My suv 99 yukon has a wire short somewhere it seems to be grounding out it runs at low voltage when idling but when go to rev it up it drains power to the point of stalling,i connected a wire from battery to wire in plug on top alternator it doesnt help but when i tap it on positive post it trys to charge?

SOURCE: starter runs constantly when u connect the battery

Check the wire from the battery at the starter there is a tab to keep it from spinning when you tighten the nut,it may be touching the other nut on the solenoid causing the starter to spin.You can also remove the wire on the solenoid that engages it then it should not spin.If it does it is a starter problem

SOURCE: 2002 gmc yukon, rich fuel code, low fuel pressure @40

you may have two oxugen sensors on your yukon. if so the oxygen sensor that controls that bank may be bad. from what you mentioned in your complaint, it sounds like it is the oxygen sensor.

Greg Bernett

• 2993 Answers
• Posted on Mar 20, 2009

SOURCE: 1983 GMC G2500 Alternator Belt Diagram

REMOVAL & INSTALLATION Fig. 1: A gauge is recommended, but you can check belt tension with thumb pressure
Fig. 2: Loosen the component's mounting and adjusting bolts slightly to remove or adjust the belt(s)
Fig. 3: Push the component toward the engine and slip off the belt
Fig. 4: Slip the new belt over the pulley
Fig. 5: Pull outward on the component and tighten the mounting bolts
Fig. 6: Accessory mountings found on 6.2L diesel engines

1. Loosen the driven accessory's pivot and mounting bolts.
2. Move the accessory toward or away from the engine until the tension is correct. You can use a wooden hammer handle, or broomstick, as a lever, but do not use anything metallic, such as a prybar.
3. Tighten the bolts and recheck the tension. If new belts have been installed, run the engine for a few minutes, then recheck and readjust as necessary. It is better to have belts too loose than too tight, because overtight belts will lead to bearing failure, particularly in the water pump and alternator. However, loose belts place an extremely high impact load on the driven component due to the whipping action of the belt.
   

SOURCE: 2002 GMC Yukon, erratic idle(hi-low) when cold. 125K miles.

i now for a fact that it is the egr valve . carbon balls in side you have to take it of and clean them out

SOURCE: i have a 2002 gmc yukon denali xl with 6.0L engine

my 2002 had same problems and to fix, I loosened the hose clamp on the throttle body air intake to air box hose. Then opened the butteryfly by hand and used throttle body cleaner, used carb cleaner on another, and removed all the black grime that collects around the throttle body butterfly. About every forty thousand miles i have to do this. I have 123k on mine now and have done it three times. Fixes the low idle, dying in reverse, lite flicker and alternator dropout.

Home it works, if it does
thanks
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