[Jason hall]

Just a randon thought.

Are you getting electrical inference that is randomly firing the cam signal?

I've not read back through the topic. How is the cam signal shielded? Where is it grounded?

Mostly Factory harness , just repinned to dropbear pins and connectors . The cam trigger has a seperate wire outside the loom for the negative side as from factory the negatives are spliced and the speeduino has separate grounds for the cam and crank that go back into the ecu.

[LPG2CV]

This is not really my area, but was a thought.
When you say grounds, do you mean shielding?

I'm not convinced with the spliced -ve.

I'm sure someone who knows more about vr than me will comment.

Though if you can't fix it with setting up the trigger wheels, perhaps investigate this further.

[Jason hall]

This is not really my area, but was a thought.
When you say grounds, do you mean shielding?

I'm not convinced with the spliced -ve.

I'm sure someone who knows more about vr than me will comment.

Though if you can't fix it with setting up the trigger wheels, perhaps investigate this further.

No there’s power grounds - to chassis ground
Sensor grounds - to sensor ground pins at ecu

I said I DONT have a spliced -ve, it did from factory but I removed it so it’s go dedicated -ve Vr sensor grounds to the designated pins on the ecu as per the manual .

[Jason hall]

I set it up again at tdc.
Marked under sensor
Rotated to reset and marked tooth after reset .

Reset to tdc
Rotated until tooth after reset
Total approx 285deg

See image attached of what my gears and factory marks look like etc. it has very spurratic spark output .

It’s 12 crank
1 cam
Bosch dual igniter 7 pin
Ecu set to 3.5ms dwell as per Bosch instructions
Dual wheel
Rising /rising

I mean all I’m trying to do is get the frigging thing to output spark at fixed timing of zero degrees so I can move on with life ffs.

If any of you know the answers and are a shop/legitimate im happy to pay for assistance to just make it trigger correctly .

I have contacted speeduino and got zero responses at all about anything .

[jonbill]

What you're calling "reset" is the cam tooth passing the cam sensor, right?
It sounds like you're doing it right.
But to be sure:
Set the engine to tdc compression.
Rotate the engine in its normal direction until the cam tooth passes the sensor.
Continue rotating until the next crank tooth is under the crank sensor.
How many degrees in total have you rotated the crank from tdc? 258?

So, your trigger angle is approximately 258 or -102 (258-360). You then refine it it by setting crank advance to 5 and cranking it (without the plugs in) and using a timing light to see where its actually fireing. It'll probably be a few degrees out. So you add or take away a few degrees from the trigger angle until its right.

But... I think you said that it fires at a different place every time, is that right?
Thats not a problem with your method for finding the trigger angle. Possibly the cam sensor is picking up something else as the cam tooth.
Can you share your tune and a data log and a tooth log?

[Jason hall]

Yes reset is cam tooth passing cam sensor .

Yeah it’s minus 102/105 whatever .

when checked with timing light it’s firing at a different angle every attempt .

I have the ecu internally set via switches to vr and vr.
The sensors both work .
With ign on , engine off the crank and cam signals rise to a flat 2.5V or so ( being caused by ecu I assume , does it run some sort of 2.5v pull up when set to VR as part of the conditioning process ?)

I have just rewired the crank and cam into their own 4 wired shielded cable , so I will scope that tomorrow night but I’m sure it will make no difference.

When I got the ecu brand new from speeduino the map sensor wasn’t attached to the board so hopefully that didn’t short something internally or something weird to the ecu. ( I doubt it )

Once I get it all set back up tomorrow night i will try and get a clean scope pattern with ecu plugged in and ign on.
Then if that’s working I will do a tooth log
Then if that works I will upload it all and the tune file.

If this doesn’t work I will unpin the entire ecu except power , earth , crank and cam and see if it’s suddenly cleaned up.

I think there’s noise on the sensors somehow using a nearly entirely factory harness that worked fine . I got this abortion of a scope pattern before I decided to rewrite the sensors into shielded cable .

[jonbill]

Given your crank teeth are so small ( they look small in your sketch anyway) perhaps they're bring misread. If there's no sync loss in in the datalog then that would be my guess.

[LPG2CV]

Still no experience with VR ... however.

Look at the shape of each tooth on both Cam and Crank. The Cam builds, and then drops off sharply. The Crank doesn't. I suspect polarity is incorrect on Crank.

I'm sure someone will comment.

[Jason hall]

Still no experience with VR ... however.

Look at the shape of each tooth on both Cam and Crank. The Cam builds, and then drops off sharply. The Crank doesn't. I suspect polarity is incorrect on Crank.

I'm sure someone will comment.

Yeah that’s the issue , it’s being misread.

Polarity is correct on both sensors .

When these are scoped not connected to the ecu the patterns are fine , when connected to the ecu it becomes a rubbish mess like this and is also being “ pulled up “ to 2.5v aswell.

I thought these sensors required no pull-ups being VR and were internally conditioned to digital .

So why is ecu outputting 2.5v to them ?

[PSIG]

Not to your last questions, but noticing four very large noise spikes that are adding "teeth" to the pattern. The decoder would have a very hard time reading and sync'ing more than the expected number of teeth. Just an observation of your picture above. <shrug> Where is the noise coming from?