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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29457
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: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year 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 1 year 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 1 year 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 1 year 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 1 year 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 1 year 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 1 year ago.

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

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