Having problems with your 1999 GMC Yukon Denali ?
99 Yukon 5.7 won't start, ONLY when it rains
\015 Problem for several years, multiple dealers, still no luck.\015\012We thought we had it when we replaced the MAP sensor in Jan 08, but doing it again. I still think it has something to do with the lower air pressure when it rains. The problem has NEVER occured by washing the truck, and one shop dowsed it in water repeatedly to try to get it to induce problem. It only does this when it rains. No code is ever indicated during or after the problem.\015\012Vehicle will turn over a couple revs when key is reset (and fuel pump recycles). It turns over a few revs then quits. If you do not reset the key, and try to push the key to start from the ON position, it does not catch any revs (no fuel, because no reset) thereafter.\015\012Crank sensor, dist have also been replaced with various tries by dealers, they did nothing, no difference. MAP sensor replace seemed to solve the problem for a couple rains, until now (Live in AZ.)\015
One of my problems was with a 99 Yukon SLE and it wouldn't start when the air temp was below freezing. It would crank, but for whatever reason the fuel pump would disengage, I used to have to prime the throttle body with gas to keep it running and as soon as the engine got warm, voila! I know it doesn't sound like the same issue, but hear me out. I bought the SUV secondhand. It had an aftermarket security system installed, and according to the dealer who fixed the problem, the original installer tapped into the main wiring harness and made a mess. After replacing the wiring harness, this and a other problems miraculously disappeared. If you have anything tapping into your main wiring harness you may be getting moistur and causing a short. Hope this helps, and if not ... sorry for wasting your time.
When the dist. was replaced, did that include the cap, rotor and ignition module? what about fuel filter? coil?
Repair Help & Product Troubleshooting for 1999 GMC Yukon Denali
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