Mechanics

WON'T START IN COLD WEATHER

2000 Audi A6 • 6 cylinder AWD Automatic • 117,000 miles

My 2000 Audi A6 2.8 V6 having trouble starting in a really cold weather. This problem occurs for past 6 years. Previous owner took car to dealership 5 times. They couldn't find the problem.
When you try start the engine the starter cranks but the engine won't start.(Sounds like "dry" crank)After several attempts the engine starts but missfires, shakes, backfires. If you let engine run for minute or two and turn it off, it will start back up without any problems. Mechanics at dealership tryed change spark plugs, plug wires, couple injectors, flushed the fuel system tested computer-the same result. It runs o.K. And starts when the engine is warm, but in a cold winter morning no.
I put new spark plugs, Karlyn wires, Karlyn ignition coil pack, new battery-the same problem. It takes 10-15 times of cranking till you get engine run. After it runs for minute or two no problems, starts right away. Yesterday I took to shop, hooked up computer and everything works fine, no cylinders missfiring O2 sensors o.K. Fuel system o.K. Everything normal. We deleted faults. This morning the same problem Won't start and the check engine light came on. Please advise. Thanks.
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Laimis
January 14, 2011.



First check fuel pressure with mechanical gauge. Some engines have a "cold start valve" which only works when cranking adding addition gas to engine when cold.

Newer engines simply increase injector pulse time, which is controlled by PCM.

But, I would start with fuel pressure check.

Mmprince4000
Jan 14, 2011.