Dash lights and Rev counter

[Rodders]

I had a 2.2 (RJ22) in the T25 which was duff, replaced it with a complete RJ25, loom and ECU (thanks to Rich for the loom & bell housing).

Engine fires up good, fans work, mechanically good so far, but some electrics now baffling me, checked everything, seek advice

1) Now the Dash Charge light stays on, getting a voltage of 4v in the charge light cable, not enough to put light out, or to activate the split charge relay

2) No oil pressure light. Will be fitting a new LED tomorrow

3) no rev counter.

seems wired these all worked before, now they all dont!

the voltage regulator gives about 9.9v, which is to spec in the Bently manual.

Any thoughts?

[rjes]

The most common cause of the charging light not going out is a VW, Westfalia or aftermarket split charge relay drawing more current from the charging light wire than the alternator expects. You can get the same thing happening with a VW alternator too (if you fit a really big split charge relay, like a marine one), but Subaru alternators are more sensitive to it.
First chack that your alternator is charging by making sure the voltage goes up from about 12 to 14 when the engine is running. Assuming it is, the easiest fix is to move the split charge relay signal wire from the negative side of the charging LED (the wire to the alternator) to something which goes positive when the ignition is on. This will not affect the way anything works unless you are in the habit of leaving the ignition on while the engine is not running for some reason, in which case doing so would eventually flatten both batteries, not just the main battery.

What rev counter have you got?

With the ignition on, but not with the engine running, take the wire off the oil pressure switch and touch it on the block. If the oil light comes on, your pressure switch does not work. Swap it for the one from your EJ22 (or possibly a VW one - I think they're the same thread). I have come across them not working once or twice before.
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com

[Rodders]

Cheers Richard.
The oil pressure switch works which is the bit i'm struggling with. just not getting the light at the dash, changed led's for a new 12v one (should they be 12V ones?)
The Rev counter is standard VW T25, no idea how to check these, 3 copper tracks on the back.........
Disconnecting the 2nd charge system completly still only gives 4v, but i'm getting 14v at the primary battery (hence charging).
I'm getting one last issue sorted for the cooling system, will drive it and come back to this issue, Its taken so many hours with no step forward.

[rjes]

The LEDs in the VW dash instruments are standard, not 12V. A current limiting resistor allows then to run from 12V.

Did your VW have the dual oil pressure (DOP) system? If not the current liniting resistor is oin the flexible PCB. If so, it is part of the DOP circuit inside the speedometer.

If swapping the LED (make sure you get the polarity right if you are not familliar with LEDs) makes no difference, do a continuity check between the blue / black wire going into the dash instruments and the connector on the pressure switch. Alternatively, try shorting the blue / black wire to earth at the instrument cluster with the ignition on.The oil light should come on.

If you have the DOP system, and I fitted the VW round white 7 pin engine connector to your harness, I will have conned the DOP system into thinking the second oil pressure seitch is present. If you fitted it yourself, short earth the yellow wire.

Regarding the charging light, is is a Westy, or some other conversion which effectively uses a seperate split charge wire for the fridge as well as the aux battery?

T25 rev counters can not be driven by the signal from a Subaru ECU without modification, as the VW and Subaru signals are incompatible. If the standard rev counter used to work, your old harness must have had the 'diode mod' co combine the signals from the two coils. This works with some but not all VW rev counters, but is risky. Two customers have managed to short the rev counter wire to earth by leading it dangling, uninsulated. This instantly burns out your ignition module, and maybe some wiring, leaving you stranded. For these reasons, I have not wired any Subaru harnesses with the rev counter 'diode mod' for a few years now. A much better, but more involved solution is to modify the rev counter internalsto accept the Subaru signal.
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com