Ben

iTrader: (33)

The CPU does not directly drive the spark outputs, please see my previous post.

leboeuf

iTrader: (1)

EDIT:Ben just posted some SERIOUS drive capability!
Is that full sink/souce? Anyway, if the mspnp2 v1.3 has these kind of stats then the problem is somewhere else.
If someone is running into these issues using the old school spark driver circuits then read on.

Dave brings up some good points.
I'm going to reiterate one of Dave's comments:
Even with a 100ohm pull-up you'll be seeing a 1v drop on a 10mA load.

That's why I recommended the full swing digital buffer. +/- 50mA current drive should lick this. But Bryan has to deal with a 20 pin dip package...

Ben

iTrader: (33)

So you have an ignition module that works with some MegaSquirts, but not others. It works with some piggy backs, but not others. Yet you are blaming the MegaSquirt product. It seems more likely that the "threshold" problem is inherent to your ignition module. I think you need to at minimum provide some specs for your ignition module, specifically relating to its signal input requirements.

I also see references to a CDI module, but the module I see in photos is a standard VAG inductive module.

I think you need to provide better specs before pointing fingers.

Ben

iTrader: (33)

Source

FAB

iTrader: (4)

Let's be clear, I'm not pointing any fingers in "blame". Everything I've said to this point has been simply from observation, it won't work with some MS units when configured in wasted spark. The "threshold" is inherent to a module that MegaSquirt already has documentation on.

I'm willing to produce a harness (and provide it free of cost) to solve the problem so my customers do not have to modify their components to properly drive our kit.

You're correct, it's not a CDI module it's a standard inductive driver - THIS module.

Ben

iTrader: (33)

That's not exactly how some of your statements read, I've been following for a while but was attempting to keep some distance.

Are you using GENUINE Bosch 211 modules or Chinese knock offs? Genuine Bosch 211 modules are known to trigger in wasted spark off fairly low current outputs.

FAB

iTrader: (4)

Thinking that might have been a simple fix, I've tried the Bosch unit, and 3 other modules from various manufacturers. Unfortunately with identical results.

Impuls

iTrader: (1)

To be exact it's 99-00 MS2PNP on MS2/E release 3.2.5

Ben

iTrader: (33)

What MegaSquirt variant do you have? What is your battery voltage? What is your dwell? Datalog and msq would be helpful.

The 211 module is simple to drive. They are extremely popular, especially in Europe where they are dirt cheap and common. They are more expensive in the US. There is something else here.
I would avoid Chinese knock offs.

albumleaf

iTrader: (7)

Given the lack of answer it's pretty much confirmed that they're using the cheap knockoffs.

FAB

iTrader: (4)

I don't have MS but the system we're speaking of is owned by Impuls and he has a 99-00 MS2PNP on MS2/E release 3.2.5


Why, thank you for your kindness. They aren't Bosch but they certainly aren't cheap. The Bosch module alone would add nearly $100 to the cost of our system and offers no worthwhile benefits that justify the costs.

We use a module distributed through SMP (Standard Motor Products). Local, warranty, reliable. We also went this route because in the US the same module can be purchased through any Advance Auto Parts stores.

Erat

iTrader: (5)

Mine is a 94 DIYPNP 1.5b with the microsquirt board built by Brain himself.

Same issue.

I could possibly datalog mine as well. In fact, i may have a datalog of it somewhere, i can't remember if we got one or not.

FAB

iTrader: (4)

Dillon (Erat) owns the car we tested a handful of different modules on without changing results.

Erat

iTrader: (5)

As well as a bunch of different dwell settings. We took the dewll up to the point of smoking an ignition module.

Impuls

iTrader: (1)

"I need to know how much current the FAB9 ignition module requires.
Thanks,

Matt Cramer
DIYAutoTune.com"

Common guise..
This thread wasn't made to bash anyone.

DaWaN

Thanks for sharing the product number of the ignition module.

The Bosch datasheet clearly states it needs 10mA minimum for proper operation.

Example schematic of Bosch:


Now the module is nothing more than 4 bipolar transistors in a package, so no rocket science at all. One thing we shall not forget: bipolar transistors turn on and off due to _current_: so voltage is not that important.. You will need a certain current to make these things work OK. Too much resistance and you will run into trouble.

Looking at the example schematic they use a resistance of around 200 ohms from 5V to turn the transistor on: yielding a current of around 20mA (assuming 1.0V Ube during saturation) through the pin of the module. They use a 33 ohm resistor to turn the thing off: I think this is important as you want to turn it off quickly to generate a nice accurate spark.

Please note if you connect two channels in parallel to run wasted spark the current requirements double so you would need half the resistance to make it work OK.

I am wondering when you drive the thing directly of the pin of the MCU if the MCU is actually capable of driving 40mA. Does somebody know if you could expect 40mA ?

If you want to boost the logic signal you can clone the Bosch schematic and use any run-off-the-mill transistor with similar specs as the BCX 58.
If you want to make a bit better you can use something like a Microchip TC4469/TC4467 (or similar) with a 150 ohm (or a bit less) resistor in series with its output. You then have the ability to quickly turn the module on and off. This will somewhat limit the heat generated inside the module compared to the Bosch' example schematic.

leboeuf

iTrader: (1)

Ahh nice driver chip! I was looking for something like that this morning to post into this thread.
Fab, take note, if you can find this IC use it instead of that other one I linked.

Do you really need the 150ohm series current limiter? If your schematic is correct, it looks like the 10kohm in-line within the igniter should handle the current control?

DaWaN

Yes you really need the 150 ohm series resistor!
The schematic posted above is an example schematic for use inside the ECU to drive the ignition module, so the 10k resistor is used as a base resistor between the MCU of the ECU and the driver transistor.

The series resistance the module 'sees' during operation is 183 ohms when dwelling and 33 ohms when it needs to ignite. This is important as bipolar transistors are current driven: so without resistor you will most likely damage the transistor because of a high base current. You will only need 10mA to put the thing into saturation, anything more does not bring any benefits to your spark.

leboeuf

iTrader: (1)

Hmm interesting.
Do you have the schematic of the ignition module?
It seems unlikely that they would design it without any current limiting resistance on the input pn junction. But I've certainly been wrong before!
I could see the necessity of the series resistance if you were using a raw ignition component like the bip373, but I thought the COP ignitor was built to handle raw (high current potential) digital voltages?

JasonC SBB

Waitaminit. I thought your kit was CDI? If they're inductive and use Bosch or Boschlike modules, why does dwell not matter?

That Bosch ignition module requires a pretty heft amount of current, 10 mA.