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cummins1984

5.9L with 6.7L injectors idling

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heres a link to a short video of a 2005 5.9L Cummins idling with 6.7L injectors installed.  Sorry the video is sideways.  Filmed and uploaded on the phone and couldn’t figure how to rotate the video for upload. 

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What I noticed with the 6.7 injectors and stock tuning is as it starts to adjust for coolant temperature warming up it starts blowing more smoke out the exhaust

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Heres a quick vid on how the 5.9 reacts at startup with 6.7 injectors and stock 5.9 tuning.

 

Puffs out a lot of smoke at start up, clears away then it starts to come back after a minute or so when sitting at 750rpm.  As corrections for the warming up coolant temperature it begins to idle rough at that rpm.  Begins to sound like the timing is too high and probably too much fuel for that rpm as well.  Give it a little throttle up to 900 rpm and it clears right up, and sounds fine minus I haven’t put the intake horn back on yet lol. 

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heres a video of the truck running clean at idle and with a couple quick stomps of the throttle.  Turns out #5 injector and connector tube wasn’t seated quite right.  

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Here's a datalog screenshot of a startup and idle plus the full datalog.  It starts up pretty clean and smooth when coolant temps and ambient air temps are low but if either one is up its more smokey and rough on start up.  This is with coolant temps at about 160* and ambient air temp around 57*.  You can see at the marker the couple spikes in rail pressure where it catches.  This startup wasn't as rough as it can be.  Idle is very smooth and clean though.

5.9L with 6.7L Inj Startup.jpg

DL00011.dlg

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A datalog of a test drive.  Very very minimal smoke but a dog under full throttle.  Hitting Altitude Derate and it just starts pulling fuel.

DL00010.dlg

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Here's the tune sample.  Not much done to it.  Idle set at 800rpm, zero'd post quantity, modified main and pilot duration, lowered main timing a bit and modified main and pilot cranking timing.

sample.sty

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Got a nice smooth startup now, chatter at startup gone and not even a wisp of smoke!   I’ll post up some before and after data logs later and a sample of where the tune is currently sitting at. 

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Here's a latest tune sample with a warm startup datalog and a test run on the current log.  Will be able to see in the current warm start up datalog the actual rail pressure is a smoother transition down as it settles once the engine catches in comparison to the screenshot of a previous warm start up up above.  Rail pressure when driving follows the desired rail pressure like a dream.  Only about a +/- 300psi difference!  Previous shutdowns with the fuel rail plug I would get 180mPa spikes, have it reduced to about 150mPa!

 

Rail pressure during cranking doesn't seem to be controllable, so cranking timing needs to be played to find a happy spot where it's not too little and not too much during cranking for when it gets its spike to +9000psi when the engine starts to catch.

85G761083_008_sample.sty

Current_Tune_Test_Run.dlg

Current Warm Start Up.dlg

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