Testing Glow Plugs

Re: Testing Glow Plugs (owen)

My little International Harvester has its glow plugs wired in series also. The connections are via heavy copper bar.

The disadvantage is that if one goes down they are all lost. /forums/images/graemlins/frown.gif

Parallel operation does allow an engine to start albeit with some difficulty. Of course the plugs must be suitable for the relevant voltage.
 
dont go to all the messing about, they either work, i.e glow red hot, or dont. get a bit of wire connected to your battery that doesnt go to earth and flick it on each one in turn,if you get an obvious current draw, i.e sparking, they are ok, all the engines i have worked on have been in parallel, i.e power to each separately although a flat connection can go across them all they are still in parallel, in this case you will ave to disconnect te common feed. you can take one to a motor factors and ask him to cross reference them to get cheaper non boaty ones.
stu
 
Re: Testing Glow Plugs (owen)

if the heavy copper bar goes across them all they are in parallel, it is impossible to do them in series cause the earth is common, think about it!
stu
 
the wire goes from one to the other, on the top? how can they be in series? power to the top, other end is earthed, if they are all joined in the top it means they are in parallel, power to one goes to them all and they are earthed for the return, if they are in series the power needs to go in the top of one, insulated glow bit, wire from body to the next top, insulated body wire to the next, do you get my drift?
stu
 
exactement, peeps are getting confused by the usual solid bars connecting all the tops and not thinking it thru
stu
 
Who says the other end of the plug is always earthed?

This is all a bit futile - some systems have parallel wiring with 12V plugs and others (certainly the two I have worked on) have series wiring with 2V plugs (although at a quick glance it can look like parallel wiring - and did to me until I examined it closely).

Can we just leave it at that - open minded as to more than one possible system?

Peace be upon you!
 
i think that you are mistaken, i have worked on hundreds of different diesel engines all over the world and have yet to come across a series wired glo plug system. if nothing else it does not make engineering sense to do it in series, if one stops working they all stop and the donk doesnt start!
stu
 
My T90 was difficult to start. I removed the glow plugs and did a compession test thru glow plug holes (400psi on each cylinder so the engine was OK). Fitted new glow plugs from ASAP, ammeter goes to full scale discharge initially on heating now, after 10secs heat the engine starts with no throttle, it cured all my starting problems.
Regards, Tony
 
Remove the glow plugs and put them across a fully charged battery. They should start to glow after 7-13 seconds. A good glowplug will glow all the way down to the tip. A glowplug that is nearing the end of it's life will glow in the middle. A duff one will not glow. Be careful they get very hot.

If your using an amp meter, most glow plugs will draw upto 20 amps initially dropping quickly to 6-7 amps.

If you find your glow plugs are ok and you still have a problem, then get your injectors serviced.
 
I tested glowplugs fitted in a car engine.
I used a digital cooking thermometer- a spiked one for pushing into cooked meat. When rested on the end of the glow plug and the heater circuit switched on it should get hotter. The amount of temperature increase is not important- just that they are all similar increase in temperature. Test them one at a time. In my case the temperature rise was only a few degreees but proved they were working.
 
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