Cam sensor sync issues after 2.35 build

[Motoka]

Hi I am having some cam/crank sync issues after installing a 2.35 build into my V5 Sti Type R. I have fitted V8 AVCS heads and have moved to the G11 crank and cam trigger set up. I have not yet wired in AVCS. I am running s6 PnP.

The car runs but I have picked up a slight misfire between 2000-2500 rpm (not sure if this is sync related) and I get a sync error at higher RPM.

Current cam sensor settings as follows:

Input filter off
High trigger 4v
low trigger 0.44v

The problem persists if I turn the filter on.

I need some help with the defining the correct values based on the syncerror below as am struggling to interpret it. Cheers.

[stevieturbo]

Cant help with your problem...

But when linking to Photobucket accounts etc....people can see all public images in that account.

There are still some active that Photobucket havent removed lol

[pavlo]

With your current settings (which are reasonable I might add) it means that it needs to see over 4 volts before it will look for a low signal, and then it needs to see below 0.44v in order to recognise it's actually gone low. On that falling edge it will create a cam position event.

Your sync error shows what looks to be noise just going over 4v and then clearly under 0.44v, giving a false cam event.

You should look at a few things:

1. lower your low threshold to comfortably below the -ve level of the noise. In this case just setting the low threshold to -2 would have stopped the error from presenting as although the ECU would be looking for a low trigger (after seeing over 4 volts) it's not until it saw a proper tooth and the voltage dropped right down that it would actually create a cam event.

2. Raise the high threshold. If you were to have the high at 4.5 volts then it would not be looking for the subsequent low edge. The problem with such high trigger values is that the output from the sensor is speed dependant, and it may be that at low speed or dips in the idle down to maybe 600rpm, it would lose sync. Check your cranking/starting sync log to see what the voltage is reaching after cranking once it's fired.

3. Check your wiring. The cam sensor runs past two injectors and on some custom looms I've had problems with interference from the coils on the left hand side where the cam sensor is (right hand side if you're standing in front of the car).

4. Enable "ignore cam in 720 sync" which will ignore the cam once the engine is succesfully synced up, but in doing so you lose a layer of sync checking

3.

[Motoka]

With your current settings (which are reasonable I might add) it means that it needs to see over 4 volts before it will look for a low signal, and then it needs to see below 0.44v in order to recognise it's actually gone low. On that falling edge it will create a cam position event.

Your sync error shows what looks to be noise just going over 4v and then clearly under 0.44v, giving a false cam event.

You should look at a few things:

1. lower your low threshold to comfortably below the -ve level of the noise. In this case just setting the low threshold to -2 would have stopped the error from presenting as although the ECU would be looking for a low trigger (after seeing over 4 volts) it's not until it saw a proper tooth and the voltage dropped right down that it would actually create a cam event.

2. Raise the high threshold. If you were to have the high at 4.5 volts then it would not be looking for the subsequent low edge. The problem with such high trigger values is that the output from the sensor is speed dependant, and it may be that at low speed or dips in the idle down to maybe 600rpm, it would lose sync. Check your cranking/starting sync log to see what the voltage is reaching after cranking once it's fired.

3. Check your wiring. The cam sensor runs past two injectors and on some custom looms I've had problems with interference from the coils on the left hand side where the cam sensor is (right hand side if you're standing in front of the car).

4. Enable "ignore cam in 720 sync" which will ignore the cam once the engine is succesfully synced up, but in doing so you lose a layer of sync checking

3.

many thanks Paul that's really helpful I'll give this a go.

[Motoka]

Well that's the sync error issue resolved but I am still getting an slight mis between 2000-2500 rpm that was not there with the 2 litre block in. I have checked all the usual suspects such as airleaks, connections, plugs, coil packs etc (it has a COP conversation previously). Wiring is all good around the cam sensor.

Is is possible to get a sync related mis without the ECU actually throwing a sync error up?

[pavlo]

What's the lambda doing?

You mention in the PM that your getting a long tooth gap, but that is a crank sensor error state. Also the error will remain until cleared, so you maybe you picked up the error on cranking or initial startup. Check the logs and see when the error originated.

As for the misfire, you probably just need to map the car properly! If you're seeing your tooth gap error and feeling the misfire, are you sure you're nor just putting 2+2 together to get 9?

How is the wiring "good" around the crank sensor? I have found that VVT solenoid wiring can upset cam sensor signals on some occasions.

[Motoka]

What's the lambda doing?

You mention in the PM that your getting a long tooth gap, but that is a crank sensor error state. Also the error will remain until cleared, so you maybe you picked up the error on cranking or initial startup. Check the logs and see when the error originated.

As for the misfire, you probably just need to map the car properly! If you're seeing your tooth gap error and feeling the misfire, are you sure you're nor just putting 2+2 together to get 9?

How is the wiring "good" around the crank sensor? I have found that VVT solenoid wiring can upset cam sensor signals on some occasions.

Thanks again. Good point re the long tooth error it was cranking related before I changed the cam settings and it has not reappeared after I cleared it.

I'm am reasonably sure that it is not mapping related but am all ears She was running like a dream on the 2L with same injectors, turbo and all other ancilliaries etc. AFRs spike lean during the mis as expected (16:1 see around 23 second mark in log)). I have disabled CLL and added fuel but this has not improved matters. There is a reasonable amount of ignition advance and MAP reading looks ok. I have attached a log of when the mis appears (note long tooth gap was still present then before I cleared it)

Here is a photo of the wiring. I have not wired up AVCS yet as keen to get to the bottom of this first. The harness sits on top of the fuel rail so away from the injector and ignition coils. Perhaps the alternator harness is too close? -will try moving that.

[pavlo]

Having looked at the log, some suggestions.

Remove the AN01 and AN02 logging for normal tuning, and set it to 1000hz if you want to log it for meaningful diagnostic purposes.
Increase the logging speed of lambda to capture lambda properly (for diagnostic purpose). Your "lean spike" may not be down to a missfire, most of them are down to overrun, the only lean event looks like nothing more than genuinely not enough fuel somewhere.
Your Injection end angle is bad, this may go some way to sort your misfire
Transient fuel correction isn't doing it's job and needs tuning, but this may be sorted by a simple injection end angle change.
You're trying to inspect the fuelling but introducing lots of throttle and MAP changes, meaning your data is heavily poluted and not good for adjusting the main fuel table.
Where is your lambda sensor? Is at at the bottom of the downpipe? If so this needs moving to the top to better tune the transient aspects of the engine.

Really it looks like there is nothing wrong, other than the car needs too have some more time spent fine tuning the calibration.

I would start by doing the following:
Get the AVCS working sooner rather than later, there is NO point in mapping without AVCS and then mapping it again once it's working. Zero the cam angle measurements, put in a sensible AVCS map to begin with which you can fine tune later.
Set injection end angle to 360deg
Reduce max transient fuel correction, (it's currently going rich on snap opening of throttle).
Check your fuel table with longer pulls at a nice steady throttle in stages, just use a light fixed throttle, don't try and "hold" a MAP as your modulation of the throttle will give poor data. DO this for a few vacuum levels and light boost (1050mbar) and you will find your main map is a little ways off.

[Motoka]

Thanks Paul. I have set up the AVCS sensors and cams are now 0.5 -1 degrees at idle and 2-3 degrees at higher rpm with AVCS solenoids disconnected.

I am still running the V5/6 inlet manifold. Is it possible to drive the AVCS solenoids without using pinouts A5 and A15 which control the IACV motor on the V5/6 inlet manifold?

[pavlo]

Yes it is possible to drive the solenoids AND still have the idle motor working, done it a few times.