1988 190E 2.3 stalling - Page 3 - PeachParts Mercedes-Benz Forum

professor · #31 02-28-2009, 01:53 PM

Since the air fuel mixture tower adjustment had no effect, I went ahead this time and adjusted the EHA.
The first shot shows the set up where I monitor the rpm via the main ignition wire, the voltage on pin three set on DC to read the average effective voltage and the scope to watch the waveform as it actually changed from lean to rich. Compared to the previous results I was able to enrich the mixture this time by changing the EHA setting. In effect I increased the pressure between the upper and lower chambers of the fuel distributor.

Oh, and the car still stalls while at idle

Clearly my problem is NOT with fuel pressure or any CIS related Item.

professor · #32 02-28-2009, 03:06 PM

The only good news that I can share right now is that the car is NO LONGER BACKFIRING!

professor · #33 03-01-2009, 01:32 PM

Well here is some good news: all that tweaking yesterday may have fixed the problem. This morning the car started right up and it never stalled while idling or on my way to the junkyard to get some toys. Let's see how it does tomorrow in traffic on my way to work.

Observations:
Smooth and stable idle
No oil pressure fluctuation
No severe vacuum reading losses at the economy gauge
Car accelerates very well
No backfiring
NO STALLING... for now

slk230red · #34 03-01-2009, 02:16 PM

Quote:

Originally Posted by professor

Well here is some good news: all that tweaking yesterday may have fixed the problem. This morning the car started right up and it never stalled while idling or on my way to the junkyard to get some toys. Let's see how it does tomorrow in traffic on my way to work.

Observations:
Smooth and stable idle
No oil pressure fluctuation
No severe vacuum reading losses at the economy gauge
Car accelerates very well
No backfiring
NO STALLING... for now

I'm pulling for you Drew. Quick question, when you checked your fuel pressure, how was the leak down? Did the pressure hold when you turned of the fuel pumps?

Dave

professor · #35 03-01-2009, 02:43 PM

Quote:

Originally Posted by slk230red

I'm pulling for you Drew. Quick question, when you checked your fuel pressure, how was the leak down? Did the pressure hold when you turned of the fuel pumps?

Dave

Yes the pressure held and nicely and slowly went down until I purged it so I can unhook the CIS tool.

professor · #36 03-04-2009, 03:42 PM

Update:
The car so far hasn't stalled since I fiddled with the pressure adjustment for the EHA and the fuel mixture at the tower. As matter of fact it seems to have picked some extra power

while idling very smoothly.
I also noticed that it no longer backfires, the oil pressure gauge does not fluctuate as wildly and I think this is important, the fuel economy indicator is no longer at or over 1/4 from the left when I am at a stop in gear; as matter of fact it's almost at zero.
I tested the car in Washington DC and Baltimore traffic during rush hour

but it's all good

.
Let's see if it holds up for the rest of the week

dpkreuze · #37 03-05-2009, 12:39 PM

I knew you could do it.

professor · #38 03-05-2009, 02:42 PM

Quote:

Originally Posted by dpkreuze

I knew you could do it.

I feel fantastic, that's for sure.

professor · #39 03-05-2009, 02:58 PM

I want to thank Larry from CIS Flow Tech for his instructions and Germanstar for setting us up. Those are real good guys in the Benz community (and Ferrari).
Thanks Larry!

http://www.germanstar.net/forum/index.php/topic,26.0.html

Jigracing · #40 03-05-2009, 03:47 PM

That is encouraging news!!! I am virgin Mercedes owner with my newly purchased project car an '87 109E 2.3-16. I was watching your thread here. I am very happy to see you got it fixed. Way to go!

socaleuro · #41 03-08-2009, 04:31 PM

Quote:

Originally Posted by professor

I just finished doing some adjustments, so before I knocked the tower ball out to reach the fuel/air mixture I remeasured the fuel pressure and monitored the duty cycle.

I then drilled the ball out and adjusted the fuel mixture a tad richer but that didn't influence the idle at all. What's up with that? I did see the duty cycle change to the rich side but that's about it.

Do you have any more pictures of you testing the fuel pressure out? I am lost as to where or how you get the differential pressure, or what it even is for that matter. As far as I know, you test fuel pressure by installing a gauge w/fitting as in the 2nd picture, but your first pic also has me thrown off. What is the correct procedure?

professor · #42 03-08-2009, 07:19 PM

Connect one end like you see in Picture #2 to the test port for the lower chamber. Connect the other end to the upper chamber via the cold start outlet on the fuel distributor. If your EHA is functioning properly you should get a differential of .4 bar while pressure is on. The put pressure on the system remove your fuel pump relay and bypass the connectors to get the pump to run.

Another way is to read the upper chamber alone, then connect to the lower chamber and subtract the results. This is acceptable if you have a simple gauge with a single test line.

socaleuro · #43 03-10-2009, 12:35 AM

Quote:

Originally Posted by professor

Connect one end like you see in Picture #2 to the test port for the lower chamber. Connect the other end to the upper chamber via the cold start outlet on the fuel distributor. If your EHA is functioning properly you should get a differential of .4 bar while pressure is on. The put pressure on the system remove your fuel pump relay and bypass the connectors to get the pump to run.

Another way is to read the upper chamber alone, then connect to the lower chamber and subtract the results. This is acceptable if you have a simple gauge with a single test line.

Ah ok, thanks! I believe you posted (somewhere) that you obtained your set up from Harbor Freight, if so, is it this http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97706 ? Are there any adapters/fittings that will fit the CIS system. I don't mind checking one chamber at a time.

professor · #44 03-10-2009, 01:58 AM

Quote:

Originally Posted by socaleuro

Ah ok, thanks! I believe you posted (somewhere) that you obtained your set up from Harbor Freight, if so, is it this http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97706 ? Are there any adapters/fittings that will fit the CIS system. I don't mind checking one chamber at a time.

That's the exact kit and all fittings are included.

professor · #45 03-29-2009, 01:15 PM

Update:
It's been a month and the car hasn't stalled or even hinted a hesitation. It's running very smoothly and I haven't noticed a drop in gas mileage; I am still getting 28-30 Highway and little less in the city.