Subaru 36-2-2-2 VVT No Cam Signal

[jsiedlicki]

MS3-Pro; 1.5.1 beta 6

I am going through the recommended pre-start checks and I can not get a cam signal. It appears that MS3 is cycling the fuel pump relay on and off during cranking. Since my engine sensors are powered by a relay that is triggered by the fuel pump relay, I think may be my issue (I can hear them clicking on and off during cranking).

Why does MS3 cycle the fuel pump relay during cranking? Do I have something configured wrong?

MSQ, MSL, and Composite logs attached.

[billr]

Power/control the "sensors relay" from a source that is on whenever the MS3 is powered. The FP relay won't turn on until cranking (sync) is detected, and that requires having the CKP/CMP sensors already powered. I'm kind of surprised you are getting any FP action at all.

[jsiedlicki]

I removed the sensor relay all together by jumping pin 30 to pin 87 with no luck, same effect, FP cycles on and off, still no cam sync.
In the logs you can see the RPM drop to zero when the FP shuts off even though in the composite log the crank signal does not miss a beat.

[billr]

"even though in the composite log the crank signal does not miss a beat"

What??? There is continuous sync-loss in both the run (MSL) and composite (CSV) log. It's no wonder the FP is clicking on/off like that.

[jsiedlicki]

The sync loss is due to a lack of cam signal I believe. I get "Half Synced" indicators while cranking. When I switch to semi-sequential and wasted COP I get full sync. If I was not getting a good crank signal it would not work in that mode either.

[billr]

Sync loss can't be ignored, regardless of what the cause. If it syncs and starts runs OK with wasted-COP, post that MSQ and MSL; let's work with it like that for a while. I suspect, though, that it doesn't start, even when you think you are seeing "sync" on the dash.

Alas, I probably can help much with that weird Subaru crank/cam pattern; I have never bothered to try to understand it.

[jsiedlicki]

Just the sake of completeness, here is the tune, log, and composite log when cranking with semi-sequential and wasted cop. Again the crank signal is great, same as under full sequential. Note the fuel pump does not cycle on and off under semi-sequential mode.

I do not know if the lack of cam signal is causing the fuel pump to cycle on and off or if the fuel pump cycling on and off is preventing a cam signal from being established. Chicken and the egg type thing.

[Matt Cramer]

Does the cam signal appear if you change spark mode to "log crank and cam"?

[billr]

It doesn't look like the MAF sensor is responding. I don't know how that fits into all this, but it can't help any. Will the engine start and run, in any mode?

[whittlebeast]

For people wondering, I did a video on trigger logging that has a section on Crank and Cam logging

https://youtu.be/0-8UEyuCZ2I?t=133

Hope this helps

Andy

[jsiedlicki]

Does the cam signal appear if you change spark mode to "log crank and cam"?

No it does not appear to. But the fuel pump was not on during Log Crank & Cam so neither was the cam sensor! I''ll try again with the cam sensor powered up off a different source.

[jsiedlicki]

It doesn't look like the MAF sensor is responding. I don't know how that fits into all this, but it can't help any. Will the engine start and run, in any mode?

The MAF is unplugged. I am just trying to get a solid sync before trying to start the engine.

[jsiedlicki]

@Matt

Ok retried with the sensors powered up independently of the fuel pump, still no cam signal?

[jsiedlicki]

Ok, went back to basics. I pulled out the hall effect cam sensor and tested it. It needs a pull-up. I'll report back when I get some 1k resisters fitted into the harness for the 4 cams.

[Matt Cramer]

Great, please keep us posted on what you find.

[jsiedlicki]

That was the issue. I now have a cam signal.

[jasaircraft]

That was the issue. I now have a cam signal.

How did you do the pull up circuit?
Which of the cam sensors are you using the one on the battery side or the one on the turbo side?(turbo side in ej engines)

[jsiedlicki]

This is not an EJ engine. Its a Subaru EZ36R flat 6. I am using all 4 cam sensors (2 intake and 2 exhaust) but the primary cam signal is on bank one intake. I simply put the 1K pullup resistor into the harness close to the sensor, joining the 12V power to the sensor line.

[jasaircraft]

Thanks i will give that a try