Topic: 190E Stalling (Read 12602 times)

drewprof · « **on:** February 11, 2009, 06:00:02 PM »

I am certain that some of you have heard of my saga

Anyway here is a quick run down of the issue and what I have done so far.
The car is a 1988 190E 2.3 8V
Problem:
Car stalls when I come to a stop either right away or after a few second to minutes of idling at the stop. This can happen no matter which gear I am on, that is D, neutral or even reverse. Yes I stalled the car while in reverse

Sometimes the car does not hold after I just start, it will quickly die. It will do that on two or three tries then it will work.
The car will also stall if I leave it idling in park all on its own; it will take it a good five minutes but it will do it eventually.
What I noticed:
Before the car stalls while at a stop I notice the oil gauge fluctuate a little more than usual then the economy gauge jumps to the center while the car shudders a little then poof, it's dead. Right before that the rpm drops a little too.

When I start the car it hits almost 1K rpm but immediately drop down to 800 rpm or so. It never hangs around in high idle.

When I put the car in gear the economy gauge is never at zero like what I see on my 560SEL while not moving. Sometimes it's at 1/4 and sometimes it's almost at the halfway mark.

When it's cold outside the car does not stall as often

Here what I have done:
Replaced the following: Fuel filter, fuel pump, Fuel Pump Relay, ICV, ICV upper and lower hoses, spark plugs, wires, distributor and rotor, air filter, oil and filter, new complete exhaust including cat converter but excluding the header.
Tested the following: Voltage at the pump is stable and continuous; Fuel pressure is nominal, fuel pressure differential is right within specs; voltage at ICV is 12V; adjusted timing with a strobe, checked for vacuum leaks at intake, break booster and others (there is a small leak within the heating control valve inside the dashboard, I hear that sucker but I don't think it will effect stalling because I removed its feeder from the engine bay just to see if it will), egr circuit was clean

What is it that I am missing or need to do?

GermanStar · « **Reply #1 on:** February 11, 2009, 06:24:45 PM »

No ovp relay? That thing can cause a lot of mysterious problems when it fails...

drewprof · « **Reply #2 on:** February 11, 2009, 08:05:37 PM »

I checked the OVP's fuse and it was fine. I am going to the junkyard tomorrow and pick up a couple to play with. If it turns out to be it, then I will get a new one.

CIS Flow Tech · « **Reply #3 on:** February 15, 2009, 06:30:34 PM »

You need to hook a amp meter in-line to the EHA, set it to read ma and tell me what the current draw is when warm and idling.

Larry

drewprof · « **Reply #4 on:** February 24, 2009, 12:41:46 PM »

I got a chance to measure the current at the EHA today: it was fluctuating between + and - 1 mA.
I also replaced the Fuel Pressure Regulator for good measure and the car is still stalling.

GermanStar · « **Reply #5 on:** February 24, 2009, 01:34:25 PM »

Did you ever try an OVP?

drewprof · « **Reply #6 on:** February 24, 2009, 01:54:55 PM »

Yes, I put in another OVP and I managed to have a problem in the process that eliminated the possibility that my original OVP is bad. I also went ahead and measured the Zener threshold and the relay's characteristics and everything was fine, thanks to the diagram on the OVP itself

In addition, I discovered what happens when the OVP isn't seated properly

This morning I swapped a the crank sensor, just in case, and the car still managed to stall.
I am hearing a click as if a relay is activating just before the car stalls. It's coming from my left side as I am sitting in the car. It sounded as if it was near the door or the front speaker... Strange!

There are several behaviors that I am noting right before the cars stalls. One is a surge then a drastic drop in rpm, another is simply a drop in rpm while another is a fluctuation in rpm. The last two are accompanied by small drop in oil pressure.

Oh, by the way, I am still in the dog house with no relief in sight

drewprof · « **Reply #7 on:** February 27, 2009, 05:51:19 PM »

Some more tests that I did today:

As you can see the lower chamber's pressure is just fine. The Lambda was almost 50%.

I went ahead and knocked the fuel/air mixture anti-tapering ball out and enriched the mixture a tad while monitoring the signal. There was no change in idle whatsoever

The car managed to stall while I had FULL pressure. It didn't fluctuate at all before stall, so I am thinking electrical here. Something is telling the car to turn off.

Tomorrow is another day!

drewprof · « **Reply #8 on:** February 28, 2009, 10:53:50 AM »

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:mad::mad:

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

drewprof · « **Reply #9 on:** February 28, 2009, 12:28:43 PM »

One good new to all this is that I no longer have the backfiring.
I readjusted the EHA back and compensated the idle air mixture to get a nice 50% duty cycle square wave. So I am back to "square one" where I have NO IDEA what's wrong with the car

I did however manage to stall the car after I plugged back in the ICV electrical connection after I removed it. While disconnected the idle on the car went up a little so I am very very tempted to run the car with the ICV disconnected but I noticed that when I leave out (electrically disconnected) the mixture is much richer. Is this normal?

GermanStar · « **Reply #10 on:** February 28, 2009, 12:38:58 PM »

I agree, it seems pretty clear at this point it must be an electrical problem. It could be almost anything, even a bad harness.

CIS Flow Tech · « **Reply #11 on:** February 28, 2009, 07:32:39 PM »

Drew,
I have been very busy lately but thinking about your car. I think you need to look at the airflow sensor plate rest adj. I am trying to find a good pic with procedure and put it into a format where I can post it.

Larry

Digmenow · « **Reply #12 on:** February 28, 2009, 08:11:46 PM »

OoOooooOO pictures!

Sorry. I got nothin' else for ya.

CIS Flow Tech · « **Reply #13 on:** March 01, 2009, 06:43:07 PM »

Look in the CIS thread "Lets talk CIS" you will find info on checking and adjusting 190E airflow sensor plates

Larry

drewprof · « **Reply #14 on:** March 03, 2009, 12:24:22 PM »

Here are some observations that I have collected after I made the EHA and Fuel Air mixture adjustments combo:

1. The car is NO LONGER backfiring
2. It hasn't stalled yet while at a stop
3. It did stall a couple of times at start up
4. I no longer hear a howling noise when I am driving over 50 mph (all this time I thought it was the exhaust)
5. When at a stop and in gear the economy gauge is almost zero (it used to go between 1/4 to even 1/2 of the way in) just like my W126 which is at exactly zero at idle and in gear.
6. The oil pressure does not seem to drop a little then fluctuate while at a stop and in gear; it's pegged to 3.
7. It seems like I have way more power but that could be in my head.

Maybe I should concentrate on the Cold Start Valve now, what do you think? I noticed that when the car is started cold it doesn't really stay at 1K rpm for more than a second or two.

GermanStar · « **Reply #15 on:** March 03, 2009, 12:38:13 PM »

How many times have you taken it out since your adjustments helped? Enough to convince you it's no longer on life support?

drewprof · « **Reply #16 on:** March 03, 2009, 12:44:12 PM »

Not enough to rule that the problem is gone but the car is behaving much better than my best efforts so far.
Will see tonight when I go back home

I am going to drive through downtown Baltimore just to increase the frequency of stop and go and see how it goes.

GermanStar · « **Reply #17 on:** March 03, 2009, 12:45:44 PM »

That sounds smart, I'd give it just a little more time to make sure it hasn't just been dumb luck. I am a big fan of dumb luck though...

drewprof · « **Reply #18 on:** March 03, 2009, 12:47:54 PM »

The dumb part I know all too well; luck will be tonight when wifey is convinced that I am not dumb

drewprof · « **Reply #19 on:** March 03, 2009, 06:29:18 PM »

Well I made it home! No stalling

The howling noise was back though and the oil pressure seemed to drop while at a stop but the car held together.
A few more tests this weekend I guess.

News:

Author Topic: 190E Stalling (Read 12602 times)