Again, this problem!

[benzonline]

Looks like my 99 C230K only likes to do this in the summer. Once again just last week, it started (only when cold starts) fires up and starts choking..wanting to die for about 5 seconds and then it revs up and all is fine all day.

6 months ago I replaced my fuel filter and I thought it solved it but now its back again. Spark plugs have been done a month ago. You name it, its been done except for o2 sensor but I dont think that is the cause as its running perfect once started, aswell no check engine lights.

What gives?

[mazdalowandslow]

Ya know.. Mine does the same thing ... It happens only about once a month... and only under a cold start.

[RemoLexi]

mine does that from time to time it kinda chokes when it starts so I have to tap the gas. im thinking it may be the battery ?!

[benzonline]

Yes but its not normal....how do I fix it?

[Proven Guilty]

Test the MAS. pull the plug while it's running to see if the idle changes. it's probably on it's way out..

[benzonline]

It was just changed and had this problem before it was changed aswell. Problem only occurs in the summer.

[Proven Guilty]

Originally posted by benzonline
It was just changed and had this problem before it was changed aswell. Problem only occurs in the summer.

Don't rule out the MAS again, simply because you've changed it. Have you tested it like I just recommended?

3 things required to make a car run:
-Fuel
-Air
-Spark

It's process of elimination, and maintaining the correct balanced levels to keep it running smoothly. I've bought brand new parts, and received defective new in box, or had them fail extra quickly. My suggestion would be not using K&N air filters, and clean out all the plumbing from the air box to the throttle body. I'd bet a buck there's oil in there and that your new MAS is fubar.

A simple checklist of things to look at:
-Vacuum lines
-Plugs, Coils, Wires
-Fuel Preassure
-A:F ratios

[First Benz]

If it likes to stumble only when cold and only for a few seconds, it sounds very much like a leaking fuel pressure regulator.

An extremly easy way to check this is to pull the vaccum line off the regulator, and see if there is gas in the line. There shouldn't be ANY at all. If need be, smell the vaccum line, But most times, if the regulator is leaking, it's pretty evedent.

Check that and let us know.

Eric

[benzonline]

I will try to do this guys....thanks alot! Atleast I know where to look now.

[rako77]

hey , did u ever find the problem ? And how do i do the same test, i mean how do i find this vacuum line to the fuel pressure regulator? thanks in advance..

[First Benz]

Here's a pic, I drawed an arrow to the regulator, which has the vaccum line right on it. :)

http://i21.photobucket.com/albums/b291/Racingman24/engine.jpg

[benzonline]

Its intermittant...sometimes it does it worse or sometimes not at all. I will check the line to that regulator somehow thanks!:)

[JOESID]

Hey did you get a chance to look into yours? Mine has started doing that again too.

[rako77]

Originally posted by First Benz
Here's a pic, I drawed an arrow to the regulator, which has the vaccum line right on it. :)

http://i21.photobucket.com/albums/b291/Racingman24/engine.jpg
there are two pipes right there . which one should be checked; the thin black plastic one or the other?

[rako77]

I know this is an old thread but my 99c230k started to do the shaking and hesitating on cold starts again . It has been going on for a couple a years now and happens only during the warmer part of the year but it seems to me that now the shaking is harder and longer .
Anybody with any ideas please help...
many thanks in advance.

[mazdalowandslow]

So a little update. I should of done this about 2 months ago. I had the random start up shakes. I also devolped a shudder while under hard acceleration, that happened randomly. I replaced both ignition coils and it has seemed to solve this problem. In two months nothing.