[W126 Coupe] CIS-E Blues

[Dick Spellman]

Robert:

Anuj is referring to the 'wide open throttle' position on the throttle 
position sensor (TPS) which has two states idle position and WOT.  It's 
a 3 pin connector that is cabled to the base of the air flow meter just 
above the intake manifold and is attached by two screws to the throttle 
valve.  The sensor simply sits atop the throttle plate horizontal shaft 
and based on the shafts position knows the state of the throttle. 

I thought you said you had tested all of the sensors effecting the 
CIS-E.  So, assuming your electrics (plugs, wires, rotor) are in good 
shape it sounds more like you are dealing with a fuel pressure drop at 
4k rpm or greater.  That's why I suggested checking the pressures to see 
if fuel pumps, filters, accumulator etc are all in working order before 
stumbling down the path of a new or rebuilt fuel distributor.   So, if 
electrics check out you have to go the route of fuel pressures check next.

Regards,

Dick

Robert Karl Stonjek wrote:

> Have you tried replacing the EHA? I know you state the coil resistance 
> is correct, however you mention during reving the current goes to 
> -9mA, when it should be enriching. As you know, current has to be 
> measured passing through the component, so the problem can be at the 
> source, or the load, or even a bad ground.
>  
> I would be certain its not the EHA first. If all else fails, you can 
> try putting a diode before the EHA to prevent that negative current 
> and hesitation. You can also try keeping the WOT switch closed, which 
> will force closed loop operation.
>  
> -Anuj
>  
> The EHA appears to be working fine.  Having a background in 
> electronics, I know how to test such devices and what to expect under 
> fault conditions.  The current can only reverse if the driving device 
> reverses it - the EHA can not be responsible (it is a 'passive' device).
>  
> The WOT switch sounds promising.  What does 'WOT' stand for and where 
> do I find it?
>
> Thanks,
> Robert
>
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