Better but not fixed e28

[User Name 19]

Hi All

Thanks to Marty i got a new brain for my car which didnt start first pop, but in the morning i managed to get it started and rang fine (like normal) for 40 mins until the car got heated up close to 100 degresss

well was prob round 60-80 at the time it stopped, let it cool down drove quickly then stalled again

can get car to start with cold start off but then just stops, if i put cold start on as it starts will go for a 30secs and die's again

any ideas now - does anyone have a fault tool that gives errors codes as its strange that its doing it again even with new ecu, given it sounded better

is there a sensor that stops the car from running when it gets to hot.

cheers

otherwise it can surviive to ive got the evo done or get a Link ECU

[BM WORLD 1265]

who did the wiring conversion to the e28 body loom . e32 and e34 dont have cold start thermo time switches . all they have is a thermo sensor for the instrament cluster and one for the ecu to tell it what temp the engine is so it will run the correct amount of fuel and auto matically adjust for cold starts etc .

if you unplug one of the temp sensor plugs the engine will run fine and the gauge will not work .

if you unplug the other the engine will run rich and spluter and die because it gets over fueled and more so when the engine is warm .

the e28 loom uses a single pin temp sensor teh gauge which returns back to earth(ground etc)

so what has been wired there .

do you have pics of some of the wiring conections etc .

sounds a bit like the main ecu temp sensor is not conected back to the ecu.

best to get it checked by a bmw electrician

[User Name 19]

Hi Brent

Details of the wiring info below, would take it to bmw but they didnt even want to know last time and wiring doesnt look that great lolz, given fact it would be a 1hr ethier way to closet bmw shop

might see if i can find someone in levin that knows about wiring but thanks for the info.

M30 b35 Motor Conversion(Electrics)

Ok, even though this is from the E30 ETM, it should be the same. Let me know if any of the wire colors are not found or different, and I will try to dig up my E28 ETM. Please note that I am partially color blind so I have great difficulty telling the difference between Green and Brown. So some wires that might be Green I will call Brown and vise versa.

The connectors that need to be taken into account are C101 and C103. C101 is the 17 pin connector that plugs into the fuse box. C103 is the connector that plugs into the motor wiring harness under the dash on the passenger side. There are anywhere from 5-3 wires in C103. The wires on the side of the body are colored, BK(to instrument cluster(tach speed drive)), BR(Ground), WH/BK(to instrument cluster(fuel economy gauge drive)), GN/RD(not used(goes to one side of the OBC relay)), GN/YL(not used(goes to the other side of the OBC relay)). Now first lets concentrate on this plug. On the E28, BK goes to BK/BL, BR goes to BR, and WH/BK goes to WH. On an E30, the 2 wires that are not used in the E28 are used, which I believe are also used on the E34. These 2 wires are what cuts the ignition control when the CODE function of the OBC is used. If you are wanting to wire these in, they should connect to the one GN/RD wire. Basically, you cut the GN/RD wire and run one side down one of the unused wires and back to the other side of the GN/RD wire. In the E28, though the OBC relay should control the no start function by cutting power to the main relay, so that is why your car runs now, so I would just leave the 2 wires that aren't connected, unconnected.

Now onto the 17 pin plug on the side of the fuse box. C101. I believe that all of the connections for C101 and C103 in the E28 are contained in the E34 C101, so you will have to do some splicing up near the ECU to put in the other end of the E28 C103. The E28 plug has listed numbers I am going to refer to these number and the wire color that should come out of it on the E28 motor and what it does.

Pin 1, BU goes to alternator. Goes to alternator "charge indicator" light in instrument cluster.

Pin 2, BU/VI or BU/RD static oil level sender unit. Goes to static oil level light in the active check control unit.

Pin 4, BR/WH Coolant temp sensor driver wire. Runs to coolant temp gauge in instrument cluster.

Pin 6, GN/YL goes to the O2 sensor heater relay. Gets power from fuse 6 and in the fuse box is colored GN/WH.

Pin 7, GN/VI gets power from Pin 87 of Fuel Pump Relay and goes to fuse 1 in the fuse box.

Pin 8, BK/YL Starter trigger wire comes from the ignition key.

Pin 9, Not used

Pin 10, WH/BK To Diagnostic connector Pin 6. Said to be "not used".

Pin 12, GN Powers the coil from fuse 1 of fuse box

Pin 13, BU/WH Dynamic oil level sender unit. Goes to oil level light in active check control unit.

Pin 14, BR/GN Oil Pressure switch. Runs to oil pressure light in instrument cluster.

Pin 15, WH/BU Service indicator to Diagnostic connector.

Pin 16, GN Is the same as the GN wire in Pin 12 and is actually spliced together with the wire from Pin 12 at S127

Pin 17, GN/VI To Fuel pump relay through splice S128

The E34 uses a round style connector to plug into the fuse box. This has 20 pins so I will list what the wires in each of those do.

Pin 1, BU goes to the alternator. Comes from the Instrument Cluster "charge indicator" light. BU in the fuse box.

Pin 2, GN/YL comes from oil lever sensor. It is BU/BK in the fuse box and runs to the static oil level active check control unit, which is the same as the oil level light.

Pin 4, BR/VI comes from the coolant temp sender unit. It is BR/VI in the fuse box and goes to the Instrument cluster temp gauge.

Pin 5, BR/GN Oil pressure switch. Runs to instrument cluster oil pressure light.

Pin 6, GN/WH goes to the O2 sensor heater relay. Gets power from fuse 9 and in the fuse box is colored GN/YL.

Pin 7, GN comes from the ignition switch and goes to the Start Input, in the motronic unit and it also goes to Pin 15 on the coil. In the fuse box it is colored GN.

Pin 8, WH/BK comes from the motronic unit "present fuel rate output". Is YL/WH in fuse box and runs to Fuel Economy Gauge in the bottom of the tach.

Pin 9, BK goes to the ECU Engine speed output. This is BK in the fuse box. On the E28 this actually should be the connected in C103.

Pin 10, BU comes from the oil level sensor. It is VI/GN in the fuse box and goes to the active check control unit as the dynamic oil level light.

Pin 11, WH/GN comes from Pin 7 of the diagnostic connector. Is WH/BU in the fuse box and goes to the Service Indicator Processor.

Pin 12, GY comes from the ECU and is the trigger for the "Check Engine" light control. In the fuse box it is BR/BK. This wire is not used on the E28, since there is no check engine light.

Pin 13, GN/VI comes from Pin 87 of fuel pump relay. Is VI/RD in fuse box and runs to Fuse 11.

Pin 14, BK/WH comes from motronic unit "Speed Signal Input". Is BU/YL in fuse box and goes to the Speed Input of the Instrument Cluster.

Pin 15, BK/GN comes from Pin 30h on the coil. In the fuse box it is BK/GN and runs to the unloader relays.

Pin 16, WH/BK comes from Pin 6 of diagnostic connector and is used in the SRS system. In the fuse box it is WH/BK and is said to be not used.

Pin 18, BK/YL is the starter trigger and comes from in the car. It is also BK/YL in the fuse box. It also runs to Pin 11 of the diagnostic connector.

Pin 20, RD/YL comes from Pin 87 of the main relay. It is RD/YL and goes to power the ABS Hydraulic Unit.

I believe that the rest of the plugs aren't used.

I believe that Pin 14 is also not needed to have the car run properly.

I have yet to find out what propose it serves so I would say it doesn't need to be connected. And any of the E34 pins that I do not have connecting to a pin on the E28 harness means that it does not need to be connected, or there is no place for it to be connected.

Now here is a list of which wires need to go where.

C101 E34 to E28

Pin 1 Pin 1

Pin 2 Pin 2

Pin 4 Pin 4

Pin 6 Pin 6

Pin 13 Pin 7

Pin 18 Pin 8

Pin 16 Pin 10

Pin 7 Pin 12

Pin 10 Pin 13

Pin 5 Pin 14

Pin 11 Pin 15

Pin 7 Pin 16

Pin 13 Pin 17

C103

Pin 9 Pin 1 BK

Pin 8 Pin 3 WH/BK

I have spent now 7 hours on this, so I really hope it helps.

Written by Rob Anderson '01

[User Name 19]

I will look at what you advised this w.e

if you have facebook there are some pics on there ill try upload some, i basically wired it just below the e32 connector for the fuses, onto my e28 one

[BM WORLD 1265]

I will look at what you advised this w.e

if you have facebook there are some pics on there ill try upload some, i basically wired it just below the e32 connector for the fuses, onto my e28 one

have you played around with any of the temp sensors from teh e34 engine??

[User Name 19]

No i havnt played round with them i never managed to get the collant sensor or the tacho wired up to the dash, had to re wire it - techo - blaster coil

aftermarket coolant gauge goes to coolant sensor i will try the sensor thing cause what you said fully sounds about what it is doing ill have a look at it next chance i get to the car if it works, im going to be a happy man

[BM WORLD 1265]

No i havnt played round with them i never managed to get the collant sensor or the tacho wired up to the dash, had to re wire it - techo - blaster coil

aftermarket coolant gauge goes to coolant sensor i will try the sensor thing cause what you said fully sounds about what it is doing ill have a look at it next chance i get to the car if it works, im going to be a happy man

so which sensor did you disconect . big plug with spring clip or small plug with little wire .