Need Help - 46lb injectors maxed out!?!?

[opeterson]

I've been running megasquirt V2.2 for almost a year, and I absolutely love it. I took it very slow at first, running no boost, then a wideband, then stock 7-8 psi boost. Now I want to turn up the boost but megasquirt won't supply enough fuel.

I started out with greentops but they maxed out at 5500rpm. Then I installed 46lb/hr Ford CFI injectors, but they're at 85% duty cycle by 6k rpm. I've installed a fuel pressure guage on the fuel rail, and pressure is about 40 psi guage at idle, rising to 45-50 when en engine revs. What gives???

Here are my megasquirt constants.
http://people.virginia.edu/~osp3b/MegaSquirt.bmp

[MrBill]

sounds like you have 15% left my man :nod:

[PetesDustyVolvo]

if you're maxing out 46s on a B230 with 7-8 psi then something is either very wrong or very very right....

what is the rest of your setup?

[Morten VJ]

Req fuel = 15ms?
Running the numbers i get 8ms

Why 2 squirts simultaniosly.
I would like 2 squirts alternating or 1 squirt simultaniosly.
This will give you 1 ms more fuel to play with.

But as Pete said maxing out 46s dosen't add up

BR.

Morten

[benflynn]

i maxed greentops at 20psi

i do not think you can trust the 85% too well either, i have seen the gauge at 122%

[phillazenby740t]

i maxed greentops at 20psi

i do not think you can trust the 85% too well either, i have seen the gauge at 122%

They max out when yur af gauge says so

[The Aspirator]

They max out when yur af gauge says soThat I agree with, though it's hard to notice that point and kinda weird when you do. "needs more fuel, click click click, no change, needs more fuel! click click click, no change. wtf?". "Ahhh, check out the duty cycle gauge."

If you're still running 7psi on CFI's and you're hitting 85% dc at redline, something sounds fishy there. You never mentioned what your AFR's are at full boost and redline. Really efficient engines require more fuel at less boost, cause they're making tons of power down there. But if yours is stock-ish then something's up. Do you have any exhaust leaks between the turbo and the wideband sensor? That'll make the sensor read lean, so say you have a 1/4" hole in your downpipe, you're throwing more fuel at it to make the gauge "read" 12.0, when your engine is actually seeing like 10.0.

[MrBill]

maybe you should upgrade/change your firmware and see what happens?
Maybe 2 squirts doubles the percentage(in the MT graph at least)? Not sure on that one, who here uses more than one squirt a cycle?

[The Aspirator]

I'm running the V2.2 board, 029q2 firmware, and I use 2 injections per cycle, alternating, my reqfuel is 6.8 (both bins) and I'm running CFI's at 4.5bar pressure.

[opeterson]

I'm only running one injector driver circuit (as Linuxman often suggests) so I can't do alternating.

Required Fuel calculation suggests something like 8ms but the engine won't run unless its at 14ms or more. I think the injectors are firing at half the duty cycle that Megasquirt says. Is there any way to test the validity of the duty cycle output without boosting to 15psi and hoping for the best? Ping ping ping bang!

The engine is a mildly modified 8 valve with a T cam and 2.5" exhaust.

[The Aspirator]

Sounds like your map is scaled down alot, which is really no biggie. But if you wanted to use the 8ms ReqFuel that MS suggests you're going to have to almost double your entire map evenly. There's a tool to do just that in the VE table page, although I don't know if it'll help your problems at all.