Legal at last...next issues to sort

[kitesurfer]

Well, it's finally happened....new V5 arrived and new plates fitted to my 240Z so another one on the roads again. First legal drive and not I was not disappointed. Very very pleased with the car but as you would expect some minor issues require attention. The two most pressing ones are two gauges not working, fuel and water temperature. Can someone advise me how to pull off the 3 heater plastic control knobs. Are they removable? It would be immensely useful to remove the center section of the dash to gain access to the gauges and see if I have any power to the them. Incidently the oil pressure gauge is working together with the ammeter. Any advice on where to fault find for the non working gauges please.
Out of interest the V5 arrived in 8 working days.

 

[Farmer42]

Before taking the gauges out which is a real pain, try disconnecting the wires from the sender units and earthing them to see if the pointers actually move on each gauge. If so, you have a live feed and the fault lies with both sender units.

The fuel sender is notoriously dodgy when they are old so it just may need a clean up on the resistor element or it could just be a dirty terminal on the positive feed wire. You will need to take it out of the tank to clean the element. For the temp sender, it is probably best to get a new one from Mr F at MJP if it's faulty than try to faff about with cleaning it up.

 

[kitesurfer]

Thanks for the advice. I've stripped the water sender units out of the engine and both (if thats what they are in the attached picture) are shiwing no live at all. Even tried immersing one in boiling water but no effect.
The tank I was hoping to leave in situ and hopefully try any other method rather than remove it. I will bite the bullet and now remove it. One to check the sender unit as you suggest and the second to clear any loose rust from inside. I placed two filters in the system before the carbs and have noticed that after 23miles of initial driving the filters are showing signs of particulates. The car has been stored for many years and although the tank looks in very good condition externally I now have serious doubts to the state of the inside. The fuel pump filter was changed as it was clogged. Loojs like this weekends job then!! Incidentally what grade of petrol do you run in your car? My engine is an L28 on dual webers....95 or 97 octane?

 

[kitesurfer]

Attached photos

 

[MaximG]

Attached photos

The one with the blue connector is the water temp sender.

The one with two wires, I have no idea.

 

[jonbills]

The one with the blue connector is the water temp sender.



The one with two wires, I have no idea.

I think the two wire one is a thermostatic switch, prob to control an electric fan.

95 ron fuel is all you need.

 

[Farmer42]

Thanks for the advice. I've stripped the water sender units out of the engine and both (if thats what they are in the attached picture) are shiwing no live at all. Even tried immersing one in boiling water but no effect.
The tank I was hoping to leave in situ and hopefully try any other method rather than remove it. I will bite the bullet and now remove it. One to check the sender unit as you suggest and the second to clear any loose rust from inside. I placed two filters in the system before the carbs and have noticed that after 23miles of initial driving the filters are showing signs of particulates. The car has been stored for many years and although the tank looks in very good condition externally I now have serious doubts to the state of the inside. The fuel pump filter was changed as it was clogged. Loojs like this weekends job then!! Incidentally what grade of petrol do you run in your car? My engine is an L28 on dual webers....95 or 97 octane?

The temp sensor wire (blue connector end) looks a bit dodgy & there could be a break in it somewhere. Take the connector off and ground the bare wire and see if the gauge pointer moves. May sound a bit daft but have you checked the fuses?

It's really unusual for a gauge to go down which is why I suggest all the other possibilities first before having the hassle of taking them out along with dismantling half your dashboard. Been there & done it with both these gauges and both problems were sender units and wiring. If you had that much crud in fuel filters 10 to 1 its the sender unit that is causing you problems.

WRT fuel, it really depends on whether the head has been set up for unleaded. If not, the lower octane may cause it to pink. Until you know for sure, it won't hurt putting the higher octane in and possibly adding some lead replacement.

 

[jonbills]

You're right, I forgot some of the early US L28s had brass seats, so if you have an N42 head lead substitute would be an idea.
http://www.datsunzgarage.com/heads/

 

[kitesurfer]

Chaps, what can I say but thanks.
I've already added a substitute to the petrol, mainly concerned with ethanol though and its effects on components. I drove the car again for a few miles and am surprised at how hot the rocker cover gets. As a matter of course I have replaced the water thermostat but although everything sounds great (aside from carbs needing a tune as the car doesn't feel right at crawl speeds) I paranoid about boiling the engine as until the gauge is fixed I have no idea what is happening. Ok, yes dont drive it & yes I wont until I have things fixed. I'm also going to flush the engine in tetms of the water to make sure there are no blockages. I will then move onto the tank tomorrow and look to replace the sender unit. I have also acquired some material to form a heatshield as although the exhaust is wrapped there is a huge amount of heat rising up around the carbs which cannot be good unless it is minus 15 outside. Any further thoughts greatly appreciated and I will update with some photos of the weekends undertaking for those who are interested. Thanks again.

 

[kitesurfer]

The temp sensor wire (blue connector end) looks a bit dodgy & there could be a break in it somewhere. Take the connector off and ground the bare wire and see if the gauge pointer moves. May sound a bit daft but have you checked the fuses?

It's really unusual for a gauge to go down which is why I suggest all the other possibilities first before having the hassle of taking them out along with dismantling half your dashboard. Been there & done it with both these gauges and both problems were sender units and wiring. If you had that much crud in fuel filters 10 to 1 its the sender unit that is causing you problems.

WRT fuel, it really depends on whether the head has been set up for unleaded. If not, the lower octane may cause it to pink. Until you know for sure, it won't hurt putting the higher octane in and possibly adding some lead replacement.

You were correct on the Temperature gauge.....result!!
Earthed it out and gauge responded and travelled to right hand side / hot
New sensor to be ordered. Let you know how the petrol sender works out.

 

[kitesurfer]

Interesting day yesterday. I've decided to start a new thread called Perils of a 40 year old car which highlights a few issues to do with this thread.