As some of you know I'm planning on converting the 95 w/vq35 to run on a 300zx Z32 OBDI ecu. I remember some of you guys said we would probably have to divide the crank pos sensor signal to make it work. I have compared the two sensor types and they are definately different (VQ is a simple two wire magnet-type sensor that reads the teeth on the timing gear of the front intake cam, while the z32 has a completely different type).

That seems to be the only real problem with this. Figuring out the maf is trivial, at worse I use the 89-94 MAF (it is good for 340 hp just like the 95-99).

My question is how can the VQ possibly run with that simple two wire sensor? That can't be all that controls the timing.

 

The cam position sensor controls the timing as well.

 

Don't forget the crank pos sensor on the bellhousing, not sure what all it does exactly but I think the ECU uses both sensors somehow to determine timing.

allen

 

Oh ya, and the one on the front of the oil pan, that's the other crank pos. sensor.

allen

 

4th gen uses Crank REF and Cam POS to determine timing.

 

It actually uses the CPS (POS)...the one by the tranny bellhousing...

 

No it's not, ECU uses Crank REF to advance and retard timing. That is why when you get a 0407 it retards timing up to 2 degrees.
Also I have a SMT6 which uses the crank REF to advance/retard the timing.

 

The crank REF is the one that is between the transmission and the engine bellhousing and reads the teeth on the flywheel, correct?

Then what does the cam POS (on the timing chain cover) do?

 

Component Description
NFEC0762
The crankshaft position sensor (POS) is located on the oil pan
facing the gear teeth (cogs) of the signal plate (flywheel). It detects
the crankshaft position signal (1° signal).
The sensor consists of a permanent magnet, core and coil.
When engine is running, the gap between the sensor and the gear
teeth (cogs) will periodically change. Permeability near the sensor
also changes.
Due to the permeability change, the magnetic flux near the core is
changed. Therefore, the voltage signal generated in the coil is
changed.
The ECM receives the voltage signal and detects the crankshaft
position signal (1° signal)



Component Description
NFEC0197
The camshaft position sensor (PHASE) is located on the engine
front cover facing the camshaft sprocket. It detects the cylinder No.
signal.
The sensor consists of a permanent magnet, core and coil.
When engine is running, the gap between the sensor and the
camshaft sprocket will periodically change. Permeability near the
sensor also changes.
Due to the permeability change, the magnetic flux near the core is
changed. Therefore, the voltage signal generated in the coil is
changed.
The ECM receives the voltage signal and detects the cylinder No.
signal.


Component Description
NFEC0573
The crankshaft position sensor (REF) is located on the oil pan
(upper) facing the crankshaft pulley. It detects the TDC (Top Dead
Center) signal (120° signal).
The sensor consists of a permanent magnet, core and coil.
When engine is running, the gap between the sensor and the
crankshaft pulley will periodically change. Permeability near the
sensor also changes.
Due to the permeability change, the magnetic flux near the core is
changed. Therefore, the voltage signal generated in the coil is
changed.
The ECM receives the voltage signal and detects the TDC signal
(120° signal).

 

No. The CPS (POS) is the one that reads the timing ring on the flywheel/driveplate. The Cam Pos sensor (phase) reads the marks on the main intake cam sprocket. These two are used in conjunction for fuel and ignition timing.

 

I have the FSM and know what these sensors do. The two critical sensors are the CPS (POS) and Cam Pos sensor (Phase) as far as a/f and ignition maps are concerned.

 

Ive toyed with all three sensors and I will tell you that the cam and crank sensor by the pulley are def needed. Also if the 300zx ECU is anything like the 4th gen ECU the sensor signals have to be exact. With the SMT the slightest hiccup in its operation will throw a 0407 code. IMO your going to have to either retrofit the 300zx crank/cam sensors onto your engine or do something radical to get it all working.

 

I don't quite understand why you want to do this. Especially with all the add ons available for the stock 4-gen. SMT-6, Emanage etc.......

 

He says he's going that route because supposedly an OBDII ECU will begin to retard the timing if you add too much timing via a piggyback. So far this has only been proven to be true with the 00-up ECU's.

 

If someone has successfully run as much timing as modded 2k2s run, on 4th gens, show me.

 

4th gens with 3.0's haven't been able to run the same timing as 2k2's because of the inferior knock supression of the 3.0 heads. My point is it hasn't been proven that the 4th gen ECU will intervene with too much advance. Where'd you hear that from?

BTW I don't know of any 2k2's with advanced ignition timing, as i just learned today that the TS L-spec ECU for 2k2's leaves the a/f and ignition timing maps alone.

 

I can attest to this, my car was detonating with 13.5 A/F and +8 timing. We also tried my program on Kevlo's car and it detonated even worse, so even with the limited advance of the SMT-6 im able to detonate with pump 93. (In 90 degree weather)

With the SMT-7 I should be capable of even more advance, but this is with race gas only. Also im considering a VQ35 hybrid now as well seeing as my 96's motor is on its way out.

 

If you get the full TS ECU and not just the L-spec then it will mess with A/f and ignition timing maps.

I would really prefer something like this if we can figure out Nissans overly complex crank and cam sensors. It doesn't require the use of several piggybacks (emanage w/ all accesories or SMT-X, J&S, etc.), a JWT ecu which takes almost year to process and is still hesistant to actually listen to your tuning requests, and even with all of that you still can't do everything that a standalone or fully programmable ecu can do. Call me a dreamer but tuning shouldn't require the use of that many different components each using different programs, battling each other just to achieve the goal of controlling A/f and timing. The use of a single fully programmable system would be more reliable, simpler in the long run, and much more thorough in its tuning abilities.

Third gens have many more options since the Z32 ECU is so similar. Ask on the 300ZX forms which they would rather use, ZEMulator and that is it or JWT ECU with Emanage, with all of the harnesses, and J&S.