blue smoke

[tjsea]

I have a truck that I have been getting ready to sell it is an 86 f250 with a 6.9. I put a used engine in it that we had sitting in the shop for about a year. It starts good but it lopes a little at Idle and smokes blue when you stand on it. the guy we bought the engine from said the engine smoked when we bought it. It still has good power and the smoke goes away a little as it warms up but it is still very noticeable. I was thinking that it is probally an injector pump or injectors. I don't want to get too much money in it unless I have to. My question is should I try replacing the injectors or is probally going to need an ip or could it be something i am not even thinking about?

 

[smolkin]

This sounds exactly like my engine! What condition is the CDR in? You may be burning oil for fuel.
You probably won't want to spend $80 on a new one if you're trying to sell, but maybe a cleaning will help? Mine still smokes under heavy accel but the CDR helped alot...not to mention I use much less oil.

Even with a new IP my truck still has a lope at idle. Maybe the injectors are causing it? Or valves?

 

[tjsea]

I had replaced the cdr with a new one when I had the engine out. I had thought that might have been the problem when I bought the engine, but aperently not.

 

[mariner45]

A couple of things come to mind that might help - it did for me.

Have you had your injection pump timed properly ever ? An out of timing pump would cause smoking - I believe a blue smoke with retarded timing - Mel would know for sure.

Another often over looked thing is fuel conditioner. Do you use any fuel conditioner added to you diesel fuel ? If not I would strongly recommend you do so - it is cheap and might just help clean up the fuel system.

I recently had my engine start to lope a bit at idle and wobble when I increased the revs - it then smoothed out. It also smoked badly at idle and the exhaust smelt strongly of unburnt diesel fuel.

I put some feul treatment in and it seemed to help - so I added more at about twice the recommended dosage. More improvement - hhmmmmm!

I had to get some gravel to do some driveway repairs so I used the old F250 and had it loaded. The load was heavy enought to put the rear way down on the springs and made the front very light for steering. The gravel yard was about an hours drive from home on very hilly roads (7% gradient). I decided I would work the heck out of the engine to try and burn off any carbon that might be around the injector tips (I know about the precombustion chamber). Exhaust temps were monitored on the temp gauge I have for the turbo - and all was well.

I got home and the truck load of gravel unloaded and the truck cleaned up. Took it for a run and found the truck ran much better than before the gravel run - hhhhhhm.

Whilst the loping and smoking was going on I had convinced myself that I needed to replace at least one - if not more fuel injectors, so I bought a new set for less than $200 as insurance.

Well, I now have an engine that is running cleaner, smoother and better than it has done for years and does not burn any oil to speak of. The common demonator through this all was fuel conditioner and treatment. I had for some reason, forgotten to treat the fuel for quite some time. After putting extra doses in and working the engine hard, the problems have disappeared. I am certainly that I have also picked up some bad fuel which would cause similar problems, in the past, but can often be remedied with proper fuel treatment.

So, it might not be your problem but sure isn't going to do any harm to treat the fuel properly. Make the engine work hard for a while and at least get the injection pump timed properly if you haven't done so.

My truck engine is now running as good now asit ever has since new in 1986 - excluding some oil leaks that come and go.

HTH

mariner

 

[mariner45]

Whilst the loping and smoking was going on I had convinced myself that I needed to replace at least one - if not more fuel injectors, so I bought a new set for less than $200 as insurance.


HTH

mariner

Ooooooops ! - forgot to mention that I didn't need to change the fuel injectors after all.

I now have a brand new complete set of spares (BB) sitting on the shelf in their boxes - should I ever need them.

Cheers

mariner

 

[tjsea]

I ran the truck hard last night with an additive (I always run an additive) and the smoking and loping got a little better. I guess it just needs run hard from sitting so long. Thanks for all the help, that saves me some money.

 

[mariner45]

I ran the truck hard last night with an additive (I always run an additive) and the smoking and loping got a little better. I guess it just needs run hard from sitting so long. Thanks for all the help, that saves me some money.

Yes, a lot of owners use these trucks as daily drivers and as a consequence, the truck engines don't get worked hard enough - just babied.

So yes, a good prolonged workout for the engine is benificial - just like it is for us people - and be sure to add the treatment to the fuel !

mariner