Engine/Transmission (1998.5 - 2002) Start Cycle not happening...

[gmsboss1]

99 24V 2WD Auto 3. 54 rear end, edge comp, 320K miles.



New VP44 about 20K ago, great fuel pressure. Lift pump relocated to frame rail.



Dead Pedal for several months now (APPS?), pump it few times and everything is good again, although happening more frequently.



Now intermittently the truck will do the normal "wait to start" light goes out then motor just turns over... . in the past meant crank position sensor (replaced about 30K ago)... however this time after cranking the lift pump is not running, same thing if you just bump the key... no lift pump... . like the engine isn't getting the command to start???



Let truck sit for 15 minute and it fires right up. Very frustrating.



Need to have some ideas about solution before I head of to my mechanic and he pays for another kids college tuition after fixing my truck.



Thanks,

Don

 

[SSolderitch]

I lost the pump & heaters on pre start cycle, no wait light. I could start it just fine. It was fixed with a ECM reflash after checking all sensors & wiring. Any codes? Try another ecm just to see...

 

[ThrottleJockey]

That happens to mine. Try this.



Unplug the ECM from both batteries for 30 minutes.



Hey, it's free. Works on mine like charm.

 

[ThrottleJockey]

So what happened?

 

[gmsboss1]

Update



Truck is at shop - codes indicate APPS and Crank Position Sensor - although the CPS only showed 2 faults. Both being replaced Monday PM and then we'll see if that takes care of my problems. Companion code also indicated faults for transmission relay, but local wrench said lets start with the APPS and CPS and see if it doesn't clear everything else up.



Peace,

Don<><