I just finished replacing both VTC, but now I am getting a knock at idle
that seems to get loader the longer I sit at a light. I can accelerate from the light and it will go away at about 2500 RPMs. I have tried adjusting the timing, and it gets worse. It seems to becoming from the back head closest to the fire wall. It is definitly at the top middle of the engine near the cam, but it doesn't seem to be at the VTC. It all most sounds like a deisel chattering
I also tried a new Toyota oil filter, but that didn't seem to help.
Could the Knock sensor cause low idle knock? It is frustrating after just spending the money on the VTC and getting a louder noise that before.

Any suggestions would be greatly appreciated.

Lance

 

Did you get NEW VTC's or did you rebuild the old ones. I ask that b/c it is critical that they are aligned properly when the VTC's sprokets are reassembled.

Your noise could also be a bad lifter. but the fact that your sound goes away at 2500 makes me think its the VTC, at around 2000 rpm is when they are turned on by the computer. The sound generally goes away when they are on.

 

Brand new from Courtsey Nissan on the back side were the noise is coming from. The front I rebuilt following the TSB to the letter. The front I rebuilt and installed last week and then drove it for the week and didn't have the noise, but when replace the back one with the new one is when the noise started. I sure hope that I didn't get a bad new VTC. I wonder if the timing could be that far out because of the new VTC?. I have tried adjusting timing, but no change. I had also change the oil, but did nothing different there either, same Toyota filter and oil. It seems to run fine at road speed with no noise that I can tell.

Lance

 

ground the vtcs. if the noise goes away, then it's the vtcs. vtcs don't go on at 2500. they are on/grounded under heavey load and above ~4500 rpm.

 

Well I am running 91 octane, and have all ways. I have grounded the VTC and tried adjusting the timing. I then disconnected the battery to reset the ECU. I drove it about ten miles and it sounds like the whole top end is dropping out. It was so bad it cutt out and wouldn't start. I let it cool for about an hour and then it started again, but it sounded like the timing chains were jumping the sprockets. I couldn't even make it up my drive way, I had to pull it to the top with my rover. So I pulled it all back down and check the chain tension on both front and back chains. I rotated the crank to make sure the timing was were it should be, and it was. The chain in the back seems to be real tight, the one in the front had a little slack in it, so I pulled the sprocket to try and take the tension up. It helped some. Any suggestions please help.

Lance

 

They are off above 4500 rpm, that when the engine gets its normal torque peak.

 

At this moment it has no torque, no power. I think I have serious problems. Chains and VTC all seem to be in good shape. I was going to change the knock sensor, but Im ready to shoot the car and take the lose.

 

my bad eric... i had it backwards...

the vtcs are grounded/on under load and are ungrounded after ~4500 rpm.

 

Check all the electrical connections again. Also the connectors on the VTC are known to corrode.

One of your tensioners could possibly be bad. Something could have gone wrong with your install, you just have to go through it all again.