azmak Posted July 22, 2022 Report Share Posted July 22, 2022 I would appreciate any guidance anyone can give me. Cranking time is too long. The engine starts after about 2 seconds of turning the starter. I have changed fuel settings, cold start, etc. but no improvement. Please let me know what is wrong. It is a 350Z (VQ35DE engine) with R35 GT-R injectors and HKS supercharger. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 22, 2022 Report Share Posted July 22, 2022 Can you give us a log of some start ups. Quote Link to comment Share on other sites More sharing options...
azmak Posted July 23, 2022 Author Report Share Posted July 23, 2022 On 7/22/2022 at 6:22 PM, Adamw said: Can you give us a log of some start ups. Thank you for all your help. I have saved the Log at startup 3 times in a row. Please take a look and give me some guidance. Quote Link to comment Share on other sites More sharing options...
remski2 Posted July 23, 2022 Report Share Posted July 23, 2022 I just compared your startup to mine.. seems like yours is about 60% shorter than mine.. Your cranking-to-start is about 0.9 second.. to 1.2 seconds.. in all 3 cases.. Turn on your "pre-crank prime" and see if that helps.. But I am still interesed what others have to say... Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 24, 2022 Report Share Posted July 24, 2022 Yeah I dont think it will get much better. Most of it is "sync time" - this is when the ecu has determined engine position and phase. VQ35 trigger mode needs 360deg crank rotation to sync. In pic below; Red line is where battery voltage drops (starter motor first engages). Log time 03.218s Purple line is where RPM is first detected. Somewhere between time 03.796 & 04.046s Blue line is when ECU has determined crank and cam position and fuel and ignition are enabled. Time between 04:046 & 04.077s Green line is engine running (>400rpm). Time between 04.108 & 04.140s. So 0.922s total to start, about 0.8s of that was taken up by the ecu determining crank and cam position. There is not much you can do to improve the sync time apart from make cranking speed faster, it is really just a fact of an aftermarket ecu with a more basic trigger code since it has to work with many different types of engines. The factory nissan ecu only needs to run 1 engine type so it will have a more complex sync strategy - it will probably use both camshaft sensors and may also start in wasted spark so will sync much quicker. remski2 1 Quote Link to comment Share on other sites More sharing options...
azmak Posted July 25, 2022 Author Report Share Posted July 25, 2022 I see. If that's the case, I don't blame you. I tried "pre-crank prime" as well as many other things, but still no improvement. I will consider measures to increase the cranking speed in the future. Thank you all very much. Quote Link to comment Share on other sites More sharing options...
pvainola Posted July 25, 2022 Report Share Posted July 25, 2022 My crank time is roughly the same and I have wondered this myself. I also have a VQ35DE and HKS8555. I'm running E85. Quote Link to comment Share on other sites More sharing options...
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