Mazda 3 LF-DE Triggering

[Adam Marone]

Hi,

 

I need some help with setting up the triggering on my Mazda 3 LF-DE (early, non-VCT) engine. Crank sensor is reluctor type 36-1 and 1 on the intake cam. I have managed to start and run the engine with the sync for trigger 2 set to none but when I set it to cam x1 it will not start. The missing tooth on the crank occurs approximately 160 degrees BTDC cylinder 1 and the home trigger on the cam occurs about 10 degrees ATDC. None of the preset Mazda 3 or Duratec trigger setups will work because these later engines have VCT and different cam trigger patterns.

I'm at a dead end on this one so some help would be appreciated.

Cheers

[Adamw]

The only difference between having cam sync on or off (assuming it really is only one tooth) will be that with no sync the phase could change by 360 deg.  So, that possibly means your offset is out by 360 deg so when you turn cam sync on your are firing on the exhaust stroke.  Try adding or subtracting 360 from your current trigger offset value.

[Adam Marone]

No luck yet. I have redone the initial trigger set up procedure, locked the timing to 0 degrees and found that I was in fact firing on the exhaust stroke which was at +280 degree trigger offset. Looking back in the manual it describes the relationship between the tooth after the trigger wheel gap and the trigger, stating if the gap occurs before cylinder 1 TDC then the trigger offset will be in the negative and vise versa. So I've punched in -80 in the offset field and hit enter confirming the timing marks on the crank case lined up at 0 degrees, I then enable the injectors but did not start after several tries. I have uploaded a quick start log, notice how the engine speed jumps up to over 2300rpm during cranking. This was not the engine running as you'll see the map remained unchanged, could this signify a problem with the crank trigger? I have checked the gap between the trigger and the wheel and it is around 1mm of clearance.

Oddly, If I try and start the car with the trigger offset at +280 degrees I can get it to start but runs extremely rough.

Thanks

-80 trigger x1 cam no start.llg

Btw, here is a PCL file if you need to take a look

no start.pcl

Again, Here is a another log file with a no start. Notice again how at a certain point the engine speed changes during cranking but without any tick over. Strangely, on both logged start attempts the engine offers a few kicks once the starter is disengaged.

-80 no start 2.llg

[Adam Marone]

Here is a semi successful start and run log file with the trigger offset set to +280 degrees, supposedly firing on the exhaust stroke. I could only keep the engine alive like this with a good amount of throttle.

+280 offset x1 cam.llg

[Adamw]

In your "semi successful start" log the trigger error counter is continuously counting up and it is bouncing off the rev limiter the whole time.  So I suspect something is not what you believe it is on the trigger.  Most likely either it is not 36-1 or there is more than 1 tooth on the cam.  Can you set trig 2 sync mode to none and do another log.  If we still get trigger errors that will confirm it is not happy about the crank - if we dont get errors and it doesnt bounce off the limiter at idle that will probably confirm it is an issue with the cam.  Note it may be hard to start with the cam sync off.  if it doesnt fire let it stop before trying again, it will only sync on the correct stroke approx 50% of start attempts with no cam sync.

[Adam Marone]

Adam,

When you say "it's not happy" do you mean the cam or crank trigger is not triggering when the ecu expects it to? There is no doubt about the trigger arrangement. I've attached a picture of the trigger wheel I am using on the crank and in the other picture you will see two cam trigger types, the one on the left is the non-vvt early type which is what I have and the right one is the later vvt type which I believe Link already supports in the default mazda/duratec trigger type.

 

You'll see in the log that it didn't fire on the first crank attempt as you described, This issue is what pushed me to get the cam sync working properly.

The strange part is that with the cam sync turned on to x1 cam and timing is checked with the timing light and timing locked at 0 degrees it checks out perfectly but when fuel is turned on it doesn't start.

no cam sync.llg

[Adamw]

Ok so it looks much happier without the cam.  That means it either has more than one tooth on the cam or it is sitting right on the razor edge of the wrong spot.  Have you actually pulled the cam cover off to confirm there is only one tooth on the cam or are you assuming?  

[Adam Marone]

14 minutes ago, Adamw said:

Ok so it looks much happier without the cam.  That means it either has more than one tooth on the cam or it is sitting right on the razor edge of the wrong spot.  Have you actually pulled the cam cover off to confirm there is only one tooth on the cam or are you assuming?  

I can undoubtedly guarantee there's only one tooth on the cam. Here's a video of the cam tooth while cranking anyway.

the cams are timed using the factory cam positions. the only part that's aftermarket is the crank pulley/trigger wheel. So are you suggesting the cam tooth passes the reluctor at a time when it shouldn't be in relation to a tooth on the crank passing it's own reluctor?

Am I wrong to think that this might be fuel related? because the timing light with x1 cam active whilst cranking on the timing light seems perfect, unless the time light is not telling the whole story.

[Adamw]

I think you are going to have to get an oscilloscope connected to the cam and crank to see what is going on.  Do you have the ground and signal connected to the sensors same polarity as the pinouts below (notice they are opposite to each other)?

 

 

[Adam Marone]

Thanks for that Adam,

 

So I checked the polarity of both sensors and the crank turned out to be correct but the cam was not so I did a pin swap on the sensor side for the cam, rechecked timing with the light but still no start. Looking at the start log it gave no trigger errors whilst cranking but as soon as the key was released the engine briefly coughed and four errors came up.

I then hooked up the scope and found something interesting. You'll find the cam trigger starts to go high(?) around about the 13th tooth after the gap, this is shortly after cyl 1 TDC. The purple line is the injector pulse for cylinder 1, seeing as the cam trigger occurs just after tdc cyl1, this is nowhere near 400 degrees btdc as set by the injection timing.

I then scoped the coil for cylinder 1 whilst locked to 0 degrees and found it was exactly 360 degrees out, so I simply set the offset to +280 instead of -80 and she fired up perfectly.

Thanks a heap for helping me through this one, hugely appreciated!!

 

BTW The scope above is the incorrect -80 offset. I would upload the +280 offset scope but I've reached the data limit for the page lol.