I'm in s/w Floridain the stump grinding business. I have a 95 Suburban 2500 6.5 t.d it has been a pretty good unit( 145000 mi. )until recently. Now I have low oil pressure at idle after warm up and 20-30 lbs. at higher rpms(oil pump?) Also heavy black smoke under load and especially in turbo rpm range. This is most of the time altho it sometimes decides to run fine. The turbo turns freely and shows no looseness in the bearings. It has had a new under warranty injector pump about a year (20000mi) ago and I recently installed the new style pcm remotely mounted in the air cleaner inlet. Any good ideas what the problems are? Any and all advise much appreciated. Carl (stumpbuster)

 

im sure somebody more experienced with the 6.5 will be along to help

 

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I moved your question to here https://www.dieselbombers.com/chevy-gmc-6-2l-6-5l/ to get you some better help

 

 

Heavy smoke from 6.5 is usually no vac to the WG actuator, either WG solenoid or no vac (broken line or bad vac pump), at idle is your wg free to move? should not be, vac is supposed to hold WG shut at all times, and opens via PWM control signal from PCM which opens wg/dumps drive gas to control boost

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You mean PMD pump mounted driver, which when it gets remote mounted becomes the FSD fule solenoid driver or FSD you'll want to remember that distinction as it lets those familiar with the 6.5 where yours is. PCM power train control module is in truck behind the glove box

 

The low oil pressure doesn't make sense, so it could just be your gauge. I'm not really familiar with FL, but up here its cold in the morning, and the oil is thick at startup, so your oil pressure is quite high on startup, then as it warm it drops.

 

i would first check to make sure one of those florida stumps did'nt crinkle your oil pan up into the pickup screen on your oil pump, as for intermittent black smoke sounds like waste gate controller or w/g actuator sticking or failed