Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

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irishkeet
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Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »

Hello

Ok been reading the forum/wiki for ages and Im still a bit lost. My van is an 86 with a scooby EJ25. I popped in a complete later dash today in the hope that the wiring would be all in place and the rev counter would respond, then I could do the resistor mod to get the correct reading. Unfortunately nothin :?

This is an diagram of scooby wirng loom (wiring was done before I purchased the engine) I got with the engine
Image

An image of my dash connector
Image

which seems to link up to this image with green being the rev counter
Image


any ideas when I need to go from here, looks like the blue (rev counter wire) in the loom image is connected, tried connecting it to the green wire on the dash plug and connecting it to the clockset again but still nothing

any help much appreciated

cheers
irishkeet

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by syncroandy »

You could visually check the Subaru ECU revs wire is connected to the vans green wire at the round plug in the engine bay (T7a, pin 5). Alternatively, if you have a multimeter with a frequency range, you could check if you have a signal on the green wire at the dash end (the engine will start & run without the dash).

PS. Just noticed you mentioned a blue wire, was this a typo ?

PPS. Soz, just took in the first diagram. Personally I would run the engine speed (aka revs) signal via the green wire from the engine-bay onward, but its up to you really should works the same either way.

PPPS. I have heard tell that some main looms had no revs wire, so it's quite sensible for the guy/gal who did a 'generic' rear>front loom to include the revs 'signail'.
Last edited by syncroandy on 08 Oct 2016, 18:16, edited 1 time in total.
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »

syncroandy wrote:You could visually check the Subaru ECU revs wire is connected to the vans green wire at the round plug in the engine bay (T7a, pin 5). Alternatively, if you have a multimeter with a frequency range, you could check if you have a signal on the green wire at the dash end (the engine will start & run without the dash).

PS. Just noticed you mentioned a blue wire, was this a typo ?

PPS. Soz, just took in the first diagram. Personally I would run the engine speed (aka revs) signal via the green wire from the engine-bay onward, but its up to you really should works the same either way.

thanks Andy, yep no idea why the person who did the loom did not follow the colours, I will try your suggestions and report back.

any idea when I will find "vans green wire at the round plug in the engine bay (T7a, pin 5)"

I hope your well? :mrgreen:
Last edited by irishkeet on 08 Oct 2016, 18:01, edited 1 time in total.

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by slowcoach »

If everything else on your new cluster works, then sounds like youll be on the right track by chasing down the rev signal as above.

If you don't want to do the resistor mod with your new tach, rjes sells a little unit that converts the Scooby signal to the vw signal. (It's more than a resistor, but don't know much more, mine is on the way).

I reckon you're close!
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »

slowcoach wrote:If everything else on your new cluster works, then sounds like youll be on the right track by chasing down the rev signal as above.

If you don't want to do the resistor mod with your new tach, rjes sells a little unit that converts the Scooby signal to the vw signal. (It's more than a resistor, but don't know much more, mine is on the way).

I reckon you're close!

Hi slowcoach I'd be interested in a piccy of the RJES part when it arrives, did you have to call them?, I cant see it on their site

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by marlinowner »

Probably worth checking the dash for continuity between pin 9 and the tacho as well.
Also green wire may have been left disconnected to kill buzzer of doom depending on oil pressure switch setup.
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »

marlinowner wrote:Probably worth checking the dash for continuity between pin 9 and the tacho as well.
Also green wire may have been left disconnected to kill buzzer of doom depending on oil pressure switch setup.


thanks marlinowner

Probably worth checking the dash for continuity between pin 9 and the tacho as well - any advice on how to do this please?

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by slowcoach »

irishkeet wrote:
Hi slowcoach I'd be interested in a piccy of the RJES part when it arrives, did you have to call them?, I cant see it on their site

Hi Keith- will do. There's no info on Richards very out of date website, but he's very helpful via email or phone. Should be here in a few days.

I'm preparing my new cluster right now.

If you can verify your subaru signal up in the dash, (through plug or a separate fly lead), then I'm sure you'll sort it.
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by syncroandy »

TBH I think it's quite possibly all connected fine, and your revcounter just needs the resistor mod doing. That was my experience.
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »

syncroandy wrote:TBH I think it's quite possibly all connected fine, and your revcounter just needs the resistor mod doing. That was my experience.
Andy you could be correct, I thought the revcounter read incorrect without the mod but mine is reading nothing :roll:

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by printmonkey »

irishkeet wrote:
syncroandy wrote:TBH I think it's quite possibly all connected fine, and your revcounter just needs the resistor mod doing. That was my experience.
Andy you could be correct, I thought the revcounter read incorrect without the mod but mine is reading nothing :roll:

The needle didn't budge on mine until I did the resistor mod. It's easy to do, I bought a pack of 4 on eBay for backup but it was really quick and easy job.
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »


The needle didn't budge on mine until I did the resistor mod. It's easy to do, I bought a pack of 4 on eBay for backup but it was really quick and easy job.

PM thats good to know. I think Ill pop up some photos of my loom at both ends as I really need to understand it a bit more so hopefully some kind peeps can educate me....wish I was a bit closer to you Andy and I could pop over so you could take a look at it :mrgreen:

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by irishkeet »

came across this site while surfing which is helpful
http://busaru.com

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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by syncroandy »

The input sensitivity of the stock tacho is for a ~200v spike from the coil, vs a 12v signal from the ECU, so its not surprising the needle doesn't move without the mod.
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Re: Subaru EJ25 Connecting a VW Revcounter aaarrrggghh

Post by slowcoach »

irishkeet wrote:came across this site while surfing which is helpful
http://busaru.com
That guy's great, lots of nice videos on youtube

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