Cam Advance Leading to Cam Signal Errors

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shalco
Posts: 11
Joined: Mon Sep 05, 2011 2:52 am

Cam Advance Leading to Cam Signal Errors

Post by shalco »

Hi

I wonder if anyone can point me in the direction of where I can look for a problem i have with an S80 unit.

I have One coil per plug and Sequential running ok. Engine runs fine. However, once i activate cam control and the cam shaft begins to advance the engine cuts out as I get instantly get cam signal errors coming through.

Any advice would be greatly appreciated.

Thanks
Marcus

I've attached a datalog file in Csv format if that's of help to anyone.
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: Cam Advance Leading to Cam Signal Errors

Post by stevieturbo »

No datalog file there ?

And what engine is it ? what trigger setup ? Type of sensor used ?

You have a pretty wide window in most cases for a cam trigger, although perhaps if you were at the edge of the window the advance may push it too far.
You could try using the other edge of the tooth instead.

But would need more detail
shalco
Posts: 11
Joined: Mon Sep 05, 2011 2:52 am

Re: Cam Advance Leading to Cam Signal Errors

Post by shalco »

Sorry the file didnt upload I've attached a picture of the data log with the cam error column in orange, and cam advance figures in red.

No cam advance is around 127/128. As soon as it advances towards 136 degrees cam errors start.

I've got cam noise masking set in sequential settings, not sure if this would impact it at all.

The engines a pretty unusual one, Porsche 996, Hall effect trigger.

Thanks.
M
Attachments
Cam Data Log
Cam Data Log
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Cam Advance Leading to Cam Signal Errors

Post by Alex DTA »

Cam noise masking will give these symptoms, as the position of the cam pulse will move as the cams do.

Why have turned that on?

If you're not using mode 16 specifically for this engine, you should be using mode 26 with Upper and Lower Crank Pulse limits in Coil Per Plug settings.
shalco
Posts: 11
Joined: Mon Sep 05, 2011 2:52 am

Re: Cam Advance Leading to Cam Signal Errors

Post by shalco »

Ok, thanks that's a starter for me to look at.

I had cam masking turned on as I originally had cam errors...this was years ago mind, and also Flywheel Mode 26 didn't exist when I originally set up the engine. DTA created mode 16 for me...which may not be the best to use now as cam advance has never worked.

I've attached a cranking oscilloscope.

As a sanity check the flywheel is 60-2. TDC no cylinder on the scope is when tooth cam tooth 14 shows.

I run off the cam tooth signal 27 on the attached Oscilloscope. Lower masking is set from 24, Upper from 30. (Which on your recommendation i'll remove and re test).

So crank sensor position is set at 84 btdc (14 teeth x 6 degrees per tooth)

Cam position is set at: +78 degrees ( 27 teeth -14 teeth = 13, x6 degrees = +78 degrees

If I try mode 26 what values would go into the Upper and Lower Crank Pulse limits in Coil Per Plug settings?
Attachments
CrankOscillo.png
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Cam Advance Leading to Cam Signal Errors

Post by Alex DTA »

We have a number of these engines running on mode 16 with cams working fine. Attached is a map from one of them.
The values in this map are quite different to yours though. What firmware version is your ECU?

Back to your problem. Your cam pulse is on tooth 27, and you have cam masking from tooth 24, meaning the cam can only move 3 teeth, or about 18 degrees before the cam pulse moves out of your window. From your log above, you're getting cam errors from about 136 degrees, which is 18 degrees more than the static value of 128 degrees.
Turn off cam masking, and check you're not getting any cam errors. If not, you should be fine.

If you are, you'll need to investigate that first.
Attachments
Porsche 996.map
(45.56 KiB) Downloaded 241 times
shalco
Posts: 11
Joined: Mon Sep 05, 2011 2:52 am

Re: Cam Advance Leading to Cam Signal Errors

Post by shalco »

Wow, thank you.

I think i wrongly assumed that the cam mask would track as the cam advanced round.

I've flashed the S80 to the latest firmware in the last month.

I'll try removing the mask if its not going to play ball I'm then going to try your map, if it starts and runs the cams ok, I'll migrate my settings over to it.

I'll let you know how I got on.

Thank you again so much!
shalco
Posts: 11
Joined: Mon Sep 05, 2011 2:52 am

Re: Cam Advance Leading to Cam Signal Errors

Post by shalco »

Thanks for your advice, I removed the cam mask but had errors, put the cam mask back on but with a much wider range and it advanced without errors. :) :)

Unfortunately I couldn't get your supplied map to fire up the engine. I wonder if it was for a 993 as it had twin spark selected, which isnt available on 996 models.

I did notice the response from the cam advance mechanism is 0 below a duty cycle of 89% and 50 degrees when it hits 93%. Is this typical behavior?

Without having a chance to fine tune the intermediate values from 89-93, at first glance it almost appears as if its all or nothing on the advance??
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: Cam Advance Leading to Cam Signal Errors

Post by Alex DTA »

Great stuff.

The supplied map is for a 996, specifically this one:
Image

Twin spark can be used with coil on plug to operate them in wasted spark mode.

Interesting that yours wouldn't start. Did it synchronise?
One thing I didn't ask is if yours is a GT3, which is what the map is for. I don't think there's any difference in the cam patterns, but I could be wrong.

The cam advance should be controllable throughout the range. If it's jumping around, somethings not set correctly. Upload a copy of your map so we can see how it's been set.
shalco
Posts: 11
Joined: Mon Sep 05, 2011 2:52 am

Re: Cam Advance Leading to Cam Signal Errors

Post by shalco »

I wish it was a GT3! Sadly not, its a 2005 3.6 996 engine, these engines are fairly different and based on different blocks

it was put in a '98 Boxster by me 10 yrs ago, but has been sat idle for last 6 years. Ran ok, but always without cam advance, but does have Vtec running fine. Was a fine long distance cruiser, drove it down to Sicily just after the conversion.

Image

Is there an advantage to running coil on plug as wasted spark mode?

I'll attach the map I was trying to run the cam advance from.
Attachments
_EEC - Dev.map
(43.43 KiB) Downloaded 244 times
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