190E 2.3 8V Fuel Pressure Questions
 

What should the fuel pressure for a 1988 190E 2.3 8V be at the fuel distributor test outlet?
Should the fuel pressure creep up to its nominal value or simply leap to it when the fuel pump is on?
What are the proper setting procedures and measurements to make sure that the EHA is set up properly for the fuel pressure differential as per specs? What are those specs?

Anyone?

Fuel pressure should be 5.2-5.6 bar measured at the TOP of the distributor. Either at blind plug OR cold start injector.

There are several threads about CIS fuel pressure problems.

What is the problem with your car?

My car keeps stalling when it comes to a stop and even stalls if you leave it idling.

I rechecked the fuel pressure today and I am not getting more than 4 Bar. I must be doing something wrong with the CIS gauge tool.
Two days ago when I was testing just the lower chamber I had 5.2 Bar. Then yesterday it dropped to 3.5 Bar.
Today I hooked up the A/B with valve hook up to measure the upper and lower chamber's pressures but as noted the pressure was no higher than 4 Bar. In addition, it didn't matter if I had the valve open or closed on the CIS tool the pressure remained the same thus showing no differential. I know that I must be using the tool totally wrong considering that I am at an angry stage right now (It has been a whole year of hell trying to figure out what's stalling this car and I am tiered of dumping parts on it and I sure don't want to take it to a mechanic so I can get the usual lies session).
Right now I am breaking for lunch but I will this afternoon run some more tests and actually this time print the damned CD out.

You might look at threads with SSS mentioned.

One of the most common causes of sudden stalling issue is the air flow position...that is if the car ALWAYS reatarts after the sudden stall.

You mean the plate's clearance against the intake inlet or the metered air after the ICV?
I just came back from testing and I am only getting 4 Bar by connecting the outlet to the cold start valve on the fuel distributor to the CIS fuel pressure measuring gauge. This time I only used a single hose so I don't get confused with the two hoses setup. I then unhooked the hose and measured at the test outlet (lower chamber) and pretty much got the same result. If my gauge is measuring correctly (which in my case I ALWAYS doubt) this means that the EHA is NOT compensating to create a 0.4 Bar difference between the upper and lower chambers. I guess when it cools dwn a bit outside I will go back and turn the EHA inner allen adjustment screw clockwise to get a differential reading/setup, right?
Could it also be that because the pressure is so low that the EHA doesn't even bother to work the pressure?:confused:

Could be that I have a weak fuel pump? It's fairly new

I went back out for another series of tests. This time I simply jumped the fuel relay socket to activate the pump without the engine on.
All I got is 2.3 Bar as the main pressure.
I put back the relay and started the car and the most I got was tad below 4 Bar.

I then went ahead and replaced the fuel pressure regulator (again) and I got the same results.

h, the car smells funny when the engine it's on. I get an eye burning sensation and almost feel like throwing up (I am not working in an enclosed area)

Sounds like a pump or filter IF the tank has enough fuel.

I got the fuel pump and filter at the same time less than a year ago. The car was stalling before that then it kept on doing that until one day I set the EHA and Lambda. I was stalling free for a few months then problems came back. Now no matter what I do it ain't sticking.
Here is the situation as of now:
1. I cleaned the strainer at the fuel distributor inlet
2. After that cleaning the fuel pressure rose to 4 bar just by shorting the fuel pump relay socket without starting the engine.
3. I put the relay back and then started the engine, the pressure dropped to 3.2 or 3.5 Bar.
4. The pressure SLOWLY went up passed the 5, 5.6 the passed 6.5 bar. At 6+ the car was shuddering.
5. I shut the car down and went to bed.
6. Next day the car wouldn't start (the usual) but after I got going the pressure was still below 4 and climbed slowly to 5.
7. Revved the engine and a loud pop at the plate was heard. Must be running very lean!

My question is this: Shouldn't the pressure on the main line climb to 5.6 bar as soon as the pump is on? engine off (relay shorted), or engine on (relay in place).

The vendor for my fuel pump is willing to take it back and send me a new one. It's a Bosch but it looked slender than my original which unfortunately I had tossed away while clearing up clutter in my garage. Any ideas what I should use to plug the hose coming from the fuel tank while the fuel pump is out and being swapped?

I am at an impasse. I guess I have been for a while.
Should I just buy all the CIS parts and if that doesn't work get a new engine?

Ok, let me do this over!

I am going to simply measure the main line's fuel pressure, you guys tell me if those readings are ok and what to do next.



This time I am measuring the line itself

Overview:
Setup
http://i713.photobucket.com/albums/w...f/IMG_7477.jpg

Bleeding container and other environmentally sensitive stuff
http://i713.photobucket.com/albums/w...f/IMG_7476.jpg

Where to connect
http://i713.photobucket.com/albums/w...f/IMG_7479.jpg

Connection
http://i713.photobucket.com/albums/w...f/IMG_7478.jpg

Let it rip: Where and how to bypass the fuel pump relay to get the pump pumping
Short these two connectors
http://i713.photobucket.com/albums/w...f/IMG_7480.jpg

The red and black wires are connected together on their other ends.
http://i713.photobucket.com/albums/w...f/IMG_7481.jpg

Bleed the instrument
http://i713.photobucket.com/albums/w...f/IMG_7482.jpg

No more bubbles
http://i713.photobucket.com/albums/w...f/IMG_7483.jpg

Read instrument
http://i713.photobucket.com/albums/w...f/IMG_7484.jpg

Shut the pump by disconnecting the short (remove the wires)
then read again
http://i713.photobucket.com/albums/w...f/IMG_7485.jpg

Please submit your observations and analysis before I proceed any further. Also do submit any future steps I should take based on this result.

A little over an hour elapsed

Pump off
Instrument in line
Reading: 3 Bar

Perfect. >= 2.8 is the spec you want for holding pressure....so you are good.

Great, what's next? Should I bother with reading the upper and lower pressure differential again or just go ahead and replace the fuel distributor and air sensing plate assembly since I have one sitting next to me? (it also has a fuel pressure regulator, EHA, and position sensor)