I've tried to tackle my cold start smoke issue for years on and off and this fall I've had a few times where I've started the engine and then it will die then after a long cranking series will start up and be fine all day. The truck does a fair amount of sitting and goes days without running. This has prompted a bit of research. I know glow plugs, batteries, GPR and UVC harnesses are all good. Truck will always start but will smoke heavy light grey/white smoke unless I drive off or at least put it in gear with brake on and let temperatures climb. Doesn't smoke any other time.
With all that said I've suspected the IPR for sometime. I've measured IPR duty cycle at 23% at idle which is quite a bit higher than what others report with a good IPR of 13-15% at idle. So here's my theory. At first startup pressure in IPR isn't building properly (probably leaking IPR o-rings) and PCM/ICP adjust pressure by raising IPR duty cycle. At the injector level more fuel is being injected or pressure isn't producing a good clean spray therefore it's over fueling and combustion temps are not high enough to burn fuel leading to increase in smoke. (I know everyone says that these smoke at startup but mine is excessive. It would fill the garage if it was started in a garage.
I've found a number of posts on different forums that indicate mileage increases are seen with repairing o-rings or replacing IPR. My mileage has declined proportionally to the increase in smoke.
Additionally the smoke is not natural diesel smoke smell but the eye burning rancid smell for lack of better description. Thoughts before I go replacing o-rings or IPR?
With all that said I've suspected the IPR for sometime. I've measured IPR duty cycle at 23% at idle which is quite a bit higher than what others report with a good IPR of 13-15% at idle. So here's my theory. At first startup pressure in IPR isn't building properly (probably leaking IPR o-rings) and PCM/ICP adjust pressure by raising IPR duty cycle. At the injector level more fuel is being injected or pressure isn't producing a good clean spray therefore it's over fueling and combustion temps are not high enough to burn fuel leading to increase in smoke. (I know everyone says that these smoke at startup but mine is excessive. It would fill the garage if it was started in a garage.
I've found a number of posts on different forums that indicate mileage increases are seen with repairing o-rings or replacing IPR. My mileage has declined proportionally to the increase in smoke.
Additionally the smoke is not natural diesel smoke smell but the eye burning rancid smell for lack of better description. Thoughts before I go replacing o-rings or IPR?
