Performance Upgrades

Engine ECU Chip 4-15-06

Although chipping the 500E does not net alot of power, if you can chip it for little money, its worth it to eliminate the 155 top speed and cold start up-shift delay.  Chances are this chip only nets about 5-7 hp, but for $69, I believe its was a good investment.  This came from EBay and I am sure the seller is coping another companies product, but it is a exact fit and works as described.


So we start by pulling out the LH Computer.  See my instructions under the ASR defeat section for a how-to on this.


The chip ships with instructions on how to dissemble your computer, you will need some torx bits and a clean area to take your computer apart.


There are torx screws on both sides of the computer circuit boards.  When you remove them, put them in neat piles so you can remember which side they came from.


When all the torx screws are removed, you can remove the top circuit board and flip it over, being careful of the ribbon cable.  The computer chip is under the white plastic cover.  A small flat blade screw driver will allow you to pop this cover off.


With the white chip cover off, you can see the label of the chip.  The chip is notched at one end, be sure to remember this when it is time to install the new chip.


To remove the old chip, I used a small flat blade screw driver under each end of the chip, prying up gently, a little at a time.  Be careful, you don't want to bend any of the pins in the process.


The new chip arrives in a plastic carrier and it also comes with more detailed instructions for install.


When it is time to install your new chip, you should try not to touch the pins or bend them in the process.  Sometimes though, the chips need to be slightly bent inward before it will seat into the socket.  Be careful not to bend any of the pins, make sure the chip is aligned correctly (see the notches on the chip and the socket) and lastly, make sure it is fully seated before you put everything back together.



6-17-09 - 1992 LH Computer Install


After getting the 500e on the dyno, I noticed the stock 93 ecu runs lean, even with the performance chip installed.  This lean condition caused a serious power drop.  The 1992 500e had 7 more hp, due to WOT enrichment (322 hp vs. 315 hp for 93/94).  A common mod is to install the 1992 ECU into the later model cars, not only does this net 7 more hp, but it richens the A/F mixture.





Installation has been covered in more detail under my "ASR Defeat" section, so I won't go into too much redundant detail.  But to start, we need to remove the four alan bolts holding the top of the CAN box in place.






Since I don't have the computer removal tool, I use two long flat blade screw drivers like pictured to serve as a lever to pry out the ECU. Pry up a little at each end till the ECU is free







Top is the 92 ECU with a build date of Oct 1991 and below is the 93 ECU with a build date of March 1993







Once the ECU is back in the CAN box, press it into place till it is fully seated.  I used a small rubber mallet to tap it into place.  So far the car is running good, but the real test is to get it back on the dyno and see if I regained any of the missing hp. 





Engine Cooling Modification

The 500E (along with many other MB models) runs very hot.  One way to tackle this problem is to add something like Redlines Watter Wetter to the coolant tank.  Another way is to modify the aux cooling fans so that they come on earlier than 100 degrees.  This can be done on cars that use an independent CTS sensor and a resister.  Shown here is the CTS sensor on the M119, its under the front engine cover (cover in front of the air cleaner assembly)


To perform this modification, you need to install a resister across the CTS contacts.  Since this modification and additional details are already fully documented on another MB owners site, I will refer you to his site.  If you don't feel included to perform this mod yourself, you can also purchase a pre-made clip/resistor pack.  Visit this site for more information. In case your wondering,  I am using a 1100 ohm resister that allows the fan to come on at 92 degrees.  This modification works great.


1st Gear Start

The 500E was designed by Mercedes to start in 2nd gear with the option of starting in first gear under full throttle or by moving the shifter down to 2nd and then to the right (B).  There are several companies that sell 1st gear start kits but I always wondered if it was really necessary to pay someone for this feature.  I started out by taking apart the shifter console to get access to the mechanism that engages first gear start.


With the factory shifter, it can be tricky to maneuver the shifter gate up and out of the way.  In this picture you can see what the 1st gear start switch looks like.  I was expecting a momentary switch, but this one is basic on/off type of switch, when you move the shift level into 2nd, then over to B (to engage a 1st gear start), you see the switch move, complete the ckt and then when the shifter moves back to 2nd, the 1st gear ckt is opened again.  With the switch out and engaged (closed ckt) the car always starts in first!


I could of just left the switch in the closed position and tucked it back inside the console, but I wanted the ability to switch between 1st gear start and 2nd gear start, so I unplugged the switch and pulled the wire harness down and out where the window switches reside.  I then reinstalled the now non-functional 1st gear start switch, mainly to fill a small gap that could collect dust and other garbage. 


This is the other side of the 1st gear start switch.


Since I need the now useless fader location for a ASR defeat switch (coming soon!) the only other non-essential switch location I could use is the rear window child safety switch.  I don't need that function and it will provide me with a simple on/off switch to use for the 1st gear start.


Of course, you have to take all the switch's out and then remove all the switch holders from the tray.  I needed to remove the female pins from the child safety switch holder so I could bridge them together (otherwise the passengers in the rear seats won't be able to open the windows)


To keep this modification easily reversible, I elected to bridge these two pins together using a male-male plug, it was then shrink wrapped and tucked back into the console.


This is the child safety switch holder, without the pins.  The pins used for this switch are the same used for the headlights, and I just so happened to have some of these around (left over from a euro headlight upgrade to my W201) 


This is the 1st gear start plug and its pins, much smaller than the pins used on the child safety switch


Once I reached this point, I reassembled the shifter console with the now, non-functional 1st ear start switch


I elected to de-solder these pins and save them (along with the plastic holder) in the event I want to restore everything back to factory.


Since I happened to have some adhesive letters laying around, I modified a number 2 to fit over the pictogram of the child, so when in this position, it will now show a number 2 (to indicate the ckt is open and the car will start in 2nd gear)


Now in the process of de-soldering the originally small pins and replacing them with the larger headlight pins 


Here are the larger pins installed.  Although this picture shows the wires coming out from the ends of the pins, you actually have to insert the wires from the sides, otherwise the end caps of the pin holder won't close (I removed these and did it correctly AFTER I discovered my error).


Once I reached this point, I installed the switch and took the car for several short drives and then out on the freeway.  I was afraid with this ckt closed, the transmission might not shift correctly, but so far there everything is working fine (you don't have any control over the shift points using my method, so 1st to 2nd shifts happen around 4500 rpm, the aftermarket kits allow you to adjust this shift point) 


This is how the child safety switch looks now, with the number 2 on it. 


Here is the console back together and my newly refinish center console wood trim (more on that later).  I am really loving my 1st gear start but now I need to get motivated and install the ASR bypass to compliment this modification. (my ASR mode will be similar, it will not be using someone else's kit, a switch and a few relays are all you need.....stay tuned!)


5-09-06 - Renntech 1st Gear Start Valve Body

This is the newest toy recently received.  It is a Renntech modified 1st gear start transmission valve body.  With this installed, the 500E will always start in 1st gear.  This install is a bit tricky, so I will be enlisting my friend Steve Geyer to provide his expertise.  Renntech's installation instructions


To do the valve body swap requires a little over 4 quarts of trans fluid, since I recently just had the fluid/filter changed, I picked up enough fluid just to do the valve body swap.


This swap does not appear to be to complicated, but I recommend you have someone with a expert knowledge of MB and/or transmissions do this swap for you.


On the left is the original valve body dated 1993, on the right is the Renntech valve body dated 1999.  The center yellow valve/spring was installed on the Renntech valvebody (probably was lost in transit) and from the outside, its hard to differentiate any difference between the two.  The Renntech has one spring valve in the right hand bottom corner that does not appear to move compared to the OE valve body, so its possible that this is part of their modification to make the valve body start the car in 1st gear.  What a incredible modification this is, it really breaths new life into the 500e.  Steve made several adjustments to adjust the shifting, so it shifts very quickly.


After my transmission failed, I had it replaced with a fully rebuilt and re-engineered version.  To maintain the warranty, I couldn't use the Renntech valve body, so I sold it and installed a electronic FGS module.  I bought one from and you can see pictures of my car under the 500e installation section



This is the FGS module as shipped to me, do remember that mine was more or less a pre-production model, much has changed in the newer modules, visit the site and read up on it.


This is the inside of the FGS module, which uses a coax interface cable to the front ABS sensor and has serial interface for programming via a laptop computer.


The coax interface cable is routed up from the transmission tunnel to a grommet on the drivers side, you see the cable pulled through the factory grommet here.


With the cable routed up into the engine bay, you need to solder your coax fittings onto the end of the cable.


This is where the front ABS coax cable is located, so we need to cut it and splice/solder new ends, so we can use the included T coupler.  The FGS coax will connect to the open spot on the T.


On the inside, you need to locate your first gear start wires, on the 500e, they are attached to a switch that under the shifter, indicated by the B.  Mine were already pulled out because of the earlier FGS window switch mod I did a year or so before.


I mounted the FGS module on the transmission tunnel, next to my IPod interface


You use a laptop to program the FGS module.  You can tell it the size of tire/wheel you have and adjust when the FGS module engages and disengages.  You can also measure your speed and acceleration time.


4-1-06 - ASR Defeat Installation

In preparation of installing a on/off function for the ASR, I needed an actual ASR off switch from a R129, but these are only a momentary on/off, so I had to pick up a extra rear dome light switch and swap the covers.  The cover of the ASR switch does not accept the little spring rod, so you have to carefully file out the hole till the spring rod slides in/out easily.



I used a small round file to carefully enlarge the spring rod hold on the ASR cover.



The next step here is to take the switch completely apart.  Because we need a +12 to trigger our relays, the switch as is will not work.  If we move some of our wires around, we can get the switch to work, but the LED will not illuminate.  So as you can see from this picture, we are going to use pin 1 for ground, pin 2 for switch +12 and pin 3 is switch +12 to the relays.





With the switch apart and mounted in a small electronics vice, our next step is toe reverse the +/- leads of the LED.  This will allow the LED to light when the ASR is off.  Use a solder gun to loosen the solder and carefully remove the LED from the holder, be careful re-bending the LED wires and re-insert into the holder.  Solder the leads back and you will be done.



Once you have the hold enlarged and the spring rod moves freely, you can install the ASR cover on the rear dome light switch.  When I
picked up the rear dome light switch, I requested the socket and a length of wire to work with.  This will help facilitate the installation of the switch.  Thanks to Livin_it_up on the 190rev for hooking me up with the switch and B-pillars.



A ideal spot for our newly created ASR off switch is the center console fader location.  If you have a aftermarket stereo, most likely this switch has been bypassed.



With the center console wood removed and all the switch's disconnected, were ready to remove the OE fader switch and install our ASR off switch.



Be careful popping the switch out of its holder.  I use a small flat blade screwdriver to assist.



Here is the ASR off switch snapped into place.  You will notice that the switch is not as deep as the fader, this creates a new problem that we need to address.



You need to remove the old fader switch socket.  The next step depends upon how you are going to wire up your new ASR off switch.  When I purchased my rear dome light switch, I also requested the matching socket and a length of wire.  I was hoping it would mount into the fader switch location (which it did) but because the fader switch is deeper than the ASR off switch, you can't mount the socket into the switch assembly.  So before you reassemble the console, remember to plug your ASR off switch socket into the switch.



Moving on to the relays, we need to locate a suitable source of switched +12 and a ground.  I located these connected to the old fader switch wire harness, so I tapped into them and ran a short length of wire up to the ash tray area.



What we need are three SPDT relays, one for each ASR wire you will be splicing into.  When the relays are off, the circuit is open, allowing the ASR wires to connect and ASR to work normally.  When energized, the relays break the connections of these three wires.  This is the preferred method IMO to wire this up.  In the event of a relay failure, your ASR off switch just will not turn the ASR off.  



Although this is just my scribbled notes on the relay configuration, this is the diagram I used to wire up each of the three relays.  You can see that in the un-energized state, ASR functions normal and when energized, the connections are broken.



I created a wire harness using black, blue and red 16 awg wire (two of each color) and wired them up to the relay (using the diagram above).  I located the relays up under the ash tray and routed the wire harness out the rear of the console, up under the passenger side dash and into the kick panel on the passenger side.  You can not fit your hand up into the opening under the kick panel, so I ran a "pull" wire from the engine bay, grabbed it using some long pliers and attached it to my wire harness and then pulled the wire harness up into the engine bay from the engine bay.




Since we were done in the console, I put it back together (remembering to plug my ASR off harness socket in).  At this point, you should of already tested the switch and the function of the relays.  You should see the ASR off switch illuminate when its switched off and you should hear the relays click.  I tested the relay function using my VOM, with the positive connected to one end of my wire pair and the negative connected to the other.  You should see your VOM display change as you switch the ASR off/on.  Test each pair before you put the console back together.



This is the location I chose to pull my wire harness up into the engine bay through.  You can use a small Exacto knife to cut our the plug from this rubber grommet.  I then fed a single wire down through the hole and located that wire from the kick panel side.  Remember, you need something long that you can grab the "pull" wire with.  I then taped the wire harness to the "pull" wire and pulled it up into the engine bay and through the rubber grommet.



With the harness now pulled up into the engine bay, its time to take apart the can box.  You need to remove the cover, all the computers and the silver aluminum housing.  Your going to need a selection of torx bits, sockets and some screw drivers to do this.  Take your time as some of these torx screws are in hard to reach areas and if you drop one, they have a tendency to disappear.



Since I don't have the official MB tool for pulling the computers, you need to improvise.  You can see that I used a single screw driver as a lever rest and another as the lever.  Gently pry at each end of the computer till it pops loose, so a little at each end, you don't want to wedge it at a angle.



Once your computers are all out, you can remove the can box.  This item needs to be removed from its clips and moved out of the way, same is true for the main harness connector.  The harness connector has a lever that if you pull it up, it will pop the connector out of the harness, move both of these out of your work area.



You can see that this bracket has two 10 mm bolts that need to be removed before the can housing can be removed.



Once you have all the bolts and torx screws removed, carefully lift up the can box assembly.  Its wedged in tight, so you may have to wiggle it back/forth a bit to get it to lift up.  You need to do this step as the can box sits over these little clips you need to release so the computer sockets can be lifted up.



I used a small flat blade screw driver to release the small clips (located at each end of the computer socket).  You need to lift up the ASR computer socket, shown here in this picture.  You also need to strip back some of the tape holding the wires together.



Before you move on, now is a good time to make a hole in the can box plastic base, for your newly created wire harness.  I chose a spot directly above the hot air intake hole.  I used a unibit and a right angle cordless drill to cut my hole.  I drilled it just large enough to accommodate my wire harness encased (and wrapped in electrical tape) in loom wrap.




Here you can see my wire harness fitted through the newly drilled hole.  You need to pop up some of the other computer sockets to get enough room to do this and to route your new wires over to the correct spot.



This is the wire harness in loom and wrapped with electrical tape.  It was routed under the cooling hose so its out of sight and out of the way.  You can put the computers sockets back in once you have your harness routed over to the ASR socket location.



The wires we need to locate are 25, 35 and 37.  Renntech's instructions indicate that these should be 25 - Blue/White, 35 - Brown/Blue and 37 - Brown/Blue or Brown/Yellow.  On my 5/93 built 500E, the actual colors were 25 - Blue, 35 - Brown/Yellow and 37 - Brown/Green.  On the bottom of the socket, the numbers are listed.  I verified this by also looking at the bottom of the ASR computer and I triple checked before I cut any of the wires.  I have additional Renntech instructions and other ASR information under my Techdocs section.  Note that there is one hand written ASR relay diagram, its not the diagram I used.



Once you locate each of the correct wires, cut them and splice in your wire harness.  Use both of your blue wires for one of the ASR wires and so on.  You can solder your connections or use crimp caps, I don't recommend any other methods for securing your connections.



Before I started putting everything back together, I ran a bead of silicone around my new wire harness, you need to make sure this is sealed very well.  Moisture is not something you want getting to your computers.  Your computer sockets will snap back into place and the reassembly is the reverse of the disassembly.  This is a very worth wile modification, combined with a 1st gear start, you have unleashed the monster in your 500E.



Custom Performance Exhaust 5-28-06

In the pursuit of elusive performance gains, I decided to finally bite the bullet, drop some weight and free up the flow of exhaust gases.  Trying to source AMG or Brabus exhaust parts is difficult and expensive, so this time around, I relied upon my local shop (Dan Fast) to build me a custom exhaust matched to my vehicle.  I chose to use a set of Magnaflow twin, square exhaust tips (similar to the AMG style)



I did not want to cut my bumper valance this time, so I had the tips mounted about 1/2" below the bottom valance and aligned over the OE exhaust notch (on the inside of the valance).  These are stainless steel, polished to a high luster, so their longevity is guaranteed.



The tips took a couple of try's to get aligned properly, with the 3" pipe from the MagnaFlow Wide Open Performance muffler, it was tough to get the angle correct.  Several 90 degree pipe pieces needed to be welded together to get the desired effect.



The tips do not protrude much from the bumper, which is just the way I wanted it.



Here you see the pipe coming from the cat and up into the MagnaFlow muffler.  All the pipe was painted with a high temp black paint.  We started at the pipe right before the cats and installed a high flow MagnaFlow two into one cat (94057) and ran 3" pipe back to the muffler (11259) eliminating the heavy and restrictive resonator.



You can see the MagnaFlow muffler ere and how the 3" pipe needed several sections to get the proper angle for the exhaust tips.  The muffler was seated high up into the OE muffler location and all OE mounting points were utilized.  The high flow cat is designed for V8 applications up to 378 cid or 6.2l and a gross vehicle weight of 6000 lbs.  This is the cat recommended for the 500e by MagnaFlow (actually they recommended the same cat except with 2.5" out)



Here is another angle of the rear muffler with custom tips, this bend was a bit tricky, as I requested the tips to be mounted in notched OE location of the rear bumper.



Here you can see the hangers added to the universal MagnaFlow muffler.



Another picture showing the MagnaFlow muffler and the piping going back to the cat.  The sound of this design is as quiet as stock at idle and you really can only notice a difference during acceleration, no resonance inside the cabin either.  The sound is very similar to my C5 Corvette with Borlas on it.  I am very pleased with the results



You can see the full Magnaflow muffler and custom hangers better in this picture.



This is the pipe section that goes from the rear Magnaflow muffler, up into the high flow Maganflow catalytic converter.



This is the spot that was chosen to start the new exhaust, right where the exhaust manifolds merge and angle back under the car.  The new catalytic converter was located in the original spot with a small length of new pipe to connect it to the OE pipe.



Another angle of new exhaust from the rear muffler up to the catalytic converter.



Air Intake Panel Modification - 5/25/06

These are the panels that mount under the headlights and normally have cut outs for the wipers/squirters.  This particular set is from a 300E 2.8, a model that never came with headlight wipers, so no holes.  This will be our base for making vents that will allow more air to flow into the engine.



So the plan is to cut out a section of the panel and replace with some mesh to keep debris out of the intake.  This small home air intake vent was purchased at Home Depot for about $2.50, it has enough mesh to complete our panel project.



Using a standard wire cutter, the frame was cut away, leaving me with just the mesh material



Next I needed to determine when to start/stop the vent opening and at what angles would flow best with the headlights.  As you can see, I mounted the panels and determined that a straight vertical start point would be best on the left and a angled cut that follows the angle of the headlight bezel on the right.



I used a pencil and a straight edge square to measure my cut out.  I made it a little larger than what I wanted so filing would be necessary to get it exact.  This gives you a small margin for error when using the Dremel and cutting wheel.  I suggest the reinforced Dremel cutting wheels for this part of the project.




After about 30 minutes with a small file, the cuts were all smoothed out and slightly beveled inward for more of a rounded appearance.  I cut out the mesh so it fit perfectly into the rear of the panel.



So here is the mesh being test fitted and trimmed down so it sits flush into the panel



To adhere the mesh to the panel, I chose to use JB Weld.  With a batch mixed up, it was carefully applied all along the edges of the mesh/panel.  I used some heavy sockets and wrench's to keep the mesh flush with the panel for the 10 hours of cure time.



This is the other end of the panel with added weight to keep the mesh flush with the panel.



Here is the panel the next day after the cure.  Make sure you don't slop the JB Weld on, otherwise it can get into your mesh openings, you don't want any of it visible once the panel is installed.  Using JB Weld, I will never worry about the mesh coming unsecured.



While I wait for the paint to dry, its time to take the existing panels off and prep the area for the new vented panels.  As for the painting, I used my trusty rattle can of color matched Signal Red ( and after sanding with 400 grit and some spot putty, they were painted.



The side marker needs to be removed, then you will have access to the 10 mm nut holding one end of the panel in place.



The other 10 mm nut is accessed by opening the hood.



With the old panel off, you next need to remove the rubber trim attached to the bottom.  We will install this piece on our new panels.



Here is the bottom rubber gasket mounted to the new vented panel.  The rubber nubs were sticking up to far and were visible from the front, so something had to be done!



Next was to cut these rubber nubs down so they are not sticking up and are visible.  They were also painted red to further blend in and not stand out.



This rubber gasket won't be used with our new vented panels, so carefully remove it and store it away with your original panels.



Once I had everything removed, I did a test fit of the panel and discovered that I was able to see to much behind the panel.  The bottom portion of the headlight and the wiper motor mount in particular. 



A extra step that I had not anticipated, masking off the headlight and bumper area so I could paint the bottom portion of the headlight and wiper motor mount, black.



You can see that once painted black, these area almost disappear,  this adds to the cosmetic appearance of this particular modification.



With the painting done and the panel paint dry, it was time to install.



The finished product!  Although it would be hard to measure the added performance of this modification (especially since it really is only going to work at speed) every little bit helps in getting more performance out our your vehicle.



This project turned out well and I really like how the vent openings follow the lines of the headlights.



Another picture of the finished product.

These videos cover the Hella Euro headlights and the updated vented wiper panels.




K&N Air Filter Installation - 6-7-06

Continuing the quest for every little bit of performance, the next item to upgrade is the air filters.  Its long been known that free flowing air filters can net you a good increase in performance. (the upgraded air filter on my Corvette netted me 17 rwhp).  So we start by removing the 500E airbox

The front plastic shield of the air cleaner assembly lifts off, then we remove the two air intake pipes.  The air cleaner assembly lifts up from the front, then you slide it towards you.

With the air cleaner assembly off, we need to flip it over and release several clips on each side.  We can then remove the plastic cover exposing the air filters

With the clips released, the bottom cover (one over each filter) lifts off.


This is the cover that was just removed, now is a good time to clean up your air cleaner assembly, both inside and out.

This picture gives you an idea of the air flow through the air intake.

Of course, my favorite choice of performance filters is K&N.  They have always netted a good HP increase and have never let me down.  For the 500E, you need two of these.  Your local auto parts store should be able to order them or you can get them from EBay for around $35 each.

This is the K&N next to the OE filter

Installation is simple, they just drop in.  After about 10,000 miles +/-, you need to remove the filters and using the K&N cleaning kit, clean and then re-oil the filters.  You should always oil the side of the filter that faces the dirt (air coming in) and oil "lightly".  Many people over oil these filters and this can lead to fouling of the HFM and/or MAF with oil.  Done correctly, you should never have to worry about this kind of problem happening to you.



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