AEM Infinity - Trigger offset angle ?
 

Hi All,

Looking for some guidance on my trigger offset angle for my setup. The car wont start and here is my set up / what I have done to get to where I am.

Application is Carrera 3.2 motor with low pressure turbo using 930 J Pipe, 57lb injectors, GT3076R turbo and treadstone intercooler, with AEM infinity 6 running semi sequential firmware.

I have the clewitt cam sync sensor but have not installed it yet. Assumed that semi sequential firmware did not require a cam sync sensor.

1. Denso COP, running semi sequential firmware
2. Rothsport crank pulley with 36-1 trigger wheel, along with rothsport vr sensor and holder.

I have used the diagnostic firmware to verify (twice) that the ecu wire for coil 1 indeed is connected to coil 1 and so forth up to ecu coil 6 to coil 6. All coils have an earth wire to chassis ground (3.2 manifold stud), and a +12v. I am definately getting spark.

All injectors are also firing, confirmed with diagnostic firmware.

I assumed that the way the trigger wheel is attached to the crank pulley and location of the vr sensor holder, that my trigger offset would be 63 deg BTDC. Using this setting I got a lot of coughing but no fire. After a few days and a lot of reading on the AEM forums, I thought the trigger angle may be 360 degrees out, so increased the software angle to 423 degrees (63+360) and the damn thing fired and scared the hell out of me.

I put a timing light on it and with the timing locked at 5 degrees (rothsport pulley has a 5 deg mark) and the trigger offset decreased to 400 degrees.

I can't get it to rev for some reason but need to confirm my trigger offset angle is in the ballpark of anyone else that may have used this type of ecu / trigger wheel setup. I think the non rev issue may have to do with the trigger angle.

Thanks for any guidance anyone can provide.

Cheers,

Sandeep Syan

http://forums.pelicanparts.com/uploa...1488227408.jpg

If you are on tdc and the missing tooth is at the tdc mark and you have the clewitt vr sensor holder you would be at 49-50 degrees

If your timing light shows 5 degrees and your pulley is indicating 5 degrees, your offset should be 0.

It's correct.

Unless I'm missing something here?

Thanks xbmwguy.

I thought that the trigger angle should be in that range as well but the engine wont fire with that range of trigger angle.

I'm going to pull the fuel pump / injector relays and crank the engine with a timing light connected, while locking the spark angle in the software.

Hopefully this will tell me how far out I am. Fingers crossed !:D

Put the offset at 0.

You shouldn't have any offset with a good wheel and VR bracket bolted to dizzy bolt.

Thanks Tippy for the additional input. I won't be able to get to the garage until this evening, but will post my findings then.

Sandeep

Measuring it yourself might be best. The offset angle is just that, the number of degrees between TDC of number 1 cylinder firing, and the end of the missing tooth notch. It sounds like you will be able to measure it easily with your setup, since the trigger is on the crank snout.

Have you asked Rothsport what the offset is for their trigger package?
It's what Motec calls "CRIP" (Crank Reference Index Position).
Enter that.

Lock timing at 0 degrees in software.
Check with an adjustable timing light, adjust in software if needed until zero on the timing light lines up with 0 TDC on the pulley.
Then rev the engine, check for timing drift (it can be corrected, too).

Unlock timing, proceed with tuning.

Thanks for the additional information Speedy and Chris. Looks like I have a bit of work to do and phone calls to make before I can update this thread.

Appreciate the guidance everyone has provided.

cheers,

Sandeep

My cheap GSF was 0. Timing is more critical than AFR's. I'd be surprised if Rothsport didn't get their stuff within a few degrees of actual!

As mentioned above, try measuring yourself.

Using a 60 tooth wheel, each tooth is 6°

The example below shows the clocking used on our 356, where the lead to the missing teeth just happens to line up with the TDC mark on the crank pulley. This is because of where the crank sensor is located (custom machined bracket at fuel pump location).


Your software should allow for an adjustment either in degrees or number of teeth to lead the sensor. In my case its 11 teeth, I've seen between 10 and 13 before.

If at idle, your timing light shows 5°BTDC, and the timing in the ignition map shows 5°BTDC, then I think you have it set correctly.

It sounds like you got it to run at idle, was it smooth? Since you got it to run, but it won't rev, what's happening? When you open the throttle, is it reluctant to rev, does it cough or sputter, does it just die instantly?

Some updates
 

Thanks for the feedback bleucamaro. It idles but does not rev when the throttle is opened ... even fully.

Talked to Rothsport and Earl provided the attached picture of the proper configuration. Yellow mark is TDC #1, red is 30 Deg advanced.

http://forums.pelicanparts.com/uploa...1488319272.jpg


My pulley matches the correct configuration.... cant seem to rotate the pic :confused:

http://forums.pelicanparts.com/uploa...1488319368.jpg

So my vr sensor is mounted on the distributor stud and when the crank pulley is at TDC #1, the vr sensor is directly over tooth # 7 as below.

http://forums.pelicanparts.com/uploa...1488319701.jpg

So my trigger offset should be about 60 to 70 degrees ?? I am running semi sequential so the ecu should fire the coils twice per 720 degree cycle ... once at 60 to 70 degrees and then again at 60 to 70 degrees + 360 degrees correct ? There is no cam sync so assuming the ecu does not know which of these two options is TDC for cylinder #1 ??

That leads me back to the start of this thread ... wont fire at 60 to 70 degrees trigger offset but will fire and idle at 400 trigger degrees offset but will not rev, even at full throttle.

Will hook up the timing light again this evening and make sure all is as said. Will follow all the advice given and report back tomorrow.

Thanks for the continued feedback.

Sandeep

Set it at 0!!!!!!

They don't sell you an OFFSET trigger wheel!!!

It's not a guessing game.

A proper wheel and VR sensor is TDC out of the box.

Once it's running, you can verify IF you need to move it so many degrees. Whatever that is.

Will Do !

A few more hours before I can get back to the garage.

And your trigger wheel looks like a 36-1 trigger wheel, so count the teeth from the gap to your sensor. FYI, your TDC mark is aligned with the rising edge of tooth 2.

360° / 36 teeth = 10°/tooth. From the look of your pics, I think you're close.

The cam sensor just tells the engine what stroke you're on, running wasted spark is fine.

Per the manual, have you set the base timing (Lock timing @ 5°, verify while cranking only using timing light)?

Theres a ton of other things it can be, and without playing with it, would be hard to diagnose over the internet.

Are the coils wired correctly? ECU to coil & coil to plug? It's possible to get the banks switched

Are all the other inputs wired and functioning correctly? TPS calibrated?

Are you tuning alpha-N off idle, blending to SD?

What happens when you increase the spark advance in the tuning map while idleing, does RPM increase? Does engine sound happier?

Trigger offset, to me, is made for a few things:

1. Use it to correct minor machining differences between parts and install variances

2. Custom wheel and VR mounts (DIY level)

3. Timing drift for high RPM harmonics and electronic latency


When you purchase an aftermarket crank trigger, it damn well should be TDC or close to it right out of the box.

You should NOT have to put in degrees like 42 or 400. The company should NOT be offering a product for sell in that case!!!!

Tippy -- I think hear what you're saying, that whatever value a trigger manufacturer gives you, that should be it.
But in general, EFI systems do not accept a critical signal at exactly TDC, be it a missing tooth edge or cam synch.
Similarly, they do not have the missing tooth edge and the cam synch at the same time.
Maybe MS/3/Pro is different, but this is how AEM, Motec, and many OEMs are set up (AEM Infinity is an OEM computer).

Sandeep -- we haven't set these up to semi-sequential, only full sequential. Are you trying to trigger 2x injectors at a time, or 3x (aka batch fire, bank-to-bank).
The advice I gave you about locking timing and checking is what we do for establishing the cam synch position. It's probably the same for a missing tooth semi-sequential, but I'd recommend you search AEM's tech forum to verify, or last resort call them.

Some updates
 

Thanks for all the feedback everyone.

I am confident with the diagnostics firmware that all coils are connected correctly to the proper plugs .. coil 1 to plug 1, coil 2 to plug 2 etc ... and the injectors are also connected correctly.

I went through the setup sync procedure again .... advance locked at 0 degrees with fuel pump relay pulled.

Set trigger offset at 0 degrees and cranked engine with timing light connected to verify timing.

At offsest of 0 degrees ... cannot see TDC mark while cranking.
At offsest of 20 degrees ... cannot see TDC mark while cranking.
At offsest of 40 degrees ... cannot see TDC mark while cranking.
At offsest of 60 degrees ... cannot see TDC mark while cranking.
At offsest of 80 degrees ... cannot see TDC mark while cranking.

So on and so forth untill I hit 380 offset degrees and I start to see the TDC mark.

At offsest of 400.5 degrees the timing mark lines up with the mark in the fan housing.

Frustrating ....

I connect up the fuel pump relay and the car starts and idles, but wont rev .... same symptoms as before. I just cannot seem to get past this step.

Out of frustration, I set the trigger offset to 0 degrees and then cranked the engine for at least 20 seconds and to my surprise, it caught and idled. Sounded great and revved like it should with throttle input ! Connected the timing light and could not see the timing mark at all .... :confused:

I then checked the setup wizard, and my settings for the 36-1 Mag crank sensor had disappeared ? Reloaded the settings, cranked the engine ... no start. Shut the ecu off, turned it back on and the settings for the 36-1 mag crank sensor disappeared again :confused:

I am sure now that the ecu is not remembering my trigger wheel settings for some reason. Frustrating.

Semi sequential is supposed to fire the plugs every 360 degrees (sort of wasted spark) and also fire the injectors twice per 720 degree cycle.

Not sure if I can install the Clewitt cam sync sensor with the engine installed in the car ??

:(

Sandeep

Great that you got it running, and with the offset at 0°!

Weird about the timing marks. Did you try switching the plug wire the timing light was clamped to?

I don't see how you can expect to use COP ignition without the cam sync sensor. There is no such thing as semi-sequential COP. They also generally are not capable of wasted spark. Smart coils (driven with logic level input) have the dwell angle built into them.

So, Inwonder if you are just falling into default operation, in which case the loss of cam signal is forcing it into firing at fixed time on every rev.

Good point, Speedy.

Sandeep -- why not just install the cam synch now and go full sequential?

You can do COP wasted on MegaSquirt. Is this an AEM thing?

Only concern is not having enough dwell time at high RPM. I calculated (IIRC), that I could get to 7k RPM with the coils I chose.

Taking a quick look of VAG coils, the dwell is even lower at 3.0ms, which would allow higher RPM capability before losing spark energy.

To answer your question in regards to why it doesn't rev. There could be a couple of things. 1., your timing is so far off or 2., you are enduring noise in the input circuit causing the ECU to get confused and lose synchronization.

I just see that your VR sensor is not even close to being up top like mine.

A call to the manufacturer is needed. I CANNOT for the life of me understand why you'd need an offset other than a few degrees!!!

That tells me, they put zero thought into providing a quality product that has the potential to blow up ones motor!!!

I would NOT be guessing on timing!

Of course, once you get it close, a quick timing light check will confirm actual offset.

That does not describe Jeff and his team at Rothsport. Super type-A guy.

The product is top quality, no issues on my side with the package supplied by Rothsport. On my previous install on this motor (DTA S60 Pro) running EDIS-6, wasted spark, I just input the trigger offset of 63 degrees (missing tooth was 63 degrees before TDC #1, referenced to vr sensor location) so ECU knows that TDC #1 is coming up. It ran well and made 305 FWHP on the dyno at 8 psi.

I'll try and install the cam sync sensor with the motor in the car and report back. Looks like my only option now.

Thanks for the continued feedback.

Sandeep

I'm not saying their products are bad, but would you sell a crank trigger kit where you had to guess the offset?

I wouldnt!

The wheel SHOULD be indexed to TDC when the motor is actually TDC! I can't see it any other way.

Sorry.

I got crap for using the GoingSuperFast crank trigger. Folks claimed his products are junk. Guess what? No offset was needed. Some other 911s/turbos did due to minor variances, but that's totally acceptable.

Sorry, but if I was expected to figure out the offset on my own, I'd be removing that product and having a conversation with them.

:):):)

I had a stupid thought: I've seen 911 crank pulleys before with a 30° BTDC mark, 5° BTDC mark, and Z1 (Instead of -35°, -30°, 0° as shown in OP's pics). Is it physically possible that your crank pulley was assembled backward? That would make for a 40° delta, after TDC, which winding the clock back translates to 400°BTDC, amirite? . . . hope-not.

So if I'm understanding this correctly Sandeep, with DTA and AEM, there isn't a "wheel decoder" setting you select?

You have to give an actual angle to determine TDC?

If this is the case, my bad for pointing the finger at the crank trigger setup.

For MegaSquirt using MSExtra firmware and the tuning software TunerStudio, I simply click on 6 cylinder and 36-1 toothed wheel on a drop down menu in the ignition settings and done.

No calculating angle from 6 teeth ahead of missing tooth.

I was fortunate to have the timing be right on.

Correct Sir.

You enter the offset angle between TDC #1 and where on the trigger wheel perimeter the VR sensor is located. The ECU then knows (in my case) that once it detects the missing tooth, there will be 63 degrees of crank rotation before the engine is at TDC #1. The ECU can then determine how long before TDC #1 it has to fire the spark for cylinder 1 according to the timing tables.

Sandeep

Ok, that's tough. Surprised those aren't setup with standard configuration wheels?

Good luck!!

An update after some frustrating weeks ....
 

Wow ... what a journey. So many frustrating nights of testing and retesting, only to find the solution in the AEM manual :rolleyes:

I started the journey in to AEM Infinity by downloading the software and setting up my engine profile BEFORE I actually bought the ECU ... wanted to see what the software was capable of compared to my old DTA S60 Pro and the DTA SWIN program.

I eventually bought the ECU, wired it up, tested the connections, UPDATED the ecu firmware to V96.2, and then proceeded to upload my V96.1 profile in to the system. That was the mistake that lead to all those frustrating nights, and reaching out to this forum for help.

Apparently the ECU firmware and the desktop software have to be running the same version :D

I was wondering why all of the sample sessions that came with the program had the same version #'s (V96.2) while mine was a mix of V96.2 and V96.1

Anyhooo .... I synced the ECU firmware with the desktop software, created a new profile in V96.2, set up the engine for semi sequential with no cam sensor (even though I installed the Clewett cam sync sensor) and gave the engine a crank.

Wouldn't you know it, it fired right up :eek: and revs strong and with a bark :rolleyes: From now on I will RTFM ! Lol.

I just need to figure out the 3 wire Bosch idle valve now with the Infinity (outer 2 terminals are PWM to ground, 1 terminal inverted duty cycle with respect to the other terminal, and +12v on the middle terminal).

So it does run on semi sequential, COP ignition without a cam sensor. I will switch to fully sequential after I have tuned it a bit and got it to start more consistently on the first few cranks.

Wouldn't have had these issues if I had followed the instructions to the letter, but I think I now have a better understanding on how this ECU works. Looking forward to getting the car drivable now as Spring is just around the corner in Toronto :D

Cheers,

Sandeep

http://forums.pelicanparts.com/uploa...1490065615.jpg

If all else fails, read the instructions. Been there, done that. Glad to hear since I'm considering the Infinity 506 for my next build.

Congratulations, and keep posting Sandeep. I am a few weeks behind you!

Let us know about the Bosch idle valve as I recently purchased one and am also thinking about how to connect it.

Good job, Sandeep.

3-wire idle (3.2 Carrera) was a fail for us, and the Infinity handles the 2-wire motors (ex: 964) very well and the cars never, ever stall. I forget how our tuner modified a 3-wire to make it work like a 2-wire, but will ask him.

With MegaSquirt, you run what they call FIdle (fast idle) to one side of the ICV (coil) and then the other side of the ICV (other coil) is grounded using a 40 ohm/50 watt resistor.

It plays tug-o-war with each coil to idle.

Works great.

Middle pin is 12V.

Having done 8 or 9 efi swaps I have always indexed or " clocked" the trigger wheel to have the missing tooth at tdc. Looking at the photo of the missing tooth to be after tdc would give the reason he doesn't " see" the marks until he gets near 380-400 degrees. Can you move wheel to get missing tooth at tdc? That's why my trigger offset is always at 49-50 degrees as I use the same bracket to hold the sensor. My 2

I got a hint on how to use the 3 wire idle air control valve from the manual. They have a diagram for a BMW adapted to a 3 wire IAC. They use a mosfet transistor to invert the PWM signal and have a freewheeling diode. They also use a resistor. Should be easy.

General picture:

http://forums.pelicanparts.com/uploa...1490218650.PNG

Note: let me know if pics are upside-down!

You beat me to it Dr J.

That diagram is in the Infinity manual for the BMW example wiring diagram. I will give that example a try (need to figure out what it looks like with real components though) as I am not sure what the schematic actually means. :confused:

http://forums.pelicanparts.com/uploa...1490231590.jpg

Thanks for the update on the 2-wire Valve Chris, appreciated.

Cold weather is back in Toronto so no more garage time till it gets a bit warmer :D

Cheers,

Sandeep