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Jay, ASE Certified Technician
Category: Car
Satisfied Customers: 20398
Experience:  Nissan Certified, ASE Certified, 20+ years automotive experience
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I have an Infiniti I30. It has had a little problem starting

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I have an Infiniti I30. It has had a little problem starting but that was before I replaced my battery. This past Friday it had a little trouble turning over, but it sometimes does in the cold. Later, I tried to start it but it wouldn't fire up. It made the noise like it wanted to and it had enough crank, but no start. I had been on empty for a very short period of time driving in; we put 6 gal of gas into the car. Tried again; still no engine firing up. My friend pulled the hose off of the engine when the gas flows into it, and nothing came out when we tried to start it; so they thought it was the fuel pump. We took it to the mechanic shop where they ruled out the fuel pump and filter. Diagnostic tool indicated that it was the Idle Control Valve. Cleaned the valve and ruled that out. it starts when its hooked up to their computer, and runs. As soon as it disconnects it stops. Any ideas?
Hello and thank you for using

There was a service bulletin about the IACV. There was a issue that the valve fails and can damage the Ecm. To replace the IAC Valve and Ecm to repair. The scan tool being plugged in to keep the car running is a sign of Ecm failure, since the scan tool is applying the power to the ecm. There is power wires at the OBD2 connector. These power wires help power up the scan tool, and once powered communicates to the Ecm. That communication is giving the Ecm power. I would recommend having it looked at a Verified by a professional.

Thanks Jay!
Customer: replied 8 years ago.
You might have to break that down a little more into dummy terms. I don't know what the ECM is. The car is sitting at a shop full of mechanics.

So, from your post this is what I am gathering: The Idle Air Control Valve (is this the same as the Idle Control Valve) because if it is; they "ruled that out" already. What is an ECM? You're saying to replace the IACV and the ECM too?? The ecm is failing...because? And what is an OBD2 connecter? Does that need to be replaced as well?

I need to know why my car starts up when the computer is plugged in; but when it's pulled out, why it won't. And exactly what parts am I looking into.

My particular car had recalls on the Mass Air Flow Sensor and the O2 sensor. All of these things work in conjunction with the ignition system, I am assuming. I just don't know why the diagnostic tool is saying it's nothing once they plug it in. Obviously something is still wrong.

Please break it down to dummy terms for me. I am only slightly mechanically savy. SLIGHTLY. Thank you.
Sorry, I will give you the not so technical term. The IACV ( idle air control valve ) has been known to burn out the ECM ( engine control module / the computer ). Nissan had release a bulletin outlining if you have a IACV code stored or problem. Replacing the IACV with a updated part and replacing the ECM and then performing a idle relearn will correct the problem. So since your mechanic has been able to rule out the IACV by cleaning it, it may have already caused the computer to fail. That is why you are having so many problems. I would replace the IACV with the updated one ( that will not burn out the computer ) and replace the computer. I would mention this to your mechanic so they can verify the conditions I am describing and diagnose the car accordingly.

Thanks Jay!
Customer: replied 8 years ago.
Obivously I am freaking out now, the ECM is about 700 bucks. Any recommendations on a part place that will have a discounted part? Also, if I replace the IACV, is it completely necessary that the computer be replaced??
Customer: replied 8 years ago.
It doesn't have anything to do with the ignition relay does it?
Customer: replied 8 years ago.
One more to add: Can the computer be from a Nissan since the Infiniti and the Nissan are essentially the same thing; or does the computer have to be exactly from the same car.
I am sorry to tell you, I am simply trying to help.

The I30 and the Nissan Maxima have the same bulletin outline for the condition I described. If you replace the IACV, you still run a risk of having to replace the Ecm. I work on Nissan's and infiniti's.

One of our Parts employees has a I30 and it was found to have a IACV problem. So they replaces the IACV, then the idle went nuts. Surging from 1700 rpms to 2100 rpms. The tech was stuck and didn't want to have to put a Ecm in the car ( just like you). So I came over and looked at it and using the directions to perform a manual idle relearn, I was able to stabilize the idle at 1600 rpms, and then bring it down to spec. It is something you must be very experienced in. Some of the younger techs who may not have been around through these conditions. May not try as I have and succeeded. They would have just thrown the parts in and let it go. So I would just let your mechanic know about this condition, if he doesn't already know. So he can check the system out and use what ever resources he can to get it fixed with the least amount of cost to you.

Thanks Jay!

The Ecm relay ( EGI relay ) the ecm controls, so if there is problems with that relay then it may be possible that the ecm may be to far gone. As for the Nissan to infiniti. I would first see if you can get the part number to your Ecm, then call your local Nissan Dealer and give them the part number and see if it's available. Either way, the computer is not going to be cheap.

Thanks Jay!
Customer: replied 8 years ago.
You say the ECM was a vehicle recall; does this mean that this would be able to be replaced at a lower cost since it was a recall??
This was not a recall. It was a Service Bulletin. Big deference. A Service Bulletin just out lines a problem and it's Nissan's way of saying to fix the car this way. That is what the bulletin means.

Thanks Jay!
Customer: replied 8 years ago.
Also, if i got this straight: you said I could or could not use an Nissan computer on my Infiniti? Does it have to be an Infiniti 130 comp for 2001, or could it perhaps be one for a 2002?
2000 or 2001 computer. As I said, you would have to get the part number for your current computer and then call Nissan and give them the part number to see if they have a listing for it. If they do, then you could use a Nissan computer. If they do not have a listing for the part number, then you will have to use a Infiniti computer.

Thanks Jay!
Customer: replied 8 years ago.
Im sorry to keep this going, but since the car is not with me; how do i get the computer part number?
I know using the Infiniti scan tool or the Nissan scan tool, it can pull the Ecm part number. Or you can just call Infiniti with your Vin number and have them give you the part number to your Ecm, then turn around and call Nissan with the number and see if it is listed.

Thanks Jay!
Customer: replied 8 years ago.
Sorry about that - I have been at work. Also, they decided to try the crank shaft sensor. Before I accept the answer, what are your thoughts on this?
I have really never seen a crank sensors fail. I don't think it will change a thing.

Sorry, that is my thoughts on that. That is my honest option.

Thanks Jay!
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Customer: replied 8 years ago.
You know, they figured out it was some wires that had melted together on the crank shaft. When the mechanic went to pull them apart, the car started. Everybody was pretty much surprised. Thank you for your time