rough idle and bluish white smoke HELP

[73dieselcowboy]

Well another problem with the old 7.3 engine is a used engine put in a year ago, ran fine but a while ago it started ticking, about a week ago it started idling really rough and blowing bluish white smoke from the exhaust, not using any oil, replaced the injector pump and injector return lines yesterday and still the same injectors are about a year old and before I put the used engine in installed new gaskets through out including heads etc, it is blowing smoke at high rpm but even more at idle engine has about 100,000 miles on it, what else could it be? broken valve spring? worn valve seals? any one with some helpfull advise would be great thanks.

[chuckster57]

bluish smoke is associated with burning oil. I wonder if the valve guide seals are bad? How is the CDR? is it maybe plugged and the crankcase pressure is forcing oil passed things? Are you still in Cali?

[73dieselcowboy]

No had to come back to bc it started doin g this on the way back, just before seattle, what is the cdr I have your number with me I will try and call you, I am going to do a compression test before I go any further, thanks chuck will try to phone you in a few, Gary

[crihfieldjack]

Had the same problem this spring and found two problems. First was exhaust valve seats worn out in cylinders one and two. Next was a timing problem I don't know how it changed but by changeing the timing it cleared up 99 % of the smoke.

[73dieselcowboy]

Well hvnt been on for a while, I was thinking valves or seals thecompression in number 7 is at 250 while the othersare all at 450, im thinking I may have broken a valve spring and it took out the seal, could that be possible? I am flying back to cali for christmas and leaving the truck at a buddys, going to attack it in the new year, I have a buddy that knows of an 89 for nothing the body is rotted out I thought the 89 model had a 6.9 not a 7.3 am I right? and if so will the heads off a 6.9 fit a 7.3? thanks in advance Gary Merry Christmas to all.

[Plywood]

As far as I know blue smoke is usually oil, but burning diesel can be blue if the right temp and what not, but bluish white is probably diesel what does the smoke smell like?

The 89 should be a 7.3L. Look at the number on the block just next to and under the IP driver side, should say 7.3D

Don't know all the ins and outs, but I've read about guys using a 6.9 bottom end with 7.3 heads and calling it a 7.1.

You might have the injectors pop tested, heard about new ones being bad before.

CDR is crankcase decompression regulator, or something very similiar.
It is right to the rear of and under your air cleaner, it lets the block blow by go into the intake, but prevents the engine intake from sucking on the crankcase. In theory of you block the lower end of it and suck in it, it should close, and then when released the spring should push the valve back open. However, it is open at low rpms, so basically a bad CDR behaves the same as a good CDR at low rpms, so not your problem.