Final m30 Wiring, need some help id'ing wires.

[ping65810]

Hey everyone, quite the awesome site. I post on R3VLIMITED.COM quite a bit, as I am across the pond a little bit

I have an 87 325iS 5 spd with a 88 735iL m30b35 engine, harness (loom), e34 535i 5 spd. I have searched all the m30 articles, and here is what I am up against:

I joined engine plug to car plug, attached ground wire, power wire to starter, and + wire near ECU to the + terminal. When I turn the key, I get warning lights, OBC, etc, and I get ABS? clicking 3 times. Thats it. I read about the 3 wire plug near the ecu being a cutoff, so I worked with that tonight. It has 3 wires: Green/Wht, Green/Brwn, and solid Brown. I found the Green/Brwn to be a - wire, and so I attached that to the ground. When I touch the Green/Wht wire to the + terminal, I get the relays on, the ABS clicking, and the dash seems to indicate he same as if I turned the key. No start at all. No cranking, and can't hear the fuel pump running.

I then tested the wiring with a multi-meter, and found the following- With the key on, the Green/Wht wire puts out 12 volts. The starter is also getting power, and everything seems to be OK. When I touch the Green/Wht wire to the + terminal again, the relays click on, but still no start, etc.

I know that wire has something to do with the situation, but I can't figure out for the life of me how to get the bloody thing to start. Any help is greatly appreciated. And if it makes you feel better, my grandfather is from Manchester, and I hate Bush as much as the rest of the world does

[E30Mark]

welcome!

I don't really know anything about the m30 wiring.... but on the m20 you just took out there would have been an earth wiring connecting to the starter motor, do you know if this is still there?

I'm sure some of the m30 boys will be along soon

[ping65810]

Are you sure its an earth wire? The one I have connected is a large positive (I think), it comes out near the positive terminal and goes across the blower motor to the starter.

[E30Mark]

Yes there will be a large +ve cable, but i think there should also be a earth there, i'm sure i read it on this sight somewhere... goes to the unloader relays.

[DaveD]

there might be help on this

http://shark.armchair.mb.ca/~dave/BMW/e30/

[ping65810]

Starter is grounded through engine block. Tried switching wires around a bit, and still nothing. Only when I use the green wire do I get power to the relays, so there is def something up with that. I am still at a loss, though. Wiring is not usually my thing, and although the wire diagrams help a little, there is still no definitive guide telling me what the reasons are that it won't turn over, etc. ANY help is greatly appreciated, any at all. Thanks for the help already.

[DRIFTBOY]

Hi dude - and welcome!

I can't quite get my head round what wires you have put where exactly, but are you sure the starter has power getting to it?
If so, is the starter any good, or stuck?
Have you got the big cable going from the starter to the alternator?
The plug under the dash shouldn't make a difference, I think it's to do with automatic transmission.
Have you got the ground strap from the engine to body on?

Sorry if I'm stating the obvious!

[tekila325]

Does the engine crank or just doesn't start?

If it cranks then You might have a problem with anti-theft system if the735 had OBC. If so then there is missing +12V on the ECU which then actuates the main relay...Also carefully check the round engine connector (X20). Although it looks the same, there are some differences between 3, 5 and 7. I know I had some problems when I was swaping M20B25 from e34 into e30, but as I remember the engine ran it was just something about efficiency meter signal(yellow/white) and unload relay(black/yellow).
When You talk about green/white wire this wire should usually get 12V (Fuse 9 - 15A) when key is in ignition position (power for O2 sensor). Note that ECU itself, gives ground to main relay (Usually via Green or Green/brown wire!), when it gets +12V via green wire (probably pin 27 on ECU). I'd also check+12V on main relay (red wire).
As many BMW's I've done colour codes are:
- Green: for Ignition +12V (goes also on ignition coil)
- Green/white: Oxygen sensor heater
- Red: +12V at all times
- Brown: Ground
- Black/yellow: Unload relays
- Red/white or Red/blue: Output of main relay which powers the ECU, Fuel injectors ...

[gareth]

when i dropped mine in, i used a E32 auto engine, loom, ecu etc but with a manual box. once the obvious wires and main loom connector were connected (as you described above) mine fired straight up. the other tweaks relate to getting the econometer working and the windows / fan working without having the doors open!

do you have a good earth strap between the engine and chassis? if so, try bypassing the solenoid on the starter with a screwdriver, making sure you don't just earth the battery to anything near or everything will get all sparky!!! this will check if the engine earthing and starter are ok.

[ping65810]

I don't quite understand about grounding the solinoid, if you could elaborate a little that would be great. I am going to check the grounding strap again. What I am wondering, though, is if the engine wasn't properly grounded, then why would my icv hum when the key is turned? Unless it just needs + power, right?


Sorry for all the questions, its just wiring isn't my forte, and sometimes the answer is right in front of you an you can't see it.

[gareth]

if the ICV does humm, there must be some form of earth return for it. this is probably part of the engine loom, though its connector and would have been earthed with the large bundle of earth wires that attach on the R/H strut top, near the battery.

the power lead onto the solenoid will (piggybacked on the starter) is permanently positive. the solenoid is basically a large relay which closes when it recieves a positive feed from the ignition switch. when the solenoid closes, the power is then trasmitted to the starter motor. to complete the circuit, the starter motor is earhed onto the block which then needs to be earthed back to the chassis. (the chassis is connected to the negative termnal on the battery)

if the above is all correct, find the two fat srew terminals on the solenoid and jam something metallic (screwdriver is ideal) between them (like you're trying to lever them apart). this will bypass the solenoid, the ignition switch and any immobilisors that may be present and should spin the engine over. if nothing happens you have either a flat battery, no battery earthing, no positive feed to the starter/solenoid, no engine earthing (earth strap), or a duff starter.

if everything is ok except for the solenoid, try getting a hammer and tap it. they can stick and a tap will very often free it.

it's a bit of an essay but i hope that helps!

[ping65810]

Thanks for all the help, I am going to try using a different earth strap for the block, I am thinking this might be the problem. The Battery is brand new, and I am def getting a good ground on the chassis end. Will try to bypass if all else fails.

[ping65810]

It cranked when I bypassed the starter solinoid easily, but even with key on it won't actually run at all. The fuel pump dosen't seem to be running either. And it still won't crank with the key.

[tekila325]

Try to brick the fat +12V on starter with the with M6 tapping. If it cranks then You are not getting signal from the key. If the 735 had automatic transmission then you should find the wires which go to transmission selection lever switch, or maybe the wires on the big roun connector are missmatched.

[gareth]

my E32 735i was an auto and with the auto box disconnected, the engine started straight up.

have you tried a new ignition switch?

[Toby_Unna]

the other tweaks relate to getting the windows / fan working without having the doors open!

is that something to do with the engine then

i assumed i just buggered something up somewhere in the car during the swap. cured it using a few jumper wires to power up the necessary relays in the fuse box, bit of a bodge really but it's worked for a couple of years ok.

is there a better way? my c101 thingy only has a couple of sensor /starter wires connected now with the MS in.

[Brianmoooore]

the other tweaks relate to getting the windows / fan working without having the doors open!

is that something to do with the engine then

.

More something to do with the starter motor. There's a black/green wire from relays K5 and K7 in the fusebox, which goes, via the C101, to the smallest terminal of four on the starter motor. If the starter motor only has three terminals, then connect it to the strap that goes between the solenoid and the starter motor body.

[Brianmoooore]

Right, back to the main thread.
If the engine to body earth strap wasn't in place and there was a bypass to this in the smaller wires (as there is via one wire of the oil level sensor on engines with this), then this would be readily obvious when you tried to start it by the large quantities of smoke.
Am I correct in thinking this engine doesn't crank? If so, open up the diagnostic socket, and connect pins 11 and 14 together. Does this make it crank?
If not, connect 11 to battery + with a piece of wire. Crank now?

[gareth]

did you ever get this sorted mate?