vpr80

So my 2015 started to take a few seconds longer than usual to start. Always did it on the first crank or so with no hiccups. Now (sometimes) it takes a few extra cranks and few extra seconds. Also it seems to be more of an issue if it's cold and been standing for a while. If it was used recently, it will fire right up.

1) Tested the battery for low voltage. 12.55 volts. So that's not it.
2) Checked the OBD for codes, nothing. Not a single code.

So now I am not sure if something is *actually* wrong (or in the process of breaking down) or just growing pains now that's a few years old.
This is my wife's daily and I don't need it failing to start at the kid's school or something while I am away at work.

Any ideas?

Thanks

pcy

When you say it's cold outside, are we talking about 50 deg. F. or minus 20 deg. F. ?

vpr80

I meant the SUV is cold, not the weather. It does it in the garage in the morning.

pcy

I am just thinking out loud here...
There is a check-valve in the fuel delivery system that ensures fuel pressure is maintained while the vehicle is just sitting there. If that check-valve is letting the pressure go while the vehicle sits for few hours, then, I can see how the startup can take few additional seconds while the fuel system is pressurized.

You can test and see if that is the scenario in your case. After the vehicle sat in the garage over-night, when you get in the car in the morning, put the key in the ignition (but don't start the engine), Turn the ignition to position 1 (instrument cluster lights up). Let the fuel system pressurize for few seconds, then turn the key to start the engine. See if you notice any difference in the symptoms of the problem you mentioned.

vpr80

Interesting! Will try it tomorrow morning!

vpr80

No dice. Started right up in the morning. Then later in the day tried to crank for a few seconds. And fine again later after that. Basically, when it's normal, it fires up on the 2nd crank when speedo is just starting to sweep up. When it has issues, it takes about 5-6 times, the same amount of time it takes the dash speedo and tach to sweep all the way up and back down.

peter2772000

Dunno if this is pertinent on these german vehicles, but pcy is possibly on the right track.


I don't know if this is still the same, but on older American cars, they had a failsafe fuel-pump feed to the pump. This was in case the fuel pump relay took a dump. The symptom was longer cranking times before starting. It would take time for the oil pressure to build up in the engine, which then actuated a pressure switch which in turn fed 12v to the pump directly. If this is your scenario, could be that the signal to the fuel pump is intermittent, which would explain why sometimes it starts right up and sometimes not.

Just a thought...

Diabolis

It sounds to me like you're jumping the gun with the starts way too early. If the tach / speedo diagnostic sweep hasn't even completed and you're already on the second (or sixth) try, it's not a problem with the car - you're just trying to fire it up too early. It takes a few seconds for the ECU to perform various diagnostics and adjustments just like it takes a few seconds for the fuel pressure to build up. Wait until the speedo / tach sweep has completed and then crank it. Does it not fire up on the first try then?

Phillip Murray

unicornoffice

My ML350 Diesel W166 had this problem combined with sometimes not wanting to go into drive in the morning. Long story but replaced the main battery and all is well.