No Go with Glow Plugs

[thebudman]

OK- when I try to heat the glow plugs prior to a cold start, I notice the amp needle does not move. I assume that if the plugs are heating, the needle should bury itself and then slowly creep up to the mid-position. So, I check the fuse---- fuse is good. So, I repalced the fuse. Nothing. So I then cleaned the contacts and sprayed some WD-40 on the fuse panel. Still nothing.

All of which leads me to ask: if it's not a fuse-related issue, then what is the problem, and, more importantly, how do I fix it?

 

[Transit]

Ok, go to the CTOA site and under ARTICALS look for my diagram showing how the glow plugs are wired. This should help you see how it works.

 

[TTTTTT]

OK- when I try to heat the glow plugs prior to a cold start, I notice the amp needle does not move. I assume that if the plugs are heating, the needle should bury itself and then slowly creep up to the mid-position. So, I check the fuse---- fuse is good. So, I repalced the fuse. Nothing. So I then cleaned the contacts and sprayed some WD-40 on the fuse panel. Still nothing.

All of which leads me to ask: if it's not a fuse-related issue, then what is the problem, and, more importantly, how do I fix it?

Did you notice current draw when activating preheat switch prior. If you have a meter, probe on a clean GP tip ( each one) or busbar as you activate your preheat switch. Should read in the 8 amp range. At least then you will know for sure if power is even getting to the GP's and you will eliminate everything but the ammeter itself. After that if no power, could be a variety of things, such as switch, bad ground, bad wire -coroded/broken/ connector etc.

Good luck Dave

 

[greg_g]

Find the place near the fuel tank where a wire (probably green) attaches to the glow plug buss bar. Disconnect the wire from the buss. Put the red (+) lead from a multimeter on the wire, and the black (-) lead to ground. Rotate the keyswitch to the HEAT position. If you don't see a nominal 12 volts DC, either the wire's broken between the buss and the switch - or the switch has begun to self destruct (not uncommon for Chinese key switches)

//greg//

 

[thebudman]

Find the place near the fuel tank where a wire (probably green) attaches to the glow plug buss bar. Disconnect the wire from the buss. Put the red (+) lead from a multimeter on the wire, and the black (-) lead to ground. Rotate the keyswitch to the HEAT position. If you don't see a nominal 12 volts DC, either the wire's broken between the buss and the switch - or the switch has begun to self destruct (not uncommon for Chinese key switches)

//greg//

I will give that a try. How involved is replacing the key switch? I haven't even looked at it--- will I need to pull alot of things out of the way to be able to access it?

Also, until today, I had never heard of a "buss bar".

 

[greg_g]

Buss bar is typically the copper strip that connects the glow plugs in parallel. A few I've seen have wires strung between the glow plugs instead of the copper strip.

Keyswitch replacement is a piece of cake, provided you buy the right replacement switch. I recommend the old fashioned Ford tractor cold start switch. That gives you the added advantage of keeping the glow plugs energized while the starter motor is turning. Unscrew the jam nut that tightens the switch to the dash, push it through, pull it out from underneath.

//greg//

 

[thebudman]

Buss bar is typically the copper strip that connects the glow plugs in parallel. A few I've seen have wires strung between the glow plugs instead of the copper strip.

Keyswitch replacement is a piece of cake, provided you buy the right replacement switch. I recommend the old fashioned Ford tractor cold start switch. That gives you the added advantage of keeping the glow plugs energized while the starter motor is turning. Unscrew the jam nut that tightens the switch to the dash, push it through, pull it out from underneath.

//greg//

Thanks for the advice. Assuming it is the switch, where is the best place to get a replacement? Kragen or Napa? Or a tractor supply store? I found this one on-line for $25.00----

This Ford tractor ignition switch works with all Ford tractors with cold start. Replaces E7NN11N501AC.

 

[greg_g]

Yeah, that sounds like the right one. But - unless it's an actual (used) Ford switch - that's kinda pricey. New ones - if/when you can find them - go for $65-$70 bucks. Used ones $30-$40. More common are the Chinese clones down in the $10-$15 range. They're not as good as true Ford switches, but still a far site better than what comes with the tractor. CLICK HERE.

It's got 5 connectors in the back instead of 4. But I've installed them before, and can help you with the hookup if necessary.

//greg//

 

[Willl]

Bud, lets not assume. Do you have a volt meter ?

 

[thebudman]

Yes I do. I'll take a look at it this weekend. Thanks again for all the good advice.