Fuel Mapp Maxxed out and still almost lean! ca18det

[InteLLi]

Hi there. was on the dyno today and we hit a snag. running about 1.5bar pressure and on the fuelmap we haveto maxx the fuel on high rpm/hi load (top right corner ) we couldnt seem to figure out why. we tryed to change the k constant but it didnt change annything on hi load/rpm. Only the midrange and lo end was affekted. the midrange is as lo as possible but still goes rich. then on boost it goes upp to 12.5-13.0 afm maxed values.

plz empart your wisdom and help me!

specs:
Ca18det with forged pistons/rods
reworked head.
gt3071r turbo
tomei poncams
800cc sard injektors.
FMIC and 3"exhaust all the way.

attached the .bin file so u can take a look if u want.

[PL]

I'll try to take a look at your bin tonight but my initial thoughts are that the max injector pulsewidth is being limited by TTPmax. Have you increased these figures?

Don't happen to have a log of a dyno pull do you? Logs tell the story...

PL

[InteLLi]

I have changed the ttpmax ( i know that the tables are reversed ) to max. what if u set the k-constant to high? could that affect it?

[Zenki]

try an injection latency with 800-1000ms

and if it do not effect go down until it works correct

[PL]

It shouldn't be possible to set K constant too high. Sounds like your pulsewidth is being limited somehow. What you need to do is monitor the injection pulsewidth (logging is best here). Once you reach full boost the pulsewidth should stay pretty much constant accross RPM providing boost remains constant. If it drops off you have tuning problems. If it's remaining constant but your mixtures are still leaning out then you may have a fuel delivery issue.

Be worth putting a fuel pressure/flow rig on it anyway. Fuel pressure should be around 43psi at 0psi boost and increase 1:1 with each psi of boost. So 53psi fuel pressure at 10psi boost, 63psi at 20psi boost etc.

PL

[PL]

What AFM are you using??

PL

[InteLLi]

zeitronix zt-2 logging system. yes ive been meaning to install an fuelpressure regulator but thought that the original one should suffice.

the latency is set to the correct value provided by sard. 110ms

[Zuikkis]

I always recommend the original fuel pressure regulator, many aftermarket regulators are not linear.. That is, if boost rises 1bar, fuel pressure should rise 1bar too. Not 1.5bar or 0.5bar.

Anyway, many ca18det s13's have super crappy fuel pump power supply lines.. 20 years of dirt and corrosion does its tricks to the connections. On one s13 I measured 11 volts at fuel pump when idling, dropped to 8 volts at boost.. This would explain your symptoms.

[PL]

I always recommend the original fuel pressure regulator, many aftermarket regulators are not linear.. That is, if boost rises 1bar, fuel pressure should rise 1bar too. Not 1.5bar or 0.5bar.

Anyway, many ca18det s13's have super crappy fuel pump power supply lines.. 20 years of dirt and corrosion does its tricks to the connections. On one s13 I measured 11 volts at fuel pump when idling, dropped to 8 volts at boost.. This would explain your symptoms.
I always recommend the original fuel pressure regulator, many aftermarket regulators are not linear.. That is, if boost rises 1bar, fuel pressure should rise 1bar too. Not 1.5bar or 0.5bar.

Anyway, many ca18det s13's have super crappy fuel pump power supply lines.. 20 years of dirt and corrosion does its tricks to the connections. On one s13 I measured 11 volts at fuel pump when idling, dropped to 8 volts at boost.. This would explain your symptoms.

I totally agree on all counts. First thing to check should always be fuel pressure. I've seen soooo many examples where people just fit a big pump and then have trouble cos the factory wiring isn't good enough. It's also worth noting that both 12V supply AND earth wires of the pump should be upgraded. 1V of drop can make a big difference to fuel flow.

PL