Engine stalled at traffic lights and stop signs
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
Engine stalled at traffic lights and stop signs
Experienced more headaches with my 93 300CE, after engine warmed up, any hard stop will make RPM drop under 500, some time even kill the engine at red lights, left turn lights and stop signs. And if i shift from Park to Reverse, release brake padel right away, will kill the engine too, even IAC tried it's best to keep engine running.
I was suspect wiring issues, but after i taped up cam actuator and MAF hardness, still do the same thing. Checked T/B, it's super clean, even adjusted idel to 1200rpm, still do wont help.
We dont have MB OBD1 cable on our shop scaner, what i can do now is just diagnosis from every basic theories. I'll check if there is vaccum hose leak causing EGR working all the time or EGR stuck open. Then check spark plugs and coil tomorrow.
Any body experienced samilar condition or might have some ideas?
I was suspect wiring issues, but after i taped up cam actuator and MAF hardness, still do the same thing. Checked T/B, it's super clean, even adjusted idel to 1200rpm, still do wont help.
We dont have MB OBD1 cable on our shop scaner, what i can do now is just diagnosis from every basic theories. I'll check if there is vaccum hose leak causing EGR working all the time or EGR stuck open. Then check spark plugs and coil tomorrow.
Any body experienced samilar condition or might have some ideas?
Last edited by xsun; 04-09-2009 at 11:01 PM.
#2
Check the fuse on the OVP that sits behind the battery. It is a very common problem. Also pull off the idle control valve and shoot some carb cleaner into it.
I'm not sure about the hard stop...but the OVP is the cause of the majority of stalling problems.
I'm not sure about the hard stop...but the OVP is the cause of the majority of stalling problems.
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
What is OVP? There is a 15A fuse sitting behind the battery, fuse is good. Where is the control valve? I just see a big T/B module in the center of manifold
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Oh no, I was going with the ignition wires and spark plug cables first. For my car after we replaced the cap & rotor it will still stall sometimes. Turns out my ignition wires and plug wires were cracked and cross-firing when it was humid out so we changed them too and so far it is gone.
I think your car is a year or two early for the wiring harness issues. I believe you have the same M104 that I have.
I think your car is a year or two early for the wiring harness issues. I believe you have the same M104 that I have.
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
Oh no, I was going with the ignition wires and spark plug cables first. For my car after we replaced the cap & rotor it will still stall sometimes. Turns out my ignition wires and plug wires were cracked and cross-firing when it was humid out so we changed them too and so far it is gone.
I think your car is a year or two early for the wiring harness issues. I believe you have the same M104 that I have.
I think your car is a year or two early for the wiring harness issues. I believe you have the same M104 that I have.
Last edited by xsun; 04-10-2009 at 06:23 PM.
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
up date: by adjusting the throttle cable, no more traffic light and stop sign stalls, running 1500rpm(sounds like racing engine, huh?) at no load idel, and 900rpm with loaded idel(in D and R). But put in gear right away after start up, still make engine struggled close to stall, have to hold on brake and keep in gear for 20 something seconds till it runs stable.
it makes me think about the T/B driving mechaism(they looks complex) worn out and making idel too low ?
it makes me think about the T/B driving mechaism(they looks complex) worn out and making idel too low ?
Last edited by xsun; 04-10-2009 at 11:22 PM.
#12
It is the overvoltage protection relay. It sits behind the battery in a small red box. It will be behind the waterproof plastic shield. Before shelling out $1000 for the wiring harness, replace the OVP for $40. It is an item that usually goes bad anywhere from 50k-150k on the w124's and can cause a ton of idle and stalling problems.
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
It is the overvoltage protection relay. It sits behind the battery in a small red box. It will be behind the waterproof plastic shield. Before shelling out $1000 for the wiring harness, replace the OVP for $40. It is an item that usually goes bad anywhere from 50k-150k on the w124's and can cause a ton of idle and stalling problems.
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
You know, i'm a service tech work for GM, to define the problem and finding the reason is kind of my porfessional persuit, and slove the problem at the same time will be great.
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This sounds like either, MAF, OVP, or ICV failure to me. Seeing that you think you have ruled two of those out the OVP relay would be a cheap alternative compared to the harness. And as said earlier, the OVP relays are prone to start acting funky on higher mileage W124s.
I'm not really aware of any die-hard ways to test OVP relays for failure other than "seat of pants". Anyone else?
I'm not really aware of any die-hard ways to test OVP relays for failure other than "seat of pants". Anyone else?
#17
This sounds like either, MAF, OVP, or ICV failure to me. Seeing that you think you have ruled two of those out the OVP relay would be a cheap alternative compared to the harness. And as said earlier, the OVP relays are prone to start acting funky on higher mileage W124s.
I'm not really aware of any die-hard ways to test OVP relays for failure other than "seat of pants". Anyone else?
I'm not really aware of any die-hard ways to test OVP relays for failure other than "seat of pants". Anyone else?
Over time the OVP gets water into it and the internals fail. This is an item that you do not want to try and DIY-fix.
It is something that is part of "Stu Ritters" must have parts to carry in the car. I carry a spare in my trunk.
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I've got one of those and another MAS unit. Granted it is my old, faulty MAS but I can still drive on it if my newer MAS craps out on me.
Right, speaking of which, try and test your MAS unit. Mine also caused further stalling issues and struggling under acceleration. Turns out some of the pins get de-soldered and worn over the years and causes intermittent issues.
Right, speaking of which, try and test your MAS unit. Mine also caused further stalling issues and struggling under acceleration. Turns out some of the pins get de-soldered and worn over the years and causes intermittent issues.
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There is no way to test it. Only to check the two fuses that sits on the top under the little waterproof cap.
Over time the OVP gets water into it and the internals fail. This is an item that you do not want to try and DIY-fix.
It is something that is part of "Stu Ritters" must have parts to carry in the car. I carry a spare in my trunk.
Over time the OVP gets water into it and the internals fail. This is an item that you do not want to try and DIY-fix.
It is something that is part of "Stu Ritters" must have parts to carry in the car. I carry a spare in my trunk.
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Cool, i gnna try that right now
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There is no way to test it. Only to check the two fuses that sits on the top under the little waterproof cap.
Over time the OVP gets water into it and the internals fail. This is an item that you do not want to try and DIY-fix.
It is something that is part of "Stu Ritters" must have parts to carry in the car. I carry a spare in my trunk.
Over time the OVP gets water into it and the internals fail. This is an item that you do not want to try and DIY-fix.
It is something that is part of "Stu Ritters" must have parts to carry in the car. I carry a spare in my trunk.
#22
I am not sure exactly, but I believe it protects the electrical components from any surge in voltage. It is Mercedes' answer to replacing a $40 part rather than a part that could cost much more and be difficult to diagnose.
It is exactly as the name implies -- Overvoltage Protection Relay.
It is exactly as the name implies -- Overvoltage Protection Relay.
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lots of cars
It is something that is part of "Stu Ritters" must have parts to carry in the car. I carry a spare in my trunk.
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1993 Mercedes 320CE, 1993 audi v8 quattro, 1990 audi coupe quattro(doing 20vt project)
Just had that OVP replay apart. Inside the OVP, have three relays: K1,k2 and K3. K1 and K2 seems in same size, staped P/N and protecting resistors are same too, but have way different resistance on coil wring, one is 73oms, another is 36, i wonder that might be the problem.
Gonna order one monday. Price listing on AutopartsWay is about 100 dollars, will try local mercedes dealer, sometime, dealers have good price parts too
Gonna order one monday. Price listing on AutopartsWay is about 100 dollars, will try local mercedes dealer, sometime, dealers have good price parts too
Last edited by xsun; 04-11-2009 at 08:57 PM.