Purchased my dream truck 03 duramax extended cab shortbed. Was told truck had injector problems by owner. Wanting a project i could learn from i purchased it. Checked balanced rates on all cyls. Showed a few a bit off. Will post pics. Truck smokes a bit at idle. Then gets really bad at acceleration. Was told to check rates, compression and other things. My scanner showed cyl 6 having +-5.6 other no more than 3.01. Compression was average 340 on drivers all 8. Did the hard upper rad hose in am test and had no pressure. Also truck doesnt spit coolant nor does it consume coolant. Trucks oil did smell a tiny bit like diesel but not major. Removed driver side injectors found cyl 6 body seal pinched from previous install. Also found most of needle seats worn to a point where your finger nail gets stuck at seat area. Tested injector solenoids and tested all within 0.05 ohms. Could the worn seat in needle cause excess fuel. For knowledge purpouses could just replacing nozzles fix problem. I have ultrasonically cleaned injectors and do not have debri in them. Also i know that its easier to replace injectors but want to know if anyones done the nozzles only and fixed issue
03 duramax lb7 smoming at idle. Looking for answers
- Thread starter Dirtydmax86
- Start date
Most everyone just does a whole new set with the labor involved. Also I'd look at LDS SAC injectors
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What color is the smoke?
Causes of excessive fuel
Cylinder contribution test is high, meaning as each injector is activated one will increase engine rpm more than normal
Excessive exhaust gas temperature
Engine damage from excessive heat or hydraulic lock from excessive fuel in the cylinder
Reasoning
Worn ball seat in injector or poor end of injection cut off
Nozzle needle seat worn or damaged
Debris in control system of injector, which holds it open
Debris in nozzle needle seat holding it open
Cracked nozzle from overpressure.
I would just replace them all and save you the time building every injector can take some time and must be done properly. lb7 had a problem with injector failure
Causes of excessive fuel
Cylinder contribution test is high, meaning as each injector is activated one will increase engine rpm more than normal
Excessive exhaust gas temperature
Engine damage from excessive heat or hydraulic lock from excessive fuel in the cylinder
Reasoning
Worn ball seat in injector or poor end of injection cut off
Nozzle needle seat worn or damaged
Debris in control system of injector, which holds it open
Debris in nozzle needle seat holding it open
Cracked nozzle from overpressure.
I would just replace them all and save you the time building every injector can take some time and must be done properly. lb7 had a problem with injector failure
I don't mind taking them out 2 or 3 times I'm into learning what difference would it make between buying rebuilt set vs rebuilding it myself. So the needle seat would cause excess fuel on cyl. And make it smoke allot right. My main thing owning a duramax would be knowledge even if I deal with trial and error so any info is very appreciated
Gotcha will start looking at new injectors. Would I need to replace the high pressure lines even though they were ultra sonically cleaned
If your high pressure lines are clean of any build up and debris I'd say you're safe to use them again. I don't know much about ultrasonic cleaning procedures. And I agree with previous suggestion of the sac type nozzles. And with a new set of injectors going in I'd invest in a lift pump as well.
I tore down injectors and out them in a ultrasonic cleaner machine. Cleaned em with diesel kleen cleaner and machine provides high temp vibration cleaning. Leaves em like new. My whole dilema is weather replacing the nozles only or whole injens. Mine were very clean at pressure lines.
Yea it was obvious white smoke it would increase more as i manually upped the fuel pressure
I would recommend sticking with a set of OEM Bosch injectors. Unfortunately you can't rebuild these injectors like the original manufacturer. We can help you with all your fuel injection needs here at Lincoln Diesel Specialties. Let me know if you have any questions or concerns.
http://lincolndieselspecialties.com...004-lb7-vin-code-1-fuel-system-injectors.html
http://lincolndieselspecialties.com...004-lb7-vin-code-1-fuel-system-injectors.html
Thanks guys. I will have to think on this one. If my compression is a bit low might be looking at a new motor. Ill keep you guys posted thanks for info
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Really. Yea they were all within that range. Maybe im might need a new motor. Has 273k miles now
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I'd stick with stockers unless you plan on tuning. Aeromotive is a good pump, similar to PPE's. But anyways do a fuel return test. You might only need to replace the one. But its always a better Idea to hit up brent for all eight. Its a bitch to tear the motor apart to replace one and a few months later do it all again for another one.
Very true. I find it fun though. I figured this trucks my first project better tear this one down than my next one haha. But very well i appreciate info i didnt really do a return test. Should have done it though
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Nozzles are but one area. Bodies don't wear out, the ball seat and solenoid ball is what wears out on high milage units. Only a bosch dealer with the required calibration equipment can purchase the required parts to rebuild them completely. Many have bought the diy nozzle kits, and almost all of them end up smoking afterwards.
As to smoke colir, injectors CAN smoke blue. I have actually yet to have an lb7 come to me white smoking needing injectors. I've had one grey smoking, but the majority have been blue smoke. Just did mine for blue smoke. Doing the GM cleaner cleared up most of the blue smoke, but it would randomnly blow out a plume of blue after flushing. Remember, diesel is fuel OIL, and burns by compression same as oil will. Dribbling nozzles can easily cause blue smoke from fuel entering before cylinder heat is high enough, but not enough fuel entering to put the fire out(thats what causes white smoke).
As to smoke colir, injectors CAN smoke blue. I have actually yet to have an lb7 come to me white smoking needing injectors. I've had one grey smoking, but the majority have been blue smoke. Just did mine for blue smoke. Doing the GM cleaner cleared up most of the blue smoke, but it would randomnly blow out a plume of blue after flushing. Remember, diesel is fuel OIL, and burns by compression same as oil will. Dribbling nozzles can easily cause blue smoke from fuel entering before cylinder heat is high enough, but not enough fuel entering to put the fire out(thats what causes white smoke).