OK here the deal, 2 years ago I got for free a 87 F-250 6.9L. the guy who had it didn't have a clue about Diesels. he gave it to me thinking it had a bad engine and bad tranny(C6 auto). I put 6 GP's and new stater and it came back to life. Now it smoked blue and white smoke terrible. This would be My companys 4th one of these motors so I have alot of spare parts. I replaced the ip with a 7.3 ip the guy at the diesel shop told me he had never heared of that swap but the only difference was the 7.3 pump pressurized more fuel at a time. that solved the biggest part of the blue smoke and all the skipping. But it still blows a little blue smoke at idle but it doesn't use that much oil. I changed the injectors to a spare set i had but the same blue smoke and a litlle stumble if you push the accelerator just a little. now is it my SPARE ip or my SPARE injectors. when i get a chance i'm going to get the injectors pressure tested any ideas would help

 

Have you serviced the CDR valve?

They should be removed and washed out with kerosene or gasoline every other oil change to keep gunk from building up and not letting the diaphram move.

Also after rinsing it out let it dry by it's self, compressed air will rupture the diaphram.

 

Thanks for the info Dave , I didn't realize the CDR needed cleaned that often .

 

If you stay on top of the CDR service it is easier.
If you do it every other oil change you just need to let it soak for five minutes and rinse it out. If you do it less often you will have to let it soak for a lot longer to dissolve the buildup and rinse it out several times with a soak cycle between the rinses.

When I do mine I pull the CDR off first and throw it in a can of gasoline.
Then I drain the oil and pull the filter.
While the oil is draining I agitate the CDR a bit with fingers over the holes and rinse it out, shake all the gasoline out and lay it aside to dry.
Replace the filter and drain plug, fill with oil, grease the chassis and drive line, change the fuel filter and air filter, check the fluid levels in the differentials tranny and transfer case and power steering.
The CDR is now dry and ready to reinstall.

The CDR service added less than 10 minutes to the 6000 mile service schedule.
3000 miles it gets a chassis and drive line lube and an oil and oil filter change plus belt inspection.

And they say I abuse my truck.

 

Had not thought of that but how would the cdr cause the smoke and the stumbling.

 

The CDR is sucking oil vapor out of the crankcase.
The vapor condenses and enters the intake manifold as oil and oil vapor.
Burning engine oil produces blue smoke.

The function of the CDR is to regulate the amount of vacuum applied to the crank case.
If it is stuck open then it is always pulling in oil and oil vapor.
When the air filter is a little restricted this can be more than it should be.

You do not mention the number of miles on the engine.
I am sure an 87 would have enough miles on it that rings are getting worn and valve seals are probably getting worn. This small stuff does add up.

 

Where is this CDR VALVE. That may be why mine is smoking a bit

 

On the back side of the intake. Remove your air cleaner and you'll see it. Small, round valve about 3" across with one bolt and one hose on it.

 

Thanx, I'll check that out. Just take it off and clean it ?

 

Soak it in gasoline or kerosene.
If it has not been done for a while the gasoline will cut the oil crud out faster.

Every once in a while shake it around to agitate the gasoline and help break loose the crud.

When it rinses clear just lay it aside for a while to dry out.

Then reinstall it.

 

196'000

yea it's got some wear i'm sure. but the compression is sill good. It uses about 2 quarts every 4000. the stumbling still confuses me.

 

Oops, I pulled mine last weekend and memory served me incorrect. It has two bolts, one on each side.

 

IHdieselfan: You've got classic symptoms of injectors gone bad, or an injection pump on it's way out, or some combination of both.

 

Check fuel lines and pressure to.A bent fuel line will cause problems like yours.I had a bad fuel line on the frame ,and another leak has just sprung up in the last few days.As soon as it starts sucking a lot of air the motor will just die.Then your back to ground zero.

 

I'm gonna try the cdr valve whenever i can the truck to stop for long enough