Dwell has changed!!! Help!

Tobisen · Post by **Tobisen** » Sun Mar 16, 2008 9:34 am

This is the first time I got the engine running with my new MicroSqurit...

I have hooked up a scope, and checked the dwell at crancking speed, with the injectors unplugged.
In the settings, the dwell is set to 3,1ms
The dwell is actually 4,2 lookking at the scope...

So I got all the settings set, plugged the injectors and got the engine startet up.
It still needs alot of tuning... It did not run perfectly, but I got it idleing

After some tuning back and forward, I wend back on the scope to ckeck the dwell.
It was now 32ms!!!!
The coils was also hot!

What has happend?
In the settings the dwell is still set for 3,1ms!

Tobisen · Post by **Tobisen** » Sun Mar 16, 2008 11:29 pm

Here is my MSQ, hope someone can help me out here...!

Post by **grippo** » Mon Mar 17, 2008 4:38 pm

What does the dwell time read in MT ? During cranking the dwell may read higher than your setting because the battery is low and dwell is increased to compensate. The only other thing is that dwell may be increased during acceleration - and there are tables/ variables in MT that can be used to reduce or eliminate dwell changes from battery voltage or acceleration. But I can't think of anything that would cause a 32 ms dwell except incorrect spark output polarity - but then I would expect the dwell to be really long at cranking rather than idle.

Tobisen · Post by **Tobisen** » Tue Mar 18, 2008 7:06 am

In the megetune the dwell is -22ms!
With the ignition timinglight, I can se that no matter what I do, the ignition advance is not changeing!
It fires at 0deg!
What is the problem?

Post by **grippo** » Tue Mar 18, 2008 8:58 am

I just don't see anything in your msq to cause such behavior, so I am thinking your code is corrupted - this sometimes happens during a flash burn. I would do a reload of the code, then load the msq you have posted, and cycle power. Then check that the inputs shown in MT are really the ones you loaded.

Tobisen · Post by **Tobisen** » Tue Mar 18, 2008 12:17 pm

Can it be, that I have to change the "spark output" settings to going low?
On the scope, the image looks like it is upside down!

old guy · Post by **old guy** » Tue Mar 18, 2008 2:43 pm

I looked at your msq. and have a couple of questions.

1) Is this motor normally aspirated, because all of your map bins are all in the 200+ range, which is what you would use for a supercharged motor.
2) Your ignition map from 35 to 70 kpa is all zero's. This might be why you are not seeing any timing change.
3) Why is your trigger offset at 98.5? Did you use the trigger wizard and a timing light to set this?
4) What are you using for a map sensor, an MPX or the stock one from the motorcycle.
5) Why do you have your trigger set to rising edge?

I know all of this stuff has nothing to do with dwell, just some things that need to be taken care of.

Edit
Is this the GSXR 750 that you are working on?
I see from your other post that you are running a 4-1 trigger wheel. In yor msq. you have it set up as a 24-2.

Tobisen · Post by **Tobisen** » Tue Mar 18, 2008 3:23 pm

Ok here a quik update...
It is a GSXR750, and it is turbocharged!
I have changed the wheel to a 24-2theethed wheel.
The triggeroffset is there, cause I left it there after trying in the triggerwisard to change it back and forward without result with a timinglight...
The mapsensor is from one of the Yamaha with turbo. 250kpa 0-5v
The trigger is set to risingedge because it did not make any changes where it was...

Can the reson why the dwell is so high and the scope image is upside down that I have to change the spark settings to go low?

Can I damage anything by trying?

old guy · Post by **old guy** » Tue Mar 18, 2008 3:57 pm

If you could not get the trigger wizard to work, how do you have any idea where your timing is set? Do you understand how the trigger wizard works?
If you are triggering on rising edge you might have your VR wires reversed.
How did you calibrate the map sensor in megatune?
With 1&4 at TDC what tooth on the trigger wheel is lined up with the VR sensor?
The way your ignition map is set you are not going to have any advance at anything bellow 70 kpa.
Can you damage anything by having the ignition output wrong. Yes!!!
If you have it the wrong way and the coils are energised with the motor not runnig you will burn up the coils or the ignition drivers or both.

Tobisen · Post by **Tobisen** » Wed Mar 19, 2008 12:19 am

I see what you mean, the mapsensor is not calibrated!
Is shows 119kpa when engine is off.
That is about 10kpa to mutch! I have just set up as the one megasquirt has inside...
When the engine is running, it never comes below 70kpa, so that is why ther is no advance there...
I know I have to change the tabel, so I have more of it to use for tuning!

As I can see the triggerwisard works so, that I with a timinglight set to the same deg as the wisard, can change the offset deg for the vr sensor!
I know the offset is 75deg, so that is where I start.
But is dos not change nither with 50deg offset or 120deg!

The vr sensor is wired correct, I have cheked it with the scope!

At TDC for 1 and 4 the sensor lines up with thooth 6
That is 75deg offset from the 1thooth