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2006 QX56 ECU issue?

5K views 5 replies 2 participants last post by  gariac 
#1 · (Edited)
Pour a cup of coffee. This is a long one.

I was driving in Great Basin park heading up to the peak and my car stuttered. I had a loss of power though it kept going. It started to buck a bit. Fortunately I reached a turn off and pulled over. The idle was going up and down. No heat issues. No warning lights on the dash.

My first guess was a sensor or computer issue. I had run Torque prior to the trip and everything was fine except for the "rich to lean" issue I have always had. [More on this later.]

This being Nevada, I decided to gamble and turn off the car then restart it figuring that might clear the issue, i.e. give it a boot. I started the engine and all the problems went away. Not being totally crazy, I gave up on the hike and drove back to the hotel (about 66 miles). No problem.

I figured my best plan was to make my way to Vegas and visit the Infiniti dealer. On the way to Vegas, it started to buck. I pulled off I-15, stopped the car, started it, and all was fine.

The Vegas dealer did the full diagnostics ($145 I think). They found a couple of codes for the transmission, but they were probably old,. The ECU had a fault. They cleared it, and the fault didn't return. The ECU is about $1k to replace and about a week to get there. Given that the car was running fine, they suggested just drive home to Ca.

I had one more bucking session in the Mojave. Stop and start cleared it.

Now all the problems were in high heat, but it isn't like a never drove in the desert before.

I'm thinking of checking the ground connection to the ECU. Perhaps pull it and spray the contacts.

Any other suggestions?

Edit:

The dealer has no idea about the Rich to Lean error message. It doesn't show up in their diagnostics
 
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#3 ·
Well the Vegas dealer didn't check it. I'm not sure it would test bad since most of the time the vehicle was working fine. However I did a search on fuel pumps and some posts did indicate a temperature associated problem. I'm not opposed to replacing the pump. It looks like I could do it myself since you don't have to drop the tank. Fuel pump replacement can be tricky due to unexpected backflow. ;-)

I also noted a recall regarding the ECU in the 2006 model year. I never got a notice, but will bug Nisan Monday. But I think I will replace the fuel pump anyway. I go off-road a lot and getting stuck ruins my day! Not to mention I had to bail on a hike that burnt about 300 miles and one night in a hotel..basically wasted money due to the hickup.
 
#5 · (Edited by Moderator)
Looks like this fuel pump has had a few revisions. The current part number is 17040ZQ60C. This makes the 4th model they have used. Now I know often the new model numbers might mean just a different supplier for the same part, but 3 revs is a lot.

Most of the time I drive around with the back folded down, that is I don't need to carry more than one passenger most of the time. So as a confidence builder I think I will haul out the seat and try to get to the panel.

My model year had the sender "upgraded" as part of a recalll. They replaced a near perfect fuel gauge with one that makes me fill up with about 4 gallons to spare. It will be interesting to see if the dealer pulled the carpet or just cut it like the photo on the forum.

As a follow up, I had the ECU replaced. That plus a new switch for the cruise control got everything running again.

The odd bucking is probably due to cracked exhaust manifolds, which I will start a new thread.
 
#6 · (Edited by Moderator)
Engine stuttering problem solved

I used to have an issue with the engine stuttering on long drives. The weird thing was I could pull off the road, stop the engine, then start it again and the problem would go away. It was suggested that the fuel pump was the issue. Sounded crazy to me, but I did finally replace the fuel pump and the problem went away. I wanted to do at least two long trips to make sure it was really solved. So far, so good. The solution still doesn't make any sense to me. ;-)

This is on a 2006 QX56. I probably replaced it around 130k. I'm at 144k now.
 
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