hpgtowing Posted July 18, 2005 Share Posted July 18, 2005 Got a 1981 Mack Heavy spec. single axle Mack Wrecker.. big 29,000 Rear.. with a homes 850 Wrecker back... Maxi Torque 5 speed with a 4 speed Brownlipe aux. .. Truck weight is about 35 to 36,000 LBS.... iT HAS A 285 TIP TURBINE MOTOR... The truck has about 160,000 miles.... The motor was inframed just before I bought it.. about 2 years ago... I had the injection pump gone over, adjusted the valves... but the truck just is lazy.. no torque and down on power..... Any ideas? Thanks Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted July 18, 2005 Share Posted July 18, 2005 check the throttle linkage to see if its slipped a few teeth on the shaft going into the pump.have had a simmilar problem on a company truck before, this was the reason?Trent Quote Link to comment Share on other sites More sharing options...
hpgtowing Posted July 18, 2005 Author Share Posted July 18, 2005 Thanks Trent.. It's worth a look for sure.... Thanks.. Steve Quote Link to comment Share on other sites More sharing options...
fullfuel01 Posted July 19, 2005 Share Posted July 19, 2005 is the truck smoking black when pulling? because if you don't see any smoke look on the intake manifold forthe little piston, when he's game over truck won't smoke because it cut the fuel to the pump... Quote Link to comment Share on other sites More sharing options...
b61mack Posted July 19, 2005 Share Posted July 19, 2005 Steve ,check the puff limiter, unhook it see if it runs better, even if is working right if you unhook it it will run better Ron Quote Link to comment Share on other sites More sharing options...
hpgtowing Posted July 19, 2005 Author Share Posted July 19, 2005 I'll check the puff eliminator today.. I didn't even think of that... Thanks..Steve Quote Link to comment Share on other sites More sharing options...
hpgtowing Posted July 20, 2005 Author Share Posted July 20, 2005 Ron I disconnected the puff eliminator... Yeah it did run better... Considerably when up in a hiher gear.. You could now feel the truck wanna pull... it's still a bit lazy... I'm gonna replace the spring check valve (T-shaped Valve) at the injection pump... I'm told these weaken after a while and tend to reduce fuel pressure slightly.... I'll keep you posted... Steve Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted July 20, 2005 Share Posted July 20, 2005 I have the puff limiter on a air switch mounted on the dash. bob tailing I notice an increase in accelaration from a dead stop or low rpm. when the truck is loaded it just feels the same. check your Fuel press if its good check your fuel feed lines from the tank. sometimes rust can collect in the lines or air from a crack will hinder flow to the pump. Trent Quote Link to comment Share on other sites More sharing options...
b61mack Posted July 20, 2005 Share Posted July 20, 2005 Steve you might take the short fuel lines to the filters off and see if you can look through them , i have had them where they look good on the outside but closed on the inside , like trent said you might check all the fuel lines, i have a 76 285hp with a 5 speed 3.87 rears ,it will run with a 350hp cummins with 90000 lbs + pulls good Ron Quote Link to comment Share on other sites More sharing options...
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