2003 Duramax smokes at red lights

durabroke · March 31, 2014

Engines runs good, but smokes, not black, when I stop at lights. Anybody know the source of problem?

oldscsc · March 31, 2014

Does it smoke white? How many miles does it have in it?

Not the news you want to hear, but being a (presumably) high mileage LB7, you're probably in for eight new injectors.

scooby5121 · March 31, 2014

White smoke.usually indicates antifreeze burning (coolant)

Dirty smoke injectors

KMGZ400 · April 1, 2014

Could be injectors going.. Check out duramaxforum.com... May be more helpful over there

Prokopchuk_9 · April 2, 2014

Ur injector cups are leaking more than likely, get balance rates tested. Try dabbing ur dipstick on some white paper towel, if you get a light brown ring form around the dark brown/black oil spot. Your diesel is making oil aka injector is hung open or injector cup is leaking/cracked and it's collecting diesel in the crankcase. VERY common problem from 01-04.

It's not wise to run it like that, you can melt a piston or worse totally implode a rotating assembly. I would park it and get it fixed before any driving. Hope this helps man.

durabroke · April 5, 2014

140,000 miles. Smoke not all black, but not white.

Now it won't start. Is there a lift pump or not? Someone said the injector pump brings up the fuel??

Prokopchuk_9 · April 5, 2014

140,000 miles. Smoke not all black, but not white.

Now it won't start. Is there a lift pump or not? Someone said the injector pump brings up the fuel??

Well what colour is it? Is it greyish? White?

Did you check to see if it's making oil? Bring it to somebody who can check injector rates!! Don't run it!

And no, no lift pump...injection pump pulls the fuel. Could be a FPR going wacky on you also, could be a couple different things. Check your oil for fuel...FIRST thing I would do.

oldmann · April 5, 2014

Time to replace injectors. Get your $3500 dollar bill out.

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Prokopchuk_9 · April 5, 2014

Time to replace injectors. Get your $3500 dollar bill out.

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You don't know that, chances are high but really you do not know. Do not tell a fella to open his wallet wide like that when you don't even know what the problem is...be nice lol. It could be a little more than 3500 bucks...maybe something as simple as a fuel pressure regulator...nobody knows without proper diagnoses.

oldmann · April 5, 2014

If it hasn't had injectors yet, it is due. Obviously get it analyzed by a dealer before throwing parts at it.

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Prokopchuk_9 · April 5, 2014

If it hasn't had injectors yet, it is due. Obviously get it analyzed by a dealer before throwing parts at it.

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Again, making assumptions. You dknt know if it's "due", I've seen em go 250 I've seen em go 50k...it's the luck of the draw with an lb7. But that's the first place I would be looking, injector balance rates. Or check if fuel is in the oil.

gmtech4 · April 5, 2014

You don't know that, chances are high but really you do not know. Do not tell a fella to open his wallet wide like that when you don't even know what the problem is...be nice lol. It could be a little more than 3500 bucks...maybe something as simple as a fuel pressure regulator...nobody knows without proper diagnoses.

^^^^^^^^^ +1000

durabroke · April 5, 2014

Two guys say no fuel pump. Here is the fuel pump O'Reilly shows. Is this the CP3?

http://www.oreillyauto.com/site/c/detail/PFP0/E16141/02535.oap?year=2003&make=Chevrolet&model=Silverado%2B2500%2BHD&vi=5016973&ck=Search_C0401_5016973_1174&pt=C0401&ppt=C0025

Prokopchuk_9 · April 5, 2014

Two guys say no fuel pump. Here is the fuel pump O'Reilly shows. Is this the CP3?

http://www.oreillyauto.com/site/c/detail/PFP0/E16141/02535.oap?year=2003&make=Chevrolet&model=Silverado+2500+HD&vi=5016973&ck=Search_C0401_5016973_1174&pt=C0401&ppt=C0025

Like a few have said, do not just buy parts get it diagnosed properly. Get it to a dealer and get a proper diagnoses. Do not listen to a keyboard mechanic at a parts store. A Duramax does NOT have a fuel pump, the cp3 (injection pump) pulls the fuel from the tank.

Get it diagnosed by a professional. Make sure to check injector balance rates and your cp3 vitals (actual rail pressure vs desired rail pressure)

If it's a fuel issue a dealer will hone in on the issue pretty quick. Wish I could help! I could tell you within 15 minutes what type of issue you're having also. Do you have the ability to pull any codes?