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1) Date: 23.04.2012. Trigger log looks perfect, but completely at random some spark events just doesn't happen. Sometimes spark is missed even at idle speed, but it gets a lot worse above idle.

Here's a screenshot from trigger log at about 2500rpm. Maybe someone could help.


First, you need to upload a triggerlog and .vemslog so that we can walk through all your settings to find something faulty.

Do you use the same config as the pictures you have in MembersPage/Gachax/Software ?

You have to change your Angular width of tooth to 30 .

Change your ignitions outputs in use to 6. Ignition outputs (from top to bottom):

0 2 1 0 2 1

Ref Table(From top to bottom as it shows):

0 8 4 0 8 4

Try this and it will probably work alot better.

// Erikk

Wow, newer thought someone would actually reply! Thank you!

here is the triggerlog I don't have usable vemslog as I was fighting with IAC all the time when recording those logs. I found this issue with spark events and continued on logging trigger not a whole log. Anyway they seem to be not directly related in time, I mean if I record trigger log I cannot record vemslog at the same time.

And yes, the configuration is the same as in MembersPage/Gachax/Software. I uploaded current config file as well

I tried to change Angular width of tooth to 30, but then engine wasn't working at all. In any case, if I understand it correctly, 15 degrees is the actual width of a tooth of my trigger wheel (description in MembersPage/Gachax/Hardware), although I don't know how VEMS is using this number in calculations.

I was actually thinking of using all 6 ignition outputs (hoping it'll do something to spark events as I'm stuck with this and don't know what else could be changed), but how can I do that if I have 3 coils. Can I just solder 2 outputs together in one? Wouldn't that burn something? Other way would be to enable Dual Output Mode, but then there will be twice the power to coil (although I'm not electrician to know these things) and both outputs will have to be soldered together for the same reason of 3 wasted spark coils.


You´re welcome.

Try this config and reply with results:

Now I understand what you meant by using 6 ignition channels :). It somehow didn't occur to me that I can use the same ignition output twice in output settings. Thanks again, I'll report back this weekend.


Date 29.04.2012

Solved!!! It works with a new config. I played with settings and realized that those 15 degrees was the real cause.

As I mentioned engine didn't sound as good with 30 degree setting, but no spark events are missing. So I changed the TDC After the trigger settings and got it working.

2) Date: 24.04.2012. As I mentioned in Hardware section, it appears I have burned stepper outputs. But I'm not sure how to properly test it. When I test it with VemsTune output test, or test it when ignition is turned on (powering VEMS) there is no power in any of 4 stepper outputs, only grounds in 3 of them (test is done with standard DVM).

The way I initially hooked my unipolar stepper (at the time I had no clue there are 2 types of stepper motors) was as pictured in PhatBob?'s guide. It didn't work, so I applied power to additional 2 pins of the stepper motor (there are 6 of them - 4 for the coils and 2 for the power +12V). With this wiring stepper just jiggled in place and got hot over time.

So, the question is, is it possible to fix the outputs and what should be replaced inside VEMS to fix it? I'm trying to figure this out because current 2 wire IAC is very inconsistent and every time I start the engine it fluctuates and I have to change the IAC frequency setup to get it working. It works properly only when the engine is hot and even then it has to be changed if restarted.

First we need to enable the Stepper motor output by setting the S259 ch7 output to be permanently on using the waterpump activation.

Go to [tt]Extras->Fan / Water Pump / FuelPump[/tt] and set the water pump Start Temperature to -40 (its default) and its channel to S259 7"

Somehow missed this as it didn't seem to be relevant... I'll try that and report hopefully by placing this 2nd issue to Solved Issues page :).

Well, just figure I hadn't enabled Stepper chip in the first place. According to manual:

"Enable the Stepper Motor Driver

It isn't working unfortunately. It just assigns stepper output to water pump, but that can be done in Outputs section of VemsTune. Which is the place where I assigned stepper output to idle control.

So I guess both questions stand. How to properly test those outputs and what to do if test is negative?

Date 30.09.2013


Soldered new stepper chip. The old one had a hole in it... apparently I had burnt it.

3)Engine is not running smoothly or not running at all. Not sure what caused the issue, but it was running fine some while ago.

Log file running fine (except O2 sensor not connected and not tuned at all, so VE, ignition and other tables are more or less ok only at low RPM):

Log file - not fine (like some cylinders are not working):

I updated the firmware and re-soldered some wires in between. Now I'm back with the old firmware and all the wires are checked a 100 times. So it cannot be firmware or those wires (power to ignition coils). It just started to get worse and now it's almost impossible to fire the engine up.

I suspect it's ignition coil driving 1st and 6th cylinders. The spark is weak when testing and last time I was able to start the engine only by increasing a dwell time. I tried other ignition outputs and swapped coils, so I'm pretty sure it's that coil also resistance is within specs (at least primary coil as it cannot be measured for secondary). So, I will try to test with some other coils and spark plugs.

Anyway, the question is - is it possible to see that huge difference (the way engine runs) in both logs attached? I tried to understand individual_power graphs in log view, but they seem to be very inconsistent in both logs... I was looking at individual_power 2,3,4 as my ignition channels are 0,1,2. But I don't see them being so smooth as in some other example cases I found in forums. Is it something wrong with my setup, because it's also inconsistent when the engine was running fine?

(fphil) VT offers a very useful test mode to check ignition link

(gachax) I've done tests with ignition output test mode, therefore I'm sure the coil is bad. The real question is can it be seen in the log. I'm new to this (working on the car in my free time which is not much unfortunately) and individual_power seems to be very interesting thing to look at, but as I mentioned it's very inconsistent even in the first log when engine was running smooth (in low RPM at least).

Date 18.11.2013


Spark plugs where damaged for some reason... although testing showed good spark. Changed them and it runs smooth.