Hey everyone. I have a 1991 f250 7.3idi and I have a no start situation. I turn the key on to cycle the plugs and as soon as I do the wait to start goes away immediately and all it does is click non stop.. I replaced all 8 plugs and the glowplug module. And still the same thing. Keep in mind I didnt have this problem before I replaced anything. The cycle worked fine before. I just started throwing money at it hoping it would fix it.
Glow plug relay clicking. No start
- Thread starter dakota
- Start date
sjwelds
Full Access Member
What brand of glow plugs did you go with?
Randy Bush
Full Access Member
Did you check and see if your have power going to the plugs when cycling? Something could be hooked up wrong or a faulty part.
MICHAEL MICHAUD
Full Access Member
Yes what brands did you replace both module and glow plugs with. Make sure the wires are secure to each plug.
I have bought cheap eBay parts several times that I installed and they did nothing. Always buy quality parts and you will avoid these headaches.
Motorcraft glow plugs should be used otherwise you risk a poorly made glowplug snapping off in the head during removal or even worse the tips can break off because of the extreme heat then that tip will be floating around in your engine. Not good.
Not sure what glow plugs modules are good. Plenty of guys on here probably have spare glow plugs modules.
Check all your ground connections and the wiring for the module make sure they are correctly oriented.
Why did you replace these in the first place?
Why don't you try to reinstall old module and see if it works...
I suspect the wiring plug is melted feeding the glowplug system.
Over on the pass side valve cover you should see a group of wires going across the valve cover heading toward the pass side innner fender, and about in front of the A/C coil housing that sticks out, there will be a plug for this wiring. Grab this plug and inspect it carefully. It may be partially melted.
If it's melted, the two large yellow wires are the ones causing it to overheat. And it is these two large yellow wires that feed your glowplug controller.
On mine the rest of the plug with the little wires was ok and I was able to keep the plugs and still use them for the little wires. What I did was cut the yellow wires off near each plug, and then crimped ring connectors on all 4 ends. I then took small boltsand nuts and bolted the yellow wires back together, it doesn't matter if you get them mixed up. Bolting them back together lets you take them apart again later, if you ever want to do any work to the engine you need to be able to take these wires apart and swing them out of the way for access to get the valve cover off and anything else you may be doing.
Over on the pass side valve cover you should see a group of wires going across the valve cover heading toward the pass side innner fender, and about in front of the A/C coil housing that sticks out, there will be a plug for this wiring. Grab this plug and inspect it carefully. It may be partially melted.
If it's melted, the two large yellow wires are the ones causing it to overheat. And it is these two large yellow wires that feed your glowplug controller.
On mine the rest of the plug with the little wires was ok and I was able to keep the plugs and still use them for the little wires. What I did was cut the yellow wires off near each plug, and then crimped ring connectors on all 4 ends. I then took small boltsand nuts and bolted the yellow wires back together, it doesn't matter if you get them mixed up. Bolting them back together lets you take them apart again later, if you ever want to do any work to the engine you need to be able to take these wires apart and swing them out of the way for access to get the valve cover off and anything else you may be doing.
I can confirm, mine clicked exactly like this when my main power wire to the controller went bad. Don't believe your multi-meter saying there are 12V with no load, it may look fine until it tries to pull all the current for the plugs. I've been screwed by that more times than I can count with fuel pumps and other electric things.
Bio-Bradley
Registered User
Good Advice. Thanks. I've been trying to test my glow plug relay as I'm having trouble starting my 89 ford f350 7.3 idi. I have an aftermarket system someone installed with a button to push & hold located under the dash. I installed a voltmeter to measure what's going on in the electrical system as I've had a little trouble with electrical and dead batteries. When I push the button, sometimes the voltmeter drops about 1 volt and sometimes it doesn't. With my basic knowledge of electrical theory... when I push the button, the glow plug relay is under load, there should be a drop in the voltmeter because it's calling for power. If not, then I have an issue with either the push button device, wiring from the push button device to the relay or the relay itself. Anyone care to confirm or correct me? Thanks!
