No start

[RustyShackleford]

2000 k2500 Vortec 5.7 (not an LS!)

Friends truck hasn’t ran in 3 months. Said truck wouldn’t start. I tested coil. It’s good. Plugs were showing a yellow spark. Inside the dist cap it was a little chalky with some white crusty stuff but it didn’t look too bad. I changed the distributor cap and rotor anyway and the truck started. He drove it off for 3-4 miles. The next morning it’s not starting again. Any ideas?

 

[Schurkey]

1. What is the fuel pressure? Does the pump prime when key is turned on?

2. What is the battery voltage? Does the engine crank at a normal speed?

3. Connect a scan tool, look at the data stream.

 

[Eveready]

Sounds like a fuel issue if you are getting spark. Fuel pressure, fuel filter and most likely the fuel pump especially if he is over the 100,000 mile mark.

 

[skylark]

Does it still have a weak, yellow spark? Is it weak and yellow at the coil wire? Your diagnosis has me suspicious of the coil.

 

[RustyShackleford]

Coil is arc-ing blue
Fuel pump is running
Replaced distributor tonight with a known good one. The one I pulled out fell apart. The black ring at the top where the rotor screws to fell off the shaft. I thought surely that’s it. Well, it still wouldn’t start. It’ll start off ether. I’m going to drive it tomorrow for 10 miles or so to get the ecm to close the loop and see if it throws any codes. It sat for so long that the battery died and killed any existing codes

 

[PlayingWithTBI]

If it starts with ether, like @Schurkey said, check your fuel pressure s/b at least 60 PSI with key on, no start.

 

[RustyShackleford]

48psi fuel pressure
Fuel pump was replaced in May
Going to replace fuel filter and see what happens

 

[PlayingWithTBI]

48psi fuel pressure
Fuel pump was replaced in May
Going to replace fuel filter and see what happens

Yeah, not enough. Could be filter, although doubtful since the engine isn't running. Could be regulator or a cheap fuel pump. Did you buy a Delphi or AC Delco pump?

 

[RustyShackleford]

Changed filter and went up to 50
I thought it was the fuel pump, but I hooked the gauge up to my truck that is the same body style and engine. Mine has 50psi also and it runs/starts fine. So....i don’t know if gauge is calibrated that great.
We have discovered that it won’t start off the battery. When we hook up a 200amp battery charger the truck will start. So...we bought a brand new battery today. The sumb**** still wont start unless a battery charger is on it.
The fuel pressure regulator is inside the upper intake right? What’s the test on that?

 

[Schurkey]

...so fix the high-resistance in the wire harness. Corroded battery cable ends? Corroded battery terminals? Corroded cables--green copper under the insulation? Corroded wire harness connections or splices?

Did you load test the battery? Did you ever bother to measure the open-circuit voltage at the battery?

Did you connect a scan tool and look at the data stream to see what voltage the computer is getting?