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Nissan optical never as fast to start on aftermarket ECU?


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So my TB48 Nissan optical CAS is as per the attached pic. I know that the factory ECU never shuts down. All fuel trims, idle learning etc is stored in RAM. I've noticed that people with aftermarket ECUs never have it crank and start as quick as the factory ECU.

My theory is that the factory ECU stores which cylinder it is up to in RAM all the time. It does often take longer to turn over if the battery has been disconnected which supports this theory. Aftermarket ECUs power off when you turn ign off or shortly after so it would be impossible for an aftermarket ECU to know which cylinder it is up to when starting the vehicle. Is that fair to say?

If I swap to a CAS wheel where each of the 6 slots all have a different length, will a G4X be able to start the car without needing to go all the way around to the home slot?

CAS.JPG

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Dave beat me to it but I was just about done with a similar reply.

As far as I have seen only nissans with a distributor use the single wide slot triggerdisc like you show in your pic (early SR20, RB30, and a couple of others). So the engines that have a distributor can start up fast since the ecu doesnt need to know the correct cylinder - the coil just sparks at every inner slot and the distributor will always send the spark to the correct cylinder.  The injectors just fire in batch mode until it syncs so they can fire a spark as soon as the first inner slot is seen.

As far as I can see on google the TB48 is coil on plug and the factory CAS should already have the trigger wheel with different sized windows?   So that should be able to sync within 120deg without "remembering" the shut down engine position.

With the G4X if you use the trigger disc with different sized windows and set trigger mode to "Nissan 360 Opto" then the ecu will sync as soon as it sees the first inner window (i.e. a 6cyl will sync within 120deg crank revolution).

 

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With the 360 opto mode in G4X it looks at the ignition mode and the number of cylinders to determine the trigger 2 tooth pattern so I would recommend against changing between distributor and non distributor disks if you are not changing your ignition system too. The G4X should sync faster than the G4+ but you still require enough crank etc enrichment to make it fire quickly.

If you do change the trigger disc without changing the ignition system you can use the 360 opto widest slot mode but this mode will not sync as quickly as the regular 360 opto mode.

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5 hours ago, Vaughan said:

With the 360 opto mode in G4X it looks at the ignition mode and the number of cylinders to determine the trigger 2 tooth pattern so I would recommend against changing between distributor and non distributor disks if you are not changing your ignition system too. The G4X should sync faster than the G4+ but you still require enough crank etc enrichment to make it fire quickly.

If you do change the trigger disc without changing the ignition system you can use the 360 opto widest slot mode but this mode will not sync as quickly as the regular 360 opto mode.

Yeah I definitely won't be changing the wheel if it's already got the good one. I'll only change it if it's like in the picture but I suspect the picture is wrong..

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5 minutes ago, bradsm87 said:

Yeah I definitely won't be changing the wheel if it's already got the good one. I'll only change it if it's like in the picture but I suspect the picture is wrong..

If you are using a direct spark ignition setup and it has the disk with 5 equal gaps and one large you will need to change the disk for it to work properly in the 360 opto mode. Are the TB48 all direct spark from factory?

You should be able to check your disk style by cranking it over and performing a trigger scope.

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