Speeduino is now on Github Sponsors (Rather than Patreon): https://github.com/sponsors/noisymime
Help with building your Speeduino, installing it, getting it to run etc.
By LAV1000
#46090
Which hall sensor are you using ?
Looks like it is not an automotive type.

If you make a tooth log > save file > post file on the forum.
Also make a data log of a starting attempt and post it.

If you don't know or don't understand it just let us know.
No shame in asking !
By davettf2
#46584
Just for info, my Cagiva Elefant (906 Ducati engine) has approximately the following cranking speeds:

Spark plugs in - 300 rpm
Spark plugs out - 1100 rpm

These were from measurements taken from the crankshaft sensor when fault finding the original Weber Marelli system.

Cheers
Dave
By LAV1000
#46585
davettf2 wrote:
Fri Nov 20, 2020 4:19 pm
Just for info, my Cagiva Elefant (906 Ducati engine) has approximately the following cranking speeds:

Spark plugs in - 300 rpm
Spark plugs out - 1100 rpm

These were from measurements taken from the crankshaft sensor when fault finding the original Weber Marelli system.

Cheers
Dave
That is a huge difference !!
Between plugs in and out it shouldn't be more then 150-200 difference.
Was this data read from the Marelli system ?
By davettf2
#46592
Hi, it was using the crank rotation sensor, I'll dig out the picoscope traces and double check and see if I can add them to the mail. I may have made a whoopsy on my calcs so will double check.

Cheers
Dave
By davettf2
#46596
An 'Oops' moment, forgot that the flywheel has more than one pulse per rev. Its an easy thing to redo as I have a test lead which can be inserted into the line. Thus will recheck later this weekend / early next week. (will need to just top up the battery charge as its been idle for several weeks).
Cheers
Dave
User avatar
By Chris Wolfson
#46618
If, for a moment, I consider your crank speed slowing down to be a normal behavior, my solution would be like this:
Position the relevant tooth on your crank at a position where the crank speed is high during cranking.
Compensate for this in TS, so the ECU calculates TDC from that position.
Now enable fixed pre-ignition for start-up.
Last step is to find an ignition point where your engine starts.

What the ECU does now: You have a stable cranking signal and the software calculates TDC. After the engine fires on the calculated point, everything goes as usual. The triggering tooth does not have to be at TDC. Maybe you did not realize this?

As I know more Duc engines starting with inductive pickups than with out, all working fine, maybe find another solution in fixing things causing this problem?

There could be many cause for your problem, not directly connected to Speeduino stuff:
Worst idea, there could be some kind of defect in your engine bearings. I had engines that still turned well without compression, but slowed down with plugs installed.
I suppose you did not reduce the flywheel mass? This has the same effect. Engines don´t start with to low rotating mass.
Then some other ideas to check:
Ground connection battery/ engine/ frame. Cause for the funniest problems, not realized by the smartest engineers, until anything else was renewed for xxl $.
Some with wires and connectors in the positive rail.
Magnet switch in the starter assembly worn out. In this case starter measures fine, but has no power. Check by bypassing.
A single winding in the starter burnt out. Starter seems to work normal, but was no power.
Bearings of the starter gear worn out.

Quite some things to check.
Don´t rule anything out, just because it is inconvenient to check until you have proved it is not the cause!
Vehicles with high use have defects from wearing out, those with very little use suffer from not being used. Those in between both conditions break down just for the fun of it... So never speculate, but check!

God luck!
By davettf2
#46629
Hi Peeps
Ah, the delights of posting before checking data! I've now re-run the traces for the engine with the following results:

Crank rpm during start cycle - 306 rpm (Plugs IN)
Crank rpm during start cycle - 319 rpm (Plugs OUT)

Traces hopefully attached are from the exist weber marelli system which is working OK, but is now 30 years old and has an issue that the voltage for the fuel pump relay is only just sufficient. Thus the drive to change, plus it gives me a project to do.
To achieve the traces with the plugs out you need, on an Elefant, to remove the fuel tank, which means removing all the bodywork. My original plan was to replace the existing cam gear with a version having an additional tooth wheel. However, as the bike was without the bodywork it seemed a good time to remove the generator cover and check spacing. Unfortunately there is insufficient space to attached a second tooth wheel. The possibility to use a later case, sensor further out and looks at the gear not the blade, is not practical as the existing crankcase will need to be relieved to allow the sensor to fit. Thus will now look at alternative locations.
Attachments
Cam and Crank.jpg
Cam and Crank.jpg (175.37 KiB) Viewed 87 times
Camshaft Sensor Plugs IN.jpg
Camshaft Sensor Plugs IN.jpg (109.12 KiB) Viewed 87 times
Camshaft Sensor Plugs OUT.jpg
Camshaft Sensor Plugs OUT.jpg (105.61 KiB) Viewed 87 times
By LAV1000
#46631
Might be better to create a own posting
So we don't pollute RCP212 postings.
As I see it crank does 8 pulses to 1 puls from cam.
If i get my calculations right given your rpm figures it should be 4 crank notches and 2 cam notches.
I did mention before to someone else or on an other forum, look at a cam wheel from a Ducati ST2 944 it has a 48-2 pattern.
If you need measurements I have one lying around.
Attachments
CamWheel (2019_08_05 13_57_12 UTC).jpg
CamWheel (2019_08_05 13_57_12 UTC).jpg (1016.38 KiB) Viewed 85 times

Even after removing the iat sensor and tps jumper […]

Hi, on my 2004 10.8 VVT MX5 (Miata) engine, there[…]

Ive not looked at the log, but you probably need t[…]

ATmega2561?

2561 also has its advantages Nice video! BTW wha[…]

Still can't find what you're looking for?