I hope someone out there can help. I have a 2003 Duramax 6.6 L 2500 HD that is having problems starting cold and hot. Read forums this morning and tried several things. Checked batteries first, cold. Using a batter load tester they both had 12.5 volts before starting. Running they have 14.5 volts. I cracked the bleeder screw and checked the O-ring. It is fine. No cracks or flattened. Pumped bulb to make sure there was no air, nothing. Tightened screw back. Checked shrader valve and it has plenty of pressure. Bulb was completely full this morning before checking for air leaks. Tight as a rock. Checked WIF sensor, no leakage. I have placed a secondary fuel pump on the rail to assist the CP3 pushing 14 psi. No leakage around secondary pump. When trying to start first thing in morning it takes 20-30 seconds crank time, sometimes longer to start. May take 3-4 attempts. Glow plug light will stay on for only 4-6 seconds, unplugged. When truck is warm and has stopped for an hour or two will have problem starting again. This truck is a dealership vehicle and they are unable to figure out the problem. This truck has never had a flash update for the ECM. The truck throws no codes. Replaced all glow plugs. No smoke ever shows. Once the truck is started and running, it runs perfect. Starting problem only. Any suggestions would be greatly appreciated. Thank you.

I would be looking a the injector return flow rate. Did the dealership perform this test on you truck when it was in?

You have covered some of the basic steps as far as the supply system but the best starting point is to scan the vehicle when it is hard starting. What you want to look for is the rail pressure PID. If you are not reaching 1400 psi the ECM will not fire the injectors. I suspect this is your issue because you do not have any smoke while cranking. Observing this pressure value will tell you if it is in fact a fuel system issue or not.

Thank you for the information. Taking it to dealership tomorrow to have the ECM flashed. Been test driving and noticed another problem. The cluster panel will start reading incorrectly. Driving at 65 mph the speedometer will drop to 30 mph. Increase speed and the speedometer will drop in speed. Also noticed oil gauge fluctuating. RPM seemed to keep pace with what I think the truck should be running. Any info on that deal? Will check rail pressure tomorrow as well. While out test driving pulled into 3 different location parking lots. Shut off truck, sat there for about 15 minutes, tried to start, would not. One time I had to shoot a little ether to it. Cranked over 5 times and would never hit. Crank times at one point reached 45 seconds.

Thanks for all the help.

Thank you for the information. Taking it to dealership tomorrow to have the ECM flashed. Been test driving and noticed another problem. The cluster panel will start reading incorrectly. Driving at 65 mph the speedometer will drop to 30 mph. Increase speed and the speedometer will drop in speed. Also noticed oil gauge fluctuating. RPM seemed to keep pace with what I think the truck should be running. Any info on that deal? Will check rail pressure tomorrow as well. While out test driving pulled into 3 different location parking lots. Shut off truck, sat there for about 15 minutes, tried to start, would not. One time I had to shoot a little ether to it. Cranked over 5 times and would never hit. Crank times at one point reached 45 seconds.

Thanks for all the help.
Hey bud, I hate to be the voice of doom, but I have owned my own shop for 8 years now and 90% of the time I see this trouble its off to the dealership for injectors. I think I have sent 6 trucks total so far and 1 of them 2X's. So long as you are less than 200K miles and/or 7 years. Its covered. BTW, stay away from ANY diesel having an intake heater or glow plugs with that starting fluid!:eek:. You can cause extreme damage to the truck and/or yourself if it ignites outside of the cylinder!!

I took the truck to the dealership to run a complete scan since their mechanic never ran one. It threw 56 codes and it also showed the fuel rail pressure was pushing at most 900 lb. According to their scanning unit it should have been pushing 4980 lbs. Talked to dealership owner and he was not willing to invest the money in it to get it fixed. Lost that one:(. Thank for all your help and advice.

my 03 has the same problem 85000 miles 7 years will be up in may of this year, should i take to the dealer to have it checked, if warranty pays for injectors how much do i end up paying???

my 03 has the same problem 85000 miles 7 years will be up in may of this year, should i take to the dealer to have it checked, if warranty pays for injectors how much do i end up paying???
Hey, I dont know the particular aspects of the warranty policy, but I would take the truck to the dealer for certain if you believe the injectors are in trouble. Check your crank case to see if there is an abnormally high level of oil. I just recentley had a customer go to dealer with a clear injector fault. He has 75000 miles and its an 03 also. No programmer, intake, exh...nada! Bone stock. They denied him the warranty work and charged him $300+ for diagnostics of nothing!! THEY DID ABSOLUTELY NOTHING! I am so pissed this happened b/c they should have just replaced them under warranty. I told him to call GM corporate b/c he is covered. This was yesterday so we shall see.

my 03 has the same problem 85000 miles 7 years will be up in may of this year, should i take to the dealer to have it checked, if warranty pays for injectors how much do i end up paying???


truck failed to start 2 days ago after being shut off for about 1 hour. changed fuel filter, checked glow plug buss bar,checked glow plug relay, checked 175 amp fuse. let it set for 2 days, pumped up filter primer and on second try of cranking it started. dealer cant check it till tuesday but my friend has a scanner and we got code p1094c. any one have any idea what that code means.

truck failed to start 2 days ago after being shut off for about 1 hour. changed fuel filter, checked glow plug buss bar,checked glow plug relay, checked 175 amp fuse. let it set for 2 days, pumped up filter primer and on second try of cranking it started. dealer cant check it till tuesday but my friend has a scanner and we got code p1094c. any one have any idea what that code means.

p1094 is a low rail pressure at idle code probably looking at a bad cp3 or fpr, wouldn't hurt to have the injectors checked though.

I took the truck to the dealership to run a complete scan since their mechanic never ran one. It threw 56 codes and it also showed the fuel rail pressure was pushing at most 900 lb. According to their scanning unit it should have been pushing 4980 lbs. Talked to dealership owner and he was not willing to invest the money in it to get it fixed. Lost that one:(. Thank for all your help and advice.

Did they even run the tests required under the special policy? They don't sound like they know what they are doing. Try another dealer?

sounds like bad injectors to me, excessive return rates.