Please Help. I have a Cold Start Issue....
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Senior User
Joined: Oct 2005
Posts: 484
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Please Help. I have a Cold Start Issue....
Hi guys. I really am scratching my head and out of ideas.
Truck: 2000 7.3 diesel 4x4 dually
Problem: difficulty starting when cold
What it does:
1.) When turning on the key, the wait to start light comes on, but the volt gauge does not show a load like the glow plugs are on.
2.) Then, I turn the key about 5 cycles and let the corresponding supposed glow plug rotations run their course, and try to start it and is just turns over and over. Then, all of a sudden the volt guage drops and I wait for the glow plug to actually get hot now that they are getting power and it starts right up. And I mean right up.
3.) Then, I can turn it off and cycle the key and the glow plugs still load the battery and it of course starts just fine.
What I have done:
1.) New batteries and they test just fine.
2.) New GPR and tested the new one; it works perfectly.
3.) Cleaned all connections.
4.) Repetitively cursed at it......
5.) If jumping the relay to heat the glow plugs it starts right up every time.
Any ideas?
Truck: 2000 7.3 diesel 4x4 dually
Problem: difficulty starting when cold
What it does:
1.) When turning on the key, the wait to start light comes on, but the volt gauge does not show a load like the glow plugs are on.
2.) Then, I turn the key about 5 cycles and let the corresponding supposed glow plug rotations run their course, and try to start it and is just turns over and over. Then, all of a sudden the volt guage drops and I wait for the glow plug to actually get hot now that they are getting power and it starts right up. And I mean right up.
3.) Then, I can turn it off and cycle the key and the glow plugs still load the battery and it of course starts just fine.
What I have done:
1.) New batteries and they test just fine.
2.) New GPR and tested the new one; it works perfectly.
3.) Cleaned all connections.
4.) Repetitively cursed at it......
5.) If jumping the relay to heat the glow plugs it starts right up every time.
Any ideas?
Fleet Mechanic
Joined: Sep 2006
Posts: 1,329
Likes: 0
From: IN
Sounds like the new relay is working intermittently or it is not getting the signal to switch on from the PCM. Have you tested the relay when the battery gauge looks like the glow plugs did not fire I would check to see if the glow plug side of the relay had battery voltage when that happens.
Thread Starter
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Senior User
Joined: Oct 2005
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Sounds like the new relay is working intermittently or it is not getting the signal to switch on from the PCM. Have you tested the relay when the battery gauge looks like the glow plugs did not fire I would check to see if the glow plug side of the relay had battery voltage when that happens.
Thanks for the response. I have tried a couple of different GPRs. It does the exact same thing every time.
Honestly, I am stumped.
Thanks,
T. Bauer
Thread Starter
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Senior User
Joined: Oct 2005
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I have no codes. Don't those throw a code?
Fleet Mechanic
Joined: Sep 2006
Posts: 1,329
Likes: 0
From: IN
No I don't believe they do the only things in the glow plug system that throw codes are the glow plug circuits.
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Fleet Mechanic
Joined: Sep 2006
Posts: 1,329
Likes: 0
From: IN
Also to help out there is a 7.3 section on here you will get more responses there. That is where I usually am.
Here:
https://www.ford-trucks.com/forums/forum31/
A lot of good knowledgeable people over there not that there is not here but there a lot more 7.3 people over there that don't come over here.
Here:
https://www.ford-trucks.com/forums/forum31/
A lot of good knowledgeable people over there not that there is not here but there a lot more 7.3 people over there that don't come over here.
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Logistics Pro
Joined: Mar 2002
Posts: 3,881
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From: Wake Forest, NC
You need to find what part of the glow plug relay circuit is failing, the power or the signal. If it is fairly repeatable, you can check to see if the glow plug relay is getting the signal, or if the relay isn't closing.
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Senior User
Joined: Oct 2005
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I have power to the relay on the main feed from the battery. I also have power on both of the little ones. According to my ford book, this is how it is supposed to be as it says that the PCM grounds the circuit. So, how does one test the oil temperature switch? Is there an ohm test?
Logistics Pro
Joined: Mar 2002
Posts: 3,881
Likes: 84
From: Wake Forest, NC
You will have power to ground from both of the little ones. The power flows through the internal coil to the ground input side. Basically the power is stopped in the ECM. When the ECM grounds the circuit, it allows the power to flow through. You need to see if the ECM is grounding one of them. You will see one of them drop voltage if/when the ECM grounds it.
Thread Starter
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Senior User
Joined: Oct 2005
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You will have power to ground from both of the little ones. The power flows through the internal coil to the ground input side. Basically the power is stopped in the ECM. When the ECM grounds the circuit, it allows the power to flow through. You need to see if the ECM is grounding one of them. You will see one of them drop voltage if/when the ECM grounds it.