late spark issue

[SDCE]

Looking for some help - we have an engine on the dyno that we are trying to get started and broken in.
Engine is a V8, using coil on plug, 4 tooth crank wheel, VR pick up set at 75BTDC, 1 window cam sensor, halleffect pick up set at 90 BTDC.
Tuning software tunerstudios MS and MS3 release 1.3.4

Issue is we command spark 10* advanced but spark is very late, way after TDC.
msq attached - no datalog as we can't even get it to run. Any ideas or insight as to what we are missing or overlooking will be much appreciated.

Separate question - what Hz will a Ford IAC need?

[CRSTune]

You can datalog cranking, which will help us.

Have you actually timed the motor with a timing light? You likely need to adjust the tooth offset.

Ford IAC valves typically run at 300hz.

[SDCE]

You can datalog cranking, which will help us.

Have you actually timed the motor with a timing light? You likely need to adjust the tooth offset.

Ford IAC valves typically run at 300hz.

Thank you!

I'll try datalogging but won't it only show what the computer is doing and not when the ignition event actually happens in the combustion chamber?

As far as timing with light, the spark is so late that there is no combustion pressure in the cylinder, which means no resistance on ignition circuit to get inductive clamp on the timing light to read.

Don't mind moving the tooth offset but why would it need to be moved 50-80* from the actual mechanical set point to get the "correct" final ignition curve commanded?

https://goo.gl/photos/muDQbPLBoCrTSW3i7

[CRSTune]

We want to know what the computer is doing. From there, we can sync it with mechanical operation. If it differs from what we expect, then we have a different problem. For example, if you command 10deg BTDC and get 15deg BTDC at the crank, you have an offset problem. If you command 10deg BTDC but the ECU commands 15deg BTDC instead, we have a software problem.

A timing light will still read on a dead cylinder so long as there is current running through the wire.

The offset is the location of the first tooth after the first cam pulse on a non-missing tooth wheel. That can differ due to hardware latency, trigger edge, timing chain stretch or slack, etc. Don't over think it. Shoot the light and set it to match.

[Matt Cramer]

Looking for some help - we have an engine on the dyno that we are trying to get started and broken in.
Engine is a V8, using coil on plug, 4 tooth crank wheel, VR pick up set at 75BTDC, 1 window cam sensor, halleffect pick up set at 90 BTDC.
Tuning software tunerstudios MS and MS3 release 1.3.4

Issue is we command spark 10* advanced but spark is very late, way after TDC.
msq attached - no datalog as we can't even get it to run. Any ideas or insight as to what we are missing or overlooking will be much appreciated.

Separate question - what Hz will a Ford IAC need?

OK, first step is to lock the timing at a particular advance using the Fixed Advance setting (I'd use the same timing as for cranking, 10 degrees) and set the tooth #1 angle with a timing light. While the settings you describe would normally give a 75 degree trigger angle, it could be at something else depending on which edge the cam sensor is triggering on.

[SDCE]

we figured something out but does aline with any of the setup instructions .
crank trig mechanical set at 75 btdc tooth angle set to 75 also .cam on rising edge set to 90 .
This gave us a actual light reading of 280 deg which is about 90 deg late .
We left all the settings in computer alone ,moved our crank pu to165 deg and our cam to 185 which is basically the magnet 90 deg btdc +my 75 deg lead TIMING DEAD ON .
am i missing some setting ?
By the way the timing light won,t get enough induced voltage to trigger unless we put a .200 gap on the plug to create some resistance or have it under combustion pressure!

[jsmcortina]

I don't understand your description of where the sensor and magnets are.

However, if the timing strobes to match the ignition advance shown in TunerStudio, then you are good to go.

James

[jamies]

we figured something out but does aline with any of the setup instructions .
crank trig mechanical set at 75 btdc tooth angle set to 75 also .cam on rising edge set to 90 .
This gave us a actual light reading of 280 deg which is about 90 deg late .
We left all the settings in computer alone ,moved our crank pu to165 deg and our cam to 185 which is basically the magnet 90 deg btdc +my 75 deg lead TIMING DEAD ON .
am i missing some setting ?
By the way the timing light won,t get enough induced voltage to trigger unless we put a .200 gap on the plug to create some resistance or have it under combustion pressure!

Try reversing the VR polarity, your probably triggering somewhere inbetween teeth instead of the middle of the tooth.

[SDCE]

OK, first step is to lock the timing at a particular advance using the Fixed Advance setting (I'd use the same timing as for cranking, 10 degrees) and set the tooth #1 angle with a timing light. While the settings you describe would normally give a 75 degree trigger angle, it could be at something else depending on which edge the cam sensor is triggering on.

Thanks for the input Matt.

Not sure how to do what you are asking. I would have to set our #1 tooth angle at -10 to -15* +/- to get commanded timing number.
We have moved the edge we are triggering on but it doesn't help. when we had it on falling edge the crankshaft has to rotate 135* more to get to the falling edge. This puts spark event much later.

[SDCE]

I don't understand your description of where the sensor and magnets are.

However, if the timing strobes to match the ignition advance shown in TunerStudio, then you are good to go.

James

Hi James,

I attached a datalog .msl file for review and also a diagram of the sensors and magnets. Let me know if this helps? Sorry if I'm not explaining it good enough.

[Matt Cramer]

Thanks for the input Matt.

Not sure how to do what you are asking. I would have to set our #1 tooth angle at -10 to -15* +/- to get commanded timing number.
We have moved the edge we are triggering on but it doesn't help. when we had it on falling edge the crankshaft has to rotate 135* more to get to the falling edge. This puts spark event much later.

The tooth #1 angle needs to be positive. If you're getting a negative number, subtract it from 720; it sounds like you need to start at a 705 degree tooth #1 angle.

[SDCE]

Thanks for the input Matt.

Not sure how to do what you are asking. I would have to set our #1 tooth angle at -10 to -15* +/- to get commanded timing number.
We have moved the edge we are triggering on but it doesn't help. when we had it on falling edge the crankshaft has to rotate 135* more to get to the falling edge. This puts spark event much later.

The tooth #1 angle needs to be positive. If you're getting a negative number, subtract it from 720; it sounds like you need to start at a 705 degree tooth #1 angle.

Does the picture make sense, Matt? The timing light shows 80* ATDC, which is 90* late...in order for me to get it any where close, I put the tooth offset at zero and I'm still 15* ATDC. I get that I can move the tooth #1 angle a few degrees but that's not even close to helping. Theoretically, if I did what you mention, it would put me at 65* ATDC. Didn't realize I could put tooth offset bigger than 360*. Is that in the manual somewhere?

[SDCE]

Anyone have any input??

[jsmcortina]

Matt already suggested this. Please do it.

it sounds like you need to start at a 705 degree tooth #1 angle.

James

[SDCE]

705 does work ! but could someone explain the math to me or a place in manual that describes it .remember i have crank pick up mechanically set up at 75* BTDC

[jsmcortina]

http://www.msextra.com/doc/pdf/html/MS3 ... 4-140.html

James

[slow_hemi6]

It is actually fairly straight forward. The cam signal is what the ecu is waiting for so it can work out from the entered tooth No1 angle where in the 720 degree cycle the engine is. Tooth No1 is the tooth that comes onto the pickup after the cam signal has been received. What needs to be entered for tooth No1 is how far ATDC that tooth signal is from TDC/0 degrees. In your case the cam signal occurs late in the engine cycle with regards cyl1. Also In your case it was originally around 90BTDC cyl1. So if the cam signal is received at (0/720 - 90) which is 630 degrees give or take the width of that tooth depending on your selected trigger edge and any possible signal inversions caused by hardware connections. The next crank signal the ecu receives after that cam signal will be worked out in the forward rotation of crank triggers. So if you have a 75 BTDC trigger point with 90 degree magnet spacings, means you get your following positive crank triggers occurring at 15ATDC crank degrees, 105, 195, 285, 375, 465, 555,( all pre cam trigger) 645 (this is a possibility for tooth No1 as it is after 630 but not in your case as i guess the cam tooth is probably triggering on it's trailing edge) followed by 735 ATDC. So Around 735 would have been close to the correct tooth No1 angle number give or take some trimming. If you move your pickups position or change triggering edges then that all effects the final tooth No1 angle. But it is not all that hard as long as you realise tooth No1 is the one that occurs after the cam signal and tooth No1 angle has to be a positive ATDC number.

[SDCE]

I'm still having a hard time understanding why the spark happens 90* late when being set up how it is described in the manual. I've changed the diagrams in these pictures to reflect the actual timing events that we are dealing with. Maybe someone could point out where we are going wrong? It's almost as if after the cam signal, the computer misses the first crank signal and always picks it up on the following magnet which is why it is 90* late.

But it is not all that hard as long as you realise tooth No1 is the one that occurs after the cam signal and tooth No1 angle has to be a positive ATDC number.

Why do you say that the tooth No1 angle has to be a positive ATDC number, when the manual has it labeled as a BTDC number? If I set it that way, I'd subtract 75* from the first 360* rotation since I'm starting BTDC, and then add another 360* to get my ATDC number of 645. Putting that number as the tooth No1 Angle does not give me the correct ignition timing either. It only works If I set it to 705* which is the 75* shown on the balancer -90* to get to the next magnet.

[slow_hemi6]

I said in the previous post, because the cam sensor is a hall it may be triggering on the back edge of the tooth not the front. How many crank degrees wide is the cam sensor tooth?

[Matt Cramer]

If it's 90 degrees off, my guess is that the active edge of the cam sensor is triggering before the tooth when you were expecting the edge to trigger after it. Just get the timing lined up and no need to worry about it.