Warm start problems

[Frank V]

96 K2500 with 100K starts right up when cold. However; once warm and especially on hot days, the beast is reluctant if not impossible to start. What gives?

[DieselDavy]

Frank,
There a several things that could cause you problems. I have seen motors with more miles than yours just need a little glow time even though you think it is warm enough. (low compression, wore out!) The most probable problem is your starter cannot turn fast enough when it is warm/hot. Your diesel needs over 200 rpms to start. This number seems to be in dispute depending upon whom you talk to. I've heard as high as 235 rpms by one shop around here that works on our 6.2/6.5s, but I digress... Once the starter gets a few cycles and a little wear on them, they sometimes can't turn over fast enough when hot. Drop that bad boy down, have a good and trusted rebuild facility go though it and I'll bet you will be fixed up. I've changed starters in my two 6.2s so many times I can't count them without going to the maintenance logs. This warm-up issue has bit me more than once!
Dave

[britannic]

The IP pump can also be a factor in starting, especially if you have no problems from cold (kind of rules out the starter to some extent). I'm not sure if the DS4 can become retarded, but I had similar symptoms when my mechanical pump was leaking and also when the timing was retarded.

[Suburbanator]

I also must agree with Britannic, Shortly after i bought my suburban,I was having hot start problems(glow controller doesnt cycle when engine is warm)so engine would crank but not start.replaced injection pump with a reman pump, and problem solved.

[DieselDavy]

Frank,
Britannic and Suburbanator have good points about the IP but....Make sure your starter is turning fast enough first. This includes cleaning all the battery connections. You can have the best IP in town, but if you're not turning it over fast enough to begin with, she won't go! As MorePower says, check all the simple and inexpensive things first, then move on to the IP.
Dave

[gavio]

I was having a similar problem with mine - it would start OK when cold with glow plugs, but if it was too warm to cycle the glows, it wouldn't start no matter what until it cooled enough to cyle the glows again. A new starter cleared it right up.

YMMV, of course

Good Luck

[TonyL]

i had the same problem and i cleaned and/or replaced all the battery cable connections and had the batterys load tested to double check there codition and i havent had a problem since.