I've noticed over the last several weeks that my mpg's are going down significantly from 14's to single digits.

I've been seeing a little dark smoke on initial start up, also when I get into the skinny pedal it's blows a lot of a grey smoke. Also noticed some oil build up on my CAC boots near the intake spider/X pipe(or whatever it's called)

Also seems to be using a little oil, nothing real bad maybe 2qt ever 2-3000 miles.

Any help or thoughts would be appreciated, btw it's a 2000 X 7.3 with about 185,xxx on it and it's not chipped or tuned.

 

The firstthing to look for would be boost leaks. You mentioned oil at the spider, if. Those boots are loose or leaking, you would almost certainly see a dip in mpg. Also check your up pipes. If there is soot on the firewall back by the joints where the up pipe joints are, you are loosing boost energy there and it would effect mpg.

 

I've checked all the clamps, they are tight. Also don't see signs of soot on the up pipes.

 

That's a lot of oil use. You may have bad injector O-rings, you can search "Cody test". Your turbo can leak oil through the journal bearing. How are your EGTs? Boost? Do you have a scan gauge/tool?

 

I have not purchased a scan tool yet, look like I might to invest in one thou.

 

Is there any oil dripping out your tailpipe? Do you get any blue smoke on acceleration? Pull the air filter off and check your turbo wheel for play. Just some things to check.

 

While a scan tool is a great long-term investment for these high-mile rigs, some troubleshooting can be done before you go there.

 

No oil dripping out of tailpipe and just a grey smoke(looks grey in mirror) under hard acceleration, I don't see any smoke under normal acceleration.

 

Ok, So I dug into this earlier today and believe i did the "Cody test" properly.

What I did and found out, pulled air filter and tube to turbo(noticed a very little oil towards turbo looked like from ccv). Next pulled CAC tubes and had oil dripping out of them about a 1/2 quart between the 2. Pulled the spider/X pipe(or whatever its called) oil sitting on the lip of the boots going into the intake. Disconected HPOP line from the drivers side head and disconected right head HPOP line from the HPOP(noticed spring inside HPOP on thst line). Did the "Cody test" (which is a P.I.A.) after having a miss placed rag and wearing some oil on the face(glad i wear glasses) and working on it for 20-30 minutes of fighting with keeping the rubber tip sealed to the line,I did NOT here any air blowing/weeping in or around the heads(really don't know how loud it would be). I do have good hearing,lol. Also drained the fuel bowl and it was clear as could be, filter was clean also.

So what could be my problem after all this.......

Thanks again for any input. FTE ROCKS

 

This sounds like a turbo bearing - or a plugged air filter (sucking everything through the CCV).

 

Did you check the turbo wheel when you pulled off the air cleaner? You need to check for play in the wheel.

 

I check the turbo I couldn't see any play but could feel a slight "bump" (if that makes sense) in it when I pulled it in and out/up and down.

Lol air filter is a K&N(I know, I know haven't had funds to change it out) it did look fairly dirty.

I'm on the road to thanksgiving I'll have to check that out when I get home.

 

Is the wheel contacting the turbo housing? if so the bearing is going and probably leaking oil. Also change that air filter, these engines really suck air when you get on it.

 

You probably got some ******* to help put in your turbo and effed it up

 

There is no sign of the wheel touching the housing, no wear marks on either side of turbo.

Nah.... I doubt it.