Best way to check glow plug while in the engine is to remove the wire from the tip then measure the resistance between tip and GND (engine block). If resistance is infinite or very high then its burnt out. If very low then its good. This is easier than trying to put your Volt meter probe over to the battery + terminal
I may not have filmed it but I did check the resistance from the glow plug tip to block. When you check that you are looking for 2 ohms or less. I think I talked about it but its been awhile since I filmed this.
Thanks for your video...Just the way & tone of your voice gave me confidence to tackle my no start issue on my 99 F450 7.3L....Once again Thanks Yazmin Venice Beach CA ⛱️ 🏄♀️🏁⛱️🏄♀️💯
Glad I can help. When I face new complex things like this, I always remember: "How do you eat an elephant? One bite at a time". If you solve the first problem that comes up, then the next, then the next, eventually there are no more problems to solve and you've done what you set out to do.
Damn, watched a bunch of other videos before finding this. Just replaced all glow plugs with autolites while motorcraft are in the mail. lasted 2 days then tick tick tick. Unsure if it’s the glow plugs fault or the relay, harness was replaced by previous owner. Looks like I’ll be busy this weekend. Thanks a bunch ! First channel I’ve subscribed to !!
I'm honored to be your first sub. Having the motorcraft plugs should help and as long as the harness isn't a hack job that should be fine. Biggest issue is the controller relay or the controller itself. They are very finicky, which is why you see at the end of the video that I bypass the controller and go manual.
Thanks! I'm just a dude working on stuff in his yard but I do what I can. If this helps somebody, it's worth the hassle of filming and editing and getting this on RUclips.
Nice!!! I have a 90 7.3 idi Tow truck with Tach that works when it wants to and of course when it is not working their is no overdrive. Have replaced the tach sensor and computer tps with voltage setting and lasted awhile and now back to square one sure its a wiring issue. I have the schematic but do u know of where the wiring usually breaks? Or better yet have you done a video on this repair with the test procedure?
I've replaced a bunch of the sensors on the truck fighting an issue where the truck hangs on to 1st gear waaaaay too long. I've made videos about how to do most of that replacement work. Should be under the playlist for this truck. That being said, my tac sensor is fine. I've notice it has a few points worn from it not being secured properly, but I haven't found any broken wires really in that area. I vaguely remember that the signal for the tac sensor takes a funny path into the instrument cluster. Might be worth your while to make sure you have solid wiring on the printed circuit paper stuff they wire the cluster together with. I know on my instrument cluster I have a few leads that are about to give up the ghost that I had to superglue back in place so I could reinstall the cluster.
Great job on the video, thank you for doing this. I have a 1990 250 7.3. Mine is doing exactly the same thing as yours. I did all the testing step by step just like you did and ended up with the same results. I also had to do a manual switch. I'm wondering if maybe a fusible link somehow is a part of the computer control for the relay? I wish I had a wiring diagram. Im grasping at straws. Two sets of plugs, two complete controllers, good harness, good plugs, etc. BTW, what do you consider a normal resistance for each glow plug when on the work bench? I wish others did as good a video as you, keep up the good work!
Thank you for your comments. If you do a bench test of a good Motorcraft glow plug it should be 2 ohms or less. One of my theories as to why the system wouldn't work right is that I put anti-seize on the plugs which somehow altered the resistance reading, even though as you saw in the video all the plugs ohm'd out fine once installed in the cylinder heads. I have a new glowplug harness on my todo list to install, just haven't gotten around to it yet.
@@MazdaB3K I did not use anti-seize the first two times I changed them. I bought motorcraft parts off of ebay for $25, decided they may be fake so paid $130 at Ford Dealer and used anti-seize on these thinking they would be there forever. Same result unfortunately. I would appreciate it if you think of it to let me know if the new harness is the solution.
@@MichaelMaroon-oz9bp I honestly don't know. As you saw in this video, everything tested perfectly but the glow plug controller wasn't having any of it. Part of my testing was checking the voltage reads and resistance across all the harness parts and that came back fine. A new harness hopefully would have better positive locking ends for the glowplugs but otherwise there was no issue with my harness. This particular problem still bugs me as I wasn't able to solve it and had to do the manual solution.
the contacts on your steering caulome on the key switch/rod have been known to go bad as well. anyway you look at it the whole glow plug system and wiring harnesses are a fail on the 1989. Thanks for your video as i am figuring mine out today. arrggghhhhhh
Valid point, but the lock cylinder is brand new as I had to drill out the old one. Vehicle was sold to me with a frozen lock cylinder. Also had to replace the ignition switch at the base of the steering shaft and that super annoying little metal piece that broke in the tilt column to get all the ignition positioning working correctly. I'm glad this glow plug video is helping folks out because it was a PITA that I knew i had perfectly good, ford glow plugs but the controller wasn't working. My manual solution is still working just fine.
Don't know if any of the of the other videos are your cup of tea, but I have an entire playlist of videos on Bertha: ruclips.net/p/PLUFPEHCeM7-s7VKug6DzoDPr2KAlR6x4G
I have the same problem on my 93 ford f350 7.3 idi , I replaced glow plugs, module/controller, glow plug harness and still clicks Did you find the issue why it clicks ?
The glow plug controller is extremely sensitive to resistance as that is how it determines if the engine is hot or cold and how much glow to run. The only thing I could think of was that the anti-seize that I put on the glow plugs altered the resistance enough that it caused the controller to spaz out. As seen in the video, I checked everything per Ford specification and found it to be within spec. This is why ultimately I modified the glow controller to be a manual, momentary switch activation. That has been working fine since I converted it.
What do you mean that all my plugs came back as 13.1 volts. This doesn't make sense. Testing as was done with a voltmeter won;'t tell you if the resistance is low but still too high for proper glow plug operation.
Can you give me a timestamp when I said that so I can get a little more context as to why I said it? You are correct that a meter set to volts isn't going to tell you much if you are testing individual plugs. The meter would need to be set to Ohms and then you can check the resistance. However, if you are testing the ENTIRE system and you see around 10 volts on a plug when you turn on the glow plugs that's about right to indicate the glow plugs are working.
Now that I think about it, I was probably doing voltage checks from the tip of the installed plug to the block with the wire harness attached and was looking for voltage drop across the length of the plug while installed. If you have excessively high resistance across the plug or if it doesn't have a good connection to ground (the cylinder head it's screwed into) you would see a voltage drop when you check it. 13.1 was what the battery was reading at the time, so if everything was installed correctly I should see 13.1 across the plug, which I did.
Best way to check glow plug while in the engine is to remove the wire from the tip then measure the resistance between tip and GND (engine block). If resistance is infinite or very high then its burnt out. If very low then its good. This is easier than trying to put your Volt meter probe over to the battery + terminal
I may not have filmed it but I did check the resistance from the glow plug tip to block. When you check that you are looking for 2 ohms or less. I think I talked about it but its been awhile since I filmed this.
Thanks for your video...Just the way & tone of your voice gave me confidence to tackle my no start issue on my 99 F450 7.3L....Once again Thanks
Yazmin
Venice Beach CA ⛱️ 🏄♀️🏁⛱️🏄♀️💯
Glad I can help. When I face new complex things like this, I always remember: "How do you eat an elephant? One bite at a time". If you solve the first problem that comes up, then the next, then the next, eventually there are no more problems to solve and you've done what you set out to do.
Damn, watched a bunch of other videos before finding this. Just replaced all glow plugs with autolites while motorcraft are in the mail. lasted 2 days then tick tick tick. Unsure if it’s the glow plugs fault or the relay, harness was replaced by previous owner. Looks like I’ll be busy this weekend. Thanks a bunch ! First channel I’ve subscribed to !!
I'm honored to be your first sub. Having the motorcraft plugs should help and as long as the harness isn't a hack job that should be fine. Biggest issue is the controller relay or the controller itself. They are very finicky, which is why you see at the end of the video that I bypass the controller and go manual.
Great trick man , hey just saying you’d make a good hd mechanic
Thanks! I'm just a dude working on stuff in his yard but I do what I can. If this helps somebody, it's worth the hassle of filming and editing and getting this on RUclips.
Thanks for the video, very informative!
Glad this video can help you out.
Nice!!! I have a 90 7.3 idi Tow truck with Tach that works when it wants to and of course when it is not working their is no overdrive. Have replaced the tach sensor and computer tps with voltage setting and lasted awhile and now back to square one sure its a wiring issue. I have the schematic but do u know of where the wiring usually breaks? Or better yet have you done a video on this repair with the test procedure?
I've replaced a bunch of the sensors on the truck fighting an issue where the truck hangs on to 1st gear waaaaay too long. I've made videos about how to do most of that replacement work. Should be under the playlist for this truck. That being said, my tac sensor is fine. I've notice it has a few points worn from it not being secured properly, but I haven't found any broken wires really in that area. I vaguely remember that the signal for the tac sensor takes a funny path into the instrument cluster. Might be worth your while to make sure you have solid wiring on the printed circuit paper stuff they wire the cluster together with. I know on my instrument cluster I have a few leads that are about to give up the ghost that I had to superglue back in place so I could reinstall the cluster.
Great job on the video, thank you for doing this. I have a 1990 250 7.3. Mine is doing exactly the same thing as yours. I did all the testing step by step just like you did and ended up with the same results. I also had to do a manual switch. I'm wondering if maybe a fusible link somehow is a part of the computer control for the relay? I wish I had a wiring diagram. Im grasping at straws. Two sets of plugs, two complete controllers, good harness, good plugs, etc. BTW, what do you consider a normal resistance for each glow plug when on the work bench? I wish others did as good a video as you, keep up the good work!
Thank you for your comments. If you do a bench test of a good Motorcraft glow plug it should be 2 ohms or less. One of my theories as to why the system wouldn't work right is that I put anti-seize on the plugs which somehow altered the resistance reading, even though as you saw in the video all the plugs ohm'd out fine once installed in the cylinder heads. I have a new glowplug harness on my todo list to install, just haven't gotten around to it yet.
@@MazdaB3K I did not use anti-seize the first two times I changed them. I bought motorcraft parts off of ebay for $25, decided they may be fake so paid $130 at Ford Dealer and used anti-seize on these thinking they would be there forever. Same result unfortunately. I would appreciate it if you think of it to let me know if the new harness is the solution.
@@MichaelMaroon-oz9bp I honestly don't know. As you saw in this video, everything tested perfectly but the glow plug controller wasn't having any of it. Part of my testing was checking the voltage reads and resistance across all the harness parts and that came back fine. A new harness hopefully would have better positive locking ends for the glowplugs but otherwise there was no issue with my harness. This particular problem still bugs me as I wasn't able to solve it and had to do the manual solution.
What gauge wire was used for redoing the gp harness
I used 10 gauge because I had it lying around.
the contacts on your steering caulome on the key switch/rod have been known to go bad as well. anyway you look at it the whole glow plug system and wiring harnesses are a fail on the 1989. Thanks for your video as i am figuring mine out today. arrggghhhhhh
Valid point, but the lock cylinder is brand new as I had to drill out the old one. Vehicle was sold to me with a frozen lock cylinder. Also had to replace the ignition switch at the base of the steering shaft and that super annoying little metal piece that broke in the tilt column to get all the ignition positioning working correctly. I'm glad this glow plug video is helping folks out because it was a PITA that I knew i had perfectly good, ford glow plugs but the controller wasn't working. My manual solution is still working just fine.
Please make more videos, I have the same truck but a 7.3 with a turbo.
Don't know if any of the of the other videos are your cup of tea, but I have an entire playlist of videos on Bertha:
ruclips.net/p/PLUFPEHCeM7-s7VKug6DzoDPr2KAlR6x4G
I have the same problem on my 93 ford f350 7.3 idi , I replaced glow plugs, module/controller, glow plug harness and still clicks
Did you find the issue why it clicks ?
The glow plug controller is extremely sensitive to resistance as that is how it determines if the engine is hot or cold and how much glow to run. The only thing I could think of was that the anti-seize that I put on the glow plugs altered the resistance enough that it caused the controller to spaz out. As seen in the video, I checked everything per Ford specification and found it to be within spec. This is why ultimately I modified the glow controller to be a manual, momentary switch activation. That has been working fine since I converted it.
What do you mean that all my plugs came back as 13.1 volts. This doesn't make sense. Testing as was done with a voltmeter won;'t tell you if the resistance is low but still too high for proper glow plug operation.
Can you give me a timestamp when I said that so I can get a little more context as to why I said it? You are correct that a meter set to volts isn't going to tell you much if you are testing individual plugs. The meter would need to be set to Ohms and then you can check the resistance. However, if you are testing the ENTIRE system and you see around 10 volts on a plug when you turn on the glow plugs that's about right to indicate the glow plugs are working.
Now that I think about it, I was probably doing voltage checks from the tip of the installed plug to the block with the wire harness attached and was looking for voltage drop across the length of the plug while installed. If you have excessively high resistance across the plug or if it doesn't have a good connection to ground (the cylinder head it's screwed into) you would see a voltage drop when you check it. 13.1 was what the battery was reading at the time, so if everything was installed correctly I should see 13.1 across the plug, which I did.