vvel issues

[Tedmeister]

So I replaced the engine wiring harness, due to continuing electrical issues.
The mistake I made was plugging the connector meant for the throttle body
into the VVEL and vice versa. Car ran rough and would not rev past 3500 rpm and then drop to 3000rpm. Got code 0011. Took it to Nissan and was told by one mechanic who just got back from Nissan tech school that something inside the VVEL was damaged and the only way to fix it is to purchase a new head from Nissan with the VVEL attached, because the torque specs are so precise that they will not allow mechanics to change them out. I would just put another used engine in the car, before I would do that. From anyones experience can I replace the VVEL? I cannot believe that Nissan would use all different connectors and then use the same ones that if reversed can do such damage.

[sirnixalot]

I can tell you for fact as I have gone through my fair share of VVEL issues, you must change the entire cylinder head and vvel assembly as a matched pair. Mixing and matching the cylinder head and VVEL assemblies will not work out

edit* if you have mechanical damage as stated below

[phunk]

The VVEL control shaft position sensor shares a connector with the throttles apparently. I never noticed in practice but just looked in the FSM and see they have the same connector part number. Those are several inches apart, how did you mix them up??

Anyway, the VVEL control shaft position sensor is integral to the VVEL Actuator assembly which is replaceable and not part of the VVEL mechanicals under the rocker covers. The service manual outlines procedure for replacing the actuator assembly and Nissan sells them in the parts department. They are around $600 from Nissan parts stores online. The sensor you would have toasted actually comes off the actuator assembly IIRC but Nissan doesn't want you to take it off so they don't sell it separately.

So, you do not have to replace the cylinder head to replace the VVEL actuator assembly with control shaft position sensor. Unless having this sensor damaged resulted in mechanical damage to the cylinder head, I dont think youd have to replace the head to solve your problems.

[SG4247]

I agree with Phunk.

There are mechanical stops on the VVEL actuator shaft, so even if the servo motor went crazy and adjusted the valve timing incorrectly due to sensor input being wrong, there would not be any mechanical damage to the VVEL valvetrain assy because the actuator shaft travel is limited.

[phunk]

Additional note: Under no circumstances would I want my VHR cylinder head replaced by the Nissan dealer. That is just begging to turn into a long term disaster. The only positive outcome I theorize from it, would be maybe after they screwed it up a few times and the car goes in and out of the dealer trying to get it right for 3-9 months, maybe you could get them to just replace the entire engine. But I have nearly zero confidence they can get the job done correctly the first time.

[Tedmeister]

I had the impression that each connector had a different shape so as I went along the harness and located a plug in the engine and the connector went in, I thought that was it.
I did look at the engine that I took out of the motor last year, and there is one
bolt right under the actuator that connects the head to the block. From what I can see, there is no way to remove the head without removing the actuator first. If that is the case, then the whole argument about never separating the unit from the head, goes out the window.
The mechanic at Nissan said he could take an actuator off an engine from a Pathfinder that is going back to Nissan. Hate to spend another 600 and not have it fixed. It has been a long haul on this car for me, some things screwed up by the previous owner, and a lot of misteps by me. I'm learning on the fly, since "performance" or "race" mechanics have made even bigger mistakes that have taken this project backwards. All the info on this forum has helped tremendously.

[Spooler]

The actuator does get removed from the head so the long block can be disassembled. The VVEL ladder is machine fit to the head. That is the part that can not be interchanged from the head to head. Getting the actuator installed properly is the problem.

[SonicVQ]

Originally Posted by Tedmeister

I cannot believe that Nissan would use all different connectors and then use the same ones that if reversed can do such damage.

I feel your pain... This is the downside of DIY, sometimes it does cost more.

To reduce the number of different connector that need to be purchased for manufacturing, where possible the connectors are reused.

The connector on the VVEL and throttle body (RH06FB) is also used on the MAF and accelerator pedal.

This isn't a problem for Nissan as the trained techs know this or mark/note where the connector came from.


To understand what could have happened, I dug up the wiring diagram and had a look. On the throttle body connector, pins 1+2 have 12v to drive the throttle body motor.
On the VVEL connector, pins 1+2 are the 5v position sensor (variable resistor)

In a nutshell, 12v has been fed to the 5 volt position sensor (VVEL pin 1) and 12 volts has been shorted to ground (VVEL pin2)

As I see it, the VVEL module might of got smoked and/or the VVEL position sensor. You might want to check the voltage at the VVEL position sensor to verify the sensor. (see FSM for values and pin outs)

I wish you the best of luck getting this sorted out