Road tuning your R33 with PFC. How do you work around a PFC?

[Guilt-Toy]

Hi

I am sick of my cars fuel economy so I went to see my mate who has a Autronic Wide Band a/f ratio meter to give it a bit of a tune up. Anyway after setting the sensor up etc and we took it for a run we realised we have no idea how this computer works and how to tune the bloody thing.

My mate remembers using his sensor on a R31 with a rb25 pfc and he was sitting in the back while someone tuned it, and th guy was blowing up about how time consuming it is to tune.

We tried a few things and this is what we worked out ...

Go to map tracer, do a boost run or cruze run then find out where on the map you are. Then go into setting and go to the 20X20 map and tune it from there. There is 2 options in there and we had no idea what we were doing is correct or not.. The end result was a little extra power...

So does anyone here tune their own PFC or have a guide on how to do it? got any photos on which settings need to be changed for more fuel or less fuel or more timing and less timing ?

I dont know much about tuning ecu's but I want to learn.. Anyone else interested in this topic ??? Make it a sticky and lets try and get more knowledge about our skylines so they can be tuned as easily as a Microtech...

[GunMetalR33]

I would also like some info on this topic, this is what I know so far.

*First make sure that the pfc knows that you dont have the boost kit.

*Tell the pfc what afm you have (eg normal or super intake for 300z etc...)

*Use the map tracer to find where you are on the map.

*The top row on the 20 x 20 maps is revs and the one on the left side is load

*From the stock map you are goig to have to advance the timing for the top half of the map and pull some fuel out (BE CAREFULL OF KNOCKING!!!!!!!). If you advance the timing too much you car will go bang.

*I think the trick is to run as much timing as you can without getting any knock, you can acheive this by adding fuel at the top end. (You will need a bigger fuel pump).

*If you are running more boost than stock you may need a new afm as the stock one will max out, Note I have not done this as you can guess after it maxes out as the rb25 is pretty linear. (Not sure if this is a good thing or not?)

This is only what i think i know, please dont take it as absolute fact :-}

Some one out there should correct me pretty quickly anyway :-}

[Steve]

OK, my experiences:

They are pretty time consuming to tune, you should use a passenger to monitor AF ratios, knock and map points if tuning on the road.

First see if you are running closed loop or not, in ETC, under FUNCTION SELECT. It can be enabled and disabled in the same way knock warning is.

Do you have aftermarket injectors? If so you need to make injector correction on the 'injector' menu in settings. If you are using an adjustable FPR, you will need to determine the flow with the adjusted fuel pressure to make the injector correction values.

This is what the power fc uses to determine how much fuel to use when running closed loop - and can make a massive difference to your fuel economy.

If these are already OK, ie fuel correction (if applicable) and closed loop were already correct, then you may need to remap. BUT, if you needed to make changes to them, this may fix the problem, and it would be worth driving for a while to see how economy is.

Fuel economy under boost is something that probably wont make a huge difference to economy unless you are boosting 100% of the time - most fuel economy gains seems to come from sorting the maps for just driving in traffic or cruising.

To check the maps for part throttle:

Firstly, switch off the closed loop function (you will need to switch it on again later)

Maintain 60kph in 4th, check the AF ratios and which map point you are using (via the map trace). In SETTINGS, go to INJ then to the appropriate map point (as found from the map trace) - from here you can make the necessary adjustments. You should aim for A/F ratios of 14.5, as this is stoich.

Do the same for other speeds that you normally drive at, 80, 100 etc and in the gears you normally drive at those speeds at.

MAKE SURE, you monitor knock levels. If the knock starts to rise (it should be very low, 1-3 at this stage, you are just cruising), back off timing by 1 degree increments, 1 degree makes a fair difference, then check it again. This is done in the IGN menu.

That is a basic run down on cruise economy tuning.

For power, AF ratios should be alot lower - if you are tuning yourself, do a run at WOT (keep a close eye on knock) - check the map trace, then adjust fuel for those cells until it is stable - I would suggest trying around 11:1. Do runs from 2-3000rpm, then adjust until they are ok, then do 3-4000rpm, etc. Use 4th gear, as this is where most load is on the car. After you have sorted the AF ratios, then its time to attack the timing. Add timing until knock levels start to rise once again, try and keep knock under 10, when you get to 10, pull one degree, check knock is down, then repeat the process for the next cell. You will have a rough idea where the timing needs to be from the previous point.

As mentioned this is a lengthy process - it can take many hours.

******DISCLAIMER********

IF YOU DAMAGE YOUR ENGINE, I ACCEPT NO RESPONSIBILITY IN ANY WAY. I RECOMMEND YOU TAKE YOUR CAR TO AN APPROPRIATELY EXPERIENCED VEHICLE TUNER AND GET THE CAR TUNED ON A DYNO.

[Guilt-Toy]

Thanks for the reply Gun Metal!!!

Ok so why cant we make a PFC tuning guide. ???

What I have learnt from your post is that the top row is revs and left is load.

Anyone else.. ANY info will do.. we need to read and learn what to do!!

I would *LIKE* to create a HOWTO tune PFC.... get some photos and stuff with a guide on what to do...

What I will do is borrow my friends Autronic Wide band fuel ratio meter again after I learn more about the PFC and install it and take some photos and chuck em up.... See how we go with people replying.

If your interested in this thread then please say you are and tell us what you want to know because chances are others want to know the same thing. If you have answers then please answer!!

[Guest RedLineGTR]

Thanks for the info guys...answered some of my question too

[Guilt-Toy]

Steve: Can you help us with what options need to be changed on the map. do we go up values or down... what do both options do in inj ? how will changing them effect the a/f ratio or tune and drivablilty of the car...

[Steve]

with INJ map it alters fuel only. Try adjusting up or down by one or two increments at a time - and keep an eye on the AF ratios. Higher number = more fuel = you can run more timing before detonation occurs. Vice versa for lower numbers.

Changing the mixtures at cruise should not effect the driveablity of the car, just increase the economy - closed loop will also help there.

Under WOT, the leaning out the mixtures will increase power, to a point - BUT the leaner the fuel the less IGN advance you can run before detonation will occur. Also, lean fuel mixtures will give you no room for error, such as heat soaked intercooler, poor fuel, fouled plugs etc, so beware.

Advancing the timing (IGN map), higher number, will give more power, but also by running the mixtures on the rich side (say 11:1, 11.5:1), you can wind in more ignition and get a more responsive tune. Peak power may be lost though, as fuel generally makes more power with leaner (12:1) mixtures. Retarding ingnition, lower number, will have the opposite effect - you should remove ignition if there are any signs of detonation, ie adjust the number down. If the AF ratios are good, just tweak the ignition - of course keeping an eye on the knock and AF ratios as you do it.

Remember, if you tune on the edge, one little variation above what the computer can compensate for, and it may end in tears - so conservative (to a point of course) is good for the sake of safety. Once you have you AF ratios sorted, start playing with the timing. Once you have the best result you can have - Add one degree of timing across the board.

Keep a close eye on the knock sensor, it will give you a good idea of what is going on. I also monitor knock trends on the hand controller. If knock starts reaching higher levels, its very easy to just pull 1 degree at a time until its back where it should be. This is done in the IGN/INJ menu (different to IGN or INJ menu) under settings. And changes made effect all cells of the map, so just by taking 1 deg off, you have taken it off everywhere - very handy tool. BUT, once you turn the ignition off, any changes in the IGN/INJ menu you have made in will be lost.

Please be very carefull when tuning your car - it is very easy to destroy an engine, as many experienced tuners will attest to.

******DISCLAIMER********

IF YOU DAMAGE YOUR ENGINE, I ACCEPT NO RESPONSIBILITY IN ANY WAY. I RECOMMEND YOU TAKE YOUR CAR TO AN APPROPRIATELY EXPERIENCED VEHICLE TUNER AND GET THE CAR TUNED ON A DYNO.

[GunMetalR33]

Thanks for the info steve, its good to see you are will to post some lengthy threads to help others out!

My knock levels never go over 48 according to the PFC, I think I have a conservative tune and I also get about 380 k no a tank in a r33 gts-t does all this sound about right?

note: I have about 200rwkw...

[Steve]

Hmm, I wouldnt like my knock to be going so high - the highest I would like to see is in the 30s, currently I get 20s max with over 300rwkw. If it went to 48, I would be pulling a degree of timing (IGN/INJ option in SETTINGS menu)

its hard to say if 380km per tank is good, if you can tell me how many km/L you are getting it would be easier to say.

when I had around 200rwkw, I was getting 10L/100km for cruising, around 12-13 if I was driving hard.

[R33vit]

Excuse the noob question, but what is closed loop enabled disabled?

[Steve]

closed loop is when the car goes into cruise mode, it monitors the AF mixtures (via the oxygen sensor) and gradually pulls fuel until it has leaned right off - I have read of the mixtures going as lean as 18:1. This only happens when there has been no change to the throttle and load for a given (not sure how much) time.

Disabling the closed loop will mean the car runs purely from the map and wont pull the fuel.

[R33vit]

Thanx for clearing that up.. I think?

Does this mean that in closed loop you should in theory get better fuel economy?

Do I need to tune with closed loop disabled?

[Steve]

Yes you should get better fuel economy.

If you disable the closed loop when tuning, you are running purely from the maps, which is what you want.

[BOOSTD]

Disabling closed loop during tunning will not effect anything at WOT. Closed loop only needs to be diabled for light loads and cruising speed tunning.

[JasonO]

Steve,

All this closed loop stuff, have you tried switching it off to see if it imporves your idle problem.....

Sorry, Off-Topic I know, but here's my reason for putting it here.......

I have found that when setting up idle speed on the PFC, it's worth switching off the closed loop operation, and adjusting for a stoich mixture, then when you switch closed loop back on, the ECU doesn't need to do over time trying to control the mixture, which can in turn cause idle instability (too lean - too fast, too rich - too slow) even before hte AAC kicks in.

[EnricoPalazzo]

closed/open loop will have no effect on idle.

[JasonO]

closed/open loop will have no effect on idle.

I am under the impression that the ECU returns to Closed Loop operation at idle, am I wrong ?

[Steve]

I was under the same impression as you Jason, but not sure. I have tried with closed loop disabled, but made no different.

[EnricoPalazzo]

it would make sense that it returns to closed loop

[BOOSTD]

closed/open loop will have no effect on idle.

Closed loop has quite a major effect on idle. I would agree bringing the mixtures to stolich and then returning it to closed loop would give best results. Those without a PFC can do this by adjusting the idle bypass screw. I have seen a couple of lines hunting at idle because of faulty oxy sensors and aslo lean mixtures. I have had hunting and it has always been caused by lean mixtures. ie 16:1 being the center instead of 14.7:1. You can imagine with closed loop scrolling, the mixture going so lean and inducing studder and stall.

I am currently running a series 2 ecu( thanks R33vit) which runs alot happier in closed loop than the series one. Idle is always perfect and Closed loop scrolling lean rich lean rich that is , happens twice as quick as the s1. In fact every aspect of the s2 ecu feels far superior. Oh and the s2 ecu will plug and work straight into a s1.