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+--- Thread: Difficult cold starts (/showthread.php?tid=7001)
Difficult cold starts - baldur - 01-23-2016
My OM662 suddenly started to become a nightmare to get started after it's been sitting for 4 or more hours. I'm suspecting that the fuel is draining out of the injection pump as the engine catches within a second of turning the key but then nothing happens for like 30 seconds of cranking before it springs to life.
What I noticed first was that my delivery valves had fuel leaking out of the pump, so I replaced the O rings and copper washers thinking I had solved the problem but that made no difference whatsoever. I no longer have diesel dripping everywhere but the car still needs to be cranked for almost a whole minute to get it started after sitting for a few hours.
I guess the next step is to replace the O rings in the return banjo bolt, the fuel inlet fitting and lift pump connections perhaps.
Has anyone else experienced this problem? What solved it?
RE: Difficult cold starts - starynovy - 01-23-2016
As you already said, good old o-ring problem. Sometimes even joints on those transparent tubes leak air into system.
RE: Difficult cold starts - baldur - 01-23-2016
I'm considering fitting an electric lift pump. Having to use the starter to prime the injection pump is not ideal for neither battery nor starter.
RE: Difficult cold starts - starynovy - 01-23-2016
That is good idea either way, those mech. lift pumps are often tired. I recommend low pressure Facet cube/posi flow pump mounted near tank under the car for good priming since they rather push fuel than suck. 0.3-0.5Bar is more than enough for your needs.
RE: Difficult cold starts - barrote - 01-23-2016
most probably, 95%, with that simptoms is the return check valve....
the thing alow the fuel to return dwn the tank, if it was air leak it would take more than 30 seconds to fire.
well there are many things in there that can have that simptoms
good luck...
RE: Difficult cold starts - Petar - 01-23-2016
Have a similar issue, hard to start especially when warm.I can see air bubbles in the prefilter when it's running, when cold it starts somehow, when it's hot it cranks and cranks.
I've fitted a manual primer pump from a truck, looks like this:
[img] http://www.spelchek.com/upload/d/bc/dbc9661901cf85ee.jpg[/img]
W202 OM605 w/ 602 mechanical pump, so no o rings only banjo bolts.
I also suspect the pump overflow valve, trying to wrap my head around the concept of air entering there since for air to enter fuel has to exit somewhere and it can't flow back to the fuel supply i think, not with 4 non return valves (2 in the primer pump, 2 in the lift pump)