Months in several dealerships still can't figure it out.
 

Hey guys I have a Texas 2007 G35 Coupe 5AT with 80,000. The only modifications I have is a Greddy exhaust and an AEM intake.

This car has cost me plenty of dollars and headaches. The first time the I noticed the issue I was driving at 65mph and went to pass a semi and as I accelerated the car responded just fine until about 80 something mph then I felt a hard jerk and the engine just shut off. All the electronics were still functional. The physical feeling of the jerk felt as the car had down shifted which I know it did not because the engine or transmission were unresponsive after the jerk.

I took the car to the nearest dealership which was Nissan. (Infiniti dealership is 160 miles away) The only problem they found was a blown IPDM 15amp ECM fuse. This was after they said they performed all tests and came back with no trouble codes or issues.

Once again on the highway on an extremely windy day the fuse blew again. I replaced it and car runs good as new. I then took the vehicle to Infiniti were they replaced spark plugs, coils, left and right side cam shaft sensors. They had the car for a month running test because I kept taking it back because the fuse keeps blowing.

At first I thought it was because I drove the car to hard but I had a 2003 and never had these problems and I beat that one a lot worse. The fuse continues to blow under normal driving conditions. I AM HOPING TO FIND A CURE! Please help. I always carry a box of fuses everywhere I go because I'll never know when she's gonna blow.

Sounds like something is going on with your wiring. Maybe exposed wiring, bad ground, etc...

A tech on another site said he sees ignition coils take out the ECM fuse, so check those for signs of wear.

Thanks for the response. I dont know exactly how they tested the wiring but supposedly they got the all clear in all the electrical system. It is terribly frustrating that this car is awesome, then out of the blue boom blown fuse. It really drives me nuts. The fastest way to blow the fuse is when I drive very aggressively using tiptronic. ie. down shifting often, holding gear, rapid acceleration. But when it originally happened under casual highway driving and it continues to randomly happen at highway driving near 70mph+.

So this only happens at high speeds? It's never happened at lower speeds under heavy acceleration?.... say under 40 MPH?

Does it do it while the car is downshifting, since you specifically mentioned that it happens while accelerating at high speeds? I remember reading something a few years ago about someone having this happen on a Nissan with an auto tranny and it ended up being his Auto Tranny Shift Lock switch that was causing the fuse to blow on downshifts.

So when you say the engine and tranny were unresponsive, do you mean that the car wouldn't even start?

Thanks for responding. That shift lock switch sounds like a very interesting theory. Like so crazy it may work. This is my first time hearing about such a thing. It has yet to blow a fuse under 40mph unmolested.

The car won't start unless I replace the fuse. I have done so about 20 times. The power stays on for ac,windowns,radio, lights but the engine powers off and there is no throttle response. It is a scary thing everytime wondering if it will leave me stranded somewhere but I just replace that fuse and back to normal.

If it was exposed wires/grounded out wires it'd happen at 40 mph or any other speed for that matter. The fact that it does it when you drive aggressively sounds to me like it's directly related to a change in voltage. I'd look at data logs while driving. In theory you could identify where the voltage is spiking. A switch could be a culprit for sure, and anything solenoid related will throw normally a code. I'd go with partyman on this one. I can't really find anything outside of that besides having a good look at the fuse and tracing back the wires individually. Sorry to say.

I have that premium Nissan warranty I'm wondering if I put a high rated fuse the results would be??? hopefully something breaks the replace it? I am getting desperate.

I wouldn't replace any fuses other then what is there already ESPECIALLY if you still have a warranty. That would make it so easy for them to deny you coverage if a voltage spike fries something else and the fuse doesn't stop that from happening. I'd leave it with the dealership for as long as it takes to repair and have them give you a loaner.

^agreed. Fuses are there for a reason. Voltage in excess if the fuse is dangerous to the part its protecting.

Hey nightwolf,

This sounds like a one of those real headache problems because it happens intermittently, hard faults are always easier to troubleshoot. You mentioned that the fuse blowing was the IPDM 15A ECM fuse. Can you provide the specific fuse identification number? This will ensure that anyone trying to help you isolate the problem can narrow the troubleshooting down to the specific circuit. By knowing the specific circuit, it will help identify potential circuit components culprits, as well as identifying the potential suspected wiring and connectors. I only have my 2003 wiring diagrams available to me so that is all I can work with. I will try to help with what I have.

Throwing parts at it based on what others have experienced can become very expensive, so unless you have a connection that can provide parts, try to resist the urge to buy a part without at least making an educated guess.

Do you have a Service Manual? Do you know how to read a wiring diagram and use a Volt/OHM meter?

Oh Yeah! I agree with what the other guys said. Under no circumstance replace the fuse with a higher Amp rated fuse, doing this can cause more serious/costly problems to include potential fires. The correct OEM size fuse is what protects the circuit and components.

Thanks for the responses. I didn't check in and had been experimenting with a 30a instead of the 15a fuse. I didn't think I would get this kind of help and responses. I have already changed it back to the original 15a. Unfortunately I don't have the knowledge on wiring or volt meters.

At first I thought the problem was with something in the air/fuel system. Intake,throttle body, coils, sparkplugs, crank/cam sensors, 02 sensors, evap, etc. All check out positive in working condition. I feel perhaps it could be transmission related. Because the fuse blows faster and guaranteed when I have it in that mode. When I leave it in drive and go over 80mph it is a dice through sometimes the fuse will blow at 80,85,120. (Reminder: I live on the border long, straight, lonely highways 75mph speed limits)

I can't find the paper work from the dealership is there an easy way to get those fuse identification number? I believe its #77 if that is what you are referring to. And does anything with the transmission have to do with that fuse? thanks again.

They don't teach "Logic" in schools.
 

Funny :icon18: Reminds me of the doctors patient that says, "My elbow hurts when I bend it this way." Doctor tells him, "Don't bend it that way!" If the fuse blows at 80 mph leave your cruise on at 79 mph until you find the culprit...Gary