Tacho needle jumping - L series

Esky · Post by **Esky** » Fri Dec 16, 2005 5:10 pm

Hi guys - the EA82T conversion for my L sedan is almost finished, but I've got a few niggling problems left...

First, sometimes the tacho needle jumps erratically on idle. It's fine when I touch the throttle, but most of the time it goes crazy when I'm sitting at the lights.

Second, after driving for a while, the light on the ECU comes on, and just stays on. Is this supposed to happen? It doesn't appear to be flashing any sort of code, it just sits permanantly on...

Lastly, on occasion when I've been braking, the car has almost stalled - I've got the clutch in but the revs drop right down and I have to hit the throttle to stop it from cutting out. This one is pretty rare, but quite annoying.

Any hints, suggestions, advice would be great!

Thanks,
-Simon

SuBaRiNo · Post by **SuBaRiNo** » Fri Dec 16, 2005 10:34 pm

The engine light comes on when the ECU detects a problem that it can not ignore. I have found many faults with my ej22 that wasn't bad enough to make the engine light come on but made the car behave funny due to faulty sensors.

If then engine light is on there is a bad problem. It will only spit out a code with a series of flashes when the correct test terminals are connected under the dash. Hopfully these are still there from your conversion.

Dave

MY_STI · Post by **MY_STI** » Sat Dec 17, 2005 9:46 am

I had the same trouble with the tacho when i put a second hand gt40r coil in my RX, it would jump between idle and about 2k, without the actual revs changing, wasn't a problem above ~1500, put the original coil back in and it never happend again.

that doesn't really solve your problem, but might be worth a thought.

fredsub · Post by **fredsub** » Sat Dec 17, 2005 11:01 am

check you have the coil wired correctly

http://www.ausubaru.com/main/modules.ph ... highlight=

Esky · Post by **Esky** » Sat Dec 17, 2005 6:51 pm

OK, I checked the coil - all the yellow wires go to the -ve terminal, and all the b&w ones go to the +ve. I tightened the terminals up a bit, and it seems to behave much better now.

As for the ECU, when I connected the two green connectors under the dash, I got the following ECU codes:
32 Oxygen Sensor or Circuit
22 Pressure or Vacuum Switches - Fixed Value
23 Idle Switch - Fixed Value
34 Abnormal Aspirated Air Thermosensor (In Airflow Meter)
31 Speed Sensor or Circuit
And a 51, which doesn't seem to be listed for 1986 models.

Otherwise, I just get a code 12 when the engine is not running, which I believe is normal.

I tried taking it for a drive with the green connectors attached, and after a while the ECS light lit on the dash, and I got codes 51, 32, & 23 again.

Now, I know the idle switch is not very well attached (it is quite loose), and the O2 sensor is a bit of a botch job - I'm suspecting that neither of these are actually working.

Any other thoughts?

-Simon

Gannon · Post by **Gannon** » Sat Dec 17, 2005 10:44 pm

Have you checked your negative grounds (earths), this sometimes causes erratic tacho movement.

Check your grounding straps between the engine, the body and the electrical harness for corrosion or anything that looks like it would interfere in the electrical connection

Wilbur · Post by **Wilbur** » Thu Dec 22, 2005 9:57 am

Voltage reg in the alternator was gone when myne did that.