2003 Duramax Starting hard
#1
#2
did he check the connector bars on the glowplugs, they go out often on the duramax. the fuel filter housing also develops leaks that a set of o-rings usually fixes which causes it to get air into the system unless the filter head is cracked. those are the usual causes. i noticed too when mine had questionable batteries in it it would crank ok but had a harder time starting, once i put new batteries in no problems.
#3
#4
There are many things that can cause hard starts on these trucks.
Air entering the fuel filter housing from the bleed screw, improper fuel (low specific gravity, etc.) or any number of problems with glow plugs or compression (but those are usually accompanied by unburned fuel smoke and are more prone to occur in the late Fall, Winter, or early Spring).
The most expensive COMMON problem is high return rates on the injectors. If the high pressure pump can't develop >4500 PSI during cranking, the truck will crank and crank and crank until either the pressure is made or the batteries die. The slower the engine turns, the lower the pressure.
Air entering the fuel filter housing from the bleed screw, improper fuel (low specific gravity, etc.) or any number of problems with glow plugs or compression (but those are usually accompanied by unburned fuel smoke and are more prone to occur in the late Fall, Winter, or early Spring).
The most expensive COMMON problem is high return rates on the injectors. If the high pressure pump can't develop >4500 PSI during cranking, the truck will crank and crank and crank until either the pressure is made or the batteries die. The slower the engine turns, the lower the pressure.
Last edited by PHPDiesel; 07-31-2011 at 06:57 PM.
#5
I had a similar problem. When cold it seemed to take longer and longer to start. Once hot it would be crazy long. Turned out to be a faulty FPR (fuel pressure regulator). Like a 200 dollar part. I used a OTC Genisis computer to read the rail pressure. I figured it was either pump or regulator so I went with the cheapest option and it worked. Before spending the cash do the simple stuff first. Look for fuel leaks when you pressurize the fuel tank. My brother's d-max had a fuel line leak between the filter head and pump.
Good luck
---AutoMerged DoublePost---
Oh yeah, don't go crazy pressurizing the tank. We only used 5 psi and a gas cap with a valvestem in it.
Good luck
---AutoMerged DoublePost---
Oh yeah, don't go crazy pressurizing the tank. We only used 5 psi and a gas cap with a valvestem in it.
Last edited by MrHorsepower; 08-08-2011 at 10:06 PM. Reason: Automerged Doublepost
#6
I had a similar problem. When cold it seemed to take longer and longer to start. Once hot it would be crazy long. Turned out to be a faulty FPR (fuel pressure regulator). Like a 200 dollar part. I used a OTC Genisis computer to read the rail pressure. I figured it was either pump or regulator so I went with the cheapest option and it worked. Before spending the cash do the simple stuff first. Look for fuel leaks when you pressurize the fuel tank. My brother's d-max had a fuel line leak between the filter head and pump.
Good luck
---AutoMerged DoublePost---
Oh yeah, don't go crazy pressurizing the tank. We only used 5 psi and a gas cap with a valvestem in it.
Good luck
---AutoMerged DoublePost---
Oh yeah, don't go crazy pressurizing the tank. We only used 5 psi and a gas cap with a valvestem in it.
#7
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