Petrol Diagnostics

Back to Forum

Post a Response

Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% - Fixed #

Posted by Les Smith on October 24, 2009, 7:38 am

Year of Manufacture *: 1990
Engine Code or Type *: 16 valve

Hi. Merc in for mot and one of the items it failed on was co at 7%. Cant locate any adjusting screw. It is a Pier burg carb. On top is a three screw cover with a plug to add ATF.On the bottom is a screw similar to a mixture adjuster on an old SU. It has a wire attached to this screw.This screw is seized. Anyone worked on this type of carb who can point me in the right direction.
Regards
Les

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 24, 2009, 1:27 pm, in reply to "Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Mark Carter

Hi, I seem to remember a long two part tool that slid down the middle of the damper tube and located on the upper part of the needle. HTH

Regards Mark.

Modern cars, Its all wizardry and witchcraft

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on October 24, 2009, 3:06 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Kevin Apps

Les.
Normally these have injection on that year (or the ones i,v worked on did and they adjusted via a hole in the air filter case with a long allen key (2.5mm ?).
I know what Mark means (a two part tool outer part stops the dashpot from turning while the inner adjust,s mixture)but never had to use said tool on a 190.
Kev.

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by David Davies <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5218' width='330' height='300' border=0 style='border:none;'> on October 24, 2009, 5:33 pm, in reply to "Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
David Davies

Les,
The part you refer to on the base of the float chamber is a combined idle shut off valve and main jet adjuster.I'd suggest removing and renewing this.Part no.ZK7900.

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on October 24, 2009, 7:13 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Peter Mutlow

Hi Les,

Had one the same a few years ago and the adjuster is at the bottom with the wire attached. I could not shift it so it went to the dealers for them to sort.

Mark and Kev,

Think you are referring to a Stromberg Carb with that adjusting tool. Not found on Mercs as far as I know.

Regards

Pete M

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on October 24, 2009, 10:33 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Mark Carter

Hi, you may be right, it's been a while and I have slept since then

.

I do know of the adjuster on the bottom of the float chamber that you mention, I seem to remember that some had a normal "hex" head and some of them had a special tool with two locating pins to "drive" the jet, but never saw one with a wire. You live and learn every day.

Regards Mark.

Modern cars, Its all wizardry and witchcraft

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by les smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1209' width='330' height='300' border=0 style='border:none;'> on October 25, 2009, 9:22 am, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Leslie Smith

Hi All.
Thanks for the replies. Looking at Kevs reply I re read my post and noticed I put 1999 should have been 1990. Sorry

I will look again on Monday and if I cant move will refer to Davids post.
Cheers

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on October 25, 2009, 11:21 am, in reply to "Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"

Les.
Just had a rummage around the cellar and dug out an old carb data book. If you have a fax i can send the info to you.
Kev.
ps 2.3 ?
pps are you sure its a pierburg and not a stromberg as i can,t remember pierburg doing a VV.

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by les smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1209' width='330' height='300' border=0 style='border:none;'> on October 25, 2009, 6:28 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Leslie Smith

Cheers Kevin. 100% 2.3 and pierburg. Fax No 01721729813.

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by Darren Glass <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1923' width='330' height='300' border=0 style='border:none;'> on October 25, 2009, 7:31 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"

Hi Guys,

New to the Forum so be gentle.

(Background - Used to be the Mercedes Technical Support for Autologic for 5 years, prior to that 17 years at main dealer)

Coming in a bit late on this one I guess!!

We did not see many of the old carb systems at dealer but the ones we did see - never experienced siezing up of the mixture adjuster.

It is as previously mentioned - It is the single pole solenoid at the base of the carb. This is locked in place by a 22mm lock nut and by releasing the lock nut and the screwing in the solenoid (normal RH thread) will lower the mixture setting. Used to be quite sensitive by memory!!

Also these carbs used to have the diaphragm that would split / tear. (accessed by the removal of the 3 flat bladed screw on the upper housing).

Good Luck but I am sure you have resolved by now

Darren Glass
MB-Car-Tech

Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #

Posted by les smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1209' width='330' height='300' border=0 style='border:none;'> on October 25, 2009, 9:10 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Leslie Smith

Hi Darren and welcome. Never too late. Car coming in tomorrow. It is the lock nut that is seized, but now I know that this is the way to adjust the mixture I will try harder as my school teacher used to say.
Les

Fixed #

Posted by Leslie Smith on October 26, 2009, 6:26 pm, in reply to "Re: Mercedes Benz 190 2.3 1999 - Running too rich, CO 7% #"
Message modified by board administrator October 27, 2009, 11:19 am

Thanks for all the replies and Kevin for the fax. You went out your way to help and it is much appreciated. Although lock nut tight it did not help that carb was rubber mounted. Held base with water pump pliers and once loosened a straight forward job.
Regards
Les

Re: Merc 190 2.3 runnung too rich * FIX*

Posted by Paul Howd <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5151' width='330' height='300' border=0 style='border:none;'> on October 26, 2009, 6:38 pm, in reply to "Merc 190 2.3 runnung too rich * FIX*"
Paul Howd

Be aware that (assuming no other problems) the most likely reason for rich running at idle on one of these is wear on the top/thickest part of the metering needle and of the jet orifice that the needle goes into (IYSWIM)

You can compensate for this by adjusting the jet position but the likely outcome is weak mixture and loss of power at higher speed/loads.

You may need to consider the possibility of replacing the needle/jet if this proves to be the case.

« Back to index

[ Petrol Diagnostics ]

Copyright © uk autotalk