'01 K2500HD w/6.6 Dmax. 115,000 miles. original injectors.

It seems my Dmax is getting harder to start. Started noticing this in late Dec last year ('07). Engine used to start in 3 seconds or so even if fairly cold outside; if warm (or if engine was plugged in over night), 2-3 seconds cranking before it would start.

Now it appears to take up to 6 seconds of cranking for the engine to start if the engine has sat for several hours (even with the engine plugged in over night or, after the glow plugs have cycled). If the engine has been run for a while and shut off for less than an hour, 3-4 seconds of cranking is needed. I did have a problem late December where the engine appeared to start normally after about 2-3 seconds of cranking (after sitting for ~8 hours @ mid 20s temperature), but quit after running ~15 seconds. Had to crank the engine nearly 30 seconds before the engine was able to be restarted.

No SES indicator appears and the local dealer tech saw no codes set in the ECM. I changed the fuel filter 1st week of Jan '08 with no improvement in starting. Not seeing any signs of leakage from the top side (filter, fuel rail, injector lines, etc). I'm getting my fuel from a local truck stop; it's the new ultra low sulfur fuel.

Any hints? Fuel pump slow to develop pressure? Injectors failing? Would appreciate any help. It's taking at least twice as long to crank/start my engine than it used to. Thanks a bunch.

Chessy56
S. Milw, WI