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Thread: Update on my red car (still need a little advice)

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Posts: 21-30 of 49
2009-06-17 13:15:14
#21
Originally Posted by Ninety-9
When I first installed the ECU, I was required, by the guy who programmed it, to modify the 2-4-6 exhaust cam where the sensor picks up the cam position. I was to leave a single notch in the cam at a specific angle (very high tolerances). It is my guess that the 1-3-5 cam (rear of engine bay) sends cam angle data back the ECU, and the 2-4-6 cam sends RPM data back to the ECU (acting like a crank position sensor).
Both cam angle sensors should have cam position and crank position built into the discs. The ECU should be able to get crank position from either, but because you have variable valve timing on both intake and exhaust cams (you do, right?) the ECU needs to know the position of both cams which it should have by using both cam angle sensors. That's my thinking anyway. Then you modified the 2-4-6 CAS? Probably because that's the one that gives crank position. How did you modify it? Did you cover up some of the other slits in the CAS disc with something?
2009-06-17 13:47:05
#22
Originally Posted by Ninety-9
NSMO240: There was a recall on the sensors? Hmmm, I may give them a call. It was an early VQ35 (2002) Maxima.


yessir i have a 02 max, and it has had the recall already performed, if you would like i can check nissans assist and tell you exactly what it says, or you can even get me the vin from the engine and i can have one of my service writers to pull it up and let you know if there are any existing.

so i went ahead and looked up the recall anyways and it says that nissan has determined that on some 02 maxima's the crank and/or cam position sensor was not manufactured properly and may result in the engine to stall while driving, which may result in a crash, so, i would definately get that checked out for sure.
2009-06-17 14:53:36
#23
Originally Posted by BenFenner
Both cam angle sensors should have cam position and crank position built into the discs. The ECU should be able to get crank position from either, but because you have variable valve timing on both intake and exhaust cams (you do, right?) the ECU needs to know the position of both cams which it should have by using both cam angle sensors. That's my thinking anyway. Then you modified the 2-4-6 CAS? Probably because that's the one that gives crank position. How did you modify it? Did you cover up some of the other slits in the CAS disc with something?


But this is standalone, so most likely, the AEM didn't have the capability of using 2 cam sensors unmodified. Using the stock cam, the 1-3-5 cam is able to determine cam angle. Using a modified cam, the 2-4-6 cam is able to send RPM data.

The mod required a dremel and plastic covering to protect the engine from the metal shards. The stock cam has a round disc at the end, the disc has various shaped notches in it, telling the pickup the cam's angle. It was modified to have only a single part of the disc left at TDC. That way, the pickup only gets one blip at TDC signaling 1 rotation. The specs weren't too strict, I was given very high tolerances on how wide and how off I could be. Either way, the mod worked fine for the last 2 years.

Something like this:
2009-06-17 15:02:08
#24
Update, I went through some pictures, Here's a picture before I started the cut.



I have a correction to make. The cam you're looking at is the 2-4-6 cam INTAKE side. So it's the intake cam that's monitored. I also looked at some more pictures to see that the 1-3-5 monitor is also on the Intake cam as well. So scratch anything about the exhaust cam.

You can see both sensors clearly in this pic (2-4-6) in bottom left corner, (1-3-5) just under the Fuel pressure reg.


I'm almost positive the VTC is on the intake cams only and I'm tempted to recall that the cams can be advanced ranging from 0-42deg from TDC, varying by RPM. Idle should be at full advance, redline should be at full retard.
2009-06-17 18:39:42
#25
Maybe the modified part on the cam broke, and isn't sending signal. One way or the other, it is your cps (more than likely only one). Hope you get it figured out.
2009-06-17 19:08:54
#26
If there were trouble with the crank angle sensor he wouldn't get an RPM reading. Without an RPM reading he wouldn't get fuel or spark... He's getting all three I think.

Have you confirmed the injectors are firing? Maybe take the fuel rails out leaving the injectors in and crank the engine while watching the order and intensity of the fuel injection?

I mean, it's got to be fuel or spark (or compression).
2009-06-17 19:49:34
#27
He already siad that he has compression, he has spark irradically. Fuel is unknown (to me at least) so make sue you have proper fuel pressure AND volume. The crankshaft position sensor looks like its in close to the same positioning as the SR engine
2009-06-17 20:15:49
#28
Well, I am getting some fuel, I would imagine fuel would be as erratic as the spark. I can smell fuel in the combustion chamber, I'm getting backfires, and the engine (every so often) is firing off 1 or 2.

Throughout the thread, I've been realizing something. I'm almost positive, now, the intake cam sensor on the front bank is reading RPM, while the intake cam sensor on the rear bank is reading angle and timing.

My guess is that the rear pickup is malfunctioning or I have a bad wire.
2009-06-18 19:46:02
#29
There is a Crank position sensor located on all VQ's. Its located at the bottom/side of the tranny. It reads off of the flywheel. I have the complete FSM for an 04' VQ35... which is the same as an 02-03, with the exception of the external EGR.
Would you like it?
2009-06-18 20:46:22
#30
Angel, Justin,

Is it possible that disconnecting the CPS would yield the same results if it were disconnected? What I'm trying to get at is if the CPS were bad, the car would react the same way as if you were to just disconnect it?
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