Technical help wanted

having just replaced the clutch in the daughters 2003 gen3 M13 jimny, during the first road test the engine light came on. I then noticed the temperature gauge wasn’t working and the idle speed drops to about 500 rpm, suspect it’s a wiring fault since doing the clutch, but I only disconnected the main earth lead to the engine. I’m struggling to find an accurate wiring diagram And info such what voltage should be supplied to the temperature sensor etc, found the list of workshop manuals on here, but the only one that seems relevant is a 2004 manual? Any help or suggestions very much appreciated 
cheers Kevin 

Check that you didn't trap any wires between the bell housing and the engine. There is a dangly wire that falls inside at the top, I can't remember what it did.

Also if you were swinging the engine on its mounts to get the gearbox out a wire may have been pulled and disconnected- the idle speed control is an electric valve on top of the manifold.

There is also the vacuum hose to the hubs that may have fractured and affect the idle.
 

Thanks for the info, regarding the vac pipe, whilst i was under the vehicle i noticed one of the steel pipes was broken, don't know if i did it or was already broke, i repaired that before driving the car, i assumed the solenoid valves
separated the hub vacuum supply from the brake servo vacuum supply, but certainly an area worth investigating

cheers Kevin

There is a rubber pipe from a spigot on the side of the inlet manifold to the vacuum solenoids (it actually goes direct to the vacuum tank under the wing)- this is the one I meant.

Unless the vacuum solenoid valves are stuck open (which is a possibility, but won't have changed whilst you were fitting the clutch) a fractured vacuum pipe after the solenoids won't affect the idle as the solenoid valves close off a few seconds after you select 4WD.

I'd be looking for something that was trapped, pulled or broken when the engine was moving, as it starts I assume that earth is connected properly- there wasn't another earth tag that you have left loose? 

Mere speculation here, but I think you have more than one problem.

-- Low idle and engine light from a vacuum leak.

-- Temp gauge problem from a broken or shorted wire.

I would focus on the first one, Kevin, which it sounds like you are already planning. Be prepared to buy some new vac lines/hoses -- 20 yr old rubber does not like to be disturbed. Try simply plugging the vacuum port at the intake and starting it up, should tell you if you have a downstream leak in the vac circuit.

Might also be worth scanning the OBD -- error code might help troubleshoot problem #2, and perhaps the temperature data feed will too.

Thanks for your replies and advice, seems I jumped to the conclusion that it was something I had done and coupled with a poor quality multi meter got sent in the wrong direction, armed with a decent meter and the help of google I come to the conclusion that the temperature sender had failed. Enquired at local dealership who wants £103 for sender unit???  Found one at local motor factors for £9.00, engine light now goes out and idle speed behaves normally, negatively the temperature gauge now reads very hot all the time so maybe not quite the correct sender unit but at least I’m going in the right direction.

cheers Kevin