Hi, my hybrid tacho is dancing about from 0 to 8.5k. Does anyone know how to stop this. Ive got a 3tj loom with 4jh cdi wired to it. Help!

Hi, the prob is caused by the fuel sender in the fuel tank. Its either u/s or the tank is low on fuel . You can just loop out the sender to resolve the prob as i have on my track bike, but then you will have no warning of low fuel!
Hope this helps.

Ah, this would be the fuel tank sender problem.

The 4JH has a connection from the fuel tank sender to the CDI, for the fuel light on the dash. If this connection is not there, the tacho jumps to 8k.
My hybrid uses a 4JH loom, but the sender was bust and had the same problem.

I'm not sure how you will fix yours, maybe run a wire from the sender to the CDI?

Alex.

You could bolt in the T'Cat / 4JH clocks which would have the offending light ... or rig up a light on your clocks

It's not the light that is the problem, it's the connection from the tank to the CDI.
A little splice to the wiring loom should do the trick!

Alex.

Sorted, looped the fuel sender connecter and tacho reads as normal. Just have to keep an eye on the milage so I dont run out of fuel.

Sorry for digging up an old thread guys, but i've got the dreaded tacho tango going on with my hybrid. The tank is plugged into the loom but i'm still getting the dance. It was working ok before i did the engine and loom swap.

When you say that you 'looped out' the connector, does that mean that you just put a wire from one terminal to the other on the loom connection (i've got a t'cat loom and i think the plug is light green from memory)

Yet again my grasp of auto-electrics could be catalogued on the back of a postage stamp

Yup that's basically it.

I measured the resistance across the connectors on a T-Cat fuel sender and got readings just above 1k ohm depending on level. I'm sure this would explain why others have wired a 1k ohm resistor across the connectors on the T-Cat harness when the fuel sender is absent.

I would rather place the appropriate load on the ECU than just short the connections. I'll be going this route when I swap motors next month.

Hmmmmm......

Well, i tried 'looping' the connector but that didn't work, so i'll give the 1k ohm resistor a try