Power FC fuel map

[Steve]

Well, after close examination of the INJ map on my power fc, I decided that I couldnt understand what was happening, so I wrote down all the load and rpm positions, plotted them, and it still just doesnt seem right?

this is with 550cc injectors and Z32 afm - can anybody shed any light on what was done? Does it seem right? It is still not idleing right, and it seems to me that there is way too much fuel in there? Anybody out there share any thoughts?

Cheers

Steve

PS sorry the image is a bit large.

[Freebaggin]

No idea mate. What is the idle problem anyway?

[Steve]

Well, she is a bit rough and lumpy sounding, plus it sits up around 1000-1100 rpm. Once when coming back from revs she died all together. When I picked the car up, she stalled a couple of times, the guy who tuned it said to pull a couple of points out of the appropriate points and see if that helps. Also said he was not able to do cold start properly (I have since fixed that).

Just looking at the map, seems to be way too much fuel at idle. I actually pulled it back from 1.11 to 0.70 and it still idled the same, but then got paranoid that I had pulled too much:D so put most of it back in.

[Ustasa]

Steve are the injector constants reset from 100% to 67% in the settings menu?

What about the closed loop function in the etc/functions screen?

[B-Man]

Steve, it was running OK right ? Did this just happen ? Cause these are similar symptoms to mine right after - well you know what....... Rough idle, stalls at idle. Is it rough all the way through the rev range or just at idle ?

[Steve]

Ustasa, where exactly is this setting? when the injectors first went in I used the correction in the ign/ijn setting, but it doesnt save?

I havent checked for closed loop function either - I didnt know there was one:) I only have a rx7 hand controller manual that I downloaded, so I dont know a whole heap about the functions. dont know where I could get a copy of an english manual for R33 do you?

Under accelleration or foot completely off the throttle, all is good. It is only under cruise (maintaining a costant speed) or at idle that it seems a bit rough. the stalling thing is only when I come back from hard acceleration and say put the clutch in for a couple of seconds before changing down to stop - if you know what I mean. Its sort of intermittent. This was the case when I first got the car back from tune, but I suppose it is just starting to irritate me a bit:D

[Steve]

Ustasa, I just checked the setting menu, under 'injector' itts all set to 100%. the O2 F/B is set to on in etc

Does this mean it will need retuning with injectors set to 67%? It has just had a full tune expressly for the purpose of dialing in the new injectors, and the car goes really well under throttle. Even the knock reading is down and usually doesnt go over 24 even under full boost(1 - 1.2bar) high rpm running. the guy who tuned it said he had pulled a fair bit of timing and has set AF ratios at 11.8:1.

[Ustasa]

The inj/ign trim feature resets itself after power is discontinued to the unit ie. Ignition off. It’s only to be used as a tuning supplement/make quick changes.

The injector menu is next to the airflow menu in the settings screen.

Don’t worry about an English version of the R33 manual. You can extrapolate enough from the Rx-7version to get you out of trouble.

The stalling could be the A/C limits in the rev menu in the settings screen (last menu). Read the Rx-7 menu for the explanation on what the 4 functions do (5th is rev limit).

Make sure the 02 setting is on. The trouble is now that the power FC is trying to modulate the bigger injectors in closed loop mode to hold 14.5:1 thinking they are still 370cc jets. That’s why your fuel map is looking funny since huge changes have been made to try and keep the closed loop function from throwing a leg out of bed. Theoretically the numbers in the injector map indicate the equivalence ratio desired for that rpm/load point. 120=1.2 which is converted to 14.7/1.2=12.25A/F. Since the injector constants are stuffed your map is showing values as high as 150 which is as high as the Power FC can go (150 is a 50% increase from 100).

Try the changes I’ve suggested. If it doesn’t work because you end up fixing the Idle/light load but your high boost settings karks it then you may need a retune.

Any dyno figures?

[Steve]

Originally posted by Ustasa

...The injector menu is next to the airflow menu in the settings screen....

Does this need to be changed? what does it do exactly?

Make sure the 02 setting is on.  

I have checked the O2 F/B in etc, that is to on, is this correct or should I be looking somewhere else?

Any dyno figures?

230rwkw at 1 bar and a very flat torque curve (dyno is here:http://www.skylinesaustralia.com/forums/sh...0554#post490554 )

the power delivery is awesome, very good off boost, and with 1.2bar it is scary on the road:)

[Ustasa]

The injector constant resets the value that the Power FC uses in it's closed loop calculations. Since the stock unit is programmed for 370c injectors you need to change it when the capacity of the injectors are changed.

If O2 is on in the etc. menu then it's fine.

The turbo response looks pretty juicy especially at higher rpm. If you have an rpm based electronic boost controller try to dial in more boost higher up in the rev range. That way you can keep cylinder pressures consistent without tipping over the detonation/overly retarded ignition threshold. With street fuel try to make the power with boost and not a heap of ignition

[Steve]

Thanks Ustasa, the turbo is pretty good, comes on boost early and pulls hard. Unfortuneately I dont have rpm vs boost control. I tried upping the boost to 1.2bar, but I need to get traction sorted a bit better before I can do that again. Even in 4th at 1/4 - 1/3 throttle around 120kph and it stepped sideways. In fact at about 3500 to 4000 I just loose traction even under mild acceleration. Are rpm adjustable boost controllers hard to find? Could you recommend one? I have just got the power fc boost control.

I think I may have found a problem with the car. Apart from the fact that the adjustment hasnt been made for the injectors - the guy who tuned it set it up on Infinity throttle body (I have Z32). I spoke to him this arvo and he said he did it because the car seemed to prefer it under power. I am hoping a full retune isnt necessary.

I tried to drop the injector setting to 0.67, but the car just wouldnt run. I tried on 0.80 but the same story:(