Spark A and B outputting 30ms+ long pulses? SOLVED!

thedge · Post by **thedge** » Sat Aug 19, 2006 2:31 pm

Setup: 29Q2 (freshly reflashed to that), MT 2.25, V3, two VB921s. Coilpacks are a pair of Electromotive XDI packs (gm style). Ive got it configured for roughly my triggering setup (not exact on triggers), and running "Stim for Wheel" enabled.

After chasing down why my VB921s got hot even with 0.5 ms dwell, ive found that Spark A and B are putting out 30ms long pulses every few sparks. The coils charge then the VB921s go into current protection for the remaining 30-32ms. This ive verified with a scope and 0.1 ohm resistor (scope indicates voltages of about 0.65, which works out to 6.5 amps give or take).

During testing this can be seen/heard on the coilpack (several sparks, strong spark, several weak sparks) and on the LEDs, as well as on my scope. By weak I mean relative to the strong one. If I increase dwell, the weak ones get stronger. The 30ms long pulses seem to happen mostly at low RPM. If I scope the spark outputs and the 0.1 ohm resistor side by side, I can definatly see that the MS is sending the signals and the VB921s are responding until they get almost too hot to touch (which corresponds to all the sparks getting weaker) at which oil I remove power. It will do this with VB921s and coilpacks disconnected, so when its just flashing the LEDs. That rules out noise from the coilpacks or failing VB921s I think.

Some pics:

Heres a normal pulse with a 2ms dwell set in MT.

Heres another one, followed by a 34ms long pulse...

And heres the full view of what started in the previous pic.

And heres just the two spark outputs with VBs disconnected. As you can see, in this shot spark output B (blue

) is going high for about 30ms... Spark A was a normal pulse in that shot.

And heres both wigging out at the same time.

Datalogs
http://thedge.info/msefi/dwelltrouble/d ... ulse-2.xls

http://thedge.info/msefi/dwelltrouble/d ... spulse.xls

MSQs
http://thedge.info/msefi/dwelltrouble/m ... spulse.msq

http://thedge.info/msefi/dwelltrouble/m ... ulse-2.msq

I made some changes to the settings to try different things, hence two MSQs.

And lastly, a video. Its 20MB, should download fast, and you can see what im talking about best from about 45 seconds to the end.

Post by **jsmcortina** » Sun Aug 20, 2006 6:45 am

You aren't running Stim for Wheel on the vehicle with a genuine trigger wheel connected are you? That will certainly mess things up.

James

thedge · Post by **thedge** » Sun Aug 20, 2006 7:32 am

jsmcortina wrote:You aren't running Stim for Wheel on the vehicle with a genuine trigger wheel connected are you? That will certainly mess things up.

James

No this is on the bench. I have the wheel decoder configured for my wheel, would that cause an issue? Are there specific settings that need to go into the wheel decoder page for the Stim for Wheel to work right?

thedge · Post by **thedge** » Sun Aug 20, 2006 7:39 am

I also found this post by Jon K... Maybe this is some sort of Stim for Wheel thing?

http://www.msefi.com/viewtopic.php?t=19506

Post by **jsmcortina** » Sun Aug 20, 2006 8:41 am

thedge wrote:No this is on the bench.

On the bench with a stim or with a trigger wheel?
How many outputs do you have set in the stim for wheel and does this match the number of spark outputs you have set?

James

thedge · Post by **thedge** » Sun Aug 20, 2006 8:50 am

jsmcortina wrote:
thedge wrote:No this is on the bench.
On the bench with a stim or with a trigger wheel?
How many outputs do you have set in the stim for wheel and does this match the number of spark outputs you have set?

James

Bench with stim. Two trigger outputs, and I think 4 for the wheel stim... I was wondering what that other option (Number of Steps I think its called?) was for on the Stim for Wheel page...

Ill give it another try with the numbers matching and see what happens!

thedge · Post by **thedge** » Sun Aug 20, 2006 9:13 am

It works, no more long pulses!!!!!!!

Thanks James!!