W202 Not starting

[Nasco12]

OK, so it did start in the end but it took a few goes.

I have been kind of expecting this. For a few months now it has now and then been running rough on start up. Not for very long. It calms down after about 30 seconds or so. This seems to happen most often when it is cold and/or wet.

I have tried redex a few times but it doesn't seem to make much difference.

Any ideas?

 

[Nasco12]

Bump.

 

[tsa]

Not sure about the relevance of this, but have you checked the integrity of your ignition system?

My recent experience:

http://www.mbclub.co.uk/forums/engine/218625-starting-troubleshooting-175cdt-carb-fueled-w123.html

 

[John Jones Jr]

Hell, that could be caused by several things. I wouldn't know where to start bar the usual suspects particularly the MAF but not necessarily so either. Really, rather than throwing parts at it I'd advise you get it checked out by your garage. Or get new MAF, Engine Temp switch, Plugs, Coils etc.

I noticed you make no mention of the car being serviced and if the servicing is patchy one part that gets overlooked is the Fuel Filter.

All bad guess work on my behalf.

 

[Nasco12]

The fuel filter was replaced a couple of years ago so it should be OK.

My understanding is that MAF faults will give you problems at all speeds. This is something that disappears within 30 seconds of the engine firing up.

I am going to see what happens if I change the coil packs and leads. It very much sounds as if moisture is getting in.

 

[Nasco12]

Turns out that changing coil packs and leads is not easy as I thought.

First of all, I can't disconnect the leads from the spark plugs. How can this be? I have done it before! Could it have anything to do with it being cold? Or is perhaps a consequence of the engine being reluctant to start?

Second, I can't disconnect the coil pack. The lead end is fine. But the other end is very tight. Indeed, I managed to damage the connector in the attempt. Could this be the cold weather again?

 

[John Jones Jr]

There you go.

https://www.youtube.com/watch?v=f9DNQgIGrXA

 

[Nasco12]

Well, it warmed up a bit today and I was eventually able to get the leads out. I replaced the leads and placed the one coil pack I had in both positions. No dice, the car would not and will not start. This is especially annoying given that it would start yesterday.

 

[John Jones Jr]

Have you got a spark & fuel?

You could try a new Crankshaft Sensor, they're cheap and a five minute job to replace. But be candid I'm only clutching a straws when suggesting changing any parts.

May be time to get a garage or mobile mechanic to have a look at it?

 

[Nasco12]

Thanks for the suggestions. Taking it to a garage is risky in that it being an intermittent fault there is a good chance that it will have cleared itself when they come to look at it.

Worse still, I have had to top up the coolant three times in two weeks. I have no idea why. The car is worth very little and I am beginning to wonder if I shouldn't throw in the towel and have it scrapped.

 

[John Jones Jr]

Well, that's a vital piece of info. If you're losing coolant it could be the Head Gasket gone/going. What were the plugs like when you took then out?

Time to get the car inspected by a pro, firstly to find out why it's losing coolant and then go from there. I presume it's worth the cost of an inspection and report from a garage.

What's the mileage and overall general condition?

 

[Dec]

Are you sure you have the correct spark plugs fitted?

Regarding the coolant loss, do you have an expansion bottle or a vent tube coming from the radiator filler neck?

Dec

 

[Nasco12]

The head gasket went a long time ago as they always seem to with the 111.945 engine. But what they do is they leak to the outside rather than get mixed up with the oil. The oil on the dipstick and inside the cap is fine. My approach has so far been to keep topping the coolant up as and when.

Having said that, I did notice some emulsion inside the (cracked) crankcase breather. But I wouldn't have thought that was a serious matter.

The mileage is about 85,000. The condition when I bought it was not great. There was no service history and there were numerous minor issues. Since then I have changed the oil, coolant, spark plugs, air filter, oil filter and fuel filter.

I replaced the spark plugs (with NGK BCP6ES) in 2014 soon after I bought the car. The issue with rough idling only emerged (if memory serves) about a year later.

Dec, please excuse my ignorance. There is a rectangular plastic container underneath the coolant filler cap. It is situated on the left-hand side of the engine bay as you look at it.

 

[Nasco12]

This is my previous car but it's the same engine.

 

[Dec]

I once had similar starting/running problems that you describe; I had the wrong plugs fitted.

How much coolant do you have to replace each time you top up?


Dec

 

[Nasco12]

1/2 a litre.

 

[Dec]

There is a short pipe on the lower part of water pump, it’s to do with the water pump bearing and is explained at time 7:50 in the video below, might be worth checking it out to see if there is any loss of coolant from there.

Dec

https://www.youtube.com/watch?v=Qr2UwFBM90Y

[YOUTUBE]Qr2UwFBM90Y[/YOUTUBE]

 

[Nasco12]

So, it was spark plugs. I put in a set of Bosch F8DC4s and the car started first time.

Here are a couple of pics of the plugs that came out. They look a bit black to my untrained eye and 1 and 4 had either oil or water on them.

from Flickr

A few other things:

1. They weren’t easy to get out. Plug 3 was particularly reluctant.
   
2. When I took the car for a test drive there was a lot of white smoke coming out of the back. Eventually this disappeared. Any ideas what was causing it?
3. The plugs have been in for 10,000 miles and 2 years.
4. Everywhere I go e.g. Opie Oils, EuroCarParts seems to give a different answer to what plugs should be in the car. Fortunately, there’s a sticker on the slam panel and that’s what I went by.
5. There was no substantial coolant loss on the test drive. This makes me think the coolant was lost during my repeated attempts to start the car.
6. My water pump does not appear to have the outlet at the bottom (or anywhere else).

 

[John Jones Jr]

Those plugs look far older than 10k miles! More like 30k...judging by gas blowback around the insulators.

 

[Dec]

Bosch F8DC4 are same plugs that solved my problem too.
Not qualified to comment on your old plugs, see how it all goes in the next few weeks.

Dec