VEMS Community Forum
Technical => Ignition => Topic started by: andreNL on November 28, 2010, 05:16:01 pm
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Hi, after the cam sensor evrything was working
sparks injector rpm evrything worked.
Engine spluterd ones tuning for first start.
Then nothing, checked sparks nothing ???
Noticed the coil was really hot probeply fried
How is that posible?
Because when engine is standing stil no sparks
And while starting it can loose the energy.
Some how the cool hete energiezed, i Hope my igbt are Oké
I remember turning the dizzy, maybe i turned it to much
So the cap and rotor didnt contact.
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If the coil is left charging for too long it can burn out - what sort of fuse did you have on the primary coil feed?
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Its fed from the standard relay wich is fused 15amp
I know it should be lower 7 or something i think the igbt is 7amp
I Hope the igbt is Oké other wise i need to change it.
I think its the amount sparks causing the heating up of the coil
In a dizzy setup.
I am Using standard main relay for vems injectors and coil ,
And a fuel relay, fan relay fused seperated.
Cheers andré
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I think i know whats wrong,
i have a three cilinder engine with a 24-1 tooth wheel.
the hall sensor is fitted 55 degrees before tdc, the missing tooth
60 degrees before tdc.
So when de missing thooth is detected the engine still has to turn 60 degrees.
I set my tdc after trigger (the missing tooth trigger) to 115 degrees.
i set trigger theeth after missing thooth to 7 (7x15 = 105 degrees)
this is wrong because reading the forum, i need to set trigger theeth to 2 is 45 degrees (or 3 = 60)
and tdc after trigger parameter to 115 - 45 = 70 degrees.
But why did i got sparks turning engine with sparks out?
that was because trigger tooth was set at 7 is 8x15 = 120 degrees + 115 degrees after the trigger tooth
gives 235 degrees engine rotation thats enough to fire ignition on the dizzy for the next cilinder !!
in stead of firing 1-2-3 it fired 2-3-1 with 1 at tdc.
I am going to set trigger theeth to 2 and tdc after trigger to 70 ( 45 + 70 = 115)
thooth reference table will be 2 - 34 - 18
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Ref tooth table usually contain 0. So
32 0
16 or 32
0 16
will be right ref tooth tables. Second one gives later synchronization, but commonly used to prevent false synchronization possibility.
Ign and inj output tables should be filled accordingly.
If missing pass the sensor so close as 55 deg before TDC (it is bit unclear in your description), trigger tooth will be 0 and trigger angle 55deg.
But it is possible to configure trigger to next cylinder: trigger tooth 7 and trigger angle 55+30=85deg. First kind should be better.
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Sensor fitted behind the pouly fixed to the engine
55 degrees before tdc
So if the trigger passes the sensor it needs to rotate
55 degrees to get at 0/360 degrees
60 degrees later the piston is at tdc
So the piston is at 115degrees if the trigger is at sensor
I Hope it clearfies :)
You say trigger tóoth 0
And degree before tdc 115
Table 16-32-0 ???
Is posible i think
Doesnt the tooth table needs to be the same as the counted thooth after the trigger tooth?
Ie thooth after trigger thooth = 4
Table 20, 36, 4
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Sensor fitted behind the pouly fixed to the engine
55 degrees before tdc
So if the trigger passes the sensor it needs to rotate
55 degrees to get at 0/360 degrees
60 degrees later the piston is at tdc
So the piston is at 115degrees if the trigger is at sensor
By trigger you mean missing gap?
It does not matter where sensor is mounted. Only thing what matters is how much degrees needs to rotate from [missing passes the sensor] to [tdC]. If angle is 55, then my numbers are correct. If there is 115 deg then use trigger tooth 2 and trigger angle 55
next trigger tooth = 16
angular width of tooth = 30
Both above in any case!
If ref table or some of last two mentioned values are incorrect there is chance to fry some coil.
I Hope it clearfies :)
You say trigger tóoth 0
And degree before tdc 115
Table 16-32-0 ???
Is posible i think
tables work from bottom to top.
Doesnt the tooth table needs to be the same as the counted thooth after the trigger tooth?
Ie thooth after trigger thooth = 4
Table 20, 36, 4
We configure table with 0 at one position in 100% of configs. 0 is first tooth after missing gap. Then trigger point is configured by tooth count from 0 plus angle.
another important thing to check is when cam sensor signal comes. (cam sensor is a must for 3cyl with 24-1 and dizzy) Config values above will work in case if cam signal comes in such chronology: cam signal - missing gap - spark for 1st cyl.
In case if it is shifted by 1 rotation (cam signal - missing gap - exhaust stroke for 1st cyl.), config will looks different because then 1st cylinder is not reference any more.
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Cam comes just after 3 ignition 680 degrees + a little
Fitted new coil and checked it, current stay on
Cant get it of the coil software wise i think the igbt is broken :(
Changed the channel to a empty one and still 12v on the coil wires.
It looks like the igbt isnt switching off.
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So have you previously non used IGBT out of order?
Are you proof about your config? May be those channels are reused for some other purpose in config?
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You have just one ign channell used right? Could it be it is just inverted in config?
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:-[ checked inverted ok not inverted :'(
Opened the box saw it right away burned igbt
Somehow the igbt went through the heat transfer paper touching
The box with aluminium back side.
Second time i have this :(
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What firmware?
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1.1.77
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1.1.77 is not offically approved for use. I suggest 1.1.84. See here :
http://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChanges
For upgrading you need latest VemsTune: "2010-11-26 comm model testing"
http://www.vems.hu/download/VemsTune/NIGHTLY/VemsTune-Install-2010-11-26-commModel-testing.exe
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OK thx,
i upgraded vemstune to 2010-15-11 but its not stable enough crashes to much
i tried upgrading to 1.1.83 but that gave so many strange things i quickly
changed back to 1.1.77 wich looks pretty stable and functional in my setup.
But i do what you sugest upgrading vemstune to 1.1.84 and 26-11-2010.
1.1.84 isnt released either
i miss a function in vemstune to find your timing degrees of the engine.
Something like, turn engine till missing is found (light flashes in software)
push a button and turn engine till missing is found again.
you can exactly pin point tdc and ignition degrees relative to engine TDC in the software.
Now you have to messure it by hand wich is difficult to find the exact degrees in 0,25 resolution ;D
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1.1.84 at least comes with a nice comment about it's quality. They rarely turn out worse than previous versions. ;)
I don't understand why you need a software function to find the missing tooth, don't you have a strobe light?
The triggerlog will develop into kind of what you need later, as it will indicate trigger, ignition, injection and cam events.
Just do a rough assessment of the trigger tooth and TDC after the trigger, then use the ignition lock function and fine tune it.
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hi Mattias thx for the reply :)
yes i do have a timinglight but its broken ;D
and my engine istn running so its useless anyway :D
if you can exactly calculate ignition timing you dont have to worry about that
during tuning your fuel requirements and cranking and priming.
Its like rulling out timing issues and focus on fuel requirements and other settings
a DIY VEMS enthusiasts encounters.
I will update my firmware when my hardware is working well
if i update now i don not know if a certain problem is software problem or hardware
with my 'old' firmware i now ;D
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It's impossible to exactly calculate ignition timing from rotating the engine by hand, the error will be a lot higher than 0.25 degrees and I don't have to tell you how bad that is on knock-limited turbo engines. Sure, you can tune and listen for knock and get best torque on a dyno - but you won't know what exact timing you ran if you never used a strobe light to check which makes any numbers in your ignition table suspect and useless for comparison.
A timing light is the only way, if there was another way it sure would be a revolution.
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Oké i will set ignition with a timinglight once engine is running like you said.
Cheers andré
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Well got sparks again ;D
soldering at -8 degreees is not nice but it works again sparks on all cilinders
with a dizzy setup using 23-39-7 as tooth table and trigger tooth 7 after de missing tooth.
but now other problem >:( my 3th injector is flowing fuel in closed position ???
i know its closed because when i open it manual in Vems it sprays loads of fuel extra and
is clicking. it looks like the needle seat is leaking so much its even dangerous for my engine.
Lucky i have a spare injector gonne replace it tomorrow.
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Hi All ;D
Inspring weekend for me, trying to start my engine
but my injectors where broken. i bought 2 bigger from ebay wich should
balanced cleaned and seals renewed but two of four didnt close properly
and where flooding my engine >:(
I had a spare set of smaller injectors same high impedance and connectors wich are oke :D
so thats working oke now, i'll source down some new bigger injectors later this or next year.
i also did some theoratical thinking about how vems triggers ignition and injectors.
I have a 24-1 trigger wheel
The sensor is located 55degrees before TDC and the missing thooth is 60 degrees (4 tooth) before TDC
together Piston travels 115degrees after the missing to TDC.
Now if i set trigger theeth to 7 and trigger degrees after trigger tooth in the primeray trigger settings at 115 degrees
and in the ignition tooth table bottom up 23-39-7 then ignition acurs 115+(8x15)+(8x15) is 355 degrees wich is 240 degrees after
the first cilinder TDC and is exactly my second cilinder ignition. (1-2-3 firing order)
if i am wright this is cool because you can exactly time your injection event.
example: 4 cilinder 1-4-2-3 firing order 60-2 trigger wheel (10 degrees tooth distance.)
inlet closes 185 degrees after TDC inlet stroke.
You set your missing thooth 170 degrees after TDC,
primery trigger tooth to 0 (10 degrees later)
degrees after trigger tooth 5 degrees.
Now injection starts at 185 degrees after TDC (inlet stroke)
To get ignition timed to for example 10 degrees before TDC
the piston has to travel 165 degrees is 16 theeth + 5 degrees.
so you set your ignition tooth table to 46-76-106-16
and add 5 degrees to the degrees after trigger tooth in the primery trigger settings. (10 degrees in the setting)
I hope my thought are right, now figering out how the injection table works.
Its working in reversed order but is it following the firing sequence 3-2-1 or ignition events 2-3-1?
Cheers hope my thought are wright and it helps the forum ;D :D
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I didn't bother making sens of what you wrote.. sorry.
With 24-1 primary trigger on the crank the trigger tooth table is top to bottom on a 4 cyl engine is always like this : 36,24,12,0
(most put the 0 at the first cell in the table, because it syncs faster, this also shifts the ignition table correspondingly)
You can't time your injection events unless you have cam sync, and that's just the way it is.
When you have your ignition table set correctly, then set the injection table with the corresponding cylinder injector on the same row as the ignition tables output for that cylinders coil. If you have cam sync, you can then set the injection timing table, which indicates the number of crank degrees after ignition for each cyl, so about 400-450 degrees or so works pretty well for emissions and steady idle, better throttle response.