Mechanics help? Long crank, cold-start, hot-weather.

[kkelley]

I am a pretty decent home wrencher, but this one has me stumped.

My car (2001 VW with 1. 8l turbo engine) has developed an issue over the last two summers.

When the weather gets warmer the car will have a hard time starting. As the temperatures increase, the crank time will also increase. It is only durning a cold-start, once the engine is warmed up it starts normally. In cool to cold weather it fires right up.

I have software on my computer that allows me full dealer diagnostics from my lap-top. Real time readings of the coolant and ambient air temps look normal, i. e. before starting they are the same, and the coolant goes up from there. Fuel pressure after the pump primes is good, and doesn't bleed off for a while. Allowing the pump to prime before cranking doesn't change anything. Once it does fire, the first second or two are a little rough and puts out some black smoke. Car runs great all other times.

So, if anyone has any input, I'd appreciate it and am willing to try just about anything.

 

[JHumphries]

Could it be a loss of compression that goes away with oil pressure?
Try doing a dry compression test with the engine cold. Then add a small amount of oil to each cylinder and do the compression test again. If the pressure readings are not close, the rings are going bad. If both sets of numbers, wet and dry, are low, it is usually the valves.

 

[kkelley]

Thanks, compression as of this spring was 190's across the board without oil added to the cylinders on a cold motor.