HELP!!! POT removal
 

What do I need to do to remove the pot? I know about marking the air flow body, but what else has to be removed? I have my father's car partly disassembled right now. Do you have to remove any fuel lines to get to it? There is a cylinder thing right in front of it with 3 different fuel lines and 1 vacuum line connected to it that goes to the breather hose on air cleaner. What is that vacuum for/do? Does that have to be removed? I loosened the top line and gas started spraying out. I retightened it as of now. How much fuel should I expect to lose out of each line? Should I just put a bucket under the car to try and catch as much as possible? It is so miserable when trying to do this in 90+degrees in sunlight. I want to see if my POT is worn out and needs replacement. It has 160,000 miles on it. It is a 1987 300E. What else is going to get in my way? Sorry but I am kind of torn apart on what I should do exactly. I don't want to mess anything up.
Thanks
David

david, can only suggest that you define 'pot'. the learned people here able to provide assistance may not be familiar with that specific term.

airmass POTENTIOMETER. Sorry for any confusion.

I just happen to know what you are talking about.. Looks like you will have to remove the fuel pressure regulator ( the thing you are referring to), and perhaps also the idle control regulator..

Not that much fuel will come out.. You should be able to easilly catch it with a rag..

read this thread if you haven't already..

http://www.peachparts.com/shopforum/tech-help/65863-aiflow-meter-pot-source-bosch-cis.html

I lost the "boot" piece that is on the fuel pressure regulator. I haven't noticed anything different about the way it runs. What else would I have to remove to get the potentiometer?
Thanks so much
David

Don't know your layout, but on our 190E I had to remove the pressure regulator at both gas connections to the fuel distributor on top of the airflow meter, and the bolt that clamps it down. The hose that connects its vent to the breather hose is designed to contain gas that would spurt out if the diaphram ruptures. Gas flow was momentary, but avoid disconnecting the INPUT gas line to the regulator.

The pot was held on with four T-15 torx screws covered by a pair of pry-off plastic covers.

Steve

Is the input line the one that is a rubber hose then goes into a solid line? I am done, and I did NOT remove that one. That is the only one that I did NOT remove. I removed the small line on the bottom of the regulator and the one that is on top of the regulator. The one that is on the top is a short one. Is that the input?
Thanks
David

P.S.
Why shouldn't I disconnect the INPUT line if I didn't?

The one you did not remove is the input to the regulator. It is the main line from the fuel pump/filter/accumulator. The ones you removed are the ones I also removed on mine. The short one is the pressure regulator output line (input to the fuel distributor).

Steve

After I get my new POT should I just place it on the scribe marks that are already there and then take it to a mechanic for "fine" adjusting, or should I just put it on the scribe marks and leave it as-is. (as long as it fixes the problems). What exact problems were you having with your car when you replaced yours? On mine, the smaller pad had a spot that is worn through to shiny metal. The black face was gone on that part which is the part that is at idle. Does that mean that mine has to be replaced?
Thanks
David

David, I would refer to the thread that jay3000 links to above, it details my symptoms and what I did, with comments from others. Best it seems would be to adjust the trimpot with an ohmeter, then re-attach carefully aligned to the scribe mark. Car should run fine.

Fine tune using a voltmeter from pin 2 to ground, connector attached and car idling, by rotating the body of the pot to get that reading (0.7V). This would have to be done slowly and incrementally, tapping, letting the speed stabilize, check voltage.

Steve

Stupid question......When you talk about "pins" are you talking about the 3 different ones on the POT itself?
Thanks
David

Yes. With the connector attached, I think you can pop the plastic cover off the connector, exposing the sockets for making the measurement. I haven't done so yet, of course.

Steve