Truck not starting.

[dscowell]

The other day I went to the gas station and after filling up my truck did not start back up.  It would crank but not fire.  I checked for a spark and got nothing so that should be my problem not the fuel system.  First thought was the CPS since that seems to be the most common problem.  Ended up buying a bad one so I got another one from napa that gave me all the correct readings.  After cranking so much my battery died so I tried charging or having it hooked up to another vehicle when trying to start it. I brought it to the local dealership and they said my battery just wasn't charged.  Got the truck from the dealership and it had a weak start but still started.  Drove it home the next day it didn't start.  The truck isn't even cranking now.

 

Along with replacing the CPS I also replaced the ignition coil, cap and rotor, got a new battery, refreshed all the grounds and the ICU and cleaned my battery cable terminals.  My starter was replaced a year ago along with my negative battery cable and the positive looks to be in decent shape.  

 

When I turn my truck on to accessory it will beep at me for not having my seat belt on and the stereo will light up so I am getting at least some connection.  

 

The only thing I can think of is my ECU took a dump and isn't working now.  I'm not sure where else to look any help would be appreciated.  

[dscowell]

Forgot to mention my truck is a 90 4.0L manual 

[Marine1Texas]

is your alternator working or putting out the right volt and amps?

 

Make sure it is charging the battery of course, I have seen alternator's work well when cold, then after a few when gets hot stop working all together. Make sure you battery is also up to speed and holding a charge not draining as it sits.

 

If the two above are fixed or doing as they should be, your looking at a short some where.

 

The ECU does not control the alternator or starter. however it does turn on Ignition Control Unit, it is below your coil. Ignition Control Unit contacts with the coil, make sure those contacts are clean and not corroded. That can cause low voltage to your spark plugs, looking like no spark.

 

for battery drain I would just to check the starter solenoid, I have seen them fail open and closed also seen then drain a battery dead in less then a day.