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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29572
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Have a 2001 duramax which has started smoking which smells

Customer Question

Have a 2001 duramax which has started smoking which smells like unburnt fuel, like a rich mixture. Injectors were replaced around 5 yrs ago with gm injectors, also fuel pressure regulator a year later along with injector pump. 228,000 miles. Seemed to have started after changing fuel sending unit about a year ago , son has been driving so didn't know about it until this past weekend .
Submitted: 2 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 2 years ago.

Hi there, I am Cam. Can I get your first name please?
Can You tell me when your see the smoke the most? When stopped at a light or stop sign and for a short time after taking off from said stop light?

Customer: replied 2 years ago.
James when stopped waiting for stop sign or light and pulling away. Appears heavier as it warms up, also flutters once an a while. Not like when pressure regulator went bad
Expert:  GM Tech (Cam) replied 2 years ago.

James, This is a sign that the injector nozzles are leaking a bit. AT idle the computer tires to smooth the idle out, so the injector timing changes for each cylinder, which is the balancing rate. When they leak, during idle they smoke a light gray white or black smoke. The key with this is at idle. This is typical. The diagnosis for this is to disable the injectors one at a time and watch the amount of smoke that is being produced. Any injectors that you disable that make a difference will need to be replaced. This fault was never covered under the special policy that GM put out.

Customer: replied 2 years ago.
My smoke is more bluish, and smells like raw fuel. Wouldn't leaking injectors cause blackish smoke? Since it would be burnt not raw. Went to school for diesel many moons ago, not like today's computerized systems, so just trying to get around what I remember about leaky injector nozzels and doing pop tests.
Customer: replied 2 years ago.
My original garage has gone out of business, so don't know if I can get warranty on injectors. I do have original work order, and he was a master tech for gm , until dealership closed down
Expert:  GM Tech (Cam) replied 2 years ago.

That's unfortunate. Yes it would be blue/grey/white ish. It would not be pure white, I think it depends on the fuel itself. I would look to getting them replaced again after trying an additive to the fuel.

Expert:  GM Tech (Cam) replied 2 years ago.

And sorry for the delay. I moonlight on the ambulance.