'96 Suburban 7.4L, Won't start, scanner won't read codes

Discussion in 'General Chevy & GM Tech Questions' started by EFransen, Dec 11, 2008.

  1. EFransen

    EFransen New Member

    Need some help. My '96 K2500 Suburban died on my wife while driving home. It cranks, but won't start. Checked for secondary spark - none. Checked fuses, all good. Checked coil, checked good. Replaced crankshaft position sensor on a hunch, didn't work. Borrowed a scanner & plugged in and it won't recognize that it is plugged into the truck! Checked scanner on another car, it's working fine. Re-checked fuses, all good. Ideas?
  2. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    Did you check for fuel pressure at the same time?

    The usual reason a scanner won't recognize when it's plugged in is because there is no power from the vehicle to the diagnostic port. On GM's, they routed this power through, I believe, the cigarette lighter fuse, and usually it is determined that the fuse is bad. If you insist that the fuses are all good, then you need to determine if you have power to the diagnostic port, and, if not, find out why.
  3. ct9a

    ct9a Epic Member 5+ Years 1000 Posts

    Yep, sounds like there's a break in the power going to certain points in the truck.

    Welcome to the forum btw!
  4. 04sierracrewcab

    04sierracrewcab Epic Member 5+ Years 1000 Posts


    Welcome to the site!
  5. EFransen

    EFransen New Member

    Thanks for the help! Did find that the fuse to the cigarett lighter was bad, didn't check that one before. Now the scanner reads, no codes though. I didn't check the fuel pressure yet, started trying to track down why there was no secondary spark. Re-checked to be sure, and still no spark. Ideas?
  6. Toymyster

    Toymyster Rockstar 100 Posts

    I'm trying to remember, did 96 still have a distributor? If they do, the ignition module and/ or pickup coil would be my prime suspect. Also, do check your fuel pressure, like shorty mentioned. And check all your fusible links. Other than that, I'd do a pin by pin on the ECM itself!
  7. JMoney02

    JMoney02 Epic Member 5+ Years 500 Posts

    Yes they have a Ign Module, inside the Distributer, sound as if it has quit working.........


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