Start of Injector Trouble?

[dually2002]

I have been noticing for the past month or so increasing compression knock,diesel chatter or what ever its called on my 02. Its the worst at idle and when the engine is hot. It appears to be only in one cylinder. The engine has the original injectors and just 85k with a JK tune. I got the truck in 03 with 25k and have used fuel additive,cetane booster and Donaldson fuel filters since. The engine runs great with no problems with hot starts. Is it correct to assume that increase in engine knock could be caused by bad injector(s) metering to much fuel or am I making issue out of nothing?

[Mark Rinker]

I wouldn't continue to run with a noticeable diesel knock. It only takes one cylinder with one melted piston crown to take down the other seven...

[dually2002]

Describes my truck 2002 GMC Truck C 3500 Truck 2WD V8-6.6L DSL Turbo VIN 1


Vehicle » Technical Service Bulletins » All Technical Service Bulletins » Diesel Engine - Information on Ticking Noise Notes



Diesel Engine - Information on Ticking Noise


INFORMATION

Bulletin No.: 02-06-01-022J

Date: April 24, 2009

Subject: Information on Engine Ticking Noise

Models:
2001-2007 Chevrolet Silverado (Classic)
2003-2009 Chevrolet Kodiak C4500/C5500 Series
2006-2009 Chevrolet Express
2007-2009 Chevrolet Silverado
2001-2007 GMC Sierra (Classic)
2003-2009 GMC TopKick C4500/C5500 Series
2006-2009 GMC Savana
2007-2009 GMC Sierra
with Duramax(TM) Diesel Engine RPOs LBZ, LB7, LLY, LMM
Please Refer to GMVIS

Supercede:This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 02-06-01-022I (Section 06 - Engine/Propulsion System).

Some of the above vehicles may exhibit a random ticking noise that is most audible on an engine with a coolant temperature of 70°C (158°F) or higher and from idle to approximately 1500 RPM. The noise usually is most noticeable at the rear of the driver's side front wheel well. Customers may also comment about hearing a tick noise inside the vehicle at idle such as when sitting at a drive through window. All 6600 Duramax(TM) diesel engines have this condition; however, some are more audible than others. Engine build variation from engine to engine contributes to differences in perceived volume. All Duramax(TM) engines are manufactured to very close tolerances to meet the durability and reliability standards.

This noise is caused by the relationship of the engine cylinder block, crankshaft journals, bearing inserts and the oil film. This relationship may allow a vibration that resonates through the cylinder block and is heard as a metallic ticking noise. The noise could be described as an irregular ticking or clacking sound, like random typing on a mechanical typewriter.

This condition has been present in diesel engines produced for the last 20 or more years. The overall noise reduction in engines produced today makes this noise seem new when, in fact, it was masked by other noises in the past. Many manufacturers such as Isuzu, Hino, Mitsubishi, and Nissan report a similar condition in their diesel engines. Testing and engine teardowns with this condition reveal no condition that would affect reliability or durability of this engine.

Dealers should not attempt to compare any customer vehicles exhibiting this noise with other similar vehicles as the noise is different from vehicle to vehicle and this may lead to the incorrect conclusion that the vehicle has a condition. This noise is a normal operating characteristic of the engine. This noise has no short or long term effects on the engine. Do not attempt repairs for this noise.

Important
Replacing the engine or internal components for this noise will not reduce or eliminate the noise.

Please share the information found in this bulletin with customers who inquire about this condition. In the event they have additional questions or concerns, please advise them to contact Customer Assistance for further information.




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[DmaxMaverick]

The ticking noise is not the same, or even remotely close, to an injector/fuel knock. The tick is no more than the sound of lightly tapping a pencil lead on a desk, compared to using a hammer for a fuel knock. If it knocks (sounds like a rod/valve noise on a gasser) continuously under certain situations, in time with engine RPM, it's a knock. If it "ticks" randomly, and sometimes not, and very lightly, it may be the "tick". The "tick" is notably more profound immediately following an oil change, and diminishes over time afterward. The tick is a non-issue, as it has never been connected with any failure. It's just an annoying noise.