Todays project!

http://2phast.com/500e/firstgear.htm

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1993 500E
http://2phast.com/500e/500e-sig.jpg

how much did you pick up your 500E for?

Real cheap, not much more than a clean E420, which is what I was originally looking for. I am sure the color had allot to do with the price, if it was black or silver the car probably would of sold for allot more.

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1993 500E
http://2phast.com/500e/500e-sig.jpg

wow thats impressive. will that work on e320,400e,300e, and such?? when i want to start in first i have to move to second then back to drive

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Car which i own - 1987 Mercedes Benz 300e shown here http://www.cardomain.com/memberpage/790052

I believe the cars you mention start in 1st gear already, I know the 400E/E420 does.

As for this working on other vehicles, assuming the cars have a B selection (shift down to 2nd, then to the right for B and then back again to 2nd), its possible that it may have a similar switch, you would have to take your shifter apart and locate the switch and do some tests, thats the only way to confirm. Just shifting down to 2nd does not engage 1st gear, unless of course your car starts in 1st gear by default.

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1993 500E
http://2phast.com/500e/500e-sig.jpg

This is nowhere near the effect of true first gear startOFF. Note that I mention "STARTOFF". What that means is that while the jumping of the "B" switch will indeed cause V8 and V12 pre-1996 cars to start off in, and idle in 1st gear (BTW, ONLY V8 and V12 722.3 cars!), jumping the "B" switch will cause the transmission to hold 1st gear until the upper RPM ranges...4500-5000rpm. This is not desirable if traveling in the city, day to day driving, etc. A PROPER first gear start modification allows the transmission to STARTOFF in first gear AND THEN the shift point is determined solely on your right foot. If you are barely pressing the car, as in normal city driving, making left turns, etc., the car will then instantly shift into second. Press the pedal further, the vehicle will hold first longer.

This lack of proper modulation is lost when simply bridging the "B" switch. Also, bridging the "B" switch activates the transmission kickdown indefinately.

Satish

The "right" way to do this is with a microcontroller. Mine (and bergwerks') monitor the # of pulses in a given time duration at the speedometer (internally translatable to MPH), and energize a semiconductor or relay to close the solenoid. I am presently using a simple algorithm - about 3/4 of a second, and you have to stop for 1 second to reset - but It would be easy to "let go" at some predetermined # of miles per hour. I've used mine for about a year, and it is definitely worthwhile - a perceived increase of power.

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

I would like to hear about your mod Strife, please post more info.

The way I modified the B switch allows the car to start off in 1st, it also idles in 1st gear, light throttle allows the 1st to 2nd upshift to occur at about 10 mph, at half throttle, the upshfit happens at about 4500 rpm. Full throttle (with kick down engaged) will run 1st gear up to red line before it shifts to 2nd gear. I also tested how the B ckt works (before I modified it) by shifting down to b and then back up to D. The before/after tests were the same, that is, the shift points happened at the same time. To take this a little further, I tested both a 94 and a 95 E420 (both start in 1st gear by default) and the shift patterns were almost identical. What was interesting though was how the B switch worked on the E420, when shifted into B, the car would run to red line and into fuel cut off without ever shfiting into 2nd gear. So Satish, your statement is not entirely correct.

The 1st gear start ckt diagrams are difficult to understand, but according to the MB service CD's, the ckts in both the 400E and 500E are the same, which leads me to believe the 400E uses a different valve body to engage 1st start by default or its controlled by the LH control unit, not sure yet and I have asked some MB techs to investigate the ckt diagrams to make sure I did not miss something.

Also, pulsing the B switch (black wire) to force up shfits/down shifts works good, obivously since Bergwerks and others are using this method, according to the MB mechanics I have been in contact with, providing a constant signal to the B switch is not harmfull. Having the valve body energized at all times, just means its working all the time and not turning on/off every time you want to upshift or downshift. This may sound illogical to some, but according to the techs I have spoke to, turning something on/off, on/off, on/off etc. is more harmfull to the unit then leaving it on all the time, of course this was directly communicated to me in response to my question "Will energizing the valve body all the time damage it or the transmission?". With the valve energized at all times, it fills up with fluid and then opens (my loose way of explaining this) to shift gears. So your running off of default shift points for the 1st to 2nd upshifts/downshifts.

The W124 E60 for example has a different valve body and uses different springs, so the shift points happen at different intervals (probably shifting at later rpms)

I am still investigating the 400E and whether or not the valve body controls shifting or if its something in the LH Control unit, hopefully I will have more info next week, if its a valve body then the next experiment to try is retro fit the 400E valve body into the 500E transmission.

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1993 500E
http://2phast.com/500e/500e-sig.jpg

I think that Strife's idea a is the way to go.
Bypasing the 'B' switch all the time eliminates the kickdown switch as well...
also keeps the solenoid energised all the time(not the way it is designed).
The only thing to figure out is how to transfer the spedo impulse to voltage that will control a relay or thyristor to operate the solenoid at the right time/speed.
I was thinking of using an electronic tacho curcut board, that uses the same technology using the pulse from the points and transfering it to voltage,then depends on the voltage using thyristor as electronic 'switch' will control the solenoid.
I am in research and will keep you informed with my findings...

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DRIVE IT LIKE YOU STOLE IT!

This is easier to do with a microcontroller. The attached schematic shows how to modify the speedometer input signal to a TTL/CMOS 5V compatible input for a microcontroller. The 1N4004 is there as a "fail safe" so that there is no chance that voltage could backflow to the speedometer signal. The resistor (10-15K) is there to seriously limit the current draw to something very negligible. The 4.7V Zener knocks down the 12V pulses to about 4.7V.

Attached Thumbnails

 

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

Keep in mind that the Bergwerks unit taps into the Black B switch wire and pulses this wire for 1st gear starts and upshifts/downshifts, this engages kickdown and also energizes the valve body, the only difference between what I did and what the Bergwerks module does is...

1. Bergwerks controls upshifts/downshift points, my way goes by default spring settings in the valve body
2. Bergwerks module turns kickdown/transmission valve body on/off depending upon shift point settings, my way has the kickdown/transmission valve body on all the time.
3. Bergwerks unit taps into Hall Effect sensor behind radio (speed wire for auto adjustment of radio volume depending upon speed of vehicle), I don't utilize this.

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1993 500E
http://2phast.com/500e/500e-sig.jpg

Strife.
Can you post whole schematic diagram of yor homemade module?
Its pretty nice job you did with 1st gear start module. Are there any speacial tools needed to duplicate your module? Will you consider making one for my 1990 300E and how much would you charge?
Thank you

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1999 ML430 Silver 135k ml
Smoked LED taillights, Alpine in-dash DVD player, 12" sub, Pioneer components, 2 amps, 4200k HIDs, ML55 headlights, 20" rims, mirror LED blinkers

SOLD. 1996 E320 145k ml. Burgundy

SOLD but miss it everyday 1992 500sel Black
Chime buzzer mod,Alpine CD/MP3 player with stock amp,Euro headlights,S600 grill,20" rims, BEST CAR EVER!

SOLD. 1990 300E White
187k ml,smoked tails,Euro headlights,17rims,Intake,12" sub in first aid kit,alarm/autostart,buzzer mod