[W126 Coupe] White smoke plus missfire update

[Robert Karl Stonjek]

> 
> Here is the update on my 560sel.  After raising the fuel pressure on the
> eha valve and running a few tanks of fresh gas the idle is smooth.  I do
> suspect a vacuum leak somewhere because the economy gauge is not all the
> way to the left at idle and when coasting at 40 the rpm move around
> slightly and surge car forward than slow down.
> My next problem is white smoke.  After a long drive on highway when I come
> to a stop it lets out a cloud of fog.  Or if I accelerate very hard and
> stop fast it will release a cloud of smoke when I slow down (using the
> brakes not engine).  As soon as i put some load on the motor the smoke goes
> away.  I figured that it was a tranny modulator and replaced it made it
> smoke less frequent but still does it once in a while.  I do not burn any
> antifreeze or oil (less than a quart of oil every 5k miles) Could I have
> bought a bad modulator? Or is this connected to my vacuum gremlin? BTW I'm
> using mobil one synthetic tranny fluid. 
> thanks
> Pavel
> 
> 

RKS:
You can eliminate the KE unit (fuel injection computer) simply by disconnecting it at the EHA valve.  My KE unit is not functioning properly (different symptoms to yours) and I have had the EHA connection off for nearly 1,000 miles now, though it is harder to start when the outside temperature falls below 10C.

The KE unit supposed to make the fuel mixture max lean when you take your foot off the throttle.  If it made it max rich instead then you would see a bit of smoke, but whether this is as much or as white as yours I do not know.  The test is very simple and strait forward - just remove the air filter and you will find the EHA valve on the right hand side of the Fuel distributor with the plug at the rear.  Make sure the disconnected cable will not touch the throttle linkages (tie it off somewhere).

Kind Regards
Robert Karl Stonjek
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