ECU earth?

ping · Posted: Fri Apr 15, 2011 1:49 pm Post subject: ECU earth?

Does it have a earth wire or should i put one to the case? I may have one but i'm at work and got thinking!

Kai · Posted: Sat Apr 16, 2011 5:15 pm Post subject:

No need to earth the ecu case, big no no.

There should be a bunch of earths connected together from your Subaru loom. They are terminated with a ring connector. Did you do your loom yourself??

The ecu earth should be connected/earthed to the engine block away from the alternator.
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ping · Posted: Sat Apr 16, 2011 6:05 pm Post subject:

Cjeers Kai, I found the earths connected to the manifold yesterday. I added another wire from this too the chassis but it still didn't cure my maf fault. Rjes loom by the way.

Kai · Posted: Sat Apr 16, 2011 7:32 pm Post subject:

Your extra wire shouldn't make any difference as you should have a larger earth strap between the chassis and gearbox.

Unless you have a corroded connection between them.
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ElusiveStranger · Posted: Sun Apr 17, 2011 1:36 am Post subject:

Errrm, yes earth the ECU case.

Last thing you want is EMI in the case. Subi shield all the important wires to the ECU. Last thing you want is "noise" in the ECU

Easy enough to ground the ECU, self tapper through the mounting lugs.
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Kai · Posted: Sun Apr 17, 2011 7:11 am Post subject:

@elusive,

I've read that it's not a good idea to do this, admittedy I'm no expert however i feel if it was that importation then Subaru would have simply done it.

My readings found here

http://www.vems.co.uk/VEMSInstalls/LoomGuideUnit1259.doc

Admittedly this could only apply to the specified product, but I believe it to be generic.

My point being that should the ECU ground be the chassis your opening up a path of interference and I would say the same goes for the ecu case which in my eyes would certainly increase the level of interferene.

By the way my feelings on the subject are not that strong so each to their own Laugh Out Loud

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ElusiveStranger · Posted: Sun Apr 17, 2011 9:32 am Post subject:

Subaru earth the case by using a metal bolt through the mounting lugs :-)
_________________
The advice you receive on here is worth the paper it's written on.
Your experiences are worth shed loads to others, including the f'ups - live and learn.
Wouldn't YOU rather learn by someone else's mistakes? So would they.

'78 Bay, 2 litre 091 box, EJ20 NA & the ashtray's on the 'right' side.
I don't lean forward for hills any more Grin

Bugger, missed out on "Live fast, die young"

Kai · Posted: Sun Apr 17, 2011 10:59 am Post subject:

Tushay.....

Laugh Out Loud

But it's not directly to the chassis
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ping · Posted: Mon Apr 18, 2011 8:30 am Post subject:

Hmm, i cant remember if the ecu was screwed in to plastic blocks or to the floor pan metal in the legacy.

rjes · Posted: Mon Apr 25, 2011 4:25 pm Post subject:

I'n not going to get into another pointless debate about this topic, other than to say that all Subaru ECU cases are already earthed by the wiring harness.
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