screw this

    Thanks in advance.
    Last edited by TurboGSR96; 05-29-2011 at 02:12 PM.

  2. #2
    Legend
    murdog94's Avatar
    Join Date
    Feb 2008
    Location
    Cloquet, Minnesota, United States
    Posts
    8,198
    Blog Entries
    12

    Default

    You will want to test the Fuel Pressure.. and it should be in the 60-66PSI with the key on.. and no exceed 75PSI with the motor running. also what other codes are you getting because the Distributors in those trucks are notorious for going bad as well..
    Mike

    Currently

    1997 Chevy S-10 Blazer 4X4 with 330K miles and counting (Hunting rig).

    2009 Saturn Aura XE (wifes car)

    2011 F-150 Crew 4X4

    "Hold it to the floor till you see God.... Then Brake!!!!"

  3. #3

    Default

    I had to run hard to get it to blow the code, P0306 Cyl 6 Misfire... same code its been blowing for a long time. I did check the fuel pressure last year and I know it was under 60psi key on or running, but that was before I replaced the Reg/Spiders. I will check it again this week thx for your reply.

Similar Threads

  1. Fuel Rails and Spider
    By Mr. Sierra in forum Performance & Fuel
    Replies: 5
    Last Post: 05-24-2011, 12:39 PM
  2. Bluetooth Phone Upgrade to a 2008 GMC Sierra Denali
    By UTFan69 in forum Audio, Video & Gadget Tech
    Replies: 1
    Last Post: 02-15-2011, 08:43 PM
  3. Misfiring
    By KyleZ71 in forum General Chevy & GM Tech Questions
    Replies: 13
    Last Post: 11-12-2010, 10:10 AM
  4. Spider test on a 5.7 Vortec?
    By vicar75855 in forum GM Powertrain
    Replies: 5
    Last Post: 08-18-2010, 02:27 PM
  5. Gmc spider gears
    By crrn204 in forum Chevy Silverado Forum (GMC Sierra)
    Replies: 0
    Last Post: 02-17-2010, 09:39 AM

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
  •