Jagtem

Car is a 2008 Cayenne S, purchased about a year ago.

The car was in great cosmetic and mechanical condition when I tested it. It started and ran flawlessly during the test drive and immediately after purchase.

The issue became apparent the next day when I went to restart the car after it had already been running/driving for a while. It just gave a half a crank and then a click and failed to start. I tried it again and it started up.

This issue got worse over several months. Basically, the car would start fine from a cold condition, but once it had been driven and brought up to temp, it would often refuse to restart on the first turn of the key. However, the car would always eventually restart. Sometimes this would require several attempts of turning the key, or waiting 5 to 10 minutes, then trying again (and again). This was particularly annoying when filling up with gas, as I'd often have to sit there for a few extra minutes trying and retrying the starter. But it would always eventually start.

I replaced the battery to no effect, and finally replaced the starter motor which seemed to completely resolve the issue. After replacing the starter, the car would start flawlessly in any condition for the next several months.

However, the issue is now returning. Again, it starts fine when cold, but now sometimes when the car is hot, it is requiring two or three attempts to start. It's not as bad as it was, but it seems like it will continue to get worse. As if the starter motor is getting weaker and weaker over time.

What could be causing this behavior? I did notice when replacing the starter that the one I removed seemed to be an aftermarket unit, so I think this may be at least the 3rd starter which has been put in the car. Is there a condition that could be causing this slow degradation of the starter motor? I'm at a bit of a loss and it's quite annoying to not be able to trust the car will start when I need it to.

Any help is appreciated.

Malibu955

The symptoms do point to a failing starter. It's possible that you got a bad replacement; pandemic parts still seem to be everywhere. Did you go with an OEM Bosch starter? If so, new or rebuilt?

Jfrahm

Voltage readings would help. I wonder if you have the dual battery setup and only replaced one battery.
It could also be a problem with the voltage regulator or alternator leading to undercharging. I had this issue with an Audi, the half-charged battery was not always capable of starting the car.
Other possible issues could be a bad battery/starter cable or cable end, poor cable to ground connection or similar.

Checking battery voltage when cold, when running and right before a hot start could tell us a lot.
-Joel.

Malibu955

Also, are you having the exact same symptoms, where you get half a crank and then a click when trying to start? Or are you getting long cranking times when hot, which can point to a failing crank position sensor and/or HPFP.

Jagtem

It's a Bosch unit. Not from the dealer, but I believe it is OEM- spec. I think it's a reman. Maybe the quality is questionable? I'm currently located in a sorta-former Balkan country (Slovenia).

Same symptoms. Half a crank, then click. Cycle the key again and it will usually fire up as normal. Again, only when engine is hot. It's happening maybe 10% of the time, but I suspect it will get worse over time. With the last starter and a hot engine, I would sometimes have to cycle the key upwards of a dozen times to finally get it to start. Super stressful when there's a line of cars behind me at the gas station.

Single battery. I'll try to get voltage readings at cold/ hot/ idle. I'm currently residing in Europe (Slovenia), so unfortunately I don't have access to my own garage and most of my tools.

I'm wondering about the possibility of a bad cable connection ground. Could a hot engine bay exacerbate such an issue? Any pointers on where to check for these cables/ connections?

Malibu955

I have a reman'd Bosch as well and it's held up great for probably 6+ years now, however people have had issues with them. Plus parts in general have had a shocking drop in quality since the pandemic, so it's very likely that your new starter is failing.



Yeah, that definitely seems like a failing starter. My Cayenne had those symptoms every once in a while prior to replacing the starter, and has never had them since. I also had an XJ Cherokee with symptoms exactly like you described (and the symptoms got progressively worse) and a new starter fixed it. So all points to the reman'd Bosch starting to fail.



Here's a diagram for all of the chassis ground locations.

theprf

Electrical connections to the starter are easy. The battery wire runs from the starter to the jump start pin. The starter is grounded to the engine, and the engine ground is below the alternator.
I don't think those are the source of the trouble, much more likely a failing starter. And they are really a joy to change.