Thanks Marshall; I do indeed have a 722.303 transmission. And I found the write up on the CD. Famous RTFM syndrome. What you describe happening with the pressure line disconnected is basically no ALDA since the gauge pressure aneroid capsule gets only atm. pressure.
On 11/8/05, Marshall Booth <[EMAIL PROTECTED]> wrote: > > Marshall Booth wrote: > > 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 > > If the pressure line is disconnected, then boost pressure will not reach > the ALDA and there will never be ANY fuel enrichment (when the ALDA is > open to the atmosphere all it can do is act as an ADA and reduce fuel > flow as altitude increases and therefore atmospheric pressure > decreases). That limits the engine to 88 hp or less at altitudes above > sea level (vs 120 hp with full enrichment). > > 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 > > _______________________________________ > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://striplin.net/mailman/listinfo/mercedes_striplin.net > -- Hans Neureiter, Houston, TX '82 300SD, '95 E300D
