thats a slick way to test it. gave me a new perspective to look at it and all wiring. never thought of unplugging everything and reversing polarity and looking with a test light so you can literally see if there is voltage drop. GENIUS
I fixed my truck just from your testing idea works great better than removing valve covers on a e350 van lol. After I confirmed no resistance I went found idm from friend Truck runs great now ! Thank you very much too many ppl focus on icp or icr
I didn't see anyone else mention this, but I am pretty sure the center wire on that connection is actually the common injector power line. The 2 injector wires on either side (4 total) of it is actually the connection to the ground.
YES... you are correct.. the center wire feeds 110- 115 VDC to all injectors on that bank... injectors fire when IDM feeds it Ground. Today we have scan tools to perform BUZZ tests
The only thing I would add to this is use Halogen light bulb to ensure it can carry the full voltage, in case there's internal breakage in the wires that an ohms test won't show because it's not carrying enough current to light it, but could easily carry enough to light that little test light with only a few strands left. However I've been working on vehicles for more than 35 plus years and this overall is one of the BEST quick tests of the wiring to the IDM I've seen. Super job Seth. Super Thumbs up! Best Wishes & Blessings. Keith Noneya
Do you need to have the batteries connected to test the idm terminal? I’m using a multimeter specifically concerned about the power to ground of 23&23 to 18&26? Thanks
So I have 3 injectors on the driver side with no oil coming out of them when the truck is running the injector # 2 seamed to be working fine so I swapped it to the number 6 hole but still the injector in the number 2 hole was the only one with oil coming out of it so that tells me the injectors are good I unplugged the plug from the IDM and omed the wires back to where they plug into the valve cover they all tested good I also checked them from the injector plug back through the valve cover and they were good so now I’m thinking my IDM is bad is there anything else I should check or is there a way to test the IDM
Stop stiction with Turbo maxx the benefit doubles oil change life. very nice instruction video most people miss all the problems with 7.3 and 6.0 problems
Got a power stroke 7.3 1999 f 450 eng starts. after it warm up about 30 min running. Is when it goes to hell . Eng starts rev by itself 1200 to 1800 rpm . And when I accelerate a little it goes into rev limit ang black smoke coming out of pipe like a mad max truck Disconnect pedal no different. Replace both computer on truck same .replace icp sensor on cyl head nothing . Do I need holy water get rid of omen .
With truck running disconnect injector bank wiring harness one side and then the other. The truck should run on four cylinders even if its poor and see if it idles down. Sounds like an injector dumping fuel warm. Any oil out tailpipe could also show signs of turbo pushing oil back through intake causing the truck to double fuel like what you are talking about. Just some ideas to consider. Thanks for watching. Hope to have more videos like this one soon.
Seth Harrison I found the problem I change the oil temp sending unit and eng light went off no smoke in cold .running excellent. Thank you for your time Seth for your replied . Greatly appreciate it .
Sorry the center is powered constantly the other 2 on either side are ground for each injector. The Switch is to ground which prevents the modules from having lots of potential. Just like the Glow plug relay has constant 12v key on or key off when the key is switched the PCM checks the module resistance for 5 volts then quickly grounds out closing the relay the dash light comes on When the timer runs to the end of the 2 min or less PCM opens the circuit causing the relay to open. at no time with the key on did the pcm achieve more then 5 volts and switched everything by using the ground side. Also do not remove any harness connectors when runnin. The injectors fire with 120v A/C like your house current. This will give you a bite and may 3nd your idm
I think this is what's happening to me. Truck died earlier but I've noticed a couple times where I would go to unlock the truck & would get a bite. Now I'm getting IDM codes & no fuel just crank. Then randomly it fired. Got it home but I'm sure it'll do the same thing when it gets hot. Guess I'll be replacing all wiring and idm. Maybe glow plugs too & hold off on tune and injectors
Seth: Could you please list the All tools needed to run this test of the IDM? I have Fluke Meter what do I use for the pins for testing the IDM? thanx, diane
Pcm fuse keeps blowing at key on. #30 fuse 2000 f 250 7.3. Wont start. Changed pcm and unplugged fuel heater and waste gate. Still blows. I unplugged the injector plug on drivers side valve cover and fuse doesnt blow but wont start with drivers side unplugged. If I remember right passenger side unplugged will let it run just horrible with check engine light. Sounds like Bad wires under valve cover?
I would use a breakout pigtail, made by taking an old Dorman gasket’s external connector and internal wires, and connecting them through to an old harness connector from a junker. A good way to attach the wires, is with a row of those insulated double screw terminal blocks, which will keep them from touching, and the screw heads provide an easy to manage row of test points.
You would want to put the voltage out through the injector loops. The common (ground return wires are pins 23 and 24 for the two banks of injectors, so you could put 12 volts on that ground, and see if your test light lights up the same for each of the pins that normally carry voltage out to the injectors. Be careful, as when the IDM is live and trying to fire the injectors, it sends ~110 volt DC pulses through the wires, in the normal direction, so never mess with injector wiring while the IDM is connected and truck turning over to start, or running, without insulated gloves, or careful attention to what and where you are touching. (A worm or frayed wire can be a shock hazard when the IDM is pushing pixies through the loom)
If all 8 are buzzing the same. It should be good, but if you have insulation worn off you can get a intermittent issue. Without looking it over well it's hard to say if the wire loom is good. If you do a buzz test and not all 8 buzz you really need to check wiring, usually under valve cover
this is the best test i have ever seen. saved me a lot of time even on a duramax.
thats a slick way to test it. gave me a new perspective to look at it and all wiring. never thought of unplugging everything and reversing polarity and looking with a test light so you can literally see if there is voltage drop. GENIUS
I fixed my truck just from your testing idea works great better than removing valve covers on a e350 van lol. After I confirmed no resistance I went found idm from friend Truck runs great now ! Thank you very much too many ppl focus on icp or icr
Seth, thank you brother!!!!If you ever come out to Southern California, dinner is on me buddy!!
Stefan, troubles with the goose hauler?
Thank you very much for your instructional Video! Short , to the point quickly, spoke very clearly and understanding was easy. very helpful
Wow this was such an awesome video and very much instructional. Thank you I will definitely try this tomorrow morning!
Seth you the best. You got a student for life.
I didn't see anyone else mention this, but I am pretty sure the center wire on that connection is actually the common injector power line. The 2 injector wires on either side (4 total) of it is actually the connection to the ground.
YES... you are correct.. the center wire feeds 110- 115 VDC to all injectors on that bank... injectors fire when IDM feeds it Ground.
Today we have scan tools to perform BUZZ tests
The only thing I would add to this is use Halogen light bulb to ensure it can carry the full voltage, in case there's internal breakage in the wires that an ohms test won't show because it's not carrying enough current to light it, but could easily carry enough to light that little test light with only a few strands left. However I've been working on vehicles for more than 35 plus years and this overall is one of the BEST quick tests of the wiring to the IDM I've seen. Super job Seth. Super Thumbs up! Best Wishes & Blessings. Keith Noneya
agree on halogen.
Do you need to have the batteries connected to test the idm terminal? I’m using a multimeter specifically concerned about the power to ground of 23&23 to 18&26? Thanks
So I have 3 injectors on the driver side with no oil coming out of them when the truck is running the injector # 2 seamed to be working fine so I swapped it to the number 6 hole but still the injector in the number 2 hole was the only one with oil coming out of it so that tells me the injectors are good I unplugged the plug from the IDM and omed the wires back to where they plug into the valve cover they all tested good I also checked them from the injector plug back through the valve cover and they were good so now I’m thinking my IDM is bad is there anything else I should check or is there a way to test the IDM
Stop stiction with Turbo maxx the benefit doubles oil change life. very nice instruction video most people miss all the problems with 7.3 and 6.0 problems
Got a power stroke 7.3 1999 f 450 eng starts. after it warm up about 30 min running. Is when it goes to hell . Eng starts rev by itself 1200 to 1800 rpm . And when I accelerate a little it goes into rev limit ang black smoke coming out of pipe like a mad max truck Disconnect pedal no different. Replace both computer on truck same .replace icp sensor on cyl head nothing . Do I need holy water get rid of omen .
With truck running disconnect injector bank wiring harness one side and then the other. The truck should run on four cylinders even if its poor and see if it idles down. Sounds like an injector dumping fuel warm. Any oil out tailpipe could also show signs of turbo pushing oil back through intake causing the truck to double fuel like what you are talking about. Just some ideas to consider. Thanks for watching. Hope to have more videos like this one soon.
Seth Harrison I found the problem I change the oil temp sending unit and eng light went off no smoke in cold .running excellent. Thank you for your time Seth for your replied . Greatly appreciate it .
Sorry the center is powered constantly the other 2 on either side are ground for each injector.
The Switch is to ground which prevents the modules from having lots of potential.
Just like the Glow plug relay has constant 12v key on or key off
when the key is switched the PCM checks the module resistance for 5 volts then quickly grounds out closing the relay
the dash light comes on
When the timer runs to the end of the 2 min or less
PCM opens the circuit causing the relay to open.
at no time with the key on did the pcm achieve more then 5 volts and switched everything by using the ground side.
Also do not remove any harness connectors when runnin. The injectors fire with 120v A/C like your house current. This will give you a bite and may 3nd your idm
I think this is what's happening to me. Truck died earlier but I've noticed a couple times where I would go to unlock the truck & would get a bite. Now I'm getting IDM codes & no fuel just crank. Then randomly it fired. Got it home but I'm sure it'll do the same thing when it gets hot. Guess I'll be replacing all wiring and idm. Maybe glow plugs too & hold off on tune and injectors
Where can I get a good schematic for the IDM plug in a 2000
Great video
What if the resistance in injectors is 5.7?
Seth: Could you please list the All tools needed to run this test of the IDM? I have Fluke Meter what do I use for the pins for testing the IDM? thanx, diane
Id love to see the wiring diagram
Pcm fuse keeps blowing at key on. #30 fuse 2000 f 250 7.3. Wont start. Changed pcm and unplugged fuel heater and waste gate. Still blows. I unplugged the injector plug on drivers side valve cover and fuse doesnt blow but wont start with drivers side unplugged. If I remember right passenger side unplugged will let it run just horrible with check engine light. Sounds like Bad wires under valve cover?
Thats definitely something you could check first or a shorted injector.
You fix the problem
Seth Harrison how much power should the idm sends to thw injectors? 12 v?
My question is how do I test the IDM is firing over 100volts to the injectors
I would use a breakout pigtail, made by taking an old Dorman gasket’s external connector and internal wires, and connecting them through to an old harness connector from a junker. A good way to attach the wires, is with a row of those insulated double screw terminal blocks, which will keep them from touching, and the screw heads provide an easy to manage row of test points.
Seth what wires do you connect the power probe for the ground is it the injector feed ? Injector drive module
Deena Robbins power probe connects directly to vehicle battery power and ground
You would want to put the voltage out through the injector loops. The common (ground return wires are pins 23 and 24 for the two banks of injectors, so you could put 12 volts on that ground, and see if your test light lights up the same for each of the pins that normally carry voltage out to the injectors.
Be careful, as when the IDM is live and trying to fire the injectors, it sends ~110 volt DC pulses through the wires, in the normal direction, so never mess with injector wiring while the IDM is connected and truck turning over to start, or running, without insulated gloves, or careful attention to what and where you are touching. (A worm or frayed wire can be a shock hazard when the IDM is pushing pixies through the loom)
Would a buzz test accomplish the same results?
If all 8 are buzzing the same. It should be good, but if you have insulation worn off you can get a intermittent issue. Without looking it over well it's hard to say if the wire loom is good. If you do a buzz test and not all 8 buzz you really need to check wiring, usually under valve cover
Thank you so much
would be better to use a higher amp test light like a turn signal. etc.