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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 20072
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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I have an Infiniti FX 35 that is blowing ignition eccm fuses

Customer Question

I have an Infiniti FX 35 that is blowing ignition eccm fuses
Submitted: 1 year ago.
Category: Nissan
Expert:  Jay replied 1 year ago.

Hello my name is ***** ***** thank you for your question.

Where is the fuse exactly located so I can pull up this circuit with this fuse.

Let me know..

Customer: replied 1 year ago.
In the ipdm slot 20A
Expert:  Jay replied 1 year ago.

https://dl.dropboxusercontent.com/u/105565483/1.jpg

Can you tell me what number fuse it is using this image I provided?

Customer: replied 1 year ago.
77
Expert:  Jay replied 1 year ago.

Hang on please.. reading....

Customer: replied 1 year ago.
It will try to start then the fuse blows and it will no longer try to start
Expert:  Jay replied 1 year ago.

ok, there is allot in that circuit.. Are you a shop? How good are you at electrical?

Customer: replied 1 year ago.
I have a degree
Expert:  Jay replied 1 year ago.

ok then. Please give me a few while I extract all the data from the service manual and share it with you so you can work on isolating this short. It will take me a while to do this so hang tight please..

Customer: replied 1 year ago.
Ok
Expert:  Jay replied 1 year ago.

As I was grabbing data for you, I just remembered something.. Have you checked your coils to see if any are blistered? or did you have to replace any coils cause they were blistered?

Customer: replied 1 year ago.
I replaced all the coils 2 mos ago
Expert:  Jay replied 1 year ago.

ok.. we may be on to something.. Were they blistered?

Customer: replied 1 year ago.
No
Expert:  Jay replied 1 year ago.

Why was it changed? What was wrong with it?

Customer: replied 1 year ago.
But when hooked up to the computer it read 2 were bad so I replaced them all. Subsequently had to replace a few of them again. Then sent the eccm in for repair. Now the fuse keeps blowing
Customer: replied 1 year ago.
After I replaced them again it rand fine for 359 miles then quit running completely and the computer read errors across the board which is when I sent in the ECM
Expert:  Jay replied 1 year ago.

Ok.. Let me explain a old issue I recalled while looking up your info.

When these FX's were having coil problems, it was normally caused by the negative battery cable. To much resistance. So it would over heat the ground circuit and would damage coils. When this happens it would affect all the coils. So once this starts to happen, all the coils would need to be replaced with the battery negative cable or eventually it can burn out the Ecm. This sounds very similar to your issue.

Customer: replied 1 year ago.
what do you recommend I do now?
Expert:  Jay replied 1 year ago.

Well, I am going to share the info with you. Here it is..

https://dl.dropboxusercontent.com/u/105565483/07%20FX.pdf

https://dl.dropboxusercontent.com/u/105565483/Blistered%20coil.jpg

The second link is what I mean when I say a blistered coil. Did any of your coils look like this before replacing them?

Customer: replied 1 year ago.
Coils weren't blistered
Expert:  Jay replied 1 year ago.

If the coils were not blistered, then this may not be the issue. But I have provided you information which all has fuse 77 in the circuit so you can check and isolate the issue.

Expert:  Jay replied 1 year ago.

Do you have any more questions on this?

Customer: replied 1 year ago.
what should I do?
Expert:  Jay replied 1 year ago.

Well if the fuse blows as soon as you turn the key on, I would disable circuits to see if I can isolate the issue to a particular circuit. I gave you the Ecm power supply, Intake valve timing and Cam sensor circuit and coil circuit. so you can go through each circuit to isolate the issue.

Expert:  Jay replied 1 year ago.

If you have any more questions on this, please feel free to ask.

If not, and you're satisfied with my help, please Rate me. That is how I get credit for my work.

I hope I have provided you with Excellent Service.

Thanks Jay!

Customer: replied 1 year ago.
I see when they redid the battery growing they just grounded it to the body 6" away. Shouldn't it be grounded to the frame?
Expert:  Jay replied 1 year ago.

The body is more or less the frame. They have a subframe they use to hold the engine assembly. But the frame is built into the body

Expert:  Jay replied 1 year ago.

I thought there was another cable they recommended to replace which was from the body somewhere by cylinder 1 to the engine block also.

Expert:  Jay replied 1 year ago.

Do you have anymore questions on this?

Expert:  Jay replied 1 year ago.

If you have any more questions on this, please feel free to ask.

If not, and you're satisfied with my help, please Rate me. That is how I get credit for my work. I hope I have provided you with Excellent Service.

Thanks Ja