huggi

So my 2008 e350 4matic (118k) has been struggling to start after sitting for a few days. It's pretty linear, meaning the longer the wait, the more turns it takes to start. I initially thought it was a battery drain, so I got a battery tender. Check the voltage before starting, usually ~12.5.

Any other suggestions, this has been going on for about a year.

I also leave the key in the second position before starting for 30 seconds or so, to let the fuel pump - makes no difference.

Any other ideas what might be wrong?

Thanks

kajtek1

Is it 12.5V on cluster or on battery terminals?
12.5V battery is low, but clusters tend to show lower readings.
In your case the first troubleshooting coming to my mind is checking fuel pressure.
Fuel pressure gauges cost $19 at HF and takes only seconds to hook up.

huggi

On the cluster, it's the same voltage as when I turn the car off. I'll get the fuel pressure checked.

beejAMG

just saying, all my cars have dashcams on em and are set to turn off (parking mode) when battery hits 11.5V. came back a few times with the camera off after sometime so i figured charge is down to 11.5V. no issues in starting whatsoever.

so in your case, 12.5V should be more than enough i reckon. have you had the starter looked at? its been on for a year and you havent had it checked? you dont wanna get stuck in the worst place.

also, +1 on kajtek1's advice.

huggi

I had to replace a battery after 18 months - I just figured it was an electric drain. Only after getting the battery tender have I noticed it's unrelated to the voltage.