Vacuum pump needs replacement? (already searched on topic)

[97SubK2500]

My '97 Sub has started to show the black smoke - low power syndrome, and thanks to the accumulated postings on this forum, I've been able to get a start on figuring out the problem. Before going ahead and replacing things, I hope to confirm that this simple approach is the right thing to do.

Other than the black smoke under load, a definite loss of power, and a minor fuel economy drop, she's starting and running just fine.

The turbocharger, wastegate, wastegate actuator, vacuum pump and tubing harness are original equipment (almost 152,000 trouble-free miles up until recently), and the wastegate solenoid has 60,000 miles on it.

I measured the vacuum getting to the solenoid: less than 1.5" Hg @ idle, 10" Hg @ nearly redline with transmission in Park.

The harness tubing and connections all seem intact, based on visual and fingertip-feel inspection. The tubing has been protected by a plastic cover that looks like a small version of what you put computer / stereo cables in to keep them organized.

Is it reasonable to assume that the vacuum pump needs replacement? While I'm at it, I was thinking of replacing both the tubing harness and the solenoid - any thoughts?

Thanks in advance for any advice or information provided.

--Ian

[Turbine Doc]

Check the vac directly at the vac pump it will conform for sure the pump is dead & not a leak somewhere, if you find it is dead & since & you are F code engine (S needs vac to make EGR stuff function), rather than have it die again later or have WG solenoid issues, eliminate it, run a 1" shorter belt and use a mechanical WG control that Heath or Kennedy sell,
if pump is good prolly have a crack in nylon vac line it isnt uncommon, replace whole line or find/cut the bad spot and splice repair with rubber vac line

[More Power]

www.usdieselparts.com (http://www.usdieselparts.com) sells reman and new vacuum pumps for the 6.2/6.5 diesels. :)

Jim

[Robyn]

Just my 2 cents worth

I would replace the WG control with the Turbo master spring thing and install a chip that will eliminate the overboost codes and then set your top boost to about 7 PSI and be done with all that stuff that SUCKS :D

Good luck

Robyn

[97SubK2500]

Checked the vacuum at the pump - same reading as at the WG solenoid - less than 1.5" Hg. So, it looks like the pump is about dead. Good news is that the vac line appears not to be leaking, although on a second look, I see a slight necking down at one point in the line, so maybe that would need to be replaced, too.

I'm all for removing mechanical complication, as long as I don't create a ripple effect of headaches throughout other systems. Where would I find specifics on products and procedures for eliminating the vac pump and WG solenoid from this F code engine? Would like to get another 150,000 miles out of this old Suburban, so there should be plenty of miles to amortize any first costs.

Thanks to all who have posted.

--Ian

[97SubK2500]

Replaced the vacuum pump and vacuum lines. What a difference - almost no black smoke even loaded under full throttle, 0-60 time is back to normal (14 seconds). Fuel economy has gone back up to normal as well (16 mpg in mostly city driving).

Thanks to all who helped with advice and information.

--Ian