Does anyone mess with the other settings on the PFC besides the maps? Like Accel. injector time, and water temp correction. What do you guys set and how?

 

Those settings are there to be "messed" with so you can get a really good stable tuning...

 

O ok.....I want to learn how to "mess" with it but Im not sure how to. What do the numbers stand for? I know i sound like a moron...im really not im just really confused when it come to this PFC, but I want to learn.

 

i wont to learn too.

if you search and read past threads its like reading shakspear nothing makes 100% sense.

because most people tune via the 3 maps inj , leading, trailing, and you really don't need to mess with the other things though its frustrating having something sofisticated that you cant fully understand?

im with you i would like to learn

 

Most of those items don't require correction, and if they do, you really have to know what you are doing. You can pick up a good fuel injection tuning book that will cover all of those topics. Other than that, the only way to learn is to talk to PFC experts (of which almost none hang out here except for Chuck) or to experiment yourself. Obviously a datalogit would be required to see what you are really doing.

 

you nailed that one. i've been reading through the archives of this forum for a week now. i already knew the basics of A/F tuning and what not, though i'm not interested in actual a/f&inj tuning right now, i'm just trying to figure the damn PFC out.

 

Most commander accesiable maps do not need changing unless your car has strange characteristics.

But:
PIM Volt or RPM; good place for quick changes for testing/adjusting fuel. Lets say you AFRs are tuned per your specs for street use or drag racing. If you decided to go drifting one day, you might want to add extra fuel since your speeds will be slower (less water and IC cooling) and you will be on boost more and at contant higher revs. Just add some more fuel for cooling, after the event, change back again.

Acceleration maps. Only problem anyone has ever mentioned was light leaness on initial throttle tip-in.
Usually cured by reducing 1000 rpm decay time valuedown from 2.0ms to 1.0ms or .5ms. Or you can also increase the enrichment value higher than its 6.0ms.

FUEL/IG CORR map, temporary quick changes for tuning on the street or dyno. Keeps values only while the ign key is turned on.

WATER TEMP CORR, had to add more fuel to 50C and 30C for light load to my engine. If you engine stumbles when cold at low rpms and light load only when cold, this is where you add more fuel to correct that.

CRANKING FUEL CORR does not do much for my engine.
Used to lean or richen fuel while starting engine.

RPM SETTING, most used after IGL/IGT/FUEL CORR maps.
Set your idles and rev limit.


I have a datalogit and my air temp sensor is on my IC outlet. Mores maps available with the datalogit which I have changed. AIR TEMP vs INJ and IGT, WATER TEMP vs ING , Cooling Fan control temp, PIM values for my P17 - P20 rows.


Kyle and I have tuned together for two years experimenting. The reason to have another person there is to run the laptop and most important to watch knock levels and AFR levels when testing.

 

great information cewrx71 your always to the rescue he helped me with my maps once

thanks mate

 

Chuck: I've pulled so much fuel from the water correction map in the 50C and 30C that it is sick. Kept fouling plugs on many RX-7s when cold. One guy runs BUR7EQP on the street and 9s on the track. The 7s helped from fouling some, but taking more fuel helped as well.

Other settings: injector overlap has become popular with people with large secondaries. This setting is only available via datalogit. Fan turn-on temp everyone lowers to someing in the mid to high 80C range-also tuneable only through the datalogit. I've also played with the ignition timing on cold startup. I reduced the temp split and the amound of ignition timing at the cold side.

 

What is really amazing is that most paid "tuners" never touch these settings. As others have mentioned, owners typically start making adjustments to cure nagging issues like unstable idle, lean or rich inj transition, lean at throttle tip in, poor starting, inj temp correction to maintain tuned AFR when intake temps change, O2 f/b timing, etc., etc.

Best way to learn is to pal up with other owners to share ideas and test on multiple cars with different setups. Pick someone smart that's willing to talk, experiment, and spend lots of time driving and tuning!

My latest custom tuning cleaned up an erratic idle that would sometimes drop a few hundred rpm or increase a few hundred ... and I don't even run an ISC! Pulled the ISC years ago when it seemed to never control idle rpm right and I finally got the system nailed down. PM me if interested but I'll drop a hint, AFRs and timing don't bounce around much at idle anymore.

Issue that's bugging me now is the damn heat soak lean idle condition. Park the car, and my relocated IAT still heat soaks enough to lean out the idle too much (idle is tuned very lean for plug life) . Considering adjustment of inj temp correction map to take out very little fuel above 30 degC IATs where AFRs are well tuned.

 

twokrx7 said it very well. Team up with other RX-7 owners and go from there.

twokrx7: You comment on the ISC is so true. I learned how much a pain that device is when I went Haltech. I never got it to work right. On a different note, I have learned how to trick the PowerFC into idling without using the ISC and from there you can do all sorts of fun stuff with ign timing. I would be curious as to what your trick is ... I think you will be hard pressed into getting that heat soak problem fixed, but let me know! Do you have to adjust your idle for the different seasons?

 

Spyfish,

I used to adjust the idle air screw under the elbow from winter to summer, but with the latest tuning I'm not sure if that will be necessary. Will know next winter time.

What I did to stabilize my idle was to adjust the fuel and timing to near identical values in all cells that were used at idle. I had previously deleted my P2 and P3 rows in favor of using the two rows for boost areas. So I am idling in what most see as P1, P4 and even P5 (idle vac is as low as 11/12 with the ported motor at low rpm and 16 at high idle). This had no effect on idle as it would occasionally be several hundred rpm high or low.

The new fuel/timing works like a charm.

twok

 

Thats what I would like to do it talk with another hardcore Rex owner, but I dont know of anyone in Mass. If there is let me know and email me newenglandspeed@hotmail.com

 

twok: When I do what you are doing with the idle I try and make a valley for the engine to settle into. If the valley is not smooth enough it will do what you talked about eariler. It sounds like this is what you have done. Interesting to hear that you delete some vacuum cells. Thought about it, but I haven't run a 3 bar sensor in a long time. What kind of mpg are you getting? I am getting 18 mpg in mixed driving these days with BUR9EQs in the holes.

NESpeed: I would suggest going to auto-x and road race events. Check on other boards. Heck check on this board (northeast area) for guys in your area. You should find people that are at a similar starting point and maybe one person who is slightly more advanced. Make small small changes and go from there.

 

Awsome guys thanks

 

Spyfish,

Sorry, my Commander bracket blocks the odometer so I don't track mpg. Cruise AFR target is low 16:1, smooth with no stumble to my surprise. I suspect my highway mpg is pretty good but may never really know since I downshift and redline past every slow sh*t that parks in the fast lane on my daily commute.

twok

 

Spyfish and twok:

I just wanted to thank you guys quickly for your advice on tuning idle, for those who have not tried it their tips worked like a CHARM on my motor. I had been fumbling around with settings everywhere with not much improvement.. since creating the 'valley' to fall into it idles a whole lot smoother and steadier and actually pulls 50mm more mercury on the same idle rpm. I think the timing map had much to do with this, there were some very different settings around the cell it was using to idle.

Matt

 

How does this Acceleration Injector Time works?
What is the decay and amount relationship to the map?

I do find that during deceleration, then I start to get back to throtle, the car would stumble a little bit. This is throttle tip in right?

 

of curse
lol

 

There are two columns, one adds more time to the injectore pulse width. The other affects how long this happens.

Depending on your injectors sizes it might be something else.

 

Not sure if you still have your RX but I'm willing to talk and share some thoughts and experience anytime. Let me know.

 

Let me know if you still have your RX and would like to share some thoughts. I PM'd you as well.