Engine Wont Fire

[rodnocr]

I have a 2000 GMC Z71 with a 5.3 motor after backing up to a boat trailer to check trailer lights i didnt think to drop hitch onto ball i connected lights and turned them on now my truck wont crank it spins and fires for just a second then dies ive check all the fuses and they are good any help? thanks

[Alljackedup408]

is the security light flashing or on?

[rodnocr]

no lights flashing just charging light comes on like it always has thanks

[Alljackedup408]

check your battery voltage with a fluke meter or any multimeter... when batteries get low... the vehicles modules do funny things... i dont know how well the engine cranks over because i cant hear it but... its an easy check. and if it is bad... low on voltage.. id replace it.. then start it.. and if it runs.. check to see how much voltage the alternator is putting out. A good battery should hold 12.6 or so volts by itself.. and one being charged by an alternator will be around 14.5 or so...

[rodnocr]

UPDATE! i run the 30 min. re-learn procedure and it worked fired right up only problem now is after it cranks and runs a few minutes the security light comes on! thanks for the help

[Nick The Great]

UPDATE! i run the 30 min. re-learn procedure and it worked fired right up only problem now is after it cranks and runs a few minutes the security light comes on! thanks for the help

 

Does it start repeatedly or just the one time?

 

My truck was doing similar things and it was the battery.

[rodnocr]

yes fires every time you hit the key now just security light on

[Nick The Great]

I'm not sure then. I don't know how the security re-learn works on older trucks. My truck just wouldn't start until I did the relearn. No crank, nothing.

 

But if the truck runs, and the light is on, I have no idea.

 

Sorry.