96 C2500 dies after 10 minutes then never starts..

Discussion in 'Engine Performance + Maintenance' started by Shane Dyer, Jan 13, 2020.

Car Parts
  1. Shane Dyer

    Shane Dyer Newbie

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    Hey all! I am actually posting this for my neighbor. He has a 96 C2500 ECLB with the 350. He bought it cheap with a blown motor, put another one in it, got it running. Well a couple of times it would randomly cut off, then start right back up. Now, it only runs for about 10 minutes after letting it sit overnight. Runs perfect during that 10 or so minutes, then dies. When turning the key on, there is no fuel going to the rail, also checked spark at the coil and got nothing while cranking. He has replaced the crank position sensor, the camshaft position sensor, known good ignition module and coil. All fuses are good, wires appear to be in good shape.

    The other day we were flat towing it, he was pulling and I was steering, in neutral, with the key on, wasn't getting anything on the speedo. Also, when cranking the RPM's don't rise. Alot of people have stated on his posts on FB that its the crankshaft position sensor. How is that the case when we swapped with an old one at first, then swapped in a new one. Checked wire integrity, and there are no cuts anywhere.

    I find it odd that you have to let the truck sit overnight before it will start again. Anyone else experience this problem, or have an idea? Could the ECU be faulty? It appears previous owner had changed the ECU at one point (No P/N stickers or anything of that nature)

    We will take any advice you guys may have because we are not trying to throw the complete parts catalog at it.

    Thanks!
     
  2. texas tough

    texas tough OBS Enthusiast

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    should be OBD2 system, has he hooked a code reader to it?
     
  3. Shane Dyer

    Shane Dyer Newbie

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    So I am willing to bet that his ECU is having issues. Connected a scanner, no data available. OBD port has 12 volts coming through the power pin. (Bottom right hand pin)
     

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