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Discussion Starter #1
Hi guys
Need help with my 124 e220
The car runs fine until it warms up a bit
I've noticed the rpm are at 650 more or less Rock solid no hunting which I feel is a little lower than it should so basically after 30 minutes of driving the car just doesn't want to hold idle the rpm goes as low as possible car shudders but tries to keep going this happens only with the AC on without the AC the rpms just go low and stay there
Also the car just abruptly cuts revs off at 4 -4.5k rpms like the car is being revved white in neutral
Some how I feel both these issues are connected
Would be very grateful if someone could point me in the right direction please thanks in advance !
 

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Have you replaced your engine wiring harness ? Remove black plastic trim on engine and post a pic.

Also it would be good to have a code reader to get error codes.
 

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What is the history on the OVP relay? Have you checked the fuse/fuses?

Sent from my XT1710-02 using Tapatalk
 

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Discussion Starter #4
Have you replaced your engine wiring harness ? Remove black plastic trim on engine and post a pic.

Also it would be good to have a code reader to get error codes.
The wiring is in mint condition the car only has 56000 original KMS
I'll post the pic soon
Thanks 😊
 

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I don't believe the W111 had the bio-wiring issue anyway. Have you gone though the ignition? A bad coil wire can act just like a rev limiter.
 

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I don't believe the W111 had the bio-wiring issue anyway. Have you gone though the ignition? A bad coil wire can act just like a rev limiter.
Not W111 chassis, but a M111 engine in a W124 chassis.

W124 E220 (124.022) all come with biodegradable harnesses and wires, including ISA.
Basically, it is a HFM M111 engine in a W124 chassis, like its twins, W202 C220.

Date of production of the Main engine harness can be identified by examining the AIRFLOW socket.
It is stamped on the round socket. Check it out with your good eyes.
Besides, cable harnesses for power regulator/generator and starter are also bio stuffs.
Trigger cables for your 2 pack coils are also bio stuffs....

Given your condition, your priority check would be the ISA.
Its part no is 000 141 92 25 and updated to 001 141 02 25 while OEM VDO/SIEMENS no is 408 227 111 003Z (final ver.).

Make sure yours is good and not affected by the bio issues.
The same ISA is installed in other chassis as well so you might visit your nearby junkyard for a good search, hopefully finding a good one.


Regarding the cutting of engine RPM, it is triggered by a safe-protection mechanism of your HFM engine ECU. Thus your car currently is in "limp" home mode.

Exact causes for that might be many.
Common causes would be a power leak/jump because of the bad wire insulation, and the other would be a bad plug seal on the cam cover. Remove the spark plug wire cables and check. Normally after a good clean or installing the seal kit, and together with erasing the trouble codes, you could bring your engine back to normal.

Good luck.

"BIODEGRADABLE CABLES" in that particular years of production will self-destroy....even you have a mint W124 E220.
 

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Discussion Starter #8
I don't believe the W111 had the bio-wiring issue anyway. Have you gone though the ignition? A bad coil wire can act just like a rev limiter.
Not W111 chassis, but a M111 engine in a W124 chassis.

W124 E220 (124.022) all come with
biodegradable harnesses and wires, including ISA.
Basically, it is a HFM M111 engine in a W124 chassis, like its twins, W202 C220.

Date of production of the Main engine harness can be identified by examining the AIRFLOW socket.
It is stamped on the round socket. Check it out with your good eyes.
Besides, cable harnesses for power regulator/generator and starter are also bio stuffs.
Trigger cables for your 2 pack coils are also bio stuffs....

Given your condition, your priority check would be the ISA.
Its part no is 000 141 92 25 and updated to 001 141 02 25 while OEM VDO/SIEMENS no is 408 227 111 003Z (final ver.).

Make sure yours is good and not affected by the bio issues.
The same ISA is installed in other chassis as well so you might visit your nearby junkyard for a good search, hopefully finding a good one.


Regarding the cutting of engine RPM, it is triggered by a safe-protection mechanism of your HFM engine ECU. Thus your car currently is in "limp" home mode.

Exact causes for that might be many.
Common causes would be a power leak/jump because of the bad wire insulation, and the other would be a bad plug seal on the cam cover. Remove the spark plug wire cables and check. Normally after a good clean or installing the seal kit, and together with erasing the trouble codes, you could bring your engine back to normal.

Good luck.

"BIODEGRADABLE CABLES" in that particular years of production will self-destroy....even you have a mint W124 E220.
Thanks everyone for your your replies
Turned out to be the ecm or ecu at fault as well as the ovp relay
Problem solved !!
 
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