My 12.7L/500 HP DD has been good to me for 964000 miles but in this recent cold weather started having problems. It ran like a top until I asked it to go at -8*. It spit and sputtered at 44 mph. I figured the fuel was gelling and added a conditioner. After letting it idle for 15 min to get it into the fuel filters, I started off again. This time I could only get 35 mph. I pulled over and let it idle for 15 more minutes. While idling my speedometer went to 32mph and I got a VSS code. I turned around and headed back to the house. My speedo said 85+ mph, the tattletale (Pro Driver) on the dash said I was idling and I guess that I was moving at 40mph or so. Many phone calls later and $65 later I replaced the Vehicle Speed Sensor in the tail of the tranny. I thought all was fixed but now the truck won't start. It turns over fine but shows no sign of running on it's own. It has warmed up to 20*, was plugged in and still it won't run on it's own. I know, I know it is the ECM (computer) - right?? Somebody tell me if the old codes have to be cleared out in order for it to run. Anybody else ever have a similar problem??
No the old codes dont need to be cleared. What model is it a ddec 2 3 4 ?
It started out a DDEC III but when the ECM was replaced 5000 miles short of warranty expiration I think the put in DDEC IV specs.
Brandt, Check for ECM power, do you have a check engine light with ignition on? If you can crack a fuel line at back of head to make sure you have fuel to that point. I would not rule out fuel at those temps. VSS codes don't cause a no start condition, and 9 out of 10 times it's not the ECM.
Got her going!! It warmed to 35* yesterday and I got the idea that the fuel may have gelled and I sucked a fuel filter dry - causing a loss of prime situation. My primary filter was full but the secondary filter was 50% empty. I changed both filters and filled them up with good fuel. 15 seconds of cranking and a good blast of either and she came to life. A quick test drive allowed me to get to 75 mph with no codes. Now I need to reschedule my trip to Arkansas.
Just got back from AR where I picked up an Austin-Western Super 300 grader. Averaged 6.83 mpg down and back