I have a 2000 S430. After taking it to the dealer for rear turn singal issues, the car has problem starting when cold. The car starts, but it dies imediately. I have to keep starting it (about 15-20 times), & it finally keeps running. It appears that when the temparture goes up to about 40 C, it starts and keeps running. It appears that gas/air mixture is not right when the car is cold, and after it warms up a little, it runs OK. Is there any cold start valve/control/etc that is not working? Any help would be appreciated. The dealer denies doing anything, but it is strange that this problem started after taking it to the dealer. Thanks.

 

Hi,

Is the outside temperature display reading correctly?

Get the OBD codes scanned. these will give an indication of what might be wrong. Could be the MAF thermistor but could be many other things as well.
Codes are the starting point.

Stuart

 

Stuart,
Thanks for your reply. The outside temparture seen not to have that much affect with this problem. The problem occures even when it is about 70 degrees outside. I have change the MAF, but nothing changed.

Bruce

 

Bruce.

As I stated previously. Don't just keep changing parts. Get the codes read. That is what they are for.

Now you state that it is ENGINE, rather than AMBIENT temp sensitive, so I go with my second guess CPS but no codes found will give this greater credibility.

I don't have the budget to spend on parts. I go for a 100% diagnosis before spending a penny.

Stuart

Stuart

 

Stuart,
Thanks for your advise. If/when I take it to the dealer to check the codes, they come up with several. If I decide to change all the parts that codes show, it wouldcost me thousands. I realize that a problem may trigger several codes, but our dealer in Memphis is not any good. They want you to replace half of the engine.

 

Bruce,

I think you miss my point.

Firstly get the codes (preferably read for free)
THEN come back to us here and we will give you our opinion of what the codes MIGHT mean.

A code doesn't mean the part is faulty. It signals a fault (eg parameter out of range) but it doesn't necessarily tell you what is wrong. This is where experience and analysis/diagnosis come in.

e.g. P0300 = Muliple misfire. It doesn't indicate why. An MB dealer will fit new everything and then declare the priblem is fixed. An expensive (to the customer) way of responding with parts cost set way higher than cost. However fiddling around swapping components can be time consuming and time = money unless you do it yourself.

However P301 is Cyl. 1 misfire. This indicates something specific to Cyl 1. So by swapping Cyl. 1 plug, lead and coil pack you can see if the problem moves. If so then you have identified the cause. If not then you need to look at cyl 1 compressor, injector etc. etc

However other codes are more indicative of a component fault but still experience is needed.

Assuming the vehicle is OBDII compliant = post 1996 ish then any garage including mall service bays can read the codes (some for free).

So what are the codes. Don't immediately get the garage to respond to the codes. As them for their advice and come back. If we all agree then maybe you go back to them.

 

OK. I will have the code checked and post them. Thanks.

 

it might be the cps (crank sensor) i had a similar problem before, read this post and see if your problem is the same:
https://mercedesforum.com/m_72057/mp..._/tm.htm#72057

 

I have fixed the cold start problem. The MAF connector was loose. I just happened to look at it, and it was half way out. I pushed it in all the way, and now it starts and runs OK. But there is still the battery drainage problem. I believe it might be related to the air suspension components, but not sure.

 

Bruce.
You stated that ..."I have change the MAF, but nothing changed."
You didn't state why you changed the MAF.
Guess the plug didn't go fully home when you changed it.

You now state battery drain problem.
You give no details other than you suspect the air suspension system. Why do you suspect the air suspension system? Very unlikely this is the cause of a flat battery.

Once again codes are the best way to proceed however the most likely cause will be bad battery (age?) or poor charging circuit.
Codes that refer to systems other than the engine/trans need to be read by MB or at least a garage with specialist equipment for which a charge will no doubt be made....but this info is worth up to 50USD when you have a problem. Parts are VERY expensive and you do not want to change them unless you are sure the component is faulty.
It is unlikely to be something left on (e.g. interior light) since the system shuts down if you leave a door ajar etc after 10mins or so.

Please confirm that you do not leave the keys in the ignition or near the car. This is the most common cause of a flat battery since the presence of the key nearby stops the computers from shutting down and the small drain leads to a flat battery.

Lets have the full details and history (e.g. how long have you owned the car etc) and I will see if I can give you some direction.