[W126 Coupe] 89 560sec

[Eddie]

The US models don't have air temp sensor (they would be on the air snorkel,
where there's a plastic grommet on the side of the tube).  The altitude
sensor should be hanging off of the side of the engine bay, right in front
of the wheel well.  I believe it's on the starboard side.

 

Eddie

 

  _____  

From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com]
On Behalf Of Richard Hogarth
Sent: Thursday, April 13, 2006 7:07 AM
To: 'Robert Karl Stonjek'; 'Mercedes Coupes Mailing Lists'
Subject: RE: [W126 Coupe] 89 560sec

 

Where exactly are the air temp sensor and altitude sensors ?

-RPH

 

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From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com]
On Behalf Of Robert Karl Stonjek
Sent: Thursday, April 13, 2006 4:54 AM
To: MB Coupes
Subject: Re: [W126 Coupe] 89 560sec

> Cats were introduced in the UK in late 1990/91 on the w126 models.
> 
> However, legally, it is only post 92 cars which require cats - so they are

> easily removed, legally.
> 
> 
> talbir
> 
> 

In Australia, Cats were mandatory on all new cars from 1987.  But in Hong
Kong, which was part of the UK in 1987, the non-cat high power version was
still sold, which is where my 560 came from.

 

Unfortunately, in trying to fix a performance problem, previous owner/s
replaced the CIS-E, EZL and fuel distributor with parts meant for the
Australian version.  The problem that caused all their problems, which was
never discovered and repaired, was a faulty air temperature sensor.  I can
understand how this would happen as the sensor is not listed in the
schematic of the CIS-E as a sensor.

 

In fact it connects to the altitude sensor.  Between air temperature and air
pressure you can easily calculate air density and so the necessary fuel
mixture for optimum performance.  If any of the sensors go out of range then
the CIS-E seems to have a curious counterintuitive response.  In the case of
my car, it made the mixture progressively leaner with ever higher revs until
low power and even missing (from fuel starvation) occurred.

 

Unfortunately, simply fixing the sensor does not help matters as the CIS-E
currently in the car was set up for the CAT version of the 560, and my car
has no cat nor oxygen sensor.  Disconnecting the EHA lets the car run
nicely.  It starts OK without the 'choke', as long as you don't pump away at
that throttle (service manual says 'don't press the throttle during
starting' and 'up to 4s of cranking is normal for the 560').

 

Robert

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