Dual wheel. MT reads only half Rpm. SOLVED!

GintsK · Post by **GintsK** » Thu Nov 15, 2007 10:29 am

Hello!

Want use dual wheel setting on Honda H22 engine which use 3 trigger system: two on crank: evenly 12 and 2 tooth and one inside distributor giving one impulse per cam rotation. I want use 12tooth sensor on crank and cam sensor. Single coil on D14.

But problem isMegatune reads only half of real Rpm. I check it on real engine during cranking and on bench tests using modified base msq, other board and other signal conditioners. I checked input signals at CPU with scope - looks OK in both cases. Got half of sparks needed - two per 720deg.

ms2extra_beta20071104, Also try it on older
ms2extra_beta20070812 - on engine only.

Will be very gratful for help. Here is my settings:
Gints

Post by **jsmcortina** » Thu Nov 15, 2007 2:23 pm

I can confirm that I believe this to be a bug in the code. It relates to one line of code that I changed recently. It may work it far older betas, but I'm note sure.

In any case, I think I have fixed it, but need to test some more.

James

GintsK · Post by **GintsK** » Thu Nov 15, 2007 3:23 pm

Thanks for fast reply!

James, how old beta version I could try?

I have another question related this. We got stable rpm reading (half) with spark plugs unscrewed, but can't get stable sync when compression stroke brake crank rotation with plugs in. I count impulses between cam signal on oscillogram - there still was 24 pulses but irregular at TDC - our battery was on weak side. Does firmware do some filtering for this kind of wheel or I must look for hardware problems only?

Gints.

Post by **jsmcortina** » Thu Nov 15, 2007 3:59 pm

Check which edge (or VR polarity) of the camshaft signal you are using. It is imperative that it occurs between two teeth. If it sometimes happens before or after tooth then you will loose sync.

A non-missing tooth dual wheel setup should be pretty immune to crank speed variation. Whereas a missing tooth setup can misdetect the missing tooth due to crank compression effects.

James

GintsK · Post by **GintsK** » Fri Nov 23, 2007 6:39 am

Hello.

Just try new 2.0 beta 16 (20071122) on bench. Looks like it still do not work for me.

Half of rpms as previous. And I notice only way to get synced is chose secondary trigger from falling edge. It is problem for me because I use LM1815 for cam. And according to datasheet output edge is rising.

Can get 24xx rpm on my test .waw if I double teeth 12->24 in settings and define my crank wheel as cam wheel. It must work. But not with wrong trigger edge for cam.

My hardware settings:
12 teeth wheel -> VRIN -> VROUTINV -> TSEL selected falling edge
Cam tooth ->LM1815 ->JS10 rising edge.

Gints.

Post by **jsmcortina** » Fri Nov 23, 2007 5:48 pm

I've sent some test code. If it works I'll post another beta.

James

FunnyBoY · Post by **FunnyBoY** » Tue Nov 27, 2007 12:50 am

jsmcortina wrote:I've sent some test code. If it works I'll post another beta.

James

No it still doesnt work.

GintsK · Post by **GintsK** » Tue Nov 27, 2007 1:47 am

From here http://www.msextra.com/viewtopic.php?t=26715&start=20

jsmcortina wrote:Caution:
the prediction and wheel mode changes aren't implemented correctly in beta16. Due to pressure of work I hadn't fully tested or committed all the code I'd written.

We are working on it for beta 17.

James

Post by **jsmcortina** » Tue Nov 27, 2007 2:41 pm

FunnyBoY wrote:
jsmcortina wrote:I've sent some test code. If it works I'll post another beta.

James
No it still doesnt work.

Thanks for the bug report. Your detailed description is very helpful in fixing it.

James

mops · Post by **mops** » Tue Nov 27, 2007 2:50 pm

i dont kind of understand what tooth wheels there are on the engine....

i've seen h22 dizzy (they are different for different MY I believe)
it has two tooth thwwles. one is i believe 24 tooth (no missing) and other has only 1 tooth if memory serves me right... or maybe 2 teeth (180 degree apart...) like 4age 5valve silvertop dizzy...

i'm not aware of the crank wheel on h22 motor, but i dont have much experience with them. i had a lok at one once and AFAIK it's only dizzy sensor(s)... but what do i know...

have you tried running it wihout cam sync ? just crank it and see whether you get proper rpm readout without cam sync (set it for wasted spark, just to confirm correct rpm readout)

FunnyBoY · Post by **FunnyBoY** » Tue Nov 27, 2007 3:32 pm

GintsK wrote:From here http://www.msextra.com/viewtopic.php?t=26715&start=20
jsmcortina wrote:Caution:
the prediction and wheel mode changes aren't implemented correctly in beta16. Due to pressure of work I hadn't fully tested or committed all the code I'd written.

We are working on it for beta 17.

James

GintsK please make a short description of the problem?

FunnyBoY · Post by **FunnyBoY** » Thu Nov 29, 2007 12:35 am

James, Ken any updates?

Thanks Janis.

6040solder · Post by **6040solder** » Thu Nov 29, 2007 2:10 am

jsmcortina wrote:
FunnyBoY wrote:No it still doesnt work.
Thanks for the bug report. Your detailed description is very helpful in fixing it.

FunnyBoy, I could be wrong, but that sounded a hint sarcastic to me.

Perhaps if instead of "No it still doesnt work" you describe what you tried/why it doesnt etc and supply an msq and datalog. then they might have a little more luck making progress on it for you.

GintsK · Post by **GintsK** » Thu Nov 29, 2007 2:15 am

mops wrote:i dont kind of understand what tooth wheels there are on the engine....

i've seen h22 dizzy (they are different for different MY I believe)
it has two tooth thwwles. one is i believe 24 tooth (no missing) and other has only 1 tooth if memory serves me right... or maybe 2 teeth (180 degree apart...) like 4age 5valve silvertop dizzy...

i'm not aware of the crank wheel on h22 motor, but i dont have much experience with them. i had a lok at one once and AFAIK it's only dizzy sensor(s)... but what do i know...

have you tried running it wihout cam sync ? just crank it and see whether you get proper rpm readout without cam sync (set it for wasted spark, just to confirm correct rpm readout)

In our case there is 3 sensors: two 2 and 12 teeth on crank and one with 1tooth in dizzy. We got engine running using 2 teeth crank sensor. But it is used for cranking in OE application and due to this both teeth is close to TDC. result is imprecise fluctuating advance on running engine.
It is Accord TypeR. Turbo. VTEC...

FunnyBoY · Post by **FunnyBoY** » Thu Nov 29, 2007 2:25 am

GintsK · Post by **GintsK** » Thu Nov 29, 2007 2:20 pm

Solved!

Alpha code reads Rpms as expected and gives four sparks per cycle for our 4cyl engine. http://www.msextra.com/ms2extra/files/a ... 071124.zip

Problem with rising/falling edge was due to my hardware settings!

Background:
I have configured long output pulse from LM1815 circuit at first nonsuccessive starts - 13ms using big cap. Picture from LM1815 datasheet below. The only reason was easy to scope so long signal relatively to loong engine cycle at cranking.

After signal inverting I found sync errors from falling edge (previous problem was rising). In both cases this was LM1815 active edge usable for sync!! But problem was at other edge - sync works from it!!! Deep zooming in timebase to investigate seemingly useless edge gives an answer! Normally problem was not visible. Here falling edge scopeshoot 1div=0.02ms or 0.04% of one cycle @2400Rpm of my testfile.

Thanks, James for Your work and sorry for confusing You!

Gints.