dutch55

Our high mileage Cayenne has a frequent problem starting when warm. The car will crank for about one second, then stop. On second attempt it starts fine. Car starts fine cold.

I have read that warm start problems could be starter, a failing cam solenoid, or a temp sensor on the front of the motor, or the battery.

but I am hoping somebody might help me narrow it down before I take it to my independent mechanic. The mechanic suggested a starter, but that was based on my wife talking to him (it's her car), who probably wasn't as specific about the symptom. Any help would be appreciated.

thesteve

Was it like this?

You have to turn the sound way up to hear, but sometimes (when warm) it would crank for a split second and stall. It would start on subsequent attempts.
In my case replacing my crankshaft position sensor was the solution. (not camshaft position)
I had the corresponding code stored in memory which was revealed by my scan tool. Might be worth picking one up.

mcbit

Poor starting when warm in my 12 yrs experience with 955 and 957s generally points to increased electrical resistance: starter motor/ earth cable or battery (often accompanied by random warning lights)

dutch55

Thanks for the posts.The problem got progressively worse, and in my case, replacing coil packs eliminated the problem.

Details follow. My cheap OBD-II adapter and Android app first reported PO301 Cylinder 1 Misfire and PO358 Ignition Coil "H" Primary/Secondary. Clearing those, two days later, reported PO300 (Random/Multiple misfire, and PO301, accompanied by steady off idle part throttle acceleration roughness. Repair shop found three failing coil packs, so replaced all of them. Vehicle displayed battery/charger fault, on way home from repair shop, which cleared itself after shutoff and cold restart, with no IP light or stored fault codes), but reappeared after short trip shutoff an restart. I am guessing that is caused byb an aged weak battery.

thesteve

Good deal.