glow plug voltage

[JamieM1009]

Hey guys

I got some new glow plugs and wanted to check the current voltage to the plugs was definitely 12v as it has a manual switch that turns the glow plugs on before you start it. You just hold it down as long as u want them on for. This was already fitted when I got the m1009, the only other thing I did was the doghead mod. Now my question is what should the voltage be to each plug as I put my multimeter in the connector that goes on the top of the plug and when I pressed the switch I had 6.5 on each of the two I checked. Should it not be 12v or there abouts? If so what's likely to cause the problem? Bad earth?
thanks for any help anyone can give
j

 

[cpf240]

It should be about 12v at the glow plugs.

As yours has been modified, you really need to trace all the wiring and see how it is connected. I'm wondering if the resistor pack on the firewall is still in the circuit, but being supplied with 12v. Hard to say without more info/pictures, etc.

 

[JamieM1009]

Hey
yeah I need to have a good look at it but wanted to see if there was any common issue you guys new of to potentially save time. If the resistor has 12v to it would it reduce the voltage down to 6 like it reduces it from 24 down to 12? From what I've read since posting this its a good idea to bypass the resistor completely isn't it?

 

[MarcusOReallyus]

Yes, bypass the resistor, but first, get some measurements and see what you have. It's not a good idea to start changing things until you know where you are.
Yes, if the resistor is being supplied with 12v it will knock the voltage down to something in the neighborhood of 6 (off the top of my head).

 

[JamieM1009]

So i had a look at it & have taken this picture. I've marked up what goes where so its easier to work out whats been done. Am i right in thinking that if i just completely remove the resistor and its wiring and then just put a piece of good wire from the block above the solenoid, to the solenoid, it should resolve the issue? Sorry if this is a simple question but just wanted to get it right without burning anything out, etc. The truck does start & run ok but its been colder than usual lately and ive noticed a significant increase in the time you have to have the plugs on for, this is what led me to buying some new plugs & then checking the voltage before i put them in to make sure there wasn't 24v going to the plugs.

Thanks for any help anyone can give.

J

 

[doghead]

Am i right in thinking that if i just completely remove the resistor and its wiring and then just put a piece of good wire from the block above the solenoid, to the solenoid, it should resolve the issue?

Yes.

 

[JamieM1009]

Thanks for the response, that was the answer i was hoping for.

Does the resistor only start to reduce the voltage when i attempt to start the truck i.e. flick the switch for the plugs?

 

[MarcusOReallyus]

Exactly. If there is no current flowing, you will not see any voltage drop. Good observation.

 

[JamieM1009]

Thanks all