robkabob

My wife drives a 2010 GLK350 with about 30,000 miles. Yesterday morning, I moved the car about 50 feet and it started up just fine. We tried to go out later in the day and it wouldn't start. We tried to start it two or three times to no avail. All of the lights and other electronics work just fine, and the engine turns over as well, but the engine just doesn't start.

I didn't think it was a battery issue, but we tried to jump it anyway. No luck. I went through and checked all the fuses tonight with a flashlight but didn't see any that were blown. I'm planning to check tomorrow in the sunlight.

Any ideas? I've read for other Mercedes that the Crankshaft Position Sensor goes bad, but I haven't read anything for the GLK350. My gut tells me that it is something small since it started up fine earlier in the day, but I am out of ideas. Your thoughts would be appreciated.

robkabob

Update: I went out there this morning and rechecked the fuses, and they were all fine. I decided to try to pump the gas pedal and after some hesitation, the car started up. After I drove it around and turned it off, it started right up with no problems. If this was my vehicle, I wouldn't still be concerned, but I don't want my wife to get stranded somewhere. Any ideas what causes this?

bop11

You may have a bad (leaking) injector. Pumping the pedal has no effect on these vehicles, but holding the pedal down all the way during start will actually turn off the fuel. This simulates the old method of clearing a flooded carburetor engine and has been in the program on most cars since electronic fuel injection was first installed back in the 80's. May not be true on direct injected engines.
It also could be a heat problem in the computer. I had a Range Rover that if you started on a hot day and only moved a few feet, then turned off, was very hard to start for the next few hours. Rovers of the Mid 2000's were notorious for this.
Check with the dealer if there are any codes set.

Planethill

Resurrecting this thread as we just experienced this exact scenario with my wife's 2010 GLK350.

Cold start after sitting all night. Plenty of battery power, all electrical items work fine. When you turn the key it cranks and sounds like it's trying to start, but fails. No CEL, no "start failure" message, nothing. After three tries, I too instinctively pumped the gas pedal and BOOM, it "caught" and started right up. I gave it some high revs for 10 seconds, and everything seemed perfectly normal. I even shut it off, let it sit for a minute and it started right back up fine.

My gut feeling is it's a fuel delivery problem. Clogged filter, fuel pump/pressure, etc. Of course these things happen when you are in a rush, so she's away (and hopefully able to return! ). When she gets back I'll run a Star Diag and see if there are any weird codes.

Thoughts?

robkabob

I would be interested if you find out anything. Since I fixed this I haven't had any more problems with the car starting so I haven't investigated too much further.

Planethill

You say "Since I fixed this". What did you fix?

robkabob

Oh, I meant after I got it to start it seemed to "fix" itself. Sorry for not being clearer

Planethill

Ah. Got it!

Well I ran a full Star Diagnostic and....nothing. Everything is perfectly normal. So unless this becomes chronic I'll chalk it up to bad gas, phase of the moon, etc.

Madden shaw

Make sure floor mat is not resting on the gas pedal at all

Bill F

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