Need advice for Car which has trouble starting

[Twinkles]

My car is a 86 300e Benz german build...

its been taken care of for the most part but one of the problems that always seems to happen is it takes a long time to start. Especially when its cold outside. In summer its easier to startup. If you can give me any suggestions of what else to check for I sure would appreciate that.

Milage is high ..
its got good get up and go when needed.
it seems to do ok once it starts ...

at one time a guy checked it and said my starter was ok ..so its not the starter...

 

[exdeath]

If it's cranking fine but just doesn't start right away: temperature dependent starting difficulty is due to enrichment control. Anything to do with cold start enrichment like coolant temp sensor, cold start injector, etc. is a good place to start.

If it's actually cranking sluggish, it's the battery. Batteries are weaker in the cold period, let along aged.

 

[phucheneh]

If it's cranking fine but just doesn't start right away: temperature dependent starting difficulty is due to enrichment control. Anything to do with cold start enrichment like coolant temp sensor, cold start injector, etc. is a good place to start.

If it's actually cranking sluggish, it's the battery. Batteries are weaker in the cold period, let along aged.

This. Additional comments:

Sluggish cranking could also be mechanical. If you're using thick oil like 20w50, for example, it may be way too viscous in the winter.

If it is indeed just too much cranking before it 'hits': As stated, this is likely due to the engine not getting enough fuel in cold temperatures. Primary candidate is usually a bad ECT. If the signal is indicating an abnormally high temperature, it's going to have a harder time starting. If it's got no signal at all, the 'default' (perhaps 'failsafe' would be a more accurate term) fueling strategy may just not be rich enough for your winter temps.

Other sensors could also cause this issue, but it's less likely. MAF, MAP, IAT...anything that deals with ambient or engine temp, or the amount of air being taken in by the engine.

It wouldn't be anything like clogged injectors or low fuel pressure, as this should cause other symptoms- like fuel starvation at higher RPM's/loads.

Give us a little more info. Is this indeed an EFI car? Do you know anything about the system it uses? i.e. throttle body injected, port injected? Is there a cold start injector? Does it measure air volume ('mass airflow') or just use things like MAP (literally 'manifold absolute pressure'- intake manifold pressure) and throttle position to essentially 'guess' the incoming air volume?

Is this ONLY dependent on ambient temperature? What about engine temp? i.e. when the engine is hot but the outside temp is cold, does it start any easier? How about the length of time the car has been sitting?

 

[Twinkles]

I really do not know about those things but wish I did. I know basic info on it. sorry

Yes when the car was running say earlier in the day ..it starts with no problem ..it usually only happens in the morning when its sat all night. rarely is there any problem after it already been started in the day.

 

[Twinkles]

by the way ..I live in Arizona ..its not a cold climate place ..

 

[phucheneh]

Sounds like there's a strong possibility it might just be losing fuel pressure overnight, then.

If so, it's highly likely the problem is with the vacuum-operated fuel pressure regulator. I'm not sure where it's at on that engine...assuming it's common rail, port-injected (I think it is- you'll see a line of injectors running alongside the cylinder head, linked by a rail on top), that regulator is probably on the end of the rail. Pull the vacuum line off and see if it smell like gas. If so, the diaphragm inside is torn.

 

[Twinkles]

that would seem to be the problem ...why I say is because there is also minor problems with the vacuum locks ..and windows too .(center council only problem) on the doors it works ..so something maybe in the lines ?

 

[phucheneh]

You may have a vacuum leak in addition to the regulator problem. Or it may just be purely a vacuum leak causing the issue.

Windows are gonna be electric only. As far as vacuum door locks...ugh. It complicates things, since you've got a lot more lines than you normally would. There is a one-way valve to keep vacuum on the lock system once you shut the engine off (so you can lock/unlock without the car running), but I don't believe that will keep a leak in the door lock system from affecting the engine.

 

[Twinkles]

The Engine seems to run fine with few exceptions ..my car does need more care..but right now thats not possible... well any ways ..The engine is good ..its a solid car .. The little things that have bothered me was that its harder to start when its sat all night...or all day
but once its been started ...even if I go to say the mall ..for hours ...it will start fine after an all day at the mall ...so its odd that it will take longer time for a few more hours of "rest"

it locks well and stays locked ...that does not seem to have a problem ...just glitches at times ...which as I said ...seem to happen to the windows as well ...