Glow plug problems and question

[Freight_Train]

ok,here is the low down,Tims truck(whitehorse) has a glow plug issue.It is a 87 6.9L with a solid state controller.Well,yesterday it blew the main power wire at the starter solinoid(so much for that fuseable link!).He said he heard a pop and opened the hood to find the wire totally burned in half.Well,We have been fighting this dern truck since he got it.I suspect the controler is shot and holding the relay closed.I bet it burned up his glow plugs now.Not really wanting to spend anymore money than we have to,I ran the idea by him to just totally do away with the glow plug system as it is and go straight push button.I thought about just running the hotwire to the relay,like normal,the glow plug wires to the Zigzag resistor like factory but instead of the controler setup on the control terminals just run a hot to one terminal,a wire from the other to a pushbutton in the cab and have the push button ground out the relay and activate the glow plugs.Tim and his wife would be the only people using the truck and we have a momentary push button to install so accidental over energizing should in theory be avoided.I really hope he didn't burn out all 8 of those brand new Beru glow plugs.Oh,and from the diagrams I have found everything is in the correct location.I can just hear the relay click when he turns the key on and no other click afterwards like it is releasing.

 

[Mr_Roboto]

The controller actuates ONLY the ground for the relay. The positive side of the relay is on the ignition circuit, and off when the ignition is off.

If you believe that the controller is staying on, simply unhook the white wire running to the small terminal relay (passenger side of relay). This is also the terminal you use to rig a manual switch. The white wire is the one and only wire that the controller switches to turn on the relay and GP's.

 

[aaklingler]

that's not how i would do, i would just run the hot to the sellinoid, run the push button to the sellinoid and hook the gp's right up to the sellinoid.

 

[Freight_Train]

ok,we did some more testing today and are totally stumped!The relay and controller is actually working.Turn the key,it closes,10 seconds later it clicks again and opens.Problem is there is no voltage getting to the glow plugs.I checked the glow plugs via a test light and all showed good.Checked to see if we was getting power to the relay and we are(Per the LED test light we have at the shop...one of those green for ground red for hot deals).Got ground at the base of the zig zag resistor even when all 8 plugs are unplugged and the key is off.Showing ground at the glow plug sockets with all 8 unhooked and relay close.I even tried to jump the terminals on the relay but for some reason the plugs didn't get hot(I pulled one out and hooked it up to the harness and grounded out the body to the battery via a clamped on wire).What gives?

 

[argve]

the two big yellow wires on the glow plug relay - do you have 12v positive on these? If not start working back on those wires and figure out why. If you happen to have power on those wires then check the other side of the relay (big ziggy zaggy) see if you have power there when the relay is CLOSED - if no power there when the relay is closed then replace the relay because the contacts within are toast - yes you could probably pull it apart and clean the contacts but why when the thing is cheap cheap at the local auto parts store - just ask for a standard ford starter solenoid (yep just like the one on the fender of just about all ford products dating back to when henry ford was alive...

 

[sle2115]

the two big yellow wires on the glow plug relay - do you have 12v positive on these? If not start working back on those wires and figure out why. If you happen to have power on those wires then check the other side of the relay (big ziggy zaggy) see if you have power there when the relay is CLOSED - if no power there when the relay is closed then replace the relay because the contacts within are toast - yes you could probably pull it apart and clean the contacts but why when the thing is cheap cheap at the local auto parts store - just ask for a standard ford starter solenoid (yep just like the one on the fender of just about all ford products dating back to when henry ford was alive...

I am confused, I don't have a GP relay. The only thing on the 87 up to my limited knowledge is the controller. The only solenoid/relay on mine is for the starter, well except for the ones I added for horn/headlights/fuel pump.

I have a Ford manual scanned into a word document or .pdf (adobe) if you want a copy, shoot me an email or pm with your email and tell me which version you prefer. It is about 1.57 MB so if you are on dial up, it will take some time.

 

[Freight_Train]

yea,we have positive power(sure wish I had a meter! since I don't know the exact voltage making it there!) to the hot terminal.The relay is brand new.Worked for about 3 days.We swapped the relay over for a semi known good one(came in a bunch of Bus parts and the guy said the glow plugs fired it right up ever time!).I even tried to jump directly across the terminals but got NO spark.....Can't find any broken spot but I have a sinking suspicion we are loosing LOTS of voltage at the plug thingy on the fender since it does look like it melted some before the smaller wire at the starter solenoid blew apart.This is why I was calling you today but you was too busy watching the back side of your eye lids....Truely has both of us stumped.Tempted to just run a brand new hot wire from the fender solenoid to the Glow plug Solenoid.I did try to clamp a piece of 10 guage wire to the positive battery terminal and touch it to the GP side of the Solenoid.....Bad move.Wire sure got hot quick!

 

[Freight_Train]

You should have a solenoid since Tims is also a 87.The relay is behind teh intake on top of the controller.

 

[zigg]

I am confused, I don't have a GP relay. The only thing on the 87 up to my limited knowledge is the controller.

I believe if you look closely, you do have a relay. On the solid state units, the relay is part of the controller. It is the round unit on the top of the controller where all the wire runs to.

First, I'd check your ground and make sure it's good. Second, I'd check the glow plug side of the relay when you hit the key(during that 10 seconds when the relay is activated) and make sure there is voltage on the large terminal (the glow plugs side). If no voltage, then the relay is activating, but the contacts aren't allowing current flow.

Since you just for sure burnt up a fusible link, I'd be looking there too, and make sure you're actually getting power to the wire harness for the glow plugs.

Lastly, since you have one of those glow plugs out, it never hurts to confirm it actually heats up, even though it appears to be ok with a test light. Just holding it with pliers or something(it gets red hot!) tough the top to the +'ve side of the battery, and run a short ground jumper from the -'ve side and touch the threads of the plug, and it should glow within about 3-5 seconds.


Zigg

 

[Freight_Train]

I tested that theory and the GP got hot FAST!didn't let it get red.Just touched it long enough to start smoking and that was under a second!

 

[Diesel JD]

Those guys are right, you have a standard Ford relay in the controller, under a bunch of other stuff. I know cause I had to switch out my power relay behind the battery tray for my solid state conversion. The headlights and both pieces of the GP harness go there. Have a good one,
J.D.

 

[2manydsls]

I'd be wondering why the fuse link blew. Also, the 10 ga. wire you ran directly to the glow plug harness shouldn't have gotten hot unless it wasn't making good contact. I'd be looking for a shorted wire in the glow plug wire harness or a shorted glow plug. Use the process of elimination to determine which one. Good luck!
Ross

 

[argve]

Jon,

Call me tomorrow afternoon/evening anytime after 4pm works... Reason I was sleeping is I go into work at 7pm on Sundays to start the plant up before the rest of the gang gets there - I play the amp load game.

 

[sle2115]

I believe if you look closely, you do have a relay. On the solid state units, the relay is part of the controller. It is the round unit on the top of the controller where all the wire runs to.

Zigg

Yes, I do realize that now. I was thinking of a relay elsewhere. Thanks for unconfusing me!

 

[Freight_Train]

Well,the fusable link didn't blow.That is what gets me.The wire between the starter Solenoid and the Fusable link is what blew.