2003 6.0 no start, no codes.

Forklift Tech · October 6, 2020

2003 Chevy WT 2500HD 6.0...

No issues with this truck until now. 205,000 miles...

I was driving and the "BATTERY NOT CHARGING" message popped up. Voltage gauge began dropping. I stopped at a local parts store and swapped in a new alternator. Started the truck and no problems. Battery was charging, I was happy.

I got about 10 minutes up the road and the engine stalled. I threw it in neutral and cranked and nothing so I coasted to the side of the road. Threw the OBDII code reader on it and no codes were stored. Never could get it to start, towed it home. I fully believe that the alternator and this issue are two separate things but maybe I am wrong? I did unhook the alternator from the system and try to start the engine thinking it may have been back feeding and causing gremlins in the electrical system.

I do not have a scan tool but may be able to get ahold of one.

Once the truck was home, I found I was able to start the engine but it would immediately shut the engine down after a couple of seconds.

I thought maybe the PASSKEY system might be failing, but when I insert and turn on the key, the light goes out within a couple of seconds, so this is telling me that the system is ok. ??

I connected a fuel gauge and the pump primes to about 55-60 PSI. After cranking, it holds steady at 45 PSI without dropping. Turn the key on and it pressurizes back up to 55-60 PSI.

I unplugged the vacuum hose from FPR to see if fuel was getting through the diaphragm, and it was fine.

I assume that the PCM may be killing the ignition system so I haven't actually checked spark. The truck was starting and would run great for a few seconds.

On a whim, I went and picked up new crank and cam sensors to throw at it. I've seen these cause problems many times over the years so I figured I'd give it a shot. II started with the crank sensor and finally removed the bastard after a couple hours of hollering and screaming... I broke it and had to use the screw removal method... but, none the less I got it changed. Tried to start the truck and it just cranks. So I suppose I need to learn the damn thing.

I have not pulled the cam sensor yet. I attempted to, but it seems to want to stay in there. I can twist it and wiggle it, just can't raise it. I gave up until tomorrow as I was getting angry again.

Anyone have any ideas?

The worst part... I was on my way to meet the buyer. I had it sold...

davester · October 6, 2020

Maybe charge the battery overnight and see if that makes a difference? Take off the power connection to the truck then charge the battery, and in the morning reconnect the battery, take off the charger and try starting it up. And if it doesn't start/run at that point, check the battery voltage (should be about 12.6V).

Forklift Tech · October 7, 2020

19 hours ago, davester said:

Maybe charge the battery overnight and see if that makes a difference? Take off the power connection to the truck then charge the battery, and in the morning reconnect the battery, take off the charger and try starting it up. And if it doesn't start/run at that point, check the battery voltage (should be about 12.6V).

Thanks for the response Davester. I did fail to mention that I had good battery voltage and the engine cranked normally.

I did get back at it today. I decided to crank the engine long enough to see if a DTC would set. And it did. P0335 & P0336 both signal errors for the crank sensor. I ripped the starter back off and found that I hadn't fully seated the sensor. I lubed the ****** out of it and it went in really hard. Aftermarket crap... I decided to remove it and inspect the stator. The damn sensor pulled apart on me so I had to dig the rest out of the damn hole... I went and bought an OEM sensor and installed. Threw the starter back in and all the truck did was crank. So again, I checked for codes. Nothing... I allowed the engine to crank again for some time to try to set a code and it wouldn't.

I got out my spark tester and had no spark. I pulled up AllData and checked the PCM to ignition coil setup. I found I had lost chassis ground to the ignition coils. Tomorrow I will find the ground location and check it out. I find it odd that it was starting then shutting down, although I suppose maybe the ground was in the process of breaking. I will find out tomorrow.

SO, at the end of the day, my idiotic jump-to-conclusions self shouldn't have guessed at the crank sensor. I should have gotten my meter out in the first place... I know better, I guess I was being lazy