'97 Suburban 1500 Diesel Low MPG?---=Any Ideas?

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by timhunter, Jan 30, 2012.

  1. timhunter

    timhunter New Member

    Hello All

    I have had a 1997 Suburban 1500 LT TurboDiesel for about 6 months

    The previous owner used to gets 22mpg on the highway

    I have changed the oil & filter, fuel filter and air filter and glow plugs

    I only manage to get 16 mpg

    Anyone have any ideas


  2. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Did you ride with on a drive to prove that milage? and 22mpg on the highway at what speed 55? 16-18 sounds alot more reasonable out of the 6.5L they were known for longevity, but not alot of power, nor milage. but if you think 16-18 out of a 3ton plus vehicle is quite good.
    Ive learned that most peoples milage claims are a tad to the high side of what they ever got with them.
  3. timhunter

    timhunter New Member

    honest mileage

    The guy i bought it from was a NYC Cop and super-honest

    He had many people interested and no motive to fib

    I heard 22mpg from other sellers as well

    Also, it is the 1/2 ton 1500 not the 3/4 ton 2500
  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    I misread that (thought you had written 2500) i havent ever heard of 22mpg unless the truck was driven around 55-60mph on the highway. also how you drive as well Diesels dont like to rev at all. since everything you changed is what is going to affect that. Also with the new cleaner diesel on the market the milage has gone down some as well.
  5. timhunter

    timhunter New Member

    i bought a 97 because i have heard from many sources 20+ mpg
    i try to keep the RPM low and most of the driving is 55-60 on local roads with some 70 on the Thruway

    injection pump, injectors
    just don't know where to improve things
  6. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Well if it is still running an injector pump, or pmd wouldnt cause the milage loss, and they are upwards of $1500 or more to replace (fuel savings isnt signifigant enough to replace not broken parts) same with the injectors. (ive worked on them)

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