Adjusting Tps - Power Fc Question

[Booki]

Finally decided to adjust my TPS to hopefully fix the 4WD light coming on, as the error i got on th eattessa computer 7 long flash's anda 5 short ones, did some research and it comes up with the TPS.

My TPS voltage on iginition was under 0.4v on my hand controller, after some reading it should be above .4 and under .5v is the general concensus.

So i have adjusted my tps to read these values with the ignition on (motor not running), but under the sensor/check on the hand controller, there is a IDL option, and previously the dot was black on idle, but not with the adjustment sometimes its clear sometimes its black.

will this impact anything?

What does it mean?

I have a feeling it means the ecu is in "idle" mode, but maybe i have adjusted my TPS to much and it thinks there is some load on the motor?

Little confused and not 100% sure if my theories are correct.

Any advice would be great!

[89CAL]

The TPS is basically a 2 part sensor. One measures variable resistance to get your throttle position, so varies between 0-5V depending on the throttle position. There is also a digital (on/off) switch that will probably be what is bringing the IDL light on. It's been a while since I've played with my Power FC, but pretty sure everything you are saying sounds alright, that switch should be on (Black) when no throttle is applied, and off when throttle is applied.

0.45v I think is what generally the TPS gets set to

I had some problems with (from memory) the idle sensor light in sensor check. I thought it was under another name in my GTS-t Power FC but could be wrong

I played with the TPS after I got a new TPS sensor (chasing another issue) and never had this problem again. So not saying its the sensor but could be

I think when I originally had the problem it went away after a bit of driving.

[Booki]

Hmmmm...

So if my IDL switch is saying its off (as in not black) when the car is idling with obviously no throttle applied.

Will it be a issue?

I assume its just not running the idle map?

My car's idle is a bit shit, because i cleaned the butterfly's on my throttle bodies when I upgraded the turbo's

So that could even have something to do with it, none the less i think it was operating properly before.

EDIT: Also i thought the max reading was 4v on wide open throttle?

Edited November 9, 2013 by Booki

[89CAL]

Yeah you might not get to 5v but thats the sensor limits. Usually they operate between .5 and 4.5v

[Booki]

Anybody know what the idle switch on the PFC means?

[GTSBoy]

I don't have direct experience with RB26 TPS, but the nearest equivalent ECU I have experience with is RB20. RB20 do not have a variable resistor for the ECU. There is only closed throttle and WOT switches. The variable resistor in the RB20 ECU is unused on manuals and reports to the TCU on autos. So, not a useful example, you might think. But I shall plow on regardless. I worked out that the best way to set the TPS on RB20 was to have it so that the closed switch would come off at the slightest, tiniest hint of opening of the throttle. This would cause the ECU to double fire the injectors (they do this little double click batch fire thing as you crack the throttle) and give the best throttle response for driving off.

Fast forward to ECUs with variable resistor TPSs like RB25s and so on. You need to set the TPS voltage at idle so that the ECU activates the idle condition (so that is the IDL light on PFC) and so that it takes only a teeny, weensy movement of the throttle to make it turn off. That is generally at or near 0.45V like the guys above have said, but it may be a little more or a little less.

So, for your car, it seems like your TPS might be set just a tiny bit too high. Back it off a tiny bit so it stays convincingly in idle mode when you're idling. Job done I expect.

[Booki]

It was set correctly before but the attessa system would throw up codes because the volt reading would sometimes be low, might have to fiddle with it some more. Its at .41v with ignition and goes a little higher when the car is running.

Is that normal?

[GTSBoy]

0.41 is a little on the low side, but not out of range, and the fact that it increases with the engine running is normal because the voltage reading only occurs because it is a variable resistor across notional 5V supply, but the 5V supply is not regulated to perfection, so it tends to increase in voltage a little when the alternator boosts the 12V line. So really, it's not 0.41V in your case, because I'd only do the measurement/adjust with the engine running anyway.

[MatthewT85]

just digging this up

so ive been having idle hunt issues with hot start and also when i put the clutch in at about 2.5k+ revs

done heaps of reading about afm aac ect, have considered cleaning them again, but i did notice some say tps

i looked this morning and realised on ign or car running at idle its .35v which i understand as low, anything btwn 0.45 and 0.5 is good

so looks like it needs adjusting.

http://www.skylinesaustralia.com/forums/topic/404812-help-setting-tps-on-r33-s2/

found that thread but can i adjust the tps without a multimeter and use the powerfc hand controllers reading?
also does it affect anything tune wise?(will i need to check afrs or anything)

[Badgaz]

just digging this up

so ive been having idle hunt issues with hot start and also when i put the clutch in at about 2.5k+ revs

done heaps of reading about afm aac ect, have considered cleaning them again, but i did notice some say tps

i looked this morning and realised on ign or car running at idle its .35v which i understand as low, anything btwn 0.45 and 0.5 is good

so looks like it needs adjusting.

http://www.skylinesaustralia.com/forums/topic/404812-help-setting-tps-on-r33-s2/

found that thread but can i adjust the tps without a multimeter and use the powerfc hand controllers reading?

also does it affect anything tune wise?(will i need to check afrs or anything)

do you have a stock ecu or powerFC....idle control is either closed loop with the o2 feedback turned on or open loop (set by tuning it) if its hunting this can becuase it is running too lean at idle.

[MatthewT85]

power fc

yeah just weird that its fine most times, but only when started hot it will hunt for a couple of seconds, if i clutch in from about 2.5k and above and keep my foot on the clutch it will drop to 500 and up and down for a couple of secs then fine, just figured the tps needs adjusting as a start as its slightly low

Edited June 6, 2014 by MatthewT85

[Badgaz]

i'd recommend resetting your idle... turn the car off...unplug your tps.... start car....adjust idle air control screw on the AAC valve until you are at 750rpm. turn car off...plug tps back in...give that a try.

[MatthewT85]

yeah did that, turned it to roughly 750 was going between 730-880ish there abouts and then plugged it back in, started and it was hunting for ages(10secs didnt normalise till i took the key out and timer was counting)so that didnt help unfort if anything made it worse

[GTSBoy]

Ummm....Badgaz......closed loop idle control has nothing to do with mixtures. It is, by definition, "closed loop idle speed control" not "closed loop mixture control".

Closed loop mixture control barely works at idle anyway because the O2 sensor usually gets too cold to work quickly anyway. Regardless, they are two totally separate things.

[Badgaz]

ok lets just forget the f**kin loops then shall we? idle speed control as you say....and o2 feedback. either way...you'll need to adjust your idle mixtures if you have o2 feedback turned off.

[89CAL]

I remember when I turned my O2 feedback control off and idle didn't change at all. I was under the impression that at idle (when the TPS indicates closed throttle) then the idle IGN and fuel maps are active and the o2 sensor is all but ignored

I had some problems with my TPS not putting the car into idle control for some reason even though the voltages were fine. I pulled it off, messed around with it a bit checking it was operating fine then put it back and all of a sudden it worked again. Strange but something to think about. I ended up buying a new TPS and never seemed to have any issues with it, so maybe my old one, although it indicated it was alright, actually had a problem.

Its a good idea (Although probably not practical for the OP if Power FC is tuned and running) when first installing a Power FC, to check all the sensors and switches are O.K and adjust the TPS to the correct position before performing the Data INIT.

Problems like these are not a problem on newer ECU's. The Link I have now for example has TPS calibration in the PC Software, so if it ever seems like it has a problem, you can just recalibrate it so it knows were 0% and 100% are and its happy again. I'm still a supporter of the Power FC however, as for what most people need it is a pretty good simple replacement ECU. The Link is a much better ECU, but not everything on it is necessary for most

[MatthewT85]

cheers guys, i think i might adjust the tps to reflect 0.45v or slightly above and go from there, maybe have to look at cleaning afm and aac again.

but yeah seeing as though everything ive read has said my voltage is low might be a good starting point

[MatthewT85]

also so if i go ahead with adjusting my tps will it affect anything to the tune? will i have to get it on a dyno to check out AFRs?

[Badgaz]

I remember when I turned my O2 feedback control off and idle didn't change at all. I was under the impression that at idle (when the TPS indicates closed throttle) then the idle IGN and fuel maps are active and the o2 sensor is all but ignored

I had some problems with my TPS not putting the car into idle control for some reason even though the voltages were fine. I pulled it off, messed around with it a bit checking it was operating fine then put it back and all of a sudden it worked again. Strange but something to think about. I ended up buying a new TPS and never seemed to have any issues with it, so maybe my old one, although it indicated it was alright, actually had a problem.

Its a good idea (Although probably not practical for the OP if Power FC is tuned and running) when first installing a Power FC, to check all the sensors and switches are O.K and adjust the TPS to the correct position before performing the Data INIT.

Problems like these are not a problem on newer ECU's. The Link I have now for example has TPS calibration in the PC Software, so if it ever seems like it has a problem, you can just recalibrate it so it knows were 0% and 100% are and its happy again. I'm still a supporter of the Power FC however, as for what most people need it is a pretty good simple replacement ECU. The Link is a much better ECU, but not everything on it is necessary for most

Initially i had thought that as my ign was showing different in my logging to what it showed on the map....but i tried adjusting the fuel map at idle and watched the afr's change. it'd be nice to have power excel to see if there is an idle control system unseen through the fcdatalogit.

the tps will not affect your tune mixtures.

[MatthewT85]

so i adjusted the tps to 0.45v and it looks like ive fixed the hunting on clutch in and hot start, but ill drive it round for a couple of days before saying its 100% fixed.

also for anyone else thats gonna try i pretty much stripped the screws and had to use vice grips to loosen them first.

i think ill also do the idle reset soon too