No start in morning, will start in afternoon

I have a 2000 GMC Savana Diesel (6.5 Turbo). Nwe glow plugs, new fuel pump, new glow plug relay/controller, truck runs great. In mornings, turn key forward wait to start light does not come on. Motor turns but will not start, no power going to glow plugs. Temperature in the morning is about 65 or 70 degrees. Try to start van again about 1 or 2 in the afternoon, van starts great. Every morning will not start and every afternoon starts fine. Please help.

Well the glow plug circuit is not being activated at this time, this is the no start of course, now the why. I'd suggest getting a comprehensive manual and using the trouble tree diagnostics for this condition. Also a scan using the proper scanner may pick something out.

do you know where i can get a good shop manual ? local auto parts store don't cover diesels.I've had it pluged in to the troubleshooter one code was po380 but i thought it was from unplugging wires in the glow plug system when i was checking for power .could it be the ecm?

You can get a factory manual on E Bay or subscribe to alldata.com.

thanks the search continues

Can you please let me know if you have a solution to the problem?

I have a 2001 GMC Jimmy (not diesel) which has the same problem. No start in the morning, will start in the afternoon. Once started, it will start fine. Overnight the problem comes back again.

I am thinking about replacing the fuel pump but it is quite costly. Since yoiur new fuel pump did not fix the problem, I would certainly be more cautious.

Two things for you to try, though neither worked for me.


switch on the key to on (not start), then turn on the turn signal (left or right needs trial), then switch the key to start. my mechanic said for GMC autos sometimes this fix starting probem.
if you have another key to the truck, try it.