Early this summer we replaced the distributor caps, rotors, wires, plugs etc. on the w140. Occasionally it would have a slight miss, that they felt was perhaps due to the EGR valve which wouldn't hold a vacuum. Oddly the dealer said this part wasn't available anymore. A week back I ordered one from Rusty (thanks) plus the gasket, I suspect the parts guy mistyped the part number since not only was it available the price he quote me was complete fiction.
That arrived and I replaced it today. The service manual makes the job sound easy, the EGR is located on front of the top of the engine block, however the hard U shaped A/C tube is mounted right in front of it and it seems you need a very small diameter hex socket/extension in order to get between the tube and the rim of the EGR to tighten the forward screw/bolt (real pain given it's sitting right here...) The old EGR actually would open but leak like crazy, the vacuum setup being a gas engine has a draw from the intake manifold via a nipple screwed into the manfold right beside the EGR, then off to a generic vent valve the same as the ones you find for the overpressure hose on the ALDA. According to the manual the EGR operates according to the engine maps when the temp is > 49C and the engine RPM < 3800, to introduce exhaust into the intake manifold to reduce oxygen to reduce combustion temps to reduce NxO . I guess I see how it affects any misfires, normally when in use it it would draw a bit of air then hold the vacuum, so perhaps continuous drawing air had side-effects. After this I decided to tackle why the trunk closes funny or doesn't close. Actually it would pop open even when locked! After reviewing the docs it seems there is adjustments to mate the lid eye-latch to the vacuum assembly, then the lock assembly mates to the latch. Once you mate the dual parts together you need to adjust both the eye-latch on the lid which moves in 4 directions and the lock assembly latch on the lower frame which moves up/down, if you transverse align the lower latch the manual says the lock mech will malfuction. I guess that means pop open unexpectedly. After removing the cover plate I discover in fact one bolt holding the lower latch assembly is tight, the other is just hanging there. Oh well of course it's funky since it's allowing the latch to move transversally thus malfunctioning. Oddly it seems you need a small adult to climb into the trunk to adjust everything since everything is visible and accessible from in there. Alas one was not handy.... I resorted to using a video camera to record how everything mated, and spent a good hour attempting to get everything alighted and the height correct. 100% better, still I think I need to compare it to another w140 to understand if just closing the trunk slowly by hand should make the eye-latch activate and close things. You have to thunk it close, but now it closes each time, before it would bounce at least 75%of the time, given it was flexing the lower assembly that isn't unexpected, well and pop open unexpectedly. Tomorrow if the sun is still co-operating I'm going to replace both rear seatbelt assemblies since the weak comfort spring takeup is faulty in both seats. John 1983 300TDt 384k Kilometers (mobil 1 Delvac) 1990's 300TDt 211k Kilometers (mobil 1 Delvac) 1993 500SEL 200k Kilometers (mobil 1 Delvac) _______________________________________ http://www.okiebenz.com 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://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
