kiasu

Hey guys, not really enjoying seeing the speedo needle bump up and down at low speeds and moderate to high speeds so i've got the opportunity to pick up an RSM which is a rev speed meter, i just need to know whether i can install it on my 89' 260E. Is it doable? here's a pic of the actual product including the wiring harness.




thanks in advance

CDP

Anything is doable with the right person to install it.

A couple of my friends have ApexI products installed in their cars and I love what they have to offer. This would be perfect to mount in the center of the instrument cluster.

Is that their new design? I like the older models better...

kiasu

that is actually the series 1, so the older model i like it for its simplicity and the colour matches the older style of w124, i was thinking mounting on the steering wheel collumn, so i would view it through th esterring wheel.., so this would get wired up to the ecu? anyways ill try and get a electrical technician to sus it out

myfirstbenz

why not just have your speedo repaired?

bicylindrico

It's just the cable.

kiasu

i thought it was a common thing with all 124s.., besides im still going to be using this unit for other features once i get a hybrid motor in

shdoug

Mine does that,too. Are we in agreement that it's just the cable? Will it get worse?

myfirstbenz

Hybrid motor? Do explain

Bigpete123

This seems like a great length to go to just to get rid of that. My car doesn't do that at all... so I would think there's something wrong with your speedo/etc.

It just seems like overkill to me.

lkchris

Yer gonna need to fix yer cable anyway, because the bouncing speed reading affects yer cruise control.

Gasdrinker

haha, my car has the same problem from 30-40, and yes my cruise control is also fubar, I have replaced the cable about 3 years ago and the problem just recently came back...

bicylindrico

The cable casing can be distorted by pulling on the cluster without detaching the cable at the transmission. Instant bounce.

kiasu

bicylindrico: that could be the problem as i had my cluster repaired due to kms not ticking over anymore, but has since been fixed..could it be careless workmanship? i mean i will get this speedo cable thing fixed and get the cruise control working normally instead of just full gassing it when i set the speed..haha

but nevertheless i still need to know if i can get this wired up to the comp and sensors, theres abosolutely no writeup or history of anyone ever installing this product on the net..

myfirstbenz: 2jz-gte vvti w/ 6 speed box , should be fun

myfirstbenz

I saw that done on a late 70's SLC. I would personally have a hard time with putting a jap motor in a Benz, but hey, it's a great motor for sure. Keep us updated with photos!

kiasu

so is this doable....wiring shouldnt be a problem?, im just unsure about the type of bosch computer on the w124s..i know what they look like which is the scary part, well i think i may just go ahead and purchase it

kiasu

hey guys i've acquired the rsm, and have all installation instructions for it but it mentioned that it wont work for cars other than jap's, but ive heard of people installing these in their audi's. how are the computers on these 124's can they be wired up to a harness? are the speed sensors wired? or a mechanical cable..etc plz help

RBYCC

If you have an 89 260E, there isn't much in the way of electronics !!!!
You can pick up the engine speed signal with the green/yellow wire that runs from the EZL unit (electronics ) to the diagnostic socket, then to the OVP relay, fuel pump relay, then the tach.

The speedometer is cable driven, but there is a hall effect speed sensor mounted on the back of the speedo.
The sensor has a brown earth wire, the yellow/green engine speed wire and a third wire (color?) that runs to the fuse box then to the ignition switch.

What is the wiring diagram of the unit that you are trying to install?

kiasu

hey thanks for the reply i scanned some documents which may be relevant.

http://img.photobucket.com/albums/v6...u/scan0003.jpg
http://img.photobucket.com/albums/v6...u/scan0002.jpg
http://img.photobucket.com/albums/v6...u/scan0001.jpg

Garfunkle_W124

where did you order this?

RBYCC

Look at your basic Apexi connection diagram.
You need ignition power, constant power, rpm signal, ground, vehicle speed signal.
The Apexi colors I'll indicate first, followed by the Mercedes color to connect to.
Red to Red/Pink ( ignition power)
Orange to Red ( constant power)
Yellow to Green/Yellow ( RPM signal)
Black to Brown (ground)
Purple to ???? (vehicle speed signal)
Only place that has any kind of a vehicle speed signal is the cruise control, which picks up the signal from a hall effect sensor on the back of the speedometer. This is also the Green/Yellow wire so you may try jumpering together the Yellow and purple wires on the Apexi and connect to green/yellow, but not sure !
All of the wires you need can be found at the fuel pump relay.

Possible problem is if the hall effect sensor is not outputting correctly due to your mechanical speedometer not functioning properly.

Still not sure if it will work, as you're dealing with a very unsophisticated car in the 260E.

kiasu

so your saying to connect this unit to the fuel pump relay and the cruise control module? thats sounds so tricky, but ill inform the auto elec about it, thanks for the info, so the fuel pump relay is still in the engine bay or towards the rear of the car..

RBYCC

Reason I state the fuel pump relay is that all the wires you need are located there.
Easy to make a temporary trial connection at one convenient point, then to find wires all over the car !

kiasu

oh i understand, but is the fuel pump relay located with the fuel pump or near a fuse box in the engine bay

kiasu

i bought it interstate in australia from one of the jap boys from firesport.com

RBYCC

Fuel pump relay should be next to the OVP relay and is located behind the battery. Should have about eight terminals and the OVP has about seven with two fuses mounted on top.
All the wires that you need can be accessed at this point.