HELP: 190E air-flow meter potentiometer worn...

[aander]

Hello all,

On both of my high mileage 190E-s 2.3 4V and
16V (both 1986) the potentiometer measuring
the air flow (on the side of the chamber just
below the air filter) is worn: reading are
very erratic.

Can someone tell me what the purpose of these
sensors is:

(1) Do they work to compensate for
air/fuel mixture when accelerator pedal is
suddenly depressed?

(2) Also, how much benefit in peformance/
driveability can I expect after spending
$600+ to replace the assembly. After serveral
inquiries I understand that the potentiometer
only is not available; one needs to buy the whole
housing and that is why it costs so much.

(3) Is there an after-market replacement for
the sensor only? Or, is there a shop that would
do it?

Any info greatly appreciated.
TIA,
Tony Ander
PS: Any sources in Germany??? I will be there for
a week later this month...

[mbdoc]

Works all of the time! reporting info to computer of the "air flow position". This helps the computer to richen the mixture durning acceleration & leaning the mixture for emissions all of the rest of the time.

Will cause IDLE & acceleration problems!
Replacement WON'T help the engine to produce more HP at all.

MB part number is 000-074-23-14.
Bosch number is 0 438 121 044.
I would replace the rubber pleminum boot that mounts to it as well, MB number 103-141-00-90

[aander]

Thanks so much for the quick reply as
well as the part numbers.

May I follow up with some more questions:

Can you please check the part no. for the
same air flow sensor for my other car,
which is also a 1986 but 4V 2.3L 190E.

By replacing the part I would expect better
engine response, is this correct (no, no
HP increase, I realize.)

Also, could you recommend a Bosch outfit
for these parts? I am really shocked and
reluctant to pay so much money for such
to replace the whole assembly, when only
a "small" part is worn.

Again, thanks so much for your help!
Really great forum and members.

Tony Ander
aander@newsignal.com

[mbdoc]

On the 1986 car you can replace JUST the sensor! MB part number 000-074-01-36. Easy to replace but can be a job to calibrate to fuel system.

[aander]

Thanks MBDoc,

For everyones benefit (I hope) here are the numbers I found
by actually reading them off the parts in-situ:

1986 190E 2.3 - 16
-----------------------------
pn. of intake assembly (with the flap and potentiometer on the
side)
Bosch 0438 121 044

pn for potentiometer only (black plastic enclosure)
3 430 591 017


1986 190E 2.3 - 8 valve
-----------------------------
pn. of intake assembly
Bosch 0438 121 010

pn for potentiometer only (black plastic enclosure)
3 430 591 031

===============

MBDoc, how hard it is to calibrate this thing? Wouldn't it
just be a matter of measuring closed and open potentiometer
readings and adjusting the potentiometer position on the
side of the housing?

Is anyone out there doing this? It should be a common problem
with high-mileage cars, as these thnings wear out, so, I would
think there is a market (need) for this service. It sure would
beat the $600 for a new assembly...

Thanks to all for a great site!!!

Tony Ander
aander@newsignal.com

[tombell3@ix.netcom.com]

I have a similar problem on my 1987 190E 2.3, with only 28,000 miles. Car sat for several years while my wife was ill, and has been a problem ever since. Spent about $1,200 to have the dealer drain the rotten gas and replace lots of parts/filters, etc. Earlier this year the head gasket blew, and paid the dealer $3,100 for that repair, just to have no acceleration about 2 weeks ago, and the dealer referred me to a muffler shop to get the clogged "Cats" replaced. Did that, and while much better, still have bogging down if I floor the accelerator. Hard to get up to freeway speeds quickly. Now appears the Mass Airflow Sensor may be the culprit. On this model it appears I can replace the Airflow Meter Potentiometer to correct that problem. I have ordered one, and wondering if I should look for some other issue. I have already replaced the fuel pump, check valve, accumulator, and fuel pump filter, and rebuilt the fuel distributor some time ago. I have tried several mechanics to get this car back into good condition, but with each try, it seems something else goes wrong. Will appreciate any advice.
Thanks,
Tom Bell
tombell3@ix.netcom.com

[optimusprime]

You can replace them but will need setting up after doing so.
To learn how to and know more about it read this ,.
Go to Google search in the box put this-



Bosch CIS-E AirFlow Service Potentiometer Replacment and Adjustment