190E starts but dies as soon as I stop cranking - Page 2 - PeachParts Mercedes-Benz Forum

w123fanman · #16 07-15-2016, 08:58 AM

Let's just chalk this up as weird: the car fixed itself.

When I drove it the other day, it took forever for the engine to get to the point where it switched from running poorly to running correctly. The car was very much down on power until whatever started working correctly. Yesterday, I started it up and it started much better but was idling low for a few seconds then ran perfect. This morning, I started it up and it started normally and ran normally. So we progressed to not wanting to stay running, to not wanting to run, to running but running poorly, to running correctly and I'm not sure I had anything to do with it. I'm suspecting that could have all been related to the EZL but really not sure. I'll just keep the spare ECU, MAS relay, and EZL in my trunk just in case.

w123fanman · #17 08-22-2016, 11:58 AM

The car didn't fix itself. For the past month I have been having similar issues. It takes forever to start then idles at 480-520 rpm and will die as soon as I put any throttle for about a minute or so until it warms up. It then idles at the same speed and can bog down while trying to pull out of my driveway. After driving for a few minutes, it won't bog anymore but still idles low.

I have replaced parts but I have no clue if the replacements were any good, they were off of my parts car. It ran better than this engine ever has but it hasn't ran in over 3 years. First thing I replaced was the CIS coolant temp sensor, didn't change a thing. Last night, I changed the fuel accumulator (nasty job having 3 year old gas gushing down my arm) and it seemed to idle better when hot but when the engine was cold the morning (I changed it with the engine hot last night) it started exactly the same way as it has been for the past month.

Any ideas? I'm probably going to try to change the fuel pressure regulator then check the idle air control valve. I'm going to order a new CIS temp sensor as well.

Is there any way to tell if my fuel accumulator is bad? Or if the pressure regulator is bad? Or what resistance values I should be getting from the temperature sensor?

Ferdman · #18 08-22-2016, 01:59 PM

w123fanman, before throwing more parts at the problem it would be a good idea to have a MB-trained tech diagnose the root cause of the problem. Then buy the part(s) you need for the repair. Swapping in used parts in unknown condition will only complicate the diagnosis and repair.

w123fanman · #19 09-08-2016, 02:08 PM

Parts I have are from a car that ran far better than mine ever has, just that was 3 years ago. I am going to test my old fuel accumulator to see if it was actually bad. The car is starting better now but I don't have an explanation for that. My go to Mercedes guy is out for the next 8 months for recovery from hip replacement. He'll diagnose it for cheap or even free but if I go to any of the other local shop it'll be at least $200 to diagnose. I may call up a Mercedes guy I know 3 hours away to see what ideas he has.

Stretch · #20 09-10-2016, 04:37 AM

I'm a bit late to this party.

I assume this vehicle has been sitting for a while - as you mention "three year old gas"

Injectors are probably clogged and corroded. If you have a pop tester remove the injectors and see if they dribble / leak don't spray nicely. When working correctly these things stutter making a kind of a weird almost screeching noise. (Remember this is a CONTINUOUS injection system so they need to do this all the time)

The plunger for the fuel distributor also needs to be free and able to move nicely. The best way to check this is to remove it check visually for leaks and good motion. They can get a little sticky especially after sitting for a while.

The best thing you can do for the car is to chuck that old fuel - failing that use some sort of fuel stabiliser.

####

As for messing about with the air flow potentiometer - well that might have been a bit of a mistake - they should read about 0.7 VDC between pins one and two at an idle of 800 rpm (ish). Problem is you need the good operating temperature - idle - and duty cycle for this to come good. So it can be a pain in the arse - very difficult to adjust this when you've got problems elsewhere on the engine.

w123fanman · #21 09-10-2016, 10:45 PM

Quote:

Originally Posted by Stretch

I'm a bit late to this party.

I assume this vehicle has been sitting for a while - as you mention "three year old gas"

Injectors are probably clogged and corroded. If you have a pop tester remove the injectors and see if they dribble / leak don't spray nicely. When working correctly these things stutter making a kind of a weird almost screeching noise. (Remember this is a CONTINUOUS injection system so they need to do this all the time)

The plunger for the fuel distributor also needs to be free and able to move nicely. The best way to check this is to remove it check visually for leaks and good motion. They can get a little sticky especially after sitting for a while.

The best thing you can do for the car is to chuck that old fuel - failing that use some sort of fuel stabiliser.

####

As for messing about with the air flow potentiometer - well that might have been a bit of a mistake - they should read about 0.7 VDC between pins one and two at an idle of 800 rpm (ish). Problem is you need the good operating temperature - idle - and duty cycle for this to come good. So it can be a pain in the arse - very difficult to adjust this when you've got problems elsewhere on the engine.

Let me clarify. The parts I pulled are off of a car that sat for three years. My car hasn't, I have been driving it for nearly two years. I have had a few parts fail before that I have replaced concerning the fuel and ignition system. It has new plugs (denso non-resistor), wires (NGK, seem to be better quality than Bosch), a good used distributor and rotor (seriously looked mint, Bosch & Beru), new injectors with deals and orings (Bosch), good used EHA, good used speedometer sensor, new oxygen sensor (Bosch). I also recently changed the entire fuel distributor/air plates assembly over because my air flow potentiometer was bad and I didn't want to mess with taking a known good one off and then having to get it adjusted correctly. This one was still at the factory set position. It also had the air plate adjustment at the factory position because the ball was still in the tower. Once I installed that, the engine ran better than ever before it started having the current issues.

Stretch · #22 09-11-2016, 04:52 AM

Quote:

Originally Posted by w123fanman

Let me clarify. The parts I pulled are off of a car that sat for three years. My car hasn't, I have been driving it for nearly two years. I have had a few parts fail before that I have replaced concerning the fuel and ignition system. It has new plugs (denso non-resistor), wires (NGK, seem to be better quality than Bosch), a good used distributor and rotor (seriously looked mint, Bosch & Beru), new injectors with deals and orings (Bosch), good used EHA, good used speedometer sensor, new oxygen sensor (Bosch). I also recently changed the entire fuel distributor/air plates assembly over because my air flow potentiometer was bad and I didn't want to mess with taking a known good one off and then having to get it adjusted correctly. This one was still at the factory set position. It also had the air plate adjustment at the factory position because the ball was still in the tower. Once I installed that, the engine ran better than ever before it started having the current issues.

Oh right - OK - a bit different than I thought.

(But) the new airflow plate assembly: Did you change the fuel distributor with it?

You see strange low idle speeds might be due to sticky fuel delivery components such as the plunger in the fuel distributor, the air flow plate and the EHA (in the wrong position)

w123fanman · #23 09-12-2016, 12:52 AM

Quote:

Originally Posted by Stretch

Oh right - OK - a bit different than I thought.

(But) the new airflow plate assembly: Did you change the fuel distributor with it?

You see strange low idle speeds might be due to sticky fuel delivery components such as the plunger in the fuel distributor, the air flow plate and the EHA (in the wrong position)

I switched over the fuel distributor itself and started it. It started poorly and bogged, while revving it seemed like it wasn't giving even fuel delivery. I don't know if that could be because of the system losing pressure or what, I didn't have enough fuel in the car to run it for long. I guess my next course of action will be to get more fuel, test it again, then if that didn't work I will pull the air flow plate assembly and spray it with carb cleaner to get any junk out that might be causing it to be sticky. I don't know if the EHA is adjusted properly, I currently have one from a 3 liter on it, which I assume is adjusted differently. I have a 2.6 one that was on the engine before but I switched it to see if maybe the EHA was bad but it didn't seem to be the case. I know there are ways to adjust it but I don't have any of the tools for that and unless I can rent them for cheap I would rather not mess with it. This car is eventually getting the 3 liter M103 I have sitting in my garage with electronic fuel injection (Megasquirt III) or a M104 3.2L that already has EFI

Stretch · #24 09-12-2016, 12:59 AM

The EHA adjustment instructions on the internet seem to me to be of the "twist it a quarter turn it'll be amazing" advice that I personally avoid like the plague. Always best to measure what you are adjusting rather than using the force. If you don't have the fuel pressure kit with the 2 way switch forget it.

The first step I can recommend is to simply remove the fuel distributor from the top of the mixture device and check for a freely moving plunger.

lorainfurniture · #25 09-13-2016, 09:24 PM

When did you do the ignition system tune up?

w123fanman · #26 09-15-2016, 01:09 AM

Quote:

Originally Posted by lorainfurniture

When did you do the ignition system tune up?

I was about 10K miles ago. I am thinking I will remove the distributor cap and check for carbon buildup on it tomorrow.

w123fanman · #27 10-27-2016, 05:30 PM

I wanted to follow up on this thread for anyone who may be reading this later as I find it annoying to read thread after thread about an issue and no answer as to what the fix was.

The fix was replacing the OVP. I had tried swapping between the one in my car and a spare but it didn't change a thing. I figured my OVP was fine since nothing changed between going between the original and the spare. I tracked down my starting issue to the cold start injector. It wasn't firing. I looked at the wiring diagram and there were 3 main items on the circuit that could make the injector not fire, the MAS relay (AC and fuel pump relay in one, check you fuel pump relay if you have na older car), the CIS temp sensor, and you guessed it, the OVP. Since I couldn't do anything about the sensor or MAS relay until I got new parts, I decided to take my spare OVP and resolder it. Plugged it in and that was that. Car starts and runs so much better now.

puzzler · #28 10-30-2016, 11:31 AM

a really interesting trail of experiments and tests..conjecture and assumption..You assumed the OVP relay was fine after changing it and having the same results, right? Lots to follow here..Just as I assumed my fuel pumps were okay becuaase just previously I disconnected one pump and suddenly the car ran fine on the other pump only..Then when it died I refused to test the pumps because having TWO fail immediately at the same time?? No way..but this is exactly what happened. I was tearing the car apart looking for failed wiring and pricing out ECU replacements when finally I checked the rear pumps and sure enough, dead dead..and same with the middle pump..Easy fix but went against my assumption of the odds. Someone who did not know the car's history would have been more open minded and fixed it in 15 minutes while I chased my foregone conclusions..Thanks for the details! All useful information..