SI Board

[montokboy]

After driving my car for a few months, I noticed the mpg guage was acting funny, dancing around, and usually sticking at either the 40 or 0 mark...my temp guage shudders once in a while..and the tach hand freaks out for a second on a regular basis...and this morning the speedometer hand stopped working, from what I have learned here, it seems to be the SI board/batteries..could it be something else? is it better to pull out the si board and solder new nicads or to purchase the whole board itself? I checked and there are 2 types of boards..one is newer (upgraded) and contains the lithium batteries. Any advice on this would greatly help.

thanks
Sean

 

[jrt67ss350]

Sounds like you might be having some other electrical problems. The speedometer works independently of the SI board. It stopped working due to a different problem.

 

[KC Ron Carter]

sometimes the speedo goes away

Check the connector on the aft face of the differential, the speed sensor.

The SI can also be an issue for the speedo.

The cluster uses the power from the SI board to balance power from the speed sensor.

SI reset and batteries

With the ignition switch at (position two) and the engine not running, grounding pin seven #7 of the diagnostic connector to pin one #1 for approximately three (3) seconds will reset the oil service lights. Grounding pin seven #7 to pin one #1 for approximately twelve (12) seconds will do an inspection service reset.

More information.

http://www.specialistcarsbmw.co.uk/stevenage/service/service_lights.htm

http://www.unofficialbmw.com/images/reset1.gif


1. Ground
4. Temperature sensor
7. Reset
8. TDC sensor yellow
9. TDC sensor shield
10.TDC sensor black
11.Start signal
12.Alternator charging excitation voltage
13.Ignition coil
14.Alternator charging supply current
15.Oxygen Heater

It will signal an oil change need between 5k and 7k depending on your indicated speed since the last reset. It will signal stealer inspections at all the predesignated miles.



http://www.eskimo.com/~dalus/bmw/e36/electrical/e36_reset_service_lights.html

SI Board Swap Out

Last but not least - the SI Board. Above is a new SI Board with lithium batteries and below is the old one. Note the blown battery on the old SI Board (green circle). The light blue rectangle shows the actual service indicator LED's which appear on your dash display. These LED's are mounted on a separate circuit board which must be pulled out of the old SI Board and plugged into the new one. This is an easy task. The purple arrow shows the orientation of the SI Board relative to the driver.


If it fails to reset then you need batteries.

Varta battery 500RST OE part.

Radio Shack: part number 23-191: $6.49 for set of two; they come w/solder tabs on them.

1.2 volts / 700mAh

Charge fully B4 installation on SI board.

Consider mounting batteries "remotely" under dash, etc. in separate holder for easy removal in future (i.e. not pulling the console out and apart); you can buy a plastic holder at RS. Run leadwires from holder to SI board connections. Makes life easy if you ever need to replace batteries again.

From Radio Shack, get:
1) You'll need a twin AA battery holder ($3)
2) 2 AA NiCAD rechargeable batteries ($6)

Later,

 

[montokboy]

Anything else?

The speedometer started working again last night...so now all the guages have freaked out one time or another.....do I need a new instrument cluster?

 

[420i]

S.I.

I had a 318 with the same problem. The tach was off by a couple thousands, the m.p.g. would move about (didn't work), and the temp gage was not in good form. I opened the cluster to check the batterys and I found that someone had replaced the nicads with regular AA batteries. Needless to say my S.I. was fried. I didn't mention the the lights would flicker, too. The speedometer was not effeted though the plug, located to the left behind the cluster, may not make contact causing the speed not to register. I hope this helps.

 

[rjp325i]

KC Ron Carter: According to the BMW Enthusiasts Companion published by Bentley the #19 pin socket is the ground not #1. Did you make a typo? I have been using the #7 and #19 pin sockets for several years to reset the oil and service indicator lights. Isn't pin #1 the ignition coil & Motronic control unit?

 

[KC Ron Carter]

Hmm, must be NBD

I checked my Enthusiast's Companion, on page 123 figure 3 it shows the same 15 pin diagram from this e24 ETM. My e30 ETM is the same.

On some later books it may say pin 19 since I have never seen one I will stay with 1 + 7 since it works with old and new. I was trying to remember what was the latest model I had used this on and I can say a 1996 model.

http://members.roadfly.com/kcroncarter/etm101.htm

Later,