spent 6 hours and 150$ at the dyno today and got nothing accomplished. they tried pulling fuel at idle but no matter how much they pulled it didnt affect the afr. they also couldnt figure out why it idled at 10.9-11.2 on stock primaries. im getting all my sensor readings on the commander so what could this be? ive ran into every problem possible with this thing. please help me out?!

 

What exact steps were you taking when trying to adjust the AFR? What screens were you on? Was your Datalogit interfacing to the PFC?

 

Are you tuning it with the commander or the Datalogit?

If you have the O2 feedback on, you can't alter idle or light loads. Also, if you have O2 feedback on and have removed the airpump, the car won't idle well and will have jerky throttle inputs. The ECU has to fudge for the airpump air coming into the exhaust manifold, and if you don't have an airpump, the numbers are fudged the wrong way, making the car run not so hot.

It's also a possibility that you're running too much fuel pressure or don't have a vacuum reference hooked up to the fuel pressure regulator - both can cause unnecessary richness that you wouldn't be able to tune out.

Dale

 

very insiteful info dale.

i was not the one tuning but the tuner has never tuned through a cammander only through a datalogit so i might just purchase one. he did mention something about there may not be reference to the fpr but i dont think you can get to it without removing the uim. if it were this would it cause the whole pull to be shitty because it was really only at bad at idle. it still needed fuel pulled across the board but i guess the transition from the stock primarys to the 1000cc secondaries was smooth. figured if it had to do with the fpr it would be worst all over

and could you explain the o2feeedback/ air pump ordeal alittle. that sounds like it could be it also. im not sure in what order the previous owner modded it but if he removed the airpump after the installing the pfc that would do it?

thanks again dale i atleast have something to throw at my tuner now

 

anything else that dale didnt get ?
looking like hes the winner of 5$!
share your knowledge for a free gallon of gas, commaann

 

the pfc can only reduce fuel to a certain point with the base map injector lag settings, once you reach that point you have to adjust the lag timing on the injectors, usually this isnt much of an issue with 550 primaries, but it was slightly on mine cause once they were cleaned and flow tested they put out more fuel. On larger injectors many people have to use negative lag.

Also the PFC uses its own hidden maps to adjust for idle speed. this is at least for the ignition timing, not sure about the fuel. I prefer using manual idle tuning and removing the ISC.

It is much easier to tune using the datalogit, so if you can buy one, or borrow one i highly recommend it. I cant imagine tuning on the commander.

 

i guess the datalogit isnt being sold at the moment but the apexi pro software is only300 and i guess its not much worst. i might give that a try. and from what i saw today id have to agree that the commander was useless

 

I'm not a tuner, but I've found the ISC gives a much more consistent idle than setting it manually, not to mention my FD was much much smoother at low rpms and light throttle inputs with an ISC vs without.

 

Your first step is to check the fuel pressure. You'll be able to tell if the fpr is working and if the vacuum reference is working. You can also determine if you have a leaking injector.

Paul

 

thanks guys i will start there.

 

I've had many different configurations of modifications on my car and have done lots of self tuning and the PFC with the ISC in place has always nailed idle perfectly. If you really know what you are doing you might be able to tune idle and part throttle without the ISC but very few people have the time or skill to do this.

I'm guessing O2 feedback too - but if the tuner does not know about it they should not be let near an RX-7.

 

First off, just simply go into the Commander and see if O2 feedback is disabled. It's in the Etc menu. The enable/disable is a Japanese character, but it should be easy to tell which one is which, as most of the features will still be enabled, so you can go off what that enable logo looks like.

Really, with a PFC, there is no good reason to run a factory O2 sensor - MAYBE for emissions purposes, but the PFC, unlike the stock ECU, runs fantastic with the O2 sensor disabled and will get the exact same fuel economy - I have tested this myself.

That's a good first place to start - that will take 2 seconds to do and will give immediate results.

You should be able to order a Datalogit - as far as I know, they are readily available from New Zealand. They're a little pricey, but they're the ONLY way to go to seriously tune the PowerFC.

Testing the fuel pressure would be a good next step, and that will also tell you if the FPR is hooked up right. Look in the shop manual for the static pressure - that is, the fuel pressure with the engine off and the fuel pump running. If it's making that fuel pressure, and the idle pressure is lower and boost pressure is higher, that system is all good.

Dale

 

thanks alot dale ill be sure to do that

 

manual idle control on the PFC is a bandaid. It's a workaround that people figured out because even the datalogit gives you no control over ISC valve duty cycle or idle timing. With the ISC removed, you have no way to add extra idle air with accessories on, unless you essentially rig up your own controlled vacuum leak, which is yet another bandaid and workaround (although it does work). I like the PFC but its driveability limitations have been frustrating me lately.

Don't get me wrong though--I run manual idle control. It is a necessary evil due to the lack of adjustability for the idle system. Think about it--on a street car that seeks maximum driveability, why would you want to remove a valve that adds compensatory idle air to stabilize idle speed under all conditions? The only reason why you would get rid of it is because you can't get it to work right, and the only way you can't get it to work right is because the PFC won't let you adjust its operation with any level of precision.

If the OP's car were mine, I would first get a datalogit, and then I would make a solid effort to try and get the car to idle first with the PFC controlling idle. Sometimes you have to play around with the throttlebody screws and such, and of course make sure you have ZERO vacuum leaks. That being said, the cars I've seen with the PFC controlling idle (one 2nd gen and one FD on stock twins, stock primaries, with street port) all idled rich, in the 11-12:1 range as you are describing. With manual idle control and stock primaries, you can idle anywhere from 12.5:1 to 13.5:1 depending on your setup.

 

so what your saying is i cant set my idle at 13:1-14:1 with out deleting the isc? the car has a remanned installed by the previous owner. it wouldnt be the first thing ive found hacked on the car so i just purchased a blockoff kit and ill spend the weekend doing the simplified set up and then go back to the dyno

 

can the simplified sequential be done in a long night?

 

with manual idle control my car runs very smooth, its a little low and rough when its first started, but as it warms up it idles solid right around 1050 rpms. at around 13.8:1 afr.

My car is extensively modified and wouldnt idle correctly with the ISC. Was also very rich.

But to the OP you might have to adjust the lag settings of the injectors. You may need a dataloggit for this though.

You will notice at a certain point reducing fuel at idle will stop working and the AFR's wont change, this is because the PFC has a minimum injector on time depending on what the lag settings are.

 

datalogit is still available from rx7.com
http://rx7.com/store/rx7/fdecu.html

I dont know why everybody thinks it isnt available , maybe because now you cant get the FD specific one. The universal is what you get now so its black instead of tan.

 

i didnt see it there. people looking at the main site will see they are selling for a brief period of time

 

How about a little more info about the car's set up. What size primary injectors, secondaries, mods to the car, is the motor ported?, etc.

Tim

 

first of all i just purchased a datalogit. thanks tom93r1

dale- you were right, the o2 f/b was on.

tim-
stock primaries
1000cc secondaries
greddy intakes
greddy 3 row with piping
koyo radiator
pfc
greddy prefec b
rfl bov
aluminum ast
remanned motor stock port.
efini y pipe
act clutch and 9.5 lb flywheel
3" dp
3" resonated mid
3" corksport catback

feel like im missing something but those are the important mods.
saturday ill be doing the simplified setup when my blockoff plates come in. im thinking with all everyones information i can get this tuned out.

what numbers am i looking at on a mustang dyno?
i dynoed 202hp and 217tq at 5000rpms untuned.
i know its not a full pull but the number still seem low?
people have seen upwards of 330-350 with this setup?

 

I don't know if those numbers are wHp, but I think you'll be hard pressed (puns aside ) to make those numbers on stock twins and pressure even with your upgrades. Running higher boost has an exponentially adverse effect on stock twins. If you'd like to extract that much power reliably out of a twin setup, you might want to consider a BNR upgrade. That would allow you to run higher boost with a lot more confidence.

 

when turning off the o2 feedback, will any changes happen to the car prior to tuning?

 

it will basically run about the same, your idle could change slightly, but i doubt you would notice much of a difference

 

yeah because i didint notice any changes at all