anyone experience this effect of injecting on intake stroke ?

[Belgian1979]

Small comment after using the above mentioned number : it did have a positive effect on engine running especially at idle.

[mk e]

Mine are sized for about 35% max duty cyle to allow all the fuel to be injected into the noving air stream....but I've not gotten to the point of playing with it, the testing to date has been low power injecting against a closed intake.

Mark, you should try it. Injecting onto a closed valve quiets it down.

For initial startup I always inject to a close intake. My one is set at 360, but with my ecu, 0 would be 180 btdc, so my 360 equals your 540 I guess....lots of time before the intake opens. And thats injection end angle so I know the fuel is sitting against the hot valve.

Once I get the engine repaired I will play with the angle at power, but 0 (your 180) should just about right, which is why the reference is where it is I guess.

[Belgian1979]

I just tried something else, but only at idle so far. I disconnected my FPR and let it run with the FPR connect to ambient pressure. As was expected the engine ran rich.
As I'm injecting on a closed intake valve I would assume that my runners would be at ambient pressure when the injection event occurs. It would seem logical to do this. On the higher load areas, the engine usually runs close to ambient pressure so using ambient pressure to reference the fpr would also apply there even though the injection event might stretch out during the actual intake stroke itself.

I would however have a problem with decel, where my map would go way lower than normal so fuel pressure would be reduced accordingly. This is usually the time when I get exhaust backfiring and she runs extremely lean. I wonder if using an ambient referenced fpr would solve this lean condition and backfiring as well. Definately need to try this out although it's a lot of hassle since I would have to retune the fuel map accordingly.

[ptuomov]

I just tried something else, but only at idle so far. I disconnected my FPR and let it run with the FPR connect to ambient pressure. As was expected the engine ran rich.
As I'm injecting on a closed intake valve I would assume that my runners would be at ambient pressure when the injection event occurs. It would seem logical to do this. On the higher load areas, the engine usually runs close to ambient pressure so using ambient pressure to reference the fpr would also apply there even though the injection event might stretch out during the actual intake stroke itself.

I would however have a problem with decel, where my map would go way lower than normal so fuel pressure would be reduced accordingly. This is usually the time when I get exhaust backfiring and she runs extremely lean. I wonder if using an ambient referenced fpr would solve this lean condition and backfiring as well. Definately need to try this out although it's a lot of hassle since I would have to retune the fuel map accordingly.

Remind everyone what’s your fuel map based on. Throttle position and rpm or manifold density (pressure with temp correction) and rpm?

[Belgian1979]

ITB mode, basically a mix of speed density and Alpha-N. Low load is more influenced by map and high load more by TP.

[user-23911]

You just got it back to front AGAIN.

ITB mode, basically a mix of speed density and Alpha-N. Low load is more influenced by map and high load more by TP.

No wonder you have such problems making it run and have to start so many threads?

[Brian P]

Every production fuel-injected motorcycle uses that strategy as original equipment. (Individual throttle bodies, constant fuel pressure not referenced to manifold pressure, injection quantity mostly determined by MAP at light load and alpha-N at high load)

I don't see why it should be a problem.

[Belgian1979]

I have it connected to manifold.

[Belgian1979]

I disconnected the fpr from manifold vacuum and retuned it. Made a world of difference, especially on decel. Overal a lot better performance.

[mk e]

Sounds like progress! Sometimes its the little things that matter most.

That is how mine is setup as well. I think that is the best and most accurate way to do it with ITBs on a naturally aspirated engine.....which is why the motorcycles are all setup that way I guess.

[Belgian1979]

Yes, and the oil consumption is also gone after the changes I made. Thank God for that.

[user-23911]

You try to get a clean MAP signal at idle, you can't so you use alpha N at idle. Wasn't that the original problem?
Alpha N can't compensate for altitude or boost so you use the MAP for high load?
Whatever goes on in the middle , it doesn't matter, use both together.

[digger]

What's wrong with using alpha n all loads and then using map as barometric pressure ? You just use a lot of load sites at low rpm where needed

[ptuomov]

You try to get a clean MAP signal at idle, you can't so you use alpha N at idle. Wasn't that the original problem?
Alpha N can't compensate for altitude or boost so you use the MAP for high load?
Whatever goes on in the middle , it doesn't matter, use both together.

Alpha-N does a density correction. It just does that based on temperature and pressure sensors upstream of the throttle. M

[user-23911]

You try to get a clean MAP signal at idle, you can't so you use alpha N at idle. Wasn't that the original problem?
Alpha N can't compensate for altitude or boost so you use the MAP for high load?
Whatever goes on in the middle , it doesn't matter, use both together.

Alpha-N does a density correction. It just does that based on temperature and pressure sensors upstream of the throttle. M

Once you add temp and pressure (MAP)sensors, it's no longer pure AN, temp and pressure give density so it's now SD (the speed part is RPM, the density part is air density in the manifold), AN combination.
Exactly as I said above.


All you're doing is arguing for the sake of arguing when you just don't understand.