Hans Neureiter wrote:
I found the tube from the intake manifold to the O/L switchover valve
disconnected.
Reading the ALDA functional description I am somewhat confused.
The way I interpret this gets me to the following conclusion:
The overload protection switchover valve vents the ALDA to atm. when RPM is
below 2000 and the gauge pressure in the manifold is below a certain amount
(0.5 bar ?), thus cutting off fuel enrichment.
The ALDA regulates and limits total boost pressure in the manifold (gauge +
atm.) to a set value by adjusting the fuel enrichment.
So, with the tube from the manifold disconnected and open to atm., the ALDA
cuts off all fuel enrichment below 2000 RPM and goes to full enrichment
above this ?
I can't tell what a difference this correction made by itself, because it
was during a badly needed valve adjustment job. Every single valve was way
to tight. Some intakes didn't let a .001" feeler gage slip in.
The car now now nearly out drags the E300D.
One other question. I replaced a bad O-ring at the modulator and the leak
there stopped. But there are still ATF drips on the ground. Where is another
probable source for a leak near the front on these transmissions. I can't
find it. It's not the pan.
The transmission overload protection circuit you describe was eliminated
when Mercedes changed from the 722.1 series to the 722.3 series
transmissions in 1981. I believe that coincided with the US delivered
"S" class cars migrating from W116 to W126 chassis, but there may have
been some European 126s that had 722.1 transmissions.
I quote from 7.1-015 of the 617.95 engine manual: "Starting model year
1981, installation of transmission 722.303 instead of 722.120 has made
the transmission overload protection unnecessary. Only engine overload
protection will be installed."
Your 1982 126.120 does NOT have the circuit you are describing! There is
overboost protection if the sensor on the intake manifold senses
pressure in excess of about 1 bar.
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 182Kmi, '84 190D 2.2 229Kmi, '85 190D 2.0 161Kmi, '87 190D 2.5
turbo 237kmi
