Cam Fault but engine running ok

[Nitroking]

Hello,

I have a Ford Fiesta 1.25L (EU) running on MS3 and the story starts from my old topic here:

http://www.msextra.com/forums/viewtopic ... ta#p410317

Car has OEM 36-1 crank trigger and one tooth on the cam to sync (OEM again). Was running ok with wasted spark and semi sequential but I would like to go sequential. Initially the CAM was reading one per revolution and not always at the same spot so I thought it was noise I had to deal with. Engine was misfiring and wouldn't idle at all with loud pops off the exhaust. BTW I am running Toyota (Denso) COPs.

So I enabled Noise filtering for the CAM signal, Tach Interrupt Masking using 20ms and 30%. Engine starts fine and is working great with no lost syncs at all. But I get the CAM FAULT and CHECK ENGINE indicators. I then tried Tach Period Rejection using 20ms and 30%. No luck. Then 4ms and 30% and sometimes the car is idling ok but would not always start. I finally left it with Tach Interrupt Masking 20ms and 30% where it is working like a charm but I get the indicators on.

I attach Composite logger logs and the msq. Strange thing is that With Tach Interrupt Masking it only reads the CAM tooth ONCE and then it totally rejects it (green line for a while, then no green line at all) but the engine is working great. My guess is that MS3 is rejecting the CAM signal and is only using the CRANK missing tooth to do the rest. But with Tach Period Rejection it reads the CAM signal correctly but I still get the CAM fault..

Please whoever can help me.

Thank you

[Nitroking]

MSQ and photo of the cam tooth attached.

Thank you

[billr]

I would try a Hall sensor for the cam; I have found that VR are happier with symmetric tooth-gap spacing, which that cam tooth is not.

[Nitroking]

Yes, that tooth cam is definately not! I attached another closer pic.

However this is the OEM setup of the engine and I would like to keep it like that. Do you think it is impossible to make it work? How was the stock ECU handling it?

[Nitroking]

Any other ideas fellow ms3ers?

[Coutsi]

I had similar problem, you need to run your "Ignition option / Wheel Decoder" settings for CAM sensor in "Poll Level" mode and using composite logger give figure out where your CAM signal should appear and put that into "Check At Tooth#" then you get Full Sync, at least that solved my problem.

Remember to clear/tune your Tach Interrupt Masking settings.

[grom_e30]

what are you using to condition the signal? you appear to have a ms3x card but are sending the cam signal in on the js10 on the main board.

[Nitroking]

Thank you for your answers!

@Coutsi I thought of that too but I have read that Poll level is if your cam has a number of teeth.. If it is not causing any problems to use Poll level having one tooth then I will use it. What do you think?? My cam tooth is syncing on #14 of crank according to some clear datalogs of composite loggers I have logged (I think one of them is in the first post).

@grom_e30 I can't tell exactly, Reverant has made an expansion board for my ECU. I'll have to ask him.. It think it is a MAX9926 though..

Edit: I just tried poll level with the noise filtering I was using (Interrupt Masking) 20ms and 30%, set tooth 14, then 13 and then 15 but no luck. It gives Full-rpm Sync for a second when it starts running but then dies with pops and misfires. It does the same with and without noise filtering..

[grom_e30]

how does it look with no filtering the all of the logs show that the signal is missing?

[Nitroking]

Without filtering it pops and won't run.

But your all answers guided me to the correct (I think) procedure and now I have cleared the cam fault and get Green Full rpm sync indicator. All these with no noise filtering at all for CAS. However there is a strange thing happening:

First of all, probably the polarity was wrong. I now set "Level for phase 1" to High instead of Low. When I had it to Low and had the wrong "Check at tooth#" the cam sync signal was showing on tooth 15. So I tried Poll level with tooth 15, no luck.. Engine runs but I get cam fault. Then I changed the Level to high, tooth#15 and voila! Full rpm sync! So I checked the composite logger again and what I see is that now, with the above settings, the cam signal is showing on tooth 26!! wtf? Which is the correct one if I can understand correctly by this Ford guy with his S80 datalog (site http://www.zetecinside.com):


If you see the cam signal is showing around and on tooth 26, like mine does know.. So I then set tooth# 26 and the car runs but half-rpm synced.. If I turn it back to tooth#15 it I get full rpm sync and no check engine or cam fault! Can anyone explain how is it possible? For sure I haven't understood something correctly but what is that? Why the cam signal is showing at tooth 26 but I have to enter 15 to remove the cam fault?

Thank you again! Composite log attached (tooth#15, no noise filtering, Level for phase 1 High".

[Nitroking]

OK, so I think I figured this all out..

As I mentioned above, the correct tooth when the cam signal occurs is tooth 26. I read at the manual that you have to let the MS know at least 20 degrees before the right tooth when to expect the cam signal. That's why it didn't work when I entered 26. I entered 23, then 24 and in both cases it is working giving me a clean CAS signal and Full-rpm sync!

I believe that the noise my car has is before tooth 15 and that's why it was working when I entered 15.. So I believe that everything between 15 and 24 should work but the correct one is 24! When I entered 27 for a test it wasn't syncing fully.

So to sum up for Zetecs (Should work on any 1.25-1.4-1.6 and maybe the 1.8 and 2.0 but not the VCT ones) the following works:

Spark mode: Toothed Wheel
Falling edge
Going Low

Trigger Wheel Arrangement: Dual wheel with missing tooth
Teeth:36
Missing teeth:1
Tooth #1 Angle:80
Main wheel speed: Crank
Second trigger active on: Poll level
Level for phase 1:High
Check at Tooth#:24

Noise filtering:
Crank:On
Noise filter period:4

Cas: No filtering at all

Thank you all
Nick

[Nitroking]

Ok so as I said I have full RPM sync but now another strange thing is happening:

At idle I see the cam signal at 26th tooth. Once I rev the car at say 3000rpm I see it at the 4th at composite logger! And if you see the transition phase (10/61 at the composite log) it sits at the first tooth, then at the second and then steady at 4th every second revlution...

I drove 7miles, not even one lost sync occured!

Please help me, what is happening there?

[Nitroking]

If any of the developers can help, please advise..

Thank you

[Nitroking]

Nobody?

[grom_e30]

have you tried edge triggering on both rising and falling on the second trigger.

[Nitroking]

Yes I did.. Rising will cause it to not run. Falling does all the strange things we said and only poll mode makes the car to fully rpm sync using the "High" setting. So the correct is falling because in Poll mode the polarity is reversed..

[jsmcortina]

If any of the developers can help, please advise..

Thank you

Advise on what?

James

[Nitroking]

Ok so as I said I have full RPM sync but now another strange thing is happening:

At idle I see the cam signal at 26th tooth. Once I rev the car at say 3000rpm I see it at the 4th at composite logger! And if you see the transition phase (10/61 at the composite log) it sits at the first tooth, then at the second and then steady at 4th every second revlution...

I drove 7miles, not even one lost sync occured!

Please help me, what is happening there?

Is this normal? How can I make it read the 26th tooth all the time as this teeth seems to be the right one? And how is it possible to start reading a different tooth after slightly reving it but still syncing?

Thank you!

[jsmcortina]

how is it possible to start reading a different tooth after slightly reving it but still syncing?

With a missing-tooth crank wheel and no VVT, the cam signal is only used during starting to determine phase. Once phase has been determined, the cam signal is ignored.

James

[Nitroking]

Plus if it loses sync?

So if the engine loses sync and rpm is when it reads on tooth 14 it will misfire and go crazy right?

Can you please guide me to find the root of the problem? Why would it read tooth 14 after a while and why is it fully syncing only on poll mode? The cam just has one tooth with falling edge but on falling edge mode it won't run..