Now comes the Wiring!

[GreatOldOne]

Right, managed to get a Durite fuse holder like this:

http://www.workshoponline.co.uk/showdetails.asp?id=928

for a midi type fuse (found a new motor factors in town ), and a 60 amp fuse is on order and I'll pick that up tomorrow.

I'll mount this near the battery and then run the cables on the harness to it and then on to the positive terminal.

[MartinClan]

Looks just the job....

Robin

[GreatOldOne]

Right - here's a question. If I fit a 60 amp fuse, as Peter has, its rated for 60 amps continuous draw, and will blow at 120 amps.

Does this mean that I would need to run 60 amp cable from the battery to the fuse? The highest rated cable I have is 39 amp (56/030)... and the cables the other side - well, you've seen them in the pic. I'm guessing they're not 60 amp cables.

[MartinClan]

Originally Posted by GreatOldOne

Right - here's a question. If I fit a 60 amp fuse, as Peter has, its rated for 60 amps continuous draw, and will blow at 120 amps.

Does this mean that I would need to run 60 amp cable from the battery to the fuse? The highest rated cable I have is 39 amp (56/030)... and the cables the other side - well, you've seen them in the pic. I'm guessing they're not 60 amp cables.

How cables are rated is actually quite complex. For example a 39 amp cable will carry far in excess of 39 amps depending on the environment. It would probably take several hundred or even thousand amps to actually "blow it". The fuse is there essentially to protect the cable from overheating, melting the insulation and subsequently causing a fire.

For me I would probably have used a fuse with a lower rating - say 40. But there is a danger of using a fuse of too low a rating - it may be OK for a while but the heating effect caused by excessive current flowing through it will eventually cause it to fail. Is this fuse in the feed to the engine management system? Perhaps someone knows what it should actually be? Unfortunately the in-line fuse BMW fiited in my loom does not have any marking.

Sorry - I just realized that was a non-answer. :-(

Simple (engineers) solution. Fit a smaller fuse and carry a few spares in the car of a slightly higher rating just in case.

Robin

[GreatOldOne]

Thanks Robin

I'll run some of the 39 to it, and I'll pick up a selection of fuses from the auto spares place later on today.

You'll be sick of me (and all my questions) by the time I've finished wiring her up!

[peterux]

Do you ever get that 'DéjÃ* vu' feeling?

http://www.madabout-kitcars.com/foru...ead.php?t=1604

Incidently, I blew my 60amp fuse the other week when fitting my windscreen. I just accidently 'brushed' back of my fuse box with a spanner and it blew without any fuss or drama. The moral of the story is always disconnect the battery when working on the car but we all know that!!

(note to self: Order another fuse link!)

Just ordered some spares from this guy on ebay.

http://stores.ebay.co.uk/JCR-SUPPLIE...QQftidZ2QQtZkm

he has lots of useful stuff...worth a look........

[GreatOldOne]

More questions...

1) Should the feed to the ignition switch (The large red cable, Terminal 30?) be connected through the fuesable link? I don't think it does, as it's not shown going through a fuse before the switch on the diagrams. I'm assuming it just needs to be connected to the cut-off switch.

2) I've been looking at the wiring diagrams for the ignition switch, and I've come to the conclusion that I have a franken-car. All the diagrams I've seen (Bently, Haynes & downloaded BMW from E30 Zone) mention the 4 main connections on the switch - Red from battery to the switch (30), Black to starter (50) and the two green cables which are on terminals R & B (one of which goes to the coil - where does the other go to?)

The thing is I have four more cables on the switch - from terminals PR1, PR2, PL1 & PL2. I haven't found out what these are for yet... They're small cross section, so they're not taking a lot of load... The only thing I've come up with is they're something to do with the on-board computer my donor had.

I'm rapidly coming to the conclusion that I can't read wiring diagrams!

[GreatOldOne]

Well, at least I fathomed one thing out correctly and got the starter and ignition switch wired up to the right terminals. I got the engine to crank tonight - so I did put the engine and starter motor back together correctly.

Not quite as momentous as starting her up, but at least I could check the compression on the cylinders. Which seem to be spot on. Huzzah!

I think my cut off switch may turn out to be more of curse than a blessing. I've wired it up as per the instructions, and get nothing from the bottom terminals. The main chunky terminals are fine - it's just the lower spades that don't seem to be doing anything. I ended up bypassing it to check the cranking.

[peterux]

Originally Posted by GreatOldOne

Well, at least I fathomed one thing out correctly and got the starter and ignition switch wired up to the right terminals. I got the engine to crank tonight - so I did put the engine and starter motor back together correctly.

Not quite as momentous as starting her up, but at least I could check the compression on the cylinders. Which seem to be spot on. Huzzah!

I think my cut off switch may turn out to be more of curse than a blessing. I've wired it up as per the instructions, and get nothing from the bottom terminals. The main chunky terminals are fine - it's just the lower spades that don't seem to be doing anything. I ended up bypassing it to check the cranking.

You'll have that baby running again soon

I didn't use a cut off switch so can't help on that one,

Peter

[MartinClan]

Originally Posted by GreatOldOne

I think my cut off switch may turn out to be more of curse than a blessing. I've wired it up as per the instructions, and get nothing from the bottom terminals. The main chunky terminals are fine - it's just the lower spades that don't seem to be doing anything. I ended up bypassing it to check the cranking.

On the cut-out switches I have seen the smaller terminals are used just to earth the alterrnator via a chunky resistor to stop it going overvoltage should someone operate the cut-out switch when the engine is running. Is yours different?

Robin

PS - if you haven't already got one an automotive multimeter - or even a bulb fitted with some flying leads and croc clips - is pretty essential to debug the wiring. Even if you do know what you are doing!

[GreatOldOne]

My cut off switch has 4 spade terminals on the bottom - one pair of which do exactly what you describe. The others are supposed to be connected to the ignition switch and the coil, but when the switch is on, I don't seem to get power across them.

I have a multi meter. It's been very useful so far.

[MartinClan]

Originally Posted by GreatOldOne

2) I've been looking at the wiring diagrams for the ignition switch, and I've come to the conclusion that I have a franken-car. All the diagrams I've seen (Bently, Haynes & downloaded BMW from E30 Zone) mention the 4 main connections on the switch - Red from battery to the switch (30), Black to starter (50) and the two green cables which are on terminals R & B (one of which goes to the coil - where does the other go to?)

The thing is I have four more cables on the switch - from terminals PR1, PR2, PL1 & PL2. I haven't found out what these are for yet... They're small cross section, so they're not taking a lot of load... The only thing I've come up with is they're something to do with the on-board computer my donor had.

I'm rapidly coming to the conclusion that I can't read wiring diagrams!

I can't help for the ignition switch as I re-used the BMW loom and fusebox - I certainly have those wires but they disappear off into the loom and do I know not what (and don't care as long as everything works). Could they be something to do with the un-loader circuit (which you won't need if you are not using the BMW fusebox)

Have you looked at the wiring diagrams on www.diakom.ru. I have a complete set for 1989 vintage if they will help (In pdf format) I think they are taken from the BMW workshop manuals and are more complete than those I have found anywhere else.

Robin

[GreatOldOne]

I've been using these diagrams that I found via E30 zone:

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

specificaly, this one:

http://shark.armchair.mb.ca/~dave/BMW/e30/e30_86.pdf

As for the small terminals, It doesn't look as if they're doing much anyway, so I may just desolder them and forget about them.

Having said that though, that's what I thought I could do with those odd connectors I had near the ECU connector way back when.



Turns out that three conductor one is fairly important, as the green lead in it is the power to the main relay coil!

Good job I remembered there where things are buried under the loom tape. I just need to put a connector on it now, as the old one got snipped off.

[MartinClan]

Ignition switch wiring




Robin

[GreatOldOne]

Well, I've completed all the running electrics, and rigged up temp connections from the oil pressure and ign. warning lights.

It turns over, and the fuel pumps clatter away. I believe I can also here the injectors clacking...

All it needs now is a little application of unleaded, and fingers crossed, she should start! :-)

I've also ordered my instruments - I plumped for a matched set from ETB, as they seem to be cheaper then anywhere else, and are SVA OK out of the box (unlike the ones I wanted to get from Europa)

http://www.etbinstruments.com/ETB_Gauge_Price_List.htm

100mm Speedo and Rev Counter, 52mm Oil Pressure, Water Temp, Fuel & Volt Meter. Didn't bother with a clock, as time will mean nothing when I'm driving.

They should take a week to arrive - I'll post some pics when they do.

[MartinClan]

I was/am just about to order my instruments as well. Plan is to use Green Gauges (Caerbont) but I think I will check the prices against ETB first....

Robin

[GreatOldOne]

Jason is currently doing the happy dance. I went a got a jerry can full of unleaded on the way home.

After the pumps primed themselves, and the swirl pot filled up, she fired - nay - roared in to life. Not a cough or a splutter!

Took some video, but for some reason there is no sound... I will post it up after dinner as the other half is shouting at me to come and eat.

YAY!!!!

[Simon]

Well done - it's a great feeling when you get the engine started.



Simon

[peterux]

Originally Posted by GreatOldOne

Jason is currently doing the happy dance. I went a got a jerry can full of unleaded on the way home.

After the pumps primed themselves, and the swirl pot filled up, she fired - nay - roared in to life. Not a cough or a splutter!

Took some video, but for some reason there is no sound... I will post it up after dinner as the other half is shouting at me to come and eat.

YAY!!!!

And another BMW Sportster roars back into life

[Patrick]

yeahy good 'ol BMW engines mine was the same