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etiennekuh
Joined: 31 Jul 2008
Posts: 34
Location: netherlands
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 Posted: Tue Dec 15, 2009 9:22 am Post subject: |
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how will I notice if the opening time is to short? will the car start to stumble when more fuel is needed?
I have installed the high impedance injectors, but they won't open.
If I put 12v from the battery they still won't open, I know that low impedance injectors open with a 12v battery suply. But it could alsow be that the injectors are to old.
If someone has a solution... thank you.
I will alsow look for other high impedance injectors to test if they work.
Etienne
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tuning is like a good hobby, it never gets bored  |
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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Tue Dec 15, 2009 1:05 pm Post subject: |
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| etiennekuh wrote: | | how will I notice if the opening time is to short? will the car start to stumble when more fuel is needed? |
Don't worry about it, tuning your injector opening time is a fine tuning thing, its when you start doing stuff like going down hills engine braking that you notice.
| etiennekuh wrote: | I have installed the high impedance injectors, but they won't open.
If I put 12v from the battery they still won't open, I know that low impedance injectors open with a 12v battery suply. But it could alsow be that the injectors are to old. |
Then they are gunked up and stuck closed, if you tap 12v to any injector type it should click open. Just don't hold it there very long, don't wanna burn it out.
| etiennekuh wrote: | I will alsow look for other high impedance injectors to test if they work.
Etienne |
Good plan, one of the best things i did to simplify my tuning process was to swap out my low impedance injectors to high impedance ones. It eliminates a bunch of potential variables from the tuning process.
Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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etiennekuh
Joined: 31 Jul 2008
Posts: 34
Location: netherlands
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| Posted: Wed Dec 16, 2009 9:36 am Post subject: |
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I have good news!!! 
I have new injectors (from a 83 bmw 535) they are high impedance and work well (just one will not open sometimes, but they are old and need time to work well again, I am not worried about that.)
My injector opening time is 3 ms if I make it smaller the car leans out. and my REQF is 17.8 (the injector is 18lbs)
is 3ms opening time to long?
Another question.
My Idle valve doesn't work correct.
I have a 3 pin bosch idle valve its connect as a 2 pin valve. so 1 +, 1 ECU ground, and 1 thats connected to the ground with 25 ohm and 25 Watt resistand. It only buzzes. everything is connect the right way
In my MT I selected PWM warmup only. when I change in PWM idle setting nothing changes.
what could it be???
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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Wed Dec 16, 2009 9:51 am Post subject: |
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set your opening time to 1ms, don't adjust your opening time to compensate for not having enough fuel. Change your required fuel for that.
Min
_________________
Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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RC
Joined: 25 Mar 2007
Posts: 2637
Location: Australia
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| Posted: Wed Dec 16, 2009 12:27 pm Post subject: |
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etiennekuh,
In international and/or illiterate language:
All your questions are basic and would not be needed if you RTFM!
The 1mS injector dead time (not just opening time but the total lag incorporating opening & CLOSING) is set as default. If you RTFM you would know that. Also if you RTFM it advises that if you don`t know WTF you`re doing, and clearly you don`t, to leave all the defaults as they are.
So if you screwed up that setting it`s most likely that you have screwed around with others. And dug yourself in a deep hole, because you failed to RTFM. Some more complex issues may require searching the MS forums for additional info but all this basic stuff is well documented. Sure that sooner or later Min will tire of holding your hand or carrying you.
Probably best idea is to start a new project completely. RTFM and enter the basic known variables and leave all other settings default. Use the req fuel calculator and MS generated tables to start with.
Get it running & idling first, with no IACV or throttle stop adjusted open. Then RTFM about the Bosch IACV before playing with that. Have you upgraded the IACV driver transistor? |
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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Wed Dec 16, 2009 4:36 pm Post subject: |
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chuckle, not quite how I would have said it RC. I'm going to explain the opening time thing a bit more here etiennekuh so you fully understand why you shouldn't be messing with those numbers. Setting the opening time to 3 milliseconds means, your injector will take about 1ms to open fully (ish) and then it will spray an extra 2 milliseconds of fuel into your intake stream every time your megasquirt tells the injector to open. This is a bad thing!!!!.
Set your injector opening time to 1ms like the manual says, and then adjust your required fuel setting until you get around 13.5:1 AFR reading on a wideband oxygen sensor. From there, you need to worry about actually tuning the VE table for your car.
What VE and spark table are you using? did you generate a VE table? or are you using one of the ones that has been posted?
Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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etiennekuh
Joined: 31 Jul 2008
Posts: 34
Location: netherlands
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| Posted: Wed Dec 16, 2009 7:45 pm Post subject: |
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I read the manual over and over, some things I just donīt understand, I am still learning.....
Now thatīs a good explaination!
I am using your VE table, I donīt use sprak becaus I use the tiristeron ignition module (works verry well!)
Etienne
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Rich H
Joined: 10 Jun 2007
Posts: 2665
Location: Preston, Lancs, UK
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| Posted: Wed Dec 16, 2009 8:19 pm Post subject: |
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From my experience of a 924 on MS:
If you know of any problems - fix them.
You are totally wasting your time if your setup is not as good as you can get.
Make sure your injectors all work properly - if you have any doubts about any of them then fix it - One duff injector will throw out everything. Same for any duff spark plugs and leads.
I found I had to return to basics several times initially - get a fresh MS firmware download and start again. Leave everything as default and start as the 'getting your engine started' section of the manual. It leads you step by step through each stage. Once it starts then you can tune.
Strikes me you are trying to tune before it's even running properly....
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Thu Dec 17, 2009 1:12 am Post subject: |
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yeah my car started the first time on MS after configuring everything according to the MS manual 
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment  |
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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Thu Dec 17, 2009 8:56 am Post subject: |
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Here is a post I copied off the megasquirt forum awhile back regarding tuning your injector opening time.
| Quote: | Also, I've been playing with injector open time in my mind for awhile. Values seem to rang from .7 to 1.2 for most setups. I came across a post where you and Lance where discussing 2 alternating pulses vs 4 sequential pulses per cycle. Lance mentioned that a zero VE table value should literally be NO FUEL entering the engine. So even though I have a digital oscilloscope to bench the injectors with I asked myself what does "no fuel" mean? Well in reality no fuel is slight fuel dribble from the injectors. (If open time is set correctly.) So I set all my VE values for the lowest MAP row to zero. I then went for a drive and found a large hill. I got up to speed and down shifted letting the engine slow my car. This pulled my MAP very low to the 11 kPa range. I found that though my VE was zero I was running pig rich. My large injector open time was to blame. I then decreased this by .1 ms till I got a DEAD lean reading from my WB O2 with NO blips. This value was 1.3 ms for my setup. (Small stock injectors 19lb/hr high-impedance. Strange because though my time was set to 1.3 ms Megatune was showing 1.2 ms PW value on the gauge? I didn't realize it could go lower than the open time?)If I set the value to 1.4 ms it still would be dead lean but would blip slightly. So this seems to be a convent trick to finding the injector open time. I'm sure some fuel is dribbling out but it is so small it prob is neglectable. So do you think this is an acceptable method?
Thanks,
A.J. |
Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Thu Dec 17, 2009 9:36 am Post subject: |
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That's an interesting and easy way to check!
Since I'm running extra code, on alphaN, at 0% tps my engine goes waaaaay lean too. While my VE is set to 60 or something like that. Only does that with the LPG injectors btw.
EFI opens a whole new world with weird problems. I appreciate carbs a bit more since I've discovered EFI 
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment |
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RC
Joined: 25 Mar 2007
Posts: 2637
Location: Australia
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| Posted: Thu Dec 17, 2009 10:45 am Post subject: |
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| Martijnus wrote: | | EFI opens a whole new world with weird problems. I appreciate carbs a bit more since I've discovered EFI |
With EFI one becomes aware of minor tuning issues while attaining the "perfect tune". Most can be tuned out or compensated for. With carbs however, even if you are aware of certain problems there`s usually little you can do about it with a handful of jets and a screwdriver.
I`ve also bookmarked a few posts and info on opening time that MIn, Martijnus, and other hard core guys may find useful.
http://injector-rehab.com/kbse/lag.htm
http://www.msefi.com/viewtopic.php?f=31&t=31002&hilit=Injector+opening+time+delphi+42
http://www.msextra.com/forums/viewtopic.php?f=29&t=26531&hilit=injector+opening+time+voltage
http://www.automotivetestsolutions.com/images/escope/fuelingectortutorial/FuelInjectorWaveforms.htm
See how much the dead time varies with voltage, and it`s not a linear scale either. In MSEx the nominal time is set at 14V. as MS measures it. Actual injector voltage will be less due to the drop through the wiring and driver FET. Higher or more commonly lower voltage to the injectors will be sufficient to require a 1-2 unit change of VE.
I have spent some time researching, scoping injectors, playing with settings and the 2/4 squirts method. Ended up with 0.6mS with 0.1mS voltage comp. IIRC 1V = 80uS and 2V = 150uS. Figure that voltage should only drop at cranking and if there`s more than 1V difference there is an electrical/ charging problem. With the Bosch alt the reg is set at 14V (at the alt) and there was average 13.2V at MS. Too low IMO. Full charged battery should be 14.2V, higher than stock reg V. This was a big factor in my decision to upgrade to a GM CS alternator, with remote voltage sensing. Appears to be working very well with 14- 14.2V and considerably less variation at MS, day , night, fans on, etc.
Sorry if I got a bit OT etiennekuh. May be relevent to you at a later stage though. In the meantime all the info you need should be here:
http://www.megamanual.com/mtabcon.htm |
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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Thu Dec 17, 2009 10:58 am Post subject: |
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Nice post RC, I need to get my hands on an oscilloscope so I can play around.
You mentioned that the injector dead time changes with voltage, which is of course true, I would like to add that the injector dead time also varies with pressure! so if you change your fuel pressure, you will also change the opening/closing times of your injectors. Just a tidbit to keep in mind for those who don't realize it.
Min
_________________
Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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etiennekuh
Joined: 31 Jul 2008
Posts: 34
Location: netherlands
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| Posted: Fri Dec 18, 2009 12:49 am Post subject: |
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I have set my injector opening time to 1 ms and my reqfuel is 22.5
de car runs very great AFR is very stable! no isues with stumbeling when pushing the throttle.
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Martijnus
Joined: 29 Dec 2006
Posts: 2019
Location: Netherlands
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| Posted: Fri Dec 18, 2009 2:01 am Post subject: |
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| RC wrote: | With carbs however, even if you are aware of certain problems there`s usually little you can do about it with a handful of jets and a screwdriver.
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but then you can accept it  you'll reach the optimal possible tune and be aware of some problems...and say... whatever, I can't do anything more
With EFI, I'm never satisfied. (but again... I say to myself that this will be my optimal tune ).
I'll check those links soon, real tuning is a cheap hobby if you just fiddle around a bit with some settings and try to figure out what affects what.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)
924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment |
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