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Set up for DFI ignition Holden VN V6 buick 3.8L


MARK CHAPMAN

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When I built the loom for this boat, it was running the standard ECU (which had lots of problems inside the memcal chip). So we simply got the link and wired it into the box I had the standard one in. So there is no shielded cable for the triggers. The HT leads that go over the engine for cylinders 2,4,6 lay over top of the trigger wiring to the DFI unit and close to the loom that goes to the link. Could this play a part in the advancing? getting to much noise at higher rpms thinking the engine is in a different position? The way the timing light showed it, is that we were 56* BTDC not 28*?

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23 hours ago, Patrick Patterson said:

I have a G4+ xtreame, has 2 knock inputs 

Ah I looked back at the first post in this thread and it was a G4 Storm, I didnt notice this was an older post that had been recycled.  So yes you can set up knock control but you will typically want audio equipment also to verify the setup is detecting real knock correctly.

 

1 hour ago, Patrick Patterson said:

So there is no shielded cable for the triggers. The HT leads that go over the engine for cylinders 2,4,6 lay over top of the trigger wiring to the DFI unit and close to the loom that goes to the link. Could this play a part in the advancing? getting to much noise at higher rpms thinking the engine is in a different position? The way the timing light showed it, is that we were 56* BTDC not 28*?

Does your timing light have a wasted spark or 2 stroke mode?  As a normal timing light without this feature will show double the real advance with wasted spark ign.   

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39 minutes ago, Adamw said:

Ah I looked back at the first post in this thread and it was a G4 Storm, I didnt notice this was an older post that had been recycled.  So yes you can set up knock control but you will typically want audio equipment also to verify the setup is detecting real knock correctly.

 

Does your timing light have a wasted spark or 2 stroke mode?  As a normal timing light without this feature will show double the real advance with wasted spark ign.   

Timing light works with wasted spark. from the ecu we can lock it at 0 and read 0 and lock it at 28 and read 28 no worrys. Like I said earlier, applying level 4 filter on trig 1 fixed the fuel pump issue and steadied the spark issue. So just wondering if its more likely a trigger issue ie: getting noise at higher rpms

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Ah yeah, sorry brain fart.  The wasted spark/2 stroke timing light mode is only needed for advance timing lights which you already said you didnt have.  A static one doesnt care if it is wasted or not. 

 

2 hours ago, Patrick Patterson said:

So just wondering if its more likely a trigger issue ie: getting noise at higher rpms

Yes, it sounds like potentially EMI noise or an electronic "ground bounce" type effect if filtering helps which is why I was asking about the trigger errors and dwell instability earlier as those would usually be present if there was noise being interpreted as "edges".  A trigger scope taken with filtering at level 1 compared to a scope taken with level 4 filtering may be good enough to see something.  

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1 hour ago, Adamw said:

Ah yeah, sorry brain fart.  The wasted spark/2 stroke timing light mode is only needed for advance timing lights which you already said you didnt have.  A static one doesnt care if it is wasted or not. 

 

Yes, it sounds like potentially EMI noise or an electronic "ground bounce" type effect if filtering helps which is why I was asking about the trigger errors and dwell instability earlier as those would usually be present if there was noise being interpreted as "edges".  A trigger scope taken with filtering at level 1 compared to a scope taken with level 4 filtering may be good enough to see something.  

That's really the only thing I could put it down too. This is a trigger scope with engine off filter level 1 and the fuel pump still running. Also been advised to put a suppressor on the IGN feed to DFI module if that would be any help? and shorten the earth wire that feeds it also. I've got the loom out so I will run shielded cable from the triggers to the DFI and back to the ecu. And I will pull some timing out of the tune, but it really should handle 28* all day long. 

Trigger Scope Log 2022-04-16 12;00;25 pm.llg

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