cranking

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secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

cranking

Post by secure »

OK I'm the new question bank :D
I've noticed the late cranking on my car and tried diffrent cranking settings without any success. Is it something about the ecu architecture? I'm asking that because I see that the ecu follows some steps during cranking to get run. Preinjection and ignition settings doesnt change the things so much. I can delay the cranking time but I couldnt succeed to shorten it yet.

Cheers
Ryan.g
Syvecs Staff - Caretaker
Posts: 498
Joined: Fri May 30, 2008 4:05 pm

Re: cranking

Post by Ryan.g »

What crank and cam setup are you running?

I expect it takes a while to fire due to the ecu requiring 720 sync. If you watch the sync state in the top right hand corner. How long after it reaches 720 does it take for the engine to fire?

Ryan
pat
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Re: cranking

Post by pat »

Unless it has been changed it will be on Subaru G10, which is slow to sync due to the pattern. The crank is not capable of 360 sync on its own without the cam, so the first thing we do is wait for the 3 teeth on the cam, which may take up to 2 revolutions to appear, then the sync is verified for another revolution or two. We are looking at ways of achieving reliable sync sooner on the G10, but it is difficult. You can be naive and assume that you've synced up correctly, or you can be paranoid and assume you're wrong until proven right. We prefer the paranoid approach, engine damage can result if it's not right (I've been sat in a car with another brand of ECU which destroyed its engine because of poor sync checking). So rather than saying "yep, there's 3 cam teeth, off we go" we say "yep, there's 3 cam teeth, so what should happen next is this, then that, then the other, and if all of that happens, then and only then will we be confident enough we know where we are". For now, then answer is patience, G10 will take at least 3 turns to get going.

Hope this helps,

Pat.
secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

Re: cranking

Post by secure »

any update here? The engine sometimes runs with a Syncfault - Timer Overflow. Not sure why.
ScoobyDuck
Posts: 49
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Location: South Uk

Re: cranking

Post by ScoobyDuck »

one of my biggest issues with the ecu for me will be the cranking as my car doesnt get used a lot and so when it does it needs to start on the first couple of seconds. On the standard oem ecu thats not a problem but 2 or 3 complete rev's is not going to do an already half flat battery any good :(

Pat - can you explain how the oem ecu does it and why this cant be implimented in the syvecs ? is it because of the gate/chip design ?
I know its not good practice to just assume its all correct and fire but I dont think I've seen any standard ecu-ed subaru crank itself to death because of it ?!

cheers
Steve

EDIT: Ver3 MY97 UK
pat
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Re: cranking

Post by pat »

Steve,

Some suggestions :

1) Invest in a trickle charger. Not expensive and will keep the battery healthy. Leaving a lead/acid battery for extended periods without a maintenance charger will cause sulphation of the plates and degrade its performance, sometimes permanently

2) Replace the crank trigger wheel with a G11 one. That pattern is capable of 360 sync on its own and will save one or two revolutions whilst cranking. You can still use the G10 cam sprocket with a manual cam checklist.

As for the OEM ECU it makes assumptions. If you see only one cam tooth then you know one of two pistons is at TDC so just fire them wasted spark. If you see two cam teeth you know which piston is at TDC so just fire that. Finally if you see three then the same logic applies. The problem is... what if you "miss" one of the 2 or 3 teeth, you'de fire the wrong cylinder and end up a) doing nothing b) back firing c) turning the engine backwards... none of these are going to help the engine start any sooner! The last may stop it from ever firing again. We could make the same assumptions, and potentially get it wrong. There is no technical reason the FPGA couldn't synchronise this way, but you know what they say about assumptions....

Cheers,

Pat.
ScoobyDuck
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Location: South Uk

Re: cranking

Post by ScoobyDuck »

Pat,

1) yes - ok lol. As I mentioned at TOTB, I have space restrictions that make it impractical to lift the bonnet so I'll have to work out another way to attach a form of charging. As you say, its worth it if it doesnt get used for 2 weeks or so for the battery's sake.

2) G11 being off an 02-05 ? If thats a direct replacement fit and can be used with the V3 sti cam wheels then that a good option. 1 or 2 rev's on cranking is quite a saving!

3) OEM - yes guessing isnt good. I wonder if they wait for 2 cam teeth? i.e. see 1, you know to expect 2, so when that happens fire?

As I've already said, I've never heard of an OEM cranking and firing itself to bits but I can totally see the logic in waiting to make sure you're in total sync.
As mine is more of a small budget road car I guess I'm expecting a top end ECU to 'not care so much' lol

cheers
Steve
secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

Re: cranking

Post by secure »

Update..
Do we still on the paranoid side?
I have seen S6 Firmware Version 1.20.1 which says "..Cam trigger patterns which reduces cranking time..."
I have updated to 1.20.1 but not seen any cranking improvements. Is this applies to G10 ?
This is annoying and I will upgrade to G11 crank trigger.
Do you have the crank trigger settings for G11?

cheers
cuneyt
Ryan.g
Syvecs Staff - Caretaker
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Re: cranking

Post by Ryan.g »

Hi Cuneyt

The OMIT Changes which were applied in the 1.20 firmware were for customers which use a generic single tooth Key by Cam Strategy. This Firmware Update will not affect the G10 Setup.

Pop me a Mail at Ryan@syvecs.co.uk with your cal and i will update it for the G11 Trigger.

Ryan
secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

Re: cranking

Post by secure »

Thanks.
YHM Ryan.
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