W140 600 SEC wont rev above 4500rpm
11-25-2019 | 01:00 PM
#1
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Joined: Mar 2010
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From: London UK
2013 W204 C63 AMG, 2008 W221 S65 AMG
W140 600 SEC wont rev above 4500rpm
Hi all
I have a 1992 W140 600 SEC. It wont rev above 4500 rpm whilst driving. It hits a hard cut rev limiter at this rpm.
It had blocked cats previous to this. Before they were replaced, it would only rev to 3500 rpm with lots of hissing out of the exhaust and intake noise and a much softer limit (EG not hard cut)
As its an early 140 600, it has LH mixture formation. There are NO codes in any of the engine managment sytems. LH and EZ for both banks show correct values for things like MAF flow, o2 sensor switching and misfire detection. EFP/TPM/ISC module shows no issues and the car revs freely. The cruise control works without fault.
Initially, I thought the car may not know the gear position, but the actual value display shows the selector module in the right place, so not that.
One odd thing, I can only connect to the EZ1/EZ2 modules whilst the car is not running, when I start the engine, I lose communcations to these modules via HTTWIN.
Any pointers would be great. Thanks
I have a 1992 W140 600 SEC. It wont rev above 4500 rpm whilst driving. It hits a hard cut rev limiter at this rpm.
It had blocked cats previous to this. Before they were replaced, it would only rev to 3500 rpm with lots of hissing out of the exhaust and intake noise and a much softer limit (EG not hard cut)
As its an early 140 600, it has LH mixture formation. There are NO codes in any of the engine managment sytems. LH and EZ for both banks show correct values for things like MAF flow, o2 sensor switching and misfire detection. EFP/TPM/ISC module shows no issues and the car revs freely. The cruise control works without fault.
Initially, I thought the car may not know the gear position, but the actual value display shows the selector module in the right place, so not that.
One odd thing, I can only connect to the EZ1/EZ2 modules whilst the car is not running, when I start the engine, I lose communcations to these modules via HTTWIN.
Any pointers would be great. Thanks
