I’m a new member and this is my first post. I’m hoping you guys can help me diagnose a starting problem. Background… The truck is a 2006 5.9, w/ 57K miles, all stock except cool blue hose and TAG, all synthetic oils, engine is Amsoil 15x40. Fuel filter was changes less then 1K miles ago. I keep the truck maintained to the max and always exceed every specified service interval. I always add Power Service fuel mix (white bottle in winter, gray in summer). With cold starts in mind; in warm months it always cranks about normal duration (3 or 4 seconds) and starts. But strangely in winter months (when the grid heaters cycle before a first start), it has always started with less cranking. Now here’s my problem; last weekend it was cold (by Ca. standards) 21F and snowing, but the truck is kept in my garage. It hadn’t been started for two days. I had the garage door open for several hours as I was snow-blowing so I’m assuming the engine block was maybe close to 25F. When I went to start the truck I let the grid heaters cycle on, then turned the key and it would only turn-over “once” stopping as it was trying to fire (but it wouldn’t continue cranking). I turned the key off, cycled the heaters again, and same thing three times in a row. Each time the engine wanted to fire immediately with no cranking, but it couldn’t keep running. Important here is it would not continue cranking over. Finally on about the fourth try it fired and kept running at a below normal low idle. Then I moved it out of the garage and let it idle; after a couple minutes the high idle came on, and it was fine after warming up. What’s going on? Why wouldn’t it keep cranking over? Why does it want to fire immediately with no cranking? Are one or both batteries going? Is there a fuel problem? I buy my diesel at Safeway and did check to be sure there was no Bio-mix. Any help is appreciated

 

Did it crank over slowly? are battery connection clean and tight? Have the battery's tested at any dealership or auto repair center usually at no charge. If you have access to scanner check all the sensors before starting to see if they all read the same. Bump the starter and listen at fuel tank fill is pump running?

 

BigIron - I’ll answer in order; the weird thing was there was no cranking to be heard. The second I turned the key it immediately wanted to fire, and because of that the engine would disengage from the starter. Battery connections are clean. I’ll have the dealer do a battery test – good idea. Don’t have a scanner. I will try listening to see if I can hear the pump ticking. Thanks for the feedback and help.