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R32 GT-R G4+ to G4X upgrade , won't start


mike2016

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Adam,

I'll be home soon to test it. 

One quick question, there are many other G4X + NZ Wiring trigger setups out there, why has no one reported such issue yet? 

I talked to my builder, they already built over 10 cars with the same setup, and they have not had any issues with the trigger problem. 

 

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Ok, the ecu logs for some reason we have two of the same log and 1 with nothing.  But in all the triggerscopes with the new firmware the trigger looks like it is working fine now (it may just be luck that only good revolutions were captured but that is all I have to go on so far).  

Sorry to keep asking you to do more and more logs but it is the only way we will get it solved without being there in person...  

Can you do a PC log of another start attempt.  Also download the matching ecu log afterwards (maybe delete all logs that are presently stored in there so you know any new log is the correct one). 

Perhaps you can also do us a pc log of a start up with the G4+ so I can compare if anything else is drastically different when cranking such as inj PW etc.  

 

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I uploaded the files to 02-18 folder. It managed to start and ran for a few seconds, lots of backfires. very rough.  throttle does nothing. 

Jono and I did a scope on G4+ while it's running and cranking, i uploaded those as well. I'll try to swap the ECU later today and do a PC log. 

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Ok, from the looks of those last logs there doesnt seem to be a trigger issue anymore, I suspect that may only have been a contributor to the starting problem and not all of the difference.  

Have you tried adjusting fuel at all to see if adding or removing fuel makes it behave any different?  Backfiring normally suggests timing is off but can also happen if mixture is far enough out to cause misfires.  I have ran your G4+ map and G4X map on the engine simulator and get the same spark timing comparing both so I expect that is ok. 

As a quick/crude fuel adjustment I would just go to >fuel main and adjust the engine capacity up or down.  Try adding 500cc and subtracting 500cc and see if it runs any better either way.  

Otherwise the G4+ log will be helpful to compare too.

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i'll try adjusting the fuel later today and see what happens. 

after it started earlier today, it won't start anymore on the second try. as i wanted to get 2 different logs.  it's inconsistent. 

but why the same setting / map runs perfectly fine on G4+ but not the G4X?   are we missing something here? 

 

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One of the engineers come back to me with an interesting comment.  He said it looks like the firing order is wrong as the RPM speeds up for half a cycle then slows down for half a cycle.  However the firing order is set the same in the G4+ and G4X maps.  That would explain the backfires etc too.

Can you take a look at the board on your G4+ ecu to confirm it is definitely a GTR plug-in and not a 300Z plug-in (basically same ecu built with different firing order)?  It should have GTR/GTS printed on it somewhere.

If the G4+ is a GTR plug-in then that kind of spoils that theory but it could still be worth doing an ignition test to confirm the correct plugs fire.  To do the ignition test you pull out the coils and ground the spark plug, set ignition test to say ignition 1 and you should se a spark on cyl 1.  Then go along the engine and confirm the others.  

 

 

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that's a good point!!  if the firing order is wrong that explains everything! 

i found a picture i took of the G4+ a while back when i added expansion loom. 

can't really tell what it is but i have a feeling it's a 300Z board. 

645B7881-FED4-4C24-9512-19284BD2359B_1_105_c.jpeg

i'll be home in an hour or so, to double check what board the G4+ is

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Yep, that is a 300Z ecu, I can just see the "Z" before the Link.  

UC2KAz5.png

 

So someone has changed the wiring in your car to make the 300Z ecu work.  It would be best to change it back to factory, but if I have had enough coffee this morning I think a quick fudge of the firing order may allow it to run.

Try changing the firing order to 123456 like below and see if it starts.

5ehQebG.png

 

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G4X is working properly now!  

changed the firing order to 300ZX and it started right up! 

Sorry to have wasted everyone so much time, and thanks so much for you and your team's help. I appreciate it. 

I had no idea the shop who built the car used a 300Z ECU until now, i don't know what the reason was ....

I changed the pins back to factory on the ECU connector after we confirmed G4X is working. 

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