Pfc And Strange Ignition Retard Issue .

[GTSBoy]

That's probably because someone would have connected the reverse switch loom to the neutral switch.

[89CAL]

Or a short accross the circuits or something like that.

Is there any real issues with not having a Neutral swich working? I couldnt see why as it thinks the car is always in gear. It still starts so cant be to bad

[GTSBoy]

It's only used by the ECU to make some decisions about idle speed and that sort of thnig.

[discopotato03]

All my Datalogit shows is the switch off point as shown in the pic aboue ie 4700 RPM , I never had a reason to change it .

I was playing around with the log/monitor functions and it plainly shows this piece of shit Apexi box doing all sorts of stupid things . It still tries to retard the ignition at light throttle openings and low revs - off idle . You can sit there and watch the timing going backwards and often its to various low points . Sometimes I can blip the throttle and it briefly goes to 0 . I don't think I have TPS issues , I think this PFC is a lemon with some kind of internal electronic failings . I think it gets the right input signals and screws up internally and outputs garbage .

I think I'm just going to have to live with the fact that this units a dog and no amount of buggerising around tuning wise is going to make it right . So I will be up for an alternative computer because wasting more time and money on this one is pointless . Kill two birds with the one stone by ditching the basket case and get a more modern and versatile replacement . I need this car as a daily so I'm not going to pull the PFC and open it up looking for faults - may not be easily fixed anyway . Like my coils this PFC may well have had problems for years and I'd just put it down to my less than brilliant tuning skills .

A .

[t_revz]

That's probably because someone would have connected the reverse switch loom to the neutral switch.

Nope, I disconnected the neutral switch thinking it was the reverse switch and lights went out. Put it in reverse and lights came on. Haven't touched it since

[paulr33]

can you post the datalogit log and also your tune file?

i cant see it being the PFC and yet having a stable idle

what happens if in neutral you tap the throttle? does it do the same ign retarded?

[discopotato03]

I don't keep the logs for viewing because I see it live onthe monitor page . And yes this goes on standing still in neutral and playing with the throttle . I also see it live on the Tech Edges LCD display . I change gears and see a slight pause followed by a lightening fast lean spike . No amount of extra fuel table settings nor accel settings changes this . Its stupid , I back off and it goes rich on over run and stays that way untill I lift right off or open up again .

Idle mixtures can be anywhere from 0.86 to 0.97 Lambda yet when logging the black box hovers over the same cells . People here say PFCs don't use either table at idle and use invisible settings they make up themselves after the learn process .

The only other thing that may be problematic could be the CAS , Scott claims that after a few years they tend to go off and don't always output clean signals . I'm not sure if you can replace the plastic ring photo diode gadget or the whole unit but I'm going to do whichever anyway .

Too late for me Paul , I have a Vipec Plug in on order because its more versatile and with a good tuner capable of a more refined result than I think a PFC can . No doubt either when working properly can get the same maximums but I suspect the PFC was intended to be on par with the std Nissan system while being tunable . I think the better current crop of computers can probably do it better than the std computer could with better than OE hardware .

Anyway if I wanted to stay with the PFC I'd make sure the CAS was good , or new , because if its outputting BS then this would probably screw any computer up .

A .

[discopotato03]

I don't keep the logs for viewing because I see it live onthe monitor page . And yes this goes on standing still in neutral and playing with the throttle . I also see it live on the Tech Edges LCD display . I change gears and see a slight pause followed by a lightening fast lean spike . No amount of extra fuel table settings nor accel settings changes this . Its stupid , I back off and it goes rich on over run and stays that way untill I lift right off or open up again .

Idle mixtures can be anywhere from 0.86 to 0.97 Lambda yet when logging the black box hovers over the same cells . People here say PFCs don't use either table at idle and use invisible settings they make up themselves after the learn process .

The only other thing that may be problematic could be the CAS , Scott claims that after a few years they tend to go off and don't always output clean signals . I'm not sure if you can replace the plastic ring photo diode gadget or the whole unit but I'm going to do whichever anyway .

Too late for me Paul , I have a Vipec Plug in on order because its more versatile and with a good tuner capable of a more refined result than I think a PFC can . No doubt either when working properly can get the same maximums but I suspect the PFC was intended to be on par with the std Nissan system while being tunable . I think the better current crop of computers can probably do it better than the std computer could with better than OE hardware .

Anyway if I wanted to stay with the PFC I'd make sure the CAS was good , or new , because if its outputting BS then this would probably screw any computer up .

A .

[JonnoHR31]

I was playing around with the log/monitor functions and it plainly shows this piece of shit Apexi box doing all sorts of stupid things . It still tries to retard the ignition at light throttle openings and low revs - off idle . You can sit there and watch the timing going backwards and often its to various low points . Sometimes I can blip the throttle and it briefly goes to 0 . I don't think I have TPS issues , I think this PFC is a lemon with some kind of internal electronic failings . I think it gets the right input signals and screws up internally and outputs garbage .

This screams TPS issues to me, that sort of behavior is exactly what a PFC will do if revs rise whilst it's in idle mode (TPS voltage below .5v or whatever the cutoff is). If you really want to figure out what's causing it then figure out exactly what voltage your PFC needs to get out of idle mode, adjust the TPS to slightly below that and make sure the voltage rises linearly with the throttle.

People here say PFCs don't use either table at idle and use invisible settings they make up themselves after the learn process .

The PFC ignores the ignition map whilst in closed loop idle but it definitely uses the main fuel map. If you have AFR's jumping all over the place then make sure the cells around idle are all fairly similar values and that there aren't any weird compensations in any of the settings causing it.

I highly doubt you have a dodgy PFC, it's almost certainly something else causing your issues, you may well have similar problems with the Vipec.

[t_revz]

Well my issues are basically gone. Went to a quiet spot and played with the top 5x5 boxes and without a wideband I've had to adjust by the note of the engine and how it reacts. Every box took more fuel. Some very minimal and others VERY significant. Very small timing changes. I now only have a small hunt at one point but I couldn't get rid of it easily so I gave up as its not a spot the car spends much time at anyway.

I also saw on map tracer that when it hunted badly or revs fell right off it would be in rpm 1 and load would drop to load 7-9. In this area my ign numbers are set around 9-10 degrees so I wasn't in the idle map at all it was the main map but not where I would have expected the load point to be.

Waiting for exhaust to be done then will get it retuned but at least I can take off now at idle or with throttle and it doesn't stall

[discopotato03]

I reset the TPS from 0.40 to 0.60v and with a steady hand I can get it to step up in 0.05 increments from 0.60 to 1v and beyond, from memory full throttle is something like 4.35v .

If I can get Datalogit to show these repeatable TPS voltages then obviously power earth and signal must be ok with the tps . I think whatever ails this PFC must be internal because all the usual things seem to be alright .

I agree that the symptoms are faulty TPS like but PFC via Datalogit shows otherwise . Its still doing the small throttle off ide retard thing and I noticed once that whilst driving at lowish revs and closed throttle the timing went to zero .

One thing I noticed that did slightly help was throwing in a Jerry of Ultimate that I pumped out when first changing to Eflex E70 . It had some E70 in it because I put some in the tank to help flush the last of the petrol innitially .

I can use a blend of E70 and petrol to lean out the bits I can't control with this ailing PFCbecause while I can make it richer antwhere I cant make it leaner at part throttle whilst maintaining drivability on petrol . When it comes out of closed throttle mode it wants to peg itself at around 0.92 0.93 Lambda until the throttle is open enough to make it use the fuel map - then its more like 0.96 to 0.98 Lambda as it should be . The idiot mode seems to be around the 0.52v TPS area and thats right about where steady state cruse throttle position is much of the time .

Thinking back much of my experimentation with ethanol proved nothing because I didn't understand the true purpose of the PFC injector trim business and was treating that as a fuel trim not an injector size correction . I think I was getting better results with lower ethanol percentages mainly because I was bringing the injector trims back closer to where they should have been all along . Returning to straight petrol just proved that it can be too rich in an area that I can't lean out without problems .

Anyway back to say E20 and live with that until the vipec Plug In is fitted and tuned .

A .

Edited December 23, 2012 by discopotato03

[discopotato03]

Threw a quick dirty E25 brew together and with my best old E25 Dat files got it running reasonably quickly by setting the injector trims from 55 back to 51 . Should be 50 but had places to be and daughter disliked have lap top nursing duties . Will get it a little closer tomorrow if I get the chance but is easily good enough to get around .

If I didn't know any better I'd say the ethanol is burning faster than the BP98 which I think is why the rich spikes are briefer and lesser so to speak . Numbers and bars on the Tech Edge display change faster with ethanol in the system .

Cheers A .