6.5 issues

[tj98gmc]

truck is,, 1998 GMC 2500HD 6.5l TD (vin F)

ok,, at the beginning of last week the check engine light came one and the truck poured like a greyish colored smoke out,, checked the codes p0236 (turbo boost sensor A circuit),, when that code came up i thought to my self that i dont remember hearing the turbo when this happened,,, so i backed it out of the garage and got on the brake and built the turbo up,, i could hear it spool up,,, i left off at a little less than 2 grand,, but i heard like a click and the check engine light went out,,, since than the truck has ran like normal,, (no issues)

well today on my way back from carlisle (about a 3 hour trip) the check engine light came on and i looked back and saw grey smoke again,,, as i was driving i noticed the turbo was not spooling,,, i couldnt hear it,, i got about a hour away from home and the light went out and the turbo kicked back in,,, for the rest of the drive the turbo would go work and than stop,,, and work again a little later,,, when it wasnt working the truck poured smoke out when i was on the throttle,,,,

do you think i have a bad turbo??? or is there something else causing this??

 

[ak diesel driver]

most likely the selenoid on the drivers side valve cover but could also be a cracked vacuum line or grounds/connection or a vacuum pump issue

 

[L98TPI]

Those hard plastic vacuum lines get brittle and crack. I had to hunt down and patch three leaks to get a buddy's turbo working again and then we found the control solenoid was sticky, sometimes no boost and then it would be working but looked like the ECU had little fine control over it. After he replaced all the hose from the big line that comes out of the pump to the solenoid , to the turbo servo, with nice USA made hose and replaced the solenoid it worked like its supposed to. Getting weak and intermittent vacuum to the solenoid plus the solenoid being worn out made troubleshooting it a PITA.

 

[Jorge6.5]

I agree with the above mentioned.

Sounds like the boost is cutting out from not getting vacuum.

 

[Burning oil]

http://www.pmdcable.com/index.php?main_page=product_info&cPath=9&products_id=8

 

[tj98gmc]

good deal,, i am going to replace the solenoid and see if it takes care of it,,, if not than ill do the vac pump,,,

i did take the truck to town today,, ran fine,, like normal,, could here the turbo spool like it always has and only puffed black smoke on hard throttle,,, so im hoping the solenoid is just sticking!!!