Quote:
Originally Posted by Brian Carlton
Sam, if the modulator isn't functioning, all the efforts of precision setting of the VCV are for naught.
Test drive it with full vacuum and test drive it with no vacuum. If the results are the same, no sense bothering with the VCV until the modulator responds to vacuum.
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Brian - Correct me IF my interpretation of the above is incorrect... but by "
no vacuum " you mean to simply disconnect the modulator... but by "
full vacuum " you mean to send the full engine vacuum to the modulator
without the VCV even being connected and bleeding.
Quote:
Originally Posted by rrgrassi
DD, for the federal emissions group, get the yellow one. It is #63 on the diagram. I did post the part number in another thread, and did confirm that the part numbers posted by Sam earlier in this tread are the correct ones. I took the part numbers and had the parts guys look them up. The yellow restrictor is 2mm ID. You have to order it from MB. I was told it was $3.50 for it. The dealer did not make me pre pay it, and when I went to pick it up, they told me "No Charge", as it showed up as being pre paid. Now if I could have that happen for all the door seals...  Also, at the dealer, the orifice is now called a nozzle. |
RRGrassi – I’d love to know your source on what are the correct size of orifices in these vintage MBZs [your dealer?]. As I have pointed out the vacuum diagrams do not show the size except for in the legend and that is of little use.
Quote:
Originally Posted by dieseldan44
my #63 right now is blue. What will the increased diameter do for me? other than letting a lot more air through.... I have ordered a new modulator from FastLane..im in a holding pattern until that arrives. ill be doing some research on how best to get that thing out of there...its pretty tight on that side of the tranny.
dd
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DD - A blue restricted orifice is shown as 1mm dia. and red is 1.1 mm and the yellow that RRGrassi appears to be recommending is shown as 2mm as he reported… but my experience was that I needed the smaller orifices [ 0.7 to 0.9 mm ] to throttle down the vacuum so that then the VCV was able to carry out its bleeing function properly. I think this is why the diagrams do NOT specify the orifice size for these might very well be different on different cars right off the assembly line. I’m guessing that the use of these orifices was so that the final “fine tuning” a warmed-up running engine/tranny's vacuum control system could be accomplished merely by putting in a larger or smaller orifice rather than disassembling the VCV and tweaking things. I had a complete set of 6 orifices ready with me to use and as it turned out our car just happen to need the smaller ones. [ this was a newly rebuilt tranny]
Quote:
Originally Posted by rrgrassi
Go with whatever one is called for. Mine actually called for 2mm one according to the diagram on the dealer's parts diagram. Federal emissions called for 2mm ID, and California emissions called for 1.1 mm ID.
Less vacuum flow means firmer shifts, more means softer shifts.
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RRGrassi – Again, I’d love to know your information source for this.
Also, IF, we start using terms like “vacuum flow” we risk really confusing people for a “vacuum” is often seen as a “lack of air” when it really is just less air… so when you use the term “less vacuum flow”, does this mean less air flow which is the real physical thing that is happening!?
Quote:
Originally Posted by dieseldan44
my new modulator should get here tomorrow. i have searched and read on it's removal (don't twist, etc. etc.). i have a couple q's...
1.) Do I need to drain ATF from the main body of the tranny?
2.) How do i know where to set the pin as a 'default' setting to start the next stage of tuning?
I would assume throwing it in there and test driving it is a bad idea.
any tips in addition for removing it greatly appreciated....im ready to get dirty and frustrated by tight quarters on this one...dd
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DD – Answers/replies:
[1] – No, I would be prepared for up to 2 quarts to drain when you remove the modulator. Also I would NOT return this to the tranny… top off later with new fluid.
[2] – I would set the new modulator’s adjustment about mid way… so what I did just now was to disassemble [as far as practicable] my old modulator [1980 model 240D/300D] and found that the threaded plastic all-thread adjuster has 16 threads by count. If you can do the same with your old modulator I would suggest the same methodology. For mine, I find that the range of adjustment is about 20 turns so for me I went 10 turns as a place to start. Your’s might well be somewhat different but similar. On my style modulator it is clearly safe for you to remove the plastic all-thread adjuster “thingy” and hopefully yours is the same.
Looking forward to seeing you make that aging tranny still work acceptably for you.
By the way... do you know or can guess how many miles your tranny does have?
Regards,