Glowplug relay Question
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
Glowplug relay Question
I tested the power going to my glowplug relay. I have 12.3V at the relay. When I turn the key on I only get 10.6V out the other side. Is this normal? If this is not normal I am wondering if this is contributing to a hard cold start. Would a lower voltage to the glowplugs make them not warm up as much?
Cargo Master
Joined: Nov 2005
Posts: 2,766
Likes: 56
From: East Tawas, MI
Hi,
12.3 is good on that side/kinda. Before any one else jumps in..... Make sure you clean both battery terminals and all connections.. Grounds etc, Including your GPR!!!. Then check it again on the output side. ( Search here and you'll see the layout, tons of threads)
Big list of questions:
How old are the batteries.
How old are the glow plugs.
How old is the GPR.
Year of truck and does it have AIH.
Miles and year. (early or late)
Is there any history of problems starting in your Indiana winter.
Does the truck fire right up after sleeping on the block heater.
Sorry for the "does it's dog lick its ***** questions" but it'll save a few bucks on the track down.
Direct answer to your question. Yes . Does the voltage jump after lets say 20 seconds after the key is KOEO with no other accessories on. If it does jump back up, that will help a lot with the dog questions.
Denny
12.3 is good on that side/kinda. Before any one else jumps in..... Make sure you clean both battery terminals and all connections.. Grounds etc, Including your GPR!!!. Then check it again on the output side. ( Search here and you'll see the layout, tons of threads)
Big list of questions:
How old are the batteries.
How old are the glow plugs.
How old is the GPR.
Year of truck and does it have AIH.
Miles and year. (early or late)
Is there any history of problems starting in your Indiana winter.
Does the truck fire right up after sleeping on the block heater.
Sorry for the "does it's dog lick its ***** questions" but it'll save a few bucks on the track down.
Direct answer to your question. Yes . Does the voltage jump after lets say 20 seconds after the key is KOEO with no other accessories on. If it does jump back up, that will help a lot with the dog questions.
Denny
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
Alright,
That's a lot of info required
The batteries, cables, gpr connections were all cleaned today. The voltages mentioned are the ones I am still getting after the cleaning.
Batteries are 8 months old. Interstate MegaTrons.
Glow plugs are 7 years old.
GPR is unknown how old. I have put 105,000 miles on the truck. It was here before me.
Truck is a early 99 at heart, turbo and such all was swapped to late 99. No AIH.
276,000 miles
Yes, there has been issues starting time to time. I do know that I need injector o rings so that isn't helping any. Plugging it in does help out a lot, doesn't solve the problem all the time though.
Voltage starts at 9.3 and slowly works its way to 10.6 after 30 seconds or so. That's where it stops.
That's a lot of info required
The batteries, cables, gpr connections were all cleaned today. The voltages mentioned are the ones I am still getting after the cleaning.
Batteries are 8 months old. Interstate MegaTrons.
Glow plugs are 7 years old.
GPR is unknown how old. I have put 105,000 miles on the truck. It was here before me.
Truck is a early 99 at heart, turbo and such all was swapped to late 99. No AIH.
276,000 miles
Yes, there has been issues starting time to time. I do know that I need injector o rings so that isn't helping any. Plugging it in does help out a lot, doesn't solve the problem all the time though.
Voltage starts at 9.3 and slowly works its way to 10.6 after 30 seconds or so. That's where it stops.
Cargo Master
Joined: Nov 2005
Posts: 2,766
Likes: 56
From: East Tawas, MI
I had the same issues and I have the same truck with 230ish K on her. I FINALLY broke down, bought a stancor GPR relay, took 3 hours and replaced all glow plugs and my problems were completely solved.
My rig starts perfect even on the most bitter mornings in February up here above you in Northeast Michigan.
They are relatively cheap and easy things to do. If you have had it that long and haven't done them, you need to.
You'll be glad you did before the snow starts flying.
Denny
My rig starts perfect even on the most bitter mornings in February up here above you in Northeast Michigan.
They are relatively cheap and easy things to do. If you have had it that long and haven't done them, you need to.
You'll be glad you did before the snow starts flying.
Denny
Tuned
Joined: Sep 2007
Posts: 346
Likes: 11
From: Austin, TX
The major item that might be significantly contributing to a hard start is your injectors which you already mentioned. I had the exact same issues you do right now.
-Temps in the 50's at night and I had to have it plugged in a couple hours so it could start.
-Went round and round testing/replacing my GP's and GPR
-Switched to synthetic oil and it started easier until the temps dipped below 50.
-Replaced my injectors and the truck starts flawlessly now.
You can also test the amperage for each bank of GP's if you have a current meter. Both my banks were fine (don't remember the amperage draw) and I even measured the current at each GP. When I realized all my GP's were fine, the only thing left was to replace injectors.
BTW- Right after I replaced my injectors, it got in the mid-20's a couple times here and the truck fired up without even waiting for the GP's to heat. Injectors were my fix for my hard starts.
-Temps in the 50's at night and I had to have it plugged in a couple hours so it could start.
-Went round and round testing/replacing my GP's and GPR
-Switched to synthetic oil and it started easier until the temps dipped below 50.
-Replaced my injectors and the truck starts flawlessly now.
You can also test the amperage for each bank of GP's if you have a current meter. Both my banks were fine (don't remember the amperage draw) and I even measured the current at each GP. When I realized all my GP's were fine, the only thing left was to replace injectors.
BTW- Right after I replaced my injectors, it got in the mid-20's a couple times here and the truck fired up without even waiting for the GP's to heat. Injectors were my fix for my hard starts.
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
I am going to go ahead and replace the relay just to cover me. I am gonna order new injector orings to see if that helps some. Money for injectors isn't in the cards right now. Will go ahead a order new glowplugs to be safe. I hope I can get this figured out.
Cargo Master
Joined: Nov 2005
Posts: 2,766
Likes: 56
From: East Tawas, MI
Motorcraft glow plugs only. Don't go south on a few bucks.
I bought a cheap shop vac and **** canned it after the repair to suck the excess oil from the glow plug valley to avoid a hydrolock. Lil duct or shrink wrap tape and you can put a 3/8 hose on the vac to suck the residual oil out of the glow plug valley. Read up threads, there r tons. Pretty easy job with good music, 3 cans of brake cleaner and the batteries disconnected!!! As far as the stancor relay.....Get one despite the fact you might not think you need one, turns your world to color after the glow plug change. Buy a few feet of 3/8 tubing to spin out the glow plugs and reseat the new. Easily done. Worlds your oyster after that. Enjoy, do some threading and keep us posted.
Denny
I bought a cheap shop vac and **** canned it after the repair to suck the excess oil from the glow plug valley to avoid a hydrolock. Lil duct or shrink wrap tape and you can put a 3/8 hose on the vac to suck the residual oil out of the glow plug valley. Read up threads, there r tons. Pretty easy job with good music, 3 cans of brake cleaner and the batteries disconnected!!! As far as the stancor relay.....Get one despite the fact you might not think you need one, turns your world to color after the glow plug change. Buy a few feet of 3/8 tubing to spin out the glow plugs and reseat the new. Easily done. Worlds your oyster after that. Enjoy, do some threading and keep us posted.
Denny
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Cargo Master
Joined: Nov 2005
Posts: 2,766
Likes: 56
From: East Tawas, MI
BTW with what LCA said up there,
If your not running synthetic rotella T3, do so. That in itself made a world of difference starting my truck in the freezer. No more romps and moving vehicles for a jump start.
It's spendy but I run mine 10k between changes so it evens out using dino.
You might be surprised about your orings after you take these steps. You may see that you are fine. A hard starting diesel will reflect the same symptoms. Just saying. It's maintenance you know is needed regardless, so I would take a few baby steps and do the plugs, GPR, and a fresh oil change with the synthetic and see if your heals click.
Denny
If your not running synthetic rotella T3, do so. That in itself made a world of difference starting my truck in the freezer. No more romps and moving vehicles for a jump start.
It's spendy but I run mine 10k between changes so it evens out using dino.
You might be surprised about your orings after you take these steps. You may see that you are fine. A hard starting diesel will reflect the same symptoms. Just saying. It's maintenance you know is needed regardless, so I would take a few baby steps and do the plugs, GPR, and a fresh oil change with the synthetic and see if your heals click.
Denny
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Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Voltage in and voltage out is a nice conversation to have, but my advice would be to test the voltage going in (12.3v), and then test the same voltage in post once the key is turned on.
Your voltage drop may just be the draw from the glow plugs and not a loss of voltage through the relay.
Your voltage drop may just be the draw from the glow plugs and not a loss of voltage through the relay.
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
Thank you all for your points. I currently do run syn Rottela T-6. Will defiantly only run motor raft glow plugs. Did them about 7 years ago. So will have todo again 
. Along with injector o rings I believe.
. Along with injector o rings I believe.
Hotshot
Joined: Jan 2011
Posts: 18,849
Likes: 179
From: Puget Sound
As discussed on the phone yesterday, here is the best test for the relay:
One volt meter lead clipped to one of the big posts on the Glow Plug Relay, and one lead clipped to the other big post on the relay. You should see battery voltage, whatever it is. Turn on the key and watch the meter - it should read zero or very close to it. If this is what you have, this is all you could possibly ask the relay to do. If you still have issues with glow plugs, the relay is off your list of things to check or suspect.
One volt meter lead clipped to one of the big posts on the Glow Plug Relay, and one lead clipped to the other big post on the relay. You should see battery voltage, whatever it is. Turn on the key and watch the meter - it should read zero or very close to it. If this is what you have, this is all you could possibly ask the relay to do. If you still have issues with glow plugs, the relay is off your list of things to check or suspect.
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
Alright. So I tested this when I posted an thought I was good. Went to start the truck this morning, warmed up the glow plugs (or so I thought). Truck cranked but nothing. So I figured huh, no biggie I will let the glow plugs cycle again and let her rip. Crank but no start, with tons on white smoke out the tail pipe. So I get my multimeter out and connect the leads on the relay. Cycle the key and I get no power to the relay. Cycle the key again and this time I get the 10 volts and the truck starts. So I took at least 6 cycles to start. Could the relay be intermittent like that? Is it starting to go on me? What is the difference in the glow plug relay and a starter relay besides like $75?
Thread Starter
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Lead Driver
Joined: Mar 2004
Posts: 5,372
Likes: 108
From: Northern Indiana
I did have power on the big stud of the relay. I didn't have power accross the relay. The first time it did it. Started fine this morning though. Did have the truck plugged in last night. I didn't have the night before though.