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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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Discussion Starter #1 (Edited)
Long story short, I had a long dinner with a couple of "specialists". One guy helped engineer the 190E, one guy worked on D, K, KE-Jetronics at Bosch, and they other guy (my father) was a technician at VW and taught the "Jetronic Course". I highly trust and respect this trio and they're all friends!

I had a list of my own troubleshooting techniques I've gotten through: this forum, other forums, manuals, personal experience, and some guy that helped me out when my car overheated and later wouldn't start in the middle of NYC. The "trio of specialists" helped me improve, refine, and verify my list of troubleshooting techniques for the K/KE-Jetronic system that we have on our 190Es. There was a lot I was not aware of and there are a number of things that I may not be able to help with...beyond this list. Since these apply to the whole system, I'm assuming it applies to all of the gasoline 190Es: 1.8, 2.0 (or was that only carbs?), 2.3, 2.6, the 16 valves, and the 3.2 AMG. The trio helped me put into order what would be most-likely-to-least-likely, but they are all possibilities.

If the Engine turns but won't start

1: No fuel pressure, or less than 50 PSI. Test the fuel pump (all 190s) and pre-pump (of those 190s that have two pumps) and do a fuel pressure and volume test.

2: Jammed and/or sticking airflow sensor. Remove the air cleaner and loosen the center line on fuel distributor. This will relieve the control pressure. Press down on the center of the plate and you should feel no resistance or binding.

3: Defective cold start injector. If the injector does not function, the air-fuel ratio will be lean, preventing easy start up...tho, it may still start.

4: Shorted or defective thermo time switch. The cold start injector will not work if the thermo time switch is defective. Check this in the event that your cold start injector does not function before replacing. (I personally was not aware of this, nor do I know where it is, but I trust them)

5: Control plunger sticking. Remove the fuel distributor from the airflow sensor and check to see if it moves freely. (I can't imagine this actually happening)

6: Restricted injectors. For this to be the cause, they would have to be severely restricted, which is why it is listed last. Do an injector flow test and ensure that the delivery is near equal.


Hot starting difficulty


1: Loss of rest pressure. Do a pressure test and focus on the rest pressure. If it does not pass, check for a defective fuel pump check
valve, defective (or clogged) fuel distributor, faulty system pressure regulator, and leaking cold start injector.

2: Airflow sensor adjusted incorrectly. Check height, centering and for binding. Remove the boot and loosen the center line on fuel distributor to
relieve control pressure.

3: Sticking or binding of the control plunger. Remove the fuel distributor and ensure that the control plunger moves freely.

4: Injectors leaking. Remove the injectors from the intake manifold and with the ignition key on and engine off, press on the center plate to pressurize the system. Inspect and replace any injector that is leaking.

5: Cold start injector leaking. Same test as above.

6: Shorted thermo time switch. Cold start injector is dependent of this component.

7: Incorrect control pressure. Do a pressure test and verify that the warm control pressure is within spec.

Rough idle (cold)


1: Cold control pressure incorrect. The movement of the control plunger will be limited if the cold control pressure is too high. This in turn will limit the amount of fuel able to be delivered through the injectors. The result will be a lean ratio and will cause rough idle.

2: Auxillary air valve defective. If defective and not opening, idle cannot rise and results in rough idle. (I think I have this issue in my 2.3)

3: Airflow sensor adjusted improperly or binding. If the movement is not smooth, it will result in air-fuel ratio errors. If you've never messed with it, and no one else has, then just check for binding or extra resistance (mechanical resistance).

4: Leaking cold start injector. If the cold start injector is leaking, the engine will be over-fueled even if cold. If the cold start injector is leaking, the idle will get worse as the engine temperature increases.

5: Injectors have an unequal flow or spray pattern. Do an injector flow test and replace any that do not deliver the correct amount of fuel or have a poor spray pattern. They are $30-40 on autohausaz.com


Runs rough (warm)


1: Warm control pressure incorrect. Incorrect warm control pressure that is too high or low will cause an incorrect air-fuel ratio, thus resulting in a rough idle.

2: Airflow sensor adjusted improperly or binding. If the movement is not smooth, it will result in air-fuel ratio errors. Check for centering and correct rest height. (again, its more likely that its binding if no one has ever messed with it)

3: Leaking cold start valve. Again, will result in over-fueling the engine, resulting in a rough idle.

4: Injectors have an unequal flow or spray pattern. Do an injector flow test and replace any that do not deliver the correct amount of fuel or have a poor spray pattern.


Stalls after starting (warm)


1: Warm control pressure. If the warm control pressure is too high, the air-fuel ratio will be lean.

2: System pressure incorrect. If too high or low, the air-fuel ratio will be incorrect.


Idle speed high


1: Check auxiliary air valve. Ensure that it is closing. (Not quiet sure how to do that)

2: Vacuum leaks. Self explanatory, I hope. I'd start with the Air Flow meter and the boot below it, then all the connections on the intake manifold, and then the manifold/head connection. Also, all vacuum lines.


Backfire in intake


1: Check that CO adjustment is correct. If incorrect, backfire will result if started and under a load. (I'm not sure how to do that)

2: Boot between airflow sensor and throttle defective/leaking. Will result in a lean mixture due to extra air. Our cars are old, its rubber. It might have cracked.

3: Vacuum leaks. Self explanatory.


Misfires


1: Ignition. Inspect the cap, rotors, wires, and plugs.

2: Fuel delivery inadequate. Check for binding of airflow sensor, control plunger, incorrect control or system pressure and restricted injectors.

3: Injectors. Unequal delivery or poor spray pattern. Do a test and
replace any that are defective. ($30-40 on autohausaz.com)


Poor power


1: Control pressure too high. If the control pressure is too high, the control plungers travel will be limited, resulting in a lean running engine.

2: Check ignition components. Verify that the spark plugs, wires, cap and rotor are not worn, dirty, or defective.

3: Injectors restricted. Do a test for delivery. If an injector is restricted, fuel delivery will be limited, thus power will suffer.


Sag or stumble when accelerating

1: Airflow sensor plate binding or sticking. If binding or sticking, fuel flow will be limited.

2: Control plunger binding or sticking. If binding or sticking, fuel flow will be limited.

3: System pressure or warm control pressure incorrect. If too high, the travel of the plunger will be limited.

4: Injector flow unequal. Self explanatory.


Fuel consumption high


1: Air-fuel ratio incorrect

2: Injectors leaking

3: Cold start injector leaking


I got most of the information from our forum, other 190 forums, reading troubleshooting threads, books, manuals, and personal experience. I had my "trio of specialists" confirm everything. If you guys have any questions about the Jetronic system I'll do my best to answer them.
 

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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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704 Posts
Discussion Starter #3

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1991 190e 2.6 automatic
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760 Posts
what about the OVP relay.. am i blind.. i didnt see it in there

i would put that in

hard starts, no starts, loss of most power, abbs light on
 

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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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704 Posts
Discussion Starter #5 (Edited)
what about the OVP relay.. am i blind.. i didnt see it in there
i would put that in
hard starts, no starts, loss of most power, abbs light on
I tried to concentrate on the "fuel injection" part of the Jetronic system. The whole mostly-mechanical injection system sometimes confuses the hell out of some people. I think if the OVP relay was bad, there would be other bigger issues, but I've never tried to do anything with my car while the OVP relay was disconnected. Hm, maybe I'll try that tomorrow...but I think a healthy engine just wouldn't start. I bet information can be found in the EPC or the PDFs (both can be found on this forum by doing a search) about the OVP relay and exactly what it is connected to it. Then one should be able to determine what it could affect.

"Hard start": Hm, do you mean when only one or two pistons fire for a few seconds, and then it starts?
"No start": Its in there.
"Loss of most power": Start with the "Poor Power" Section. Also, this might mean a cracked head, leaky valves, bad pistons...it might not be connected with the Jetronic system specifically.
"ABS Light on": uhhhh....the ABS doesn't work? Sorry, but I didn't go that far with them. I do remember having the ABS light on when my alternator was dying...and I remember that the SRS light was also "kinda" on (very dim, but on)

If you have more information about the ABS and/or SRS lights, please share! I'm always looking for more information about the 190E. If mine was a show car, I'd be 110% obsessed with it!!
 

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1986 190E 2.3-16, 1992 190E 2.3, 2015 GL350 BTC, and 2020 GLS450
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2,395 Posts
Vote for sticky.

I miss illustrated drawings of the motors with views of the parts named and identified. Can you work up a graphic?
 

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2000 C230 Kompressor, 2005 Volvo S60 T5 AWD, 1992 190E 2.3 -Totaled
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951 Posts
... I miss illustrated drawings of the motors with views of the parts named and identified. Can you work up a graphic?
Vote for sticky as well.

And doesn't Haynes or Chilton have a manual like this drawn up already? I have heard that there is a Haynes and Chilton manual for these cars, but have never seen one before.
 

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2009 ML320 & 1984 190D
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229 Posts
I agree with the OVP statement.
I have personally seen and witnessed first had a OVP failure first make a running car start to misfire during a test, then stall, and enter into a non start hot or cold mode.
There was no warning or issues... I was doing a duty cycle test on my 1991 190E 2.6 when it started to splutter... I rechecked the Duty Cycle... and then it just got worse and worse, and then stalled.

Because I was in the middle of a Duty Cycle Mixture setting test, I was completely wrong footed, and assumed I had done something wrong!
It was the OVP solder joints, and after reflowing the solder, it started fine and no more issues!

To confirm, despite talk to the contrary, if the OVP fails in this model year, it does not go into limp home or open loop mode... It stops and will not restart!
 

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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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704 Posts
Discussion Starter #10
I agree with the OVP statement.
I have personally seen and witnessed first had a OVP failure first make a running car start to misfire during a test, then stall, and enter into a non start hot or cold mode.
There was no warning or issues... I was doing a duty cycle test on my 1991 190E 2.6 when it started to splutter... I rechecked the Duty Cycle... and then it just got worse and worse, and then stalled.

Because I was in the middle of a Duty Cycle Mixture setting test, I was completely wrong footed, and assumed I had done something wrong!
It was the OVP solder joints, and after reflowing the solder, it started fine and no more issues!

To confirm, despite talk to the contrary, if the OVP fails in this model year, it does not go into limp home or open loop mode... It stops and will not restart!
Honestly, replacing the OVP was one of the first things I did when I got my 190E. If something like that can be the cause of so many different issues of different magnitudes, its worth the $30-40 and 20 minutes just to replace it.
 

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2009 ML320 & 1984 190D
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Honestly, replacing the OVP was one of the first things I did when I got my 190E. If something like that can be the cause of so many different issues of different magnitudes, its worth the $30-40 and 20 minutes just to replace it.
I agree with you about it causing issues, but that was not my point.
My point was that in a perfectly running car, and one that had never shown any issues, with the engine running, sitting in a garage at the end of having its Duty Cycle adjusted, a solder joint went bad, and caused the engine to begin to splutter, and misfire, then die and be a non-starting condition.
I have seen them be, and go bad before, but normally like on Ps2cho's two earlier W124's it was odd running and abs lights... the car never failed to start or run.
Clearly the 1990 models with OVP's have more "Electronic support", and when they go bad, they don't run!
 

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w201,w124,w126
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Was hoping you could ask the three wise men about a category you missed, "Stalls after starting (cold)"

No problem with hot starting. Or cold starting. Just that it stalls quickly after starting cold. And when I say cold, the engine temp has to be below 10c.
 

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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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704 Posts
Discussion Starter #13
To clarify for everyone, this list was not meant to be a "FIX EVERYTHING", I put it together as a "Starting Point" for those of us that have common issues. I am no expert in the CIS system. I am only an enthusiast like many of us on here at Benzworld.

The 190E engineer lives in Germany, the Bosch guy lives in California, and my father (whom I highly respect) knows how the system works but has learned how to diagnose problems that come up 20+ years later from my experience.

I will talk to my father about cold starting/stalling. From personal experience, my first thoughts would be that too much air is getting into the engine, or the fuel enrichment @ cold is not rich enough. My '92 2.3 has a fuel issue. While trying to diagnose it, I unplugged a three prong plug from the fuel distributor (facing the front of the car, next to the fuel pressure regulator) and it ran really well...until the next day when it was about 40F outside and it would start, then slowly die over a couple seconds. I reconnected the plug, and it started fine. I don't think this is your issue, but its all the experience I have with cold starting/stalling.

I would suggest starting a thread about it with as many details as you can think of that might be relevant.
 

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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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704 Posts
Discussion Starter #14
I found something about the OVP Relay. If it helps, awesome!! If not, well, we can all add it to our collective pool of information about our awesome 190Es! Its a downloadable PDF. Yes, it works. Yes, its safe.

OVP_Info.pdf - FileSmelt File and Image Hosting
 

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1993 500SL
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1992 190E 2.3 8v w/ '87 5-speed and 3.27 rear, 1966 Shelby Cobra 427 S/C, 2018 Triumph Bonneville
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704 Posts
Discussion Starter #16

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I have the Haynes manual and it is well recommended. Very clear instructions for almost all repairs.
BTW super thread. I am suffering the start/sputter/stall problem, and am looking forward to trying to solder the old one..just to see if it works. In the end the 40$ is worth putting out.
 
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