Voltage problems

[ocelot]

I guess you could find a rheostat to hold 300w or so, but a little pointless. The best way is to fix the alternator, if one diode's gone, then more will follow.

I'd recommend that the first port of call is to actually prove that the alternator is duff..............14.35 is on the high side. It should start at 14.2 vdc or near and then drop to 13.8

Regards

 

[Timbo_1975]

If your voltage was really high, you'd have problems with bulbs popping and the like..?

A new reg in the alternator may well bring it down abit though...

Are you sure you are not using 8 or 10v g/plugs in your heater???

 

[Deleted account DD]

I'll cough to it, I didnt know there were so many different rated plugs :doh

The Lucas one and the bosch one I have in now are DEFINITELY 12v :thumb2

I'm not aware of any other electrical related probs

 

[Timbo_1975]

I've just been out and measured vBatt on my Terrano with a quality SykesPicavant DVM.

Static (having sat for 12hours) 12.48v
Natural idle (800rpm) 14.15v
Fast idle (2000rpm) 14.19v
Fast idle full electrical load 13.82v

This ought to give you an idea if your truck is appreciably over.

Tim.

 

[Deleted account DD]

I've just been out and measured vBatt on my Terrano with a quality SykesPicavant DVM.

Static (having sat for 12hours) 12.48v
Natural idle (800rpm) 14.15v
Fast idle (2000rpm) 14.19v
Fast idle full electrical load 13.82v

This ought to give you an idea if your truck is appreciably over.

Tim.

Thanks Tim, much appreciated and about to go and test....:thumb2

 

[Deleted account DD]

Well, very interesting stuff,

Static after standing for just under 3 hours, I get 12.63v

800rpm idle immediately after starting from cold :12.5v After a minute: 14.29v

2000rpm "normal load" varying by 0.1v averaging out at: 14.12v

2000rpm with everything electrical switched on that could be: 13.2v

To me that sounds pretty healthy and whilst I haven't hit the 14.35v (no idea why not :nenau) , which was measured at idle whilst warm without worrying about what was and wasnt switched on, but its all still in the "region of"

The voltage at the glow plus + is exactly the same as the battery terminal by my meter :thumb2

I'm starting to wonder if the system is ok and the glow plug failures are down to crap quality with a one in a whatever bit of bad luck co incidence :nenau:nenau and I'd best wait and see how long the new bosch one lasts :augie

Anyone any thoughts on that one? driving me round the ruddy bend :doh

Cheers

:thumb2:thumb2

 

[Toolbox]

I don’t think there is a lot wrong with your alternator; if it were over 14.5 volts then it would be worth doing something about it.

Is there any way of altering the on off cycle of the heater plug?

I still wonder if it’s over working?

The engine has no lift pump and relies on a vane pump in the injection pump to pull the oil up from the tank, my theory is, that it may not be having enough oil pass through it to bring the temperature down. Don’t know how the flow of the injection pump vane pump compares to a conventional lift pump, so its only me thinking out load

 

[jims-terrano]

Another way of looking at it would be how do you know your multimeter is reading correct. You seem to be correct with your last set of voltage readings though. I get very concious of my battery/charge system/starter/glow plugs when it gets cold cos it turns over ever so slow, I went through a phase of measuring the volts all the time and worried my self whitless. I know that I've got some kind of fault which I'll sort one day I'm merely highlighting that you can get too concious and be blinded by it all. May be it is just a cheap plug. Replace with a known good one and see what happens.

Jim T

 

[Deleted account DD]

I can see where youre coming from. I dont think there is a problem with the volume of oil going through because theres not been any symptoms of underfueling to the engine.

The glow plug heats the block and the thermostat takes its reading from that to switch it on and off so as I understand it the oil actually causes the metal to cool which causes the thermo to click closed and the glow plug come on. ie its not dependant on the liquid inside it only the temp of the metal.

Thats one reason I went for that type, as well as the fact it provides more heat exchange area to the oil going through.

I can see how the ones that are immersed in the oil channel could fail if the amount going through reduced :thumb2


Like I said, its driving round the bend :doh:doh:doh:doh

all comments and suggestions much appreciated


:lol:lol:lol

 

[Deleted account DD]

Another way of looking at it would be how do you know your multimeter is reading correct.

very very good point jim :thumb2 I own 2 multi meters, a draper car one and a maplins electronic one.

I've just been out and checked them against each other again. The draper is measuing 12.77v & the maplins 12.72v,

Whilst I'm happy they're working properly maybe the maplins is calibrated better than the draper? I've used the draper for the readings I've published, and things are even rosier than I reckoned for the alternator :nenau

bloody glow plugs

 

[Deleted account DD]

jeremy, sorry I should have used quotes , my last but one about the oil flow/heat was in response to your comments :thumb2

cheers

 

[Toolbox]

I can see where youre coming from. I dont think there is a problem with the volume of oil going through because theres not been any symptoms of underfueling to the engine.

The glow plug heats the block and the thermostat takes its reading from that to switch it on and off so as I understand it the oil actually causes the metal to cool which causes the thermo to click closed and the glow plug come on. ie its not dependant on the liquid inside it only the temp of the metal.

Thats one reason I went for that type, as well as the fact it provides more heat exchange area to the oil going through.

I can see how the ones that are immersed in the oil channel could fail if the amount going through reduced :thumb2


Like I said, its driving round the bend :doh:doh:doh:doh

all comments and suggestions much appreciated


:lol:lol:lol

You wouldn’t have a symptom of under fuelling as more fuel is always supplied to the injection pump than is required, what is not used is returned to the tank.

So it is reliant on the flow of oil to cool the block transferring the heat from the block to the oil, but being thermostatically controlled and not timer controlled it should be ok and low oil flow should not efect it, if the thermostat is ok.

 

[Deleted account DD]

yes , thermostat definitely clicking in and out :thumb2:thumb2:thumb2

 

[Toolbox]

yes , thermostat definitely clicking in and out :thumb2:thumb2:thumb2

But you can only asume its at the correct temp. How long on average does it stay on and then off for?

 

[Terranosaurus]

I can see where youre coming from. I dont think there is a problem with the volume of oil going through because theres not been any symptoms of underfueling to the engine.

The glow plug heats the block and the thermostat takes its reading from that to switch it on and off so as I understand it the oil actually causes the metal to cool which causes the thermo to click closed and the glow plug come on. ie its not dependant on the liquid inside it only the temp of the metal.

Thats one reason I went for that type, as well as the fact it provides more heat exchange area to the oil going through.

I can see how the ones that are immersed in the oil channel could fail if the amount going through reduced :thumb2


Like I said, its driving round the bend :doh:doh:doh:doh

all comments and suggestions much appreciated


:lol:lol:lol

I get what you're saying Daved but surely at least with the imersion type you can be sure the plugs are getting 'cooled' by the oil. With the type you have how can you be sure that the plugs are touching the metal. You could try some heat transfere compound as used in electronics etc to ensure that chips etc are actually being cooled by their heatsinks not just in proximity to them.

Try HERE

 

[Deleted account DD]

But you can only asume its at the correct temp. How long on average does it stay on and then off for?

When I had the tell tale light wired in I should have :doh but didnt time it. all I can say is it isprobably off the majority of the time which suprised me.

 

[Deleted account DD]

I get what you're saying Daved but surely at least with the imersion type you can be sure the plugs are getting 'cooled' by the oil. With the type you have how can you be sure that the plugs are touching the metal. You could try some heat transfere compound as used in electronics etc to ensure that chips etc are actually being cooled by their heatsinks not just in proximity to them.

Try HERE

But surely it doesnt matter whats acting as the heatsink, whether its the oil directly on the glow plug or glow plug onto the metal which then tranfers the heat to the oil :nenau

I do know the metal is getting hot because it burns my hand when you I it ...... been there done that I was gob smacked how efficiently it warms and stays warm.


So all in all I'm quite satisfied the oil is being warmed by running over something hot :thumb2


I agree about using thermal compound and did on this latest fit :thumb2 (got some left from comp building days) however I think this will only be a slight performance improvement.

Cheers :thumb2

 

[Terranosaurus]

Wasn't worried about it heating up - I know it will do that - more that if the glo plug isn't properly in contact with the metal it will be relying on radiant and convection(very slightly) rather than direct conduction into the metal and thus it could easily overheat the plug as they will be on for far more than their recommended duty cycle. If you've used some compound this time then it ought to negate that effect.

 

[Deleted account DD]

Wasn't worried about it heating up - I know it will do that - more that if the glo plug isn't properly in contact with the metal it will be relying on radiant and convection(very slightly) rather than direct conduction into the metal and thus it could easily overheat the plug as they will be on for far more than their recommended duty cycle. If you've used some compound this time then it ought to negate that effect.

:thumb2

the original was a very tight fit. We couildnt decode the spurious numbers of it but the new ones are the same only a couple of mill shorter.

Youre right about the air gap better not there.

However it still doesn't account for such premature premature failure :nenau

 

[DJ38]

1, There is nothing wrong with your glow plug or alternator.

2, Your issue is your plug is over heating and burning out prematurely.
Have you got your pre-heater after the fuel filter?
If so, probably time to change your filter.
Have you got clear braided fuel hose from the pre-heater?get some!
You will no doubt see tiny air bubbles in the svo.

Your problem is air in the pre heater block, the glow plug is not fully immersed in fluid causing it to over heat.
I have had three of the heaters on various motors, and found mounting them side ways so the fuel inlet is at bottom and outlet at the top cures the problem.
Hope this solves your problem.