Help Smoke
Help Smoke
Posting Guru
Joined: Sep 2002
Posts: 1,897
Likes: 0
From: Northeastern Pa - USA
what year and how many miles on it ? Could be valve guide seals or a cracked ring. Maybe an injector is going south and dumping raw fuel (unsprayed) into a cylinder making it smell rich. This could make it run a little rough at idle or certain rpm range. also an injector will make a ticking noise when it dribbles instead of sprays. When it gets weak, it will allow fuel to leak into the cylinder before proper timing (port closure) and will make that fuel try to ignite at the wrong time. Hope this helps a bit.
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Freshman User
Joined: Nov 2004
Posts: 41
Likes: 0
From: omaha ne
Thanks for info .It`s a 90 f350 4x4 auto 7.3 130,000 miles.has new timing gears,lift pump,g plugs and controler,oil pump,water pump,oil cooler,Trans redone 5,000 ago,rearend 500 miles ago 10.25-4/10,truck runs strong but when in park at about 2100 rpms i get a little miss?no knock or rattles.I tried cracking fuel lines to find dead injector but no luck.Im getting 13 mpg as it is a wrecker towtruck weight is 5 ton unloaded.All my trucks are 7.3s. 1. Blue smoke 2 .Little miss 3.Every since new trans shifts to hard (torky or jurky)only when you have your foot in it.Any more info would help thanks Patriot Towing
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
I do not see work done on the heads in your list, the valves guides have a tendancy to wear prematurely, but yours could be a bad seal. With that said check your CDR valve.......
Do you know when to service your CDR valve?
All 6.9L and 7.3L diesel engines are equipped with a CDR (Crankcase Depression Regulator) valve. Even the new 7.3L Power Stroke is also equipped with the same valve. The CDR valve is one of the leading causes of head gasket failure in these engines. The CDR valve is responsible for controlling the pressure/vacuum in the engine crankcase, and seperating the oil mist from the air and returning the oil to the crankcase. The CDR valve should be serviced every second oil change or when signs listed below are seen.
When the CDR valve is not properly serviced, engine oil enters the air intake and is drawn into the engine. The diesel engine will burn this oil as fuel, however, it is heavier and thicker than diesel fuel and, having greater BTU output, causes excessive heat in the cylinder. Due to the intake manifold design, most of the oil will migrate to #7 and #8 cylinders; the last two cylinders in the rear by the firewall. The increased temperature here will cause the cylinder head to lift off the gasket and allow water or oil to leak out the back of the cylinder head where it meets the block.
To check your CDR valve, remove the air cleaner hold down bolt and inspect it. If the bolt is covered with engine oil mist, it's time to service your CDR valve!
To service the CDR wash with a solvent, allow to dry, do not use compressed air to dry. There is a small hole in the CDR back cover, ensure it is clean and open. If black chunks of rubber are visible in the intake, on the screen then the rubber membrane has disintegrated, replace the CDR.
Do you know when to service your CDR valve?
All 6.9L and 7.3L diesel engines are equipped with a CDR (Crankcase Depression Regulator) valve. Even the new 7.3L Power Stroke is also equipped with the same valve. The CDR valve is one of the leading causes of head gasket failure in these engines. The CDR valve is responsible for controlling the pressure/vacuum in the engine crankcase, and seperating the oil mist from the air and returning the oil to the crankcase. The CDR valve should be serviced every second oil change or when signs listed below are seen.
When the CDR valve is not properly serviced, engine oil enters the air intake and is drawn into the engine. The diesel engine will burn this oil as fuel, however, it is heavier and thicker than diesel fuel and, having greater BTU output, causes excessive heat in the cylinder. Due to the intake manifold design, most of the oil will migrate to #7 and #8 cylinders; the last two cylinders in the rear by the firewall. The increased temperature here will cause the cylinder head to lift off the gasket and allow water or oil to leak out the back of the cylinder head where it meets the block.
To check your CDR valve, remove the air cleaner hold down bolt and inspect it. If the bolt is covered with engine oil mist, it's time to service your CDR valve!
To service the CDR wash with a solvent, allow to dry, do not use compressed air to dry. There is a small hole in the CDR back cover, ensure it is clean and open. If black chunks of rubber are visible in the intake, on the screen then the rubber membrane has disintegrated, replace the CDR.
