Sequential Fuel injection
#26
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To run low impedance injectors without dropping resistors, you just need an injector driver capable of PWM.
You can have sentential with or without low impedance injectors if you want. The two are not mutually exclusive.
#28
OK, I was thinking in terms of it being an advantage of doing the sequential mod for MS specifically, but then I made the mistake of thinking this was posted in the MS specific forum too.
This is getting a bit off topic, but are you suggesting that I could run two low ohm injectors per injector driver on my MS2 DIYPNP without resistors? because my understanding was that that would require the injector drivers to sink more current than they can handle.
This is getting a bit off topic, but are you suggesting that I could run two low ohm injectors per injector driver on my MS2 DIYPNP without resistors? because my understanding was that that would require the injector drivers to sink more current than they can handle.
#31
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A customer of mine run low impedance injectors on the DIYPNP for several months, without knowing. He always had problems with the USB to serial converter randomly disconnecting from the PC. At some point he did burn one of them, so we found out and replaced the injectors.
#34
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Thanks. Is it a good idea to upgrade to really large and or EV14 injectors over my 550RX7 injectors? Will a shorter injector opening time benefit me in any way?
You entered 375* to account for your 10% cam opening...is this back-timed or is the ECM counting 375* of rotation?
here's what I use.
I might want to alter it slightly, this is based around the idea that you want to have all your fuel at the valve around 10° before the intake valve opens. So I'm using End-Of-Squirt.
NA intake valve opens 5°BTDC, so I have it at 375°. which is 10° before that. 360TDC + 5BTDC + 10 = 375.
I inject fuel another 10° sooner every 1000RPM or so, stopping at 5000RPM. I did this from reading through out the web as the accept "norm".
In boost I also inject the fuel even soon every few psi.
I didn't do extensive trial and error, but this map help reduce the over VE% by a few points throughout and seems to work well for me.
I might want to alter it slightly, this is based around the idea that you want to have all your fuel at the valve around 10° before the intake valve opens. So I'm using End-Of-Squirt.
NA intake valve opens 5°BTDC, so I have it at 375°. which is 10° before that. 360TDC + 5BTDC + 10 = 375.
I inject fuel another 10° sooner every 1000RPM or so, stopping at 5000RPM. I did this from reading through out the web as the accept "norm".
In boost I also inject the fuel even soon every few psi.
I didn't do extensive trial and error, but this map help reduce the over VE% by a few points throughout and seems to work well for me.
You entered 375* to account for your 10% cam opening...is this back-timed or is the ECM counting 375* of rotation?
#36
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More like 60% DC
At WOT it's pretty unnecessary, it's quite helpful for economy at part throttle though.
Honestly if you don't have any issues currently with your injectors, then leave them. If however you're hankering after more headroom and a much improved idle quality at stoich, then hell yes upgrade.
At WOT it's pretty unnecessary, it's quite helpful for economy at part throttle though.
Honestly if you don't have any issues currently with your injectors, then leave them. If however you're hankering after more headroom and a much improved idle quality at stoich, then hell yes upgrade.
#37
First of all, i want to apologize for bringing this thread back from the grave but it seemed to have the best information about sequential injection which is relevant to my case..
So, i'm running a '91 miata with MS2 extra (by reverant). I thought i'd reconfigure the batch injection into sequential, but it did not quite go as planned..
So, i rewired the injectors according to Dimitris's instructions:
- Pin 1 (INJA) goes to cylinder 1
- Pin 2 (INJD) goes to cylinder 2
- Pin 3 (INJB) goes to cylinder 3
- Pin 4 (INJC) goes to cylinder 4
- Switch from "standard drivers" to "additional drivers" in megasquirt
Then i checked (and double checked) that each injector is only connected to the corresponding pin in the right order.
Now, the car would not start up. It fires after cranking and dies immeadiately afterwards. I did manage to get it run (barely) by pushing throttle. This caused the engine to run very lean. As soon as i release the throttle, the engine stalls.
Now, if i change back to "standard drivers" the engine runs just fine! Any ideas what might cause this behaviour?
So, i'm running a '91 miata with MS2 extra (by reverant). I thought i'd reconfigure the batch injection into sequential, but it did not quite go as planned..
So, i rewired the injectors according to Dimitris's instructions:
- Pin 1 (INJA) goes to cylinder 1
- Pin 2 (INJD) goes to cylinder 2
- Pin 3 (INJB) goes to cylinder 3
- Pin 4 (INJC) goes to cylinder 4
- Switch from "standard drivers" to "additional drivers" in megasquirt
Then i checked (and double checked) that each injector is only connected to the corresponding pin in the right order.
Now, the car would not start up. It fires after cranking and dies immeadiately afterwards. I did manage to get it run (barely) by pushing throttle. This caused the engine to run very lean. As soon as i release the throttle, the engine stalls.
Now, if i change back to "standard drivers" the engine runs just fine! Any ideas what might cause this behaviour?
#40
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Yes, all my Enhanced MS2 provide sequential. Otto, please replace each injector with a 12V auto tester, , and using the test mode, see if you can get all 4 "injectors" to light up properly. When you test each injector, only that injector must light up and none other.