Hello, sorry for making another thread but i looked for other ones and i can’t seem to find an answer, i have a 7.3 idi in fairly good condition, new batteries, alternator, injectors and injector pump, also have a new lift pump. When the block heater is plugged it will start okay-ish, and if i use starting fluid it Will start like it was brand new, but today was cold, like -15 celsius and it cranked endlessly, my glow plug system is manual, the white wire goes to a button on my dash, that if i press i can hear the relay click, but i feel like they arent working since the truck doesnt start cold, i was wondering what could cause a manual glow plug system to not get power, the glow plugs are new and the solanoid and relay is new from last year
7.3 idi hard to start unless use starting fluid or block heater
- Thread starter UslAura1
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Kdo58
Full Access Member
If it’s clicking it not a manual glow plug system. Cdd sells a kit for a manual system.
lotzagoodstuff
Full Access Member
Test each glow plug with a test light or measure impedance. By the way: what make of glow plugs did you install?
I installed the ford zd-29, but when the relay is clicking i mean it’s getting the 12v power and ground so it comes on even with the light, but i don’t feel like they’re heating at all and i wonder what could cause it, is there fuses or anything that could have gone bad with the wiring somewhere?
IDIBRONCO
IDIBRONCO
There's no fuses for the glow plug system. The wiring to the glow plugs could be bad. Even back to the main harness plug. That's between the passenger's valve cover and the fender unless you have a 92-94. I believe that's on the driver's side (someone please correct me if I'm wrong on that part).
Do you have battery power at the glow plug relay? If so do you have battery power on the output terminal to the glow plugs when energized? Just because the relay clicks does not mean you are getting power out to the glow plugs. What vendor did you get your glow plugs from?
Just to make sure we are talking the same relay yours looks something like this correct? Two small terminals and two large. relay Either large terminal can be used as input and the other becomes output.
Am I understanding you got the glow plugs from Rock Auto?
Am I understanding you got the glow plugs from Rock Auto?
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Yep, the motorcraft zd-29 from rockauto, the napa ones here are another brand so i avoid em, and yep two large terminals and two small terminals, right behind the air intake, bolted on the manifold, i will look if i have all the voltage on the output after work, and keep you updated on what i got
If you watch your dash voltmeter, when you press the glowplug manual button, the voltage should drop way down. Mine drops to about 8v. When it does that I know the glowplugs are drawing a lot of power and are working.
There is a spot that can go bad and cause problems. Near the pass side valve cover there is a large harness plug. The two thick yellow wires that feed the glowplug relay go through this plug, and they are usually melted. I was able to save my plug and still use it for the smaller wires in it, but I took the large yellow wires and cut them so I had 4 wire ends. I then crimped ring connectors on all 4 ends and used two small bolts, bolted them back together. It's handy to be able to disconnect the wiring over there when pull the valve cover and other work.
There is a spot that can go bad and cause problems. Near the pass side valve cover there is a large harness plug. The two thick yellow wires that feed the glowplug relay go through this plug, and they are usually melted. I was able to save my plug and still use it for the smaller wires in it, but I took the large yellow wires and cut them so I had 4 wire ends. I then crimped ring connectors on all 4 ends and used two small bolts, bolted them back together. It's handy to be able to disconnect the wiring over there when pull the valve cover and other work.
u2slow
bilge rat
I like to use a DC clamp ammeter to prove the glow plugs. Should be looking at 130-140A aggregate draw, IIRC. If less, you have 1 or more not working.
Continuity test is not reliable in my experience.
Continuity test is not reliable in my experience.
If you got your glow plugs from Rock Auto they may not be OEM plugs. As u2slow says an amp meter is the best test however I will disagree with the amp draw, they are actually much closer to 200a give or take. That would be for all 8 at once. Amp meter This makes a good test meter although you have to test one at a time. Go to a battery positive terminal with one lead and to the glow plug terminal with the other. Makes no difference which lead go where as the needle will swing either direction. Leave the glow plugs in the heads. If you see around 20-25A they should be good. If you see 10-12A you got some China plugs. Been there done that.
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Alright i’ll try some of those, but for now i looked with a volt meter the two large teminals on the relay, and none of them had voltage, stayed at 0.00, even when the relay was clicking when i pressed on the manual button, and one of them, the one toward the intake that is connected to the resistance i think, is loose in the relay wich is strange, and yes the amp meter in the truck lowers around 8 when i pressed the button. I’ve seen on another thread that the terminal i’ve circled in the picture below is supposed to have similar voltage with the battery when i make the relay click, so what does it mean when it doesnt have any and well, it’s a little loose like it already got hot before?
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