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Hi everyone, this is a general question regarding serveral cars i've tuned lately using Link Ecu's G4+. 

The question is i tried lots of trial and error on the cold start cranking parameters and calibrations and it really doesnt reduce the time that the engine will crank until it starts. Why's that? Using the factory ECU will start right off.

I've also done different calibration settings for the triggers using an oscilloscope and the voltage change on the arming tables doe not speed forward the cranking time.

Can you please help me to better understand how that works and how i can achieve better/faster crankings? (Keep in mind engines are not high compression.)


Kind Regards

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There are several factors which can affect time to start.  The main ones I have found are trigger pattern (also whether you are using a cam signal to sync) which can cause the ecu to take a full engine cycle. Some OEM and aftermarket ecus can start on wasted/banked and then switch to sequential which will aid faster sync.

Also, fuel pressure at ignition on/pre crank prime (is there a one way valve in the fuel system). 

Are you referring to any specific engine/car config.? 

HTH, 

Richard. 

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For the most recent i've done, i've seen some delay on cranking on a Subaru Version 8 Sti and on a Honda civic 96HC+ B18c type r. Tried playing with the arming voltage but it stills nothing compared to the factory ecu.

 

Fotis.

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I am actually in the same boat.  (subaru ej257)

I've played with multiple starting fuel settings and things never got much better. 

Hot start in my case is great. Cold start not so.. Thus it would indicate it being fuel related.

I've played with Crank Enrich Table from 20 all the way up to ~300. Seemed that there was no change. 

FYI.. I base my calculations on voltage drop (actual start crank), cam/crank signal sync and when the ecu logs the actual cranking rpm, to the point where it reached 400 rpm and then 1000. 

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9 hours ago, Fotis said:

Subaru Version 8 Sti and on a Honda civic 96HC+

For the subaru example the Link ECU may take up to 720deg to sync, the factory ECU may have done something more sophisticated with the extra missing teeth which would allow it to sync in wasted spark mode within 180deg.  For the honda with no missing teeth the link should sync within the same amount of time as the factory ecu as there are no special tricks they can do with that basic trigger pattern.

So for the honda, most likely a tune issue, for the subaru it will possibly never be as good as the factory startup.  

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