Megasquirt Alternating fire instead of staged
Thread Starter
Old [Sch|F]ool
Joined: May 2001
Posts: 12,862
Likes: 568
From: Cleveland, Ohio, USA
Alternating fire instead of staged
I can't get my car to run well at all on alternating fire. I tried two sets of injectors with no luck.
I have the two injector circuits on separate fuses. I can set the req_fuel to 9.8ms and pull the inj2 power's fuse out and it will run great, but if I set to alternating and put the fuse back in, it runs atrociously. Is this just to be expected given the location of the secondary injectors (so I need to get different firmware) or should I look for issues elsewhere?
Just for clarification, the car runs great on 2x680s, I am trying to switch to 4x440s for finer fuel control and a little more headroom. Both of my sets of 440s are high impedance and I am properly dealing with the PWM settings.
I can get it to idle (such as it is; it's a half bridge) with the four injectors in alternating fire, but it is impossible to drive on the road - adding fuel or removing fuel don't make it any better. It feels almost like an ignition problem that way - it acts like it's running far too rich and starving for fuel at the same time. But, I know it's not an ignition problem because I can pop the 680s back in, load the old MSQ, and it drives great.
I have the two injector circuits on separate fuses. I can set the req_fuel to 9.8ms and pull the inj2 power's fuse out and it will run great, but if I set to alternating and put the fuse back in, it runs atrociously. Is this just to be expected given the location of the secondary injectors (so I need to get different firmware) or should I look for issues elsewhere?
Just for clarification, the car runs great on 2x680s, I am trying to switch to 4x440s for finer fuel control and a little more headroom. Both of my sets of 440s are high impedance and I am properly dealing with the PWM settings.
I can get it to idle (such as it is; it's a half bridge) with the four injectors in alternating fire, but it is impossible to drive on the road - adding fuel or removing fuel don't make it any better. It feels almost like an ignition problem that way - it acts like it's running far too rich and starving for fuel at the same time. But, I know it's not an ignition problem because I can pop the 680s back in, load the old MSQ, and it drives great.
MegaSquirt Mod
Joined: Sep 2004
Posts: 4,721
Likes: 1
From: Maryland
Why would you try to run it without staging?
I wouldn't expect that to run well just because the injector pulse-widths would be too low to be able to accurately control the amount of fuel going in. You're probably getting down into the area pulse-width wise where the amount of fuel being injected is non-linear.
Ken
I wouldn't expect that to run well just because the injector pulse-widths would be too low to be able to accurately control the amount of fuel going in. You're probably getting down into the area pulse-width wise where the amount of fuel being injected is non-linear.
Ken
Thread Starter
Old [Sch|F]ool
Joined: May 2001
Posts: 12,862
Likes: 568
From: Cleveland, Ohio, USA
I have to run base MS1 code. For some reason, either I got two chips with no bootloader, or there's something up on my board and I can't load new firmware.
If it was a base pulsewidth problem, you'd think it would be worse with the 680s. Much of the reason I am switching to FC injectors is to get more latitude at low duty cycles.
If it was a base pulsewidth problem, you'd think it would be worse with the 680s. Much of the reason I am switching to FC injectors is to get more latitude at low duty cycles.
MegaSquirt Mod
Joined: Sep 2004
Posts: 4,721
Likes: 1
From: Maryland
Yeah, but the secondaries are way up in the intake, so a lot of the fuel they inject is probably not actually getting into the engine.
I would rather see the "unable to load firmware" problem solved since staged injection works much better than running alternating.
Ken
I would rather see the "unable to load firmware" problem solved since staged injection works much better than running alternating.
Ken
Thread Starter
Old [Sch|F]ool
Joined: May 2001
Posts: 12,862
Likes: 568
From: Cleveland, Ohio, USA
That's the question I needed answered, I suppose - has anyone had success running with the secondaries in alternate fire mode.
I guess nobody bothers anymore.
It would be nice to be able to run staged injection, I guess. But I was having problems as high as 4000rpm, at which point you'd think the secondary injectors would have been on-line for a while. I say "as high as" because we didn't bother trying to get the engine to run higher than that!
I do have a 36-1 wheel ready for if/when I use the MS for ignition. I suspect that the inability to load firmware is related to the fact that I'm on a 1.01 board and not a 2.2/3.0, so going to spark will require hefty sums of cash.
I guess nobody bothers anymore.
It would be nice to be able to run staged injection, I guess. But I was having problems as high as 4000rpm, at which point you'd think the secondary injectors would have been on-line for a while. I say "as high as" because we didn't bother trying to get the engine to run higher than that!
I do have a 36-1 wheel ready for if/when I use the MS for ignition. I suspect that the inability to load firmware is related to the fact that I'm on a 1.01 board and not a 2.2/3.0, so going to spark will require hefty sums of cash.