E30 Zone

Hi , I have BMW 320i e30 manual 1989 with L-Jetronic system without distributor.
Just wondering if anyone could help me on wiring diagram as I want to do a pin out wiring check.
many thanks in advance

Why do you think it is Jetronic? Surely a 1989 with no distributor is going to be some form of motronic?

What's the type number of the engine ECU?

sorry my mistake, found on ECU say motronic
had a problem at C191 plug and tried to reconnect all the wires at C191 had bad connections
now in a problem temp gauge doesn't work

Disconnect the C101 engine loom plug next to the fusebox, and short pin 4 of the socket on the body to earth with a short piece of wire and the ignition on. Does the temp gauge move to max?

I will check this tomorrow.
At the C191 plug there are wires, I have connected fuel injectors bank 1 and bank 2 and DME wire,
I am struggling to connect the coolant sensor with 2 pin and coolant sender with 1 pin wires
On the injector side wiring these are the colour code;Brown/Red
Brown/Orange
2 Brown/Yellow,
1 Red/White, and Brown and Violet

What have you done at the C191? Removed it completely, or attempted to retain it and repair the wires to it?
The damage usually extends up inside the insulation of the wires to the lower half, and often several inches of fresh wire has to be spliced into place to repair. It's hopeless trying to solder to copper that has become blackened - cut it back until you reach clean shiny copper.
The red/white is the common 12 volt feed to all the injectors, the brown/yellow is the control pulse to injectors 2, 4 and 6 and the brown/white is the control pulse for injectors 1, 3 and 5. These three are the thicker wires.
Brown/red and brown/orange are the wires from the coolant temp sensor (the 'blue' sensor) for the engine ECU.
Brown/purple is the wire for the temperature gauge (brown sensor) , which uses the engine metalwork for its earth return. Early M20s used a two pin gauge sensor, and there might be a brown/white wire to one side of the C191 which is only there because no one deleted it from the design.
If you're saying the brown/purple isn't connected, then this is why the gauge doesn't work.

Hi Brian
I have checked at C101 plug and the gauge moved to max
I have connected all the wires as per your above instructions the car runs alright but temp gauge when you put the ignition it moves to blue on gauge even with engine warmed up gauge stays there. Like you said to trace back the brown/purple in loom for fault.
I will check that next.

Short the single pin in the brown temp. sensor plug to earth with the ignition on, and see if the gauge moves to max. Be careful not to damage the pin in the plug by inserting something bigger than it should be into the contact bucket.

I have checked at C101 plug gauge moves to max, short the single pin Brown/Purple wire gauge moves to max. I did fit new temp sender, should I try another new temp sender . With ignition off position the temp gauge is at rest, With ignition on the gauge moves past the blue on the gauge from cold with the sender disconnected. The fuel gauge, Rpm, Service indicator lights and Check light all work except temp gauge.
I have swopped the gauge with another one still n/w. Would the SI board or the batteries be the problem.
Sorry to trouble you.

In a badly corroded C191, if the conditions are right, the temp. gauge can do strange things as a result of current flowing from the red/white injector supply to the brown/purple, but with all that sorted this should no longer happen.

Does the gauge move past the blue when you switch the ignition on if the C101 by the fusebox is unplugged?

The SI board batteries can affect the temp. gauge and tacho. if they go short circuit, because they run from the same stabilised power supply in the instrument cluster. The shorted batteries overload the power supply and pull the voltage down to these two gauges, but I've never seen or heard of what you describe.

Does the gauge move past the blue when you switch the ignition on if the C101 by the fusebox is unplugged?

yes it does

In that case it looks like there is something weird up with your instrument cluster.
You say you've already tried a replacement gauge, so the problem must be with the electronics, which are all on the SI board, so a fresh one of those would be my recommendation. You could check the voltage on the batteries first, but if the SI LEDs are behaving, they're unlikely to be at fault.

where would be the best place to get SI board, i have checked the BMW Dealer here but they can't get one.

kumar wrote: ↑

Thu Feb 27, 2020 9:43 pm

where would be the best place to get SI board, i have checked the BMW Dealer here but they can't get one.

I doubt if you would want one when they gave you the price! Try the 'parts wanted' forum on here, but check out the feedback forum for anyone that offers, or there's your local ebay or equivalent where ever you are. Look for a later board with lithium 3 volt batteries, or there's the aftermarket board by Programa, introduced a few years ago with much more modern circuitry.

P.S. You originally asked for a circuit diagram: http://www.autolib.diakom.ru/CAR/BMW/19 ... 0DIAGRAMS/

many thanks for helping me, I will come back to update once I get it sorted out.