2 More Loom Questions, Before I Start Making Mine

[GLPoomobile 958]

I'll start with the easy question first:

 

Do I need to put a 10A fuse in the wire that runs between pin 18 of the ECU, and the plug in the shunt box? The reason I ask is, my original loom does not have a fuse, but my spare one does. CAPS shows a fuse in the schematic (although this is for a 405 Mi16 set up, not a 405 Mi16 loom adapted for a 205), but surely with the shunt box being fused, I don't need an additional fuse in the cable running from it

 

 

My second question is regarding the coil. Basically I'm concerned about how my coil is wired up to the tacho on my original loom. Despite working fine, it just looks bodged and does not match the CAPS schematic. So this is what it looks like at the mo'.....

 

pin 3 of brown (under dash) plug has a thick yellow and green striped wire, and joins to a thin yellow and green striped wire going to the ignition amp

pin 4 of brown plug has a thin grey wire, and this is joined to a thick (shielded) turquoise wire going to pin 1 of the coil plug

 

But where both pairs of wires have been joined to each other, there is a 'bridge', a 1cm length of thin black wire joining all of them together Is this just so that the coil has an earth? Is it necessary? Caps does not show the coil being earthed.

 

So I just really want to know if I should ignore this and should just run a single length of wire between pin 4 of the brown plug and pin 1 of the coil, to drive the tacho?

[GLPoomobile 958]

No replies yet? Come on wiring gurus, I need answers!

 

I've taken some pictures to illustrate the bodge. Looking at it closer, I'm even more convinced that the bridged section is pointless, and I can leave it out when I build the new loom.

 

This picture shows the offending article.

 

 

 

You can see here that the thin black wire that is bridging the earth wires and the coil/tacho wires actually actually disappears up in to the turquoise wire. So this turquoise shielded cable obviously has 2 wires in it's core. If you then look at the 2nd picture, which I'll post in a moment, you can see that at the plug end, this 2nd wire inside the turquoise cable is not attached to anything......

[welshpug 1,657]

that be the shielding wire, similar to the TDC sensor it should only be earthed at one end to prevent noise/inteference

[GLPoomobile 958]

 

So as I said originally, am I right to assume that all I need to do is run this shielded wire (I'm going to re-use it) from the coil plug (pin 1) to the brown multiplug under the dash (pin 4), which goes to the tacho, without connecting any other wires in to it along the way?

 

And if you are reading, and know the answer, don't forget my question about the fuse!

[pug_ham 244 3 Cars]

So as I said originally, am I right to assume that all I need to do is run this shielded wire (I'm going to re-use it) from the coil plug (pin 1) to the brown multiplug under the dash (pin 4), which goes to the tacho, without connecting any other wires in to it along the way?

AFAIK yes. On the 8v loom I have here the shielded wire runs to the tachymetric relay plug & the brown multiplug under the dash btw but I can't find where its earthed anywhere along the run.

 

And if you are reading, and know the answer, don't forget my question about the fuse!

All the looms I've done I've removed both fuses by the relays (fuel pump & ecu) so there isn't one between the shuntbox & ecu but isn't the shuntbox a fused connection?

 

That fuse isn't fitted on the later MM8P etc looms.

 

Graham.

[jim205GTI 3]

Same here Graham i couldn't find a place for the shield to earth to. If I remember correctly i extended the shield cable to an earthing point.

 

Turquoise wire to wire 112 ( i think) for tacho and the black cable next to it for an earth point.....

[Ethos 0]

Mine was like this on the mi16 too, tacho to the grey wire then the shield wire ended up going to the earth on the gearbox.

 

Seems to be the right way to do it?

[GLPoomobile 958]

OK. Thanks for all the input. It seems t be the right way to go, so I'll make sure the shielded wire is attached to earth, but try and make it look a bit less bodged than the old one

 

Regarding the fuses, I bought some swanky weatherproof fuse holders on the off chance that I'd need to include the fuses (they look like the Superseal connectors) so I'm going to keep the fuses in the loom just for the sake of using the holders

[Alastairh 47]

You shouldn't need the fuses, as Graham says, the shuntbox should do the fused connection.

 

Al

[GLPoomobile 958]

But.....but....but, I have these lovely, cool fuse holders They need to be shown off Is there anywhere else in the 205 that uses randomly located fuses (i.e. not in the dash fusebox)?

[jackherer 543]

A fuse is a potential failure point, you need them obviously, but more than one on a circuit could make troubleshooting very long winded in the future. I would just stick with the one in the shunt box.