Strange missing at idle! Gets leaner and leaner :-/

[jimBNR32]

That's the odd thing, headlights on dropped the reading at the battery by only 0.1v, however powerFC sees a drop of 0.5v. Which it clearly doesn't like too much.
It may just be the powerFC needs to idle relearn again? perhaps that wasn't accounted for at mapping time when all the electronics are on. I did note the a/c dropped it a further 0.1v at battery which gave me a total of 14.1v at battery (14.3v with no a/c, no main beam), 12.9/13v at the powerFC (with main beam)
Soon as main beam switched off powerFC sees 13.5v again.
Just don't know if these 2 issues are related. As I don't need main beams on to see the leaning out at idle.


The leaning out at hot idle is rather annoying and I understandably want it sorted. I just can't work out if it's part or map related.
I'm going to swap in my oem injectors/afm and ecu and see what happens.
That will at least let rule in or rule out those items.

Any possibility it's something else? Doing my head in.

[Skym]

I talked to a autosparky about that lower voltage at ECU (having same problem on my car with low voltage at turbo timer, about 1 volt lower than at battery) and he said the ECU always sees lower voltage than at battery.

This has PowerFC FAQ -

http://www.paulr33.com/

It says under "What does Dataloggit do...." part that PowerFC does adjust injector lag vs battery voltage (this can make engine run lean if battery voltage drops and might not have been adjusted properly on your car) and ignition timing vs battery voltage. Basically I don't think those features are adjustable via hand controller, so need Dataloggit software, laptop, cable to access them.

Did tuner tune via laptop or hand controller????

[jimBNR32]

He did tune via the data logic kit.
I'm due a remap for some more boost soon, so I will certainly mention this, thanks for that quote.

I did note something odd, injector setting are at 120-122%. Which goes against what I usually read.
But I have heard of many rb26 folks inputting 60% odd percentage with sard/denso 700s and it not idling at all.
Must be a reason for it.

Anyway thankfully I'm borrowing a tps, coils and igniter soon. I can test these out.
If that doesn't sort it I'll swap in stock injectors/afms and ecu. Hopefully that does sort it and then that only leaves me with 3 items to question! My 700s, Nismo afms and pfc/map. With any luck it's just the map!

But your quote does seem to ring true, my voltage does get a little lower at warm idle, may simply be a case of adjusting said parameters for lower voltage!
That may even solve the main beam issue to.
:-). Fingers crossed. I'll have a chat with my tuner in next couple of days (he out the country tuning other cars).

[Skym]

You're welcome. I hope it's as simple as adjusting those battery vs ignition, fuel settings or replacing TPS, etc (crossing fingers).

[Frankyy]

the PFC lowers the idle for some reason when headlights are on or other electronics are turned on, (accessible in the commander menus) maybe your IACV is getting dirty? take it out brake clean it real good, it might need to be re adjusted, your idle might be lower then it should be and causes a miss?

but it could also be spark plugs, I know when my plugs are done it has a little miss on idle, it'll be fine above 2k RPM just doesn't perform like new plugs do

[jimBNR32]

Haven't managed to swap in tps/coils/amp yet (havent been able to pick them up from kind owner), but I did get round to popping back in my oem injectors, afms and stage1 ecu.

It did require me to tighten the throttle cable tho a tad, as it gave a strange hesitation soon as there was any touch on the throttle. Strange never had that before.

But what do you know, all problems gone!!!
No main beam issues at all. Tho I didn't monitor voltage at ecu like on powerFC commander. The car was perfectly fine with it! Not even a twitch in afrs.

I idled it for a good 1-2mintues once fully warm and no change in afrs.
My missing at idle has also completely disappeared! This was my main worry.
Car didn't like part throttle tho on cruise (shuffling I guess), really effected afrs and didn't like it, but other than that, car performed fine. Tho didn't rev it that high and kept boost at wastegate pressure just to test it out and get it warm.

Just happy to have at least found that it must be my map, Denso 700s or Nismo afms.

Which is it tho that's the question. Hopefully it's just the map.

It did note alot of my top injector orings had little nicks on them. Whether that was creating a leak I can't be sure as I never noticed a fuel smell or leaking fuel anywhere.

Could it simply be me tightening the throttle cable slightly?

I guess I could wipe the powerFC map, and run around on base map to see if it was the map? Other than that not much more else I can check on these items?

[Skym]

The throttlebodies open a bit would explain alot, as the TPS settings would have been out (fuel) for amount of air entering throttlebodies and probably fuel map would be out as well. Hesitation = engine running suddenly lean.

Leave tune until tuner can fix it.

[jimBNR32]

I tightened the cable slightly just so there wasn't or very little slack. Wasn't enough to tug and start to open the tbodies.
What your suggesting sounds like i loosened cable to close tbodies?

Tho whatever I tightened it by perhaps was enough to alter the tps very slightly when foot off the throttle. Mind you the stop screw is still the same, so surely tps is likely to read the same as the cable isnt pulling on the tbodies (there is still some slack). Be interesting to see if I pop powerFC back on if it's changed my tps values anyway.
Thought it odd tho.

Like I say on that stage1 ecu, a slight touch of throttle (but not enough to actually start opening tbodies) gave a weird momentary hesitation, not present when i ran powerFC. Amount of pressure/ movement im talking about is resting your foot on the throttle but not depressing it, so very small touch. Be interesting to know if that did change things on pfc. Tho dout my headlight issue would be solved (that defo has to be a map thing).

Least I know it isn't my alt or battery, tho I did buy a new battery due to low sitting values of other one so was werth while.

I'll get hold of mapper and let him know the info I've discovered on this thread.

[jimBNR32]

Didn't get a chance to drive car today, classic British weather. But I swapped in pfc just to give it power to read the new tps values.
Noted tps values have risen slightly. Wasn't expecting it really.
Now getting 0.41v off throttle, and 4.08v wot. Engine off obviously. Not sure if it would read any different with engine on.
I'm going to have to swap injectors and Nismo afms back anyway, (I still suspect same issues as before until I get it remapped), but be good to see tho.
Had a closer look at cable adjustment, and with it fully slack, the stopper screw still isn't touched. Odd, but ok :-/. That gave me 0.39 and 3.9v.
I tugged and adjusted the cable to the point where it was just going to open tbodies, seemed logical, and is where it stopped the odd hesitation with the stage1 ecu. I swapped in pfc again and read tps values, 0.41v and 4.08v.

I've read very very little on cable adjustment on the skyline forums, so really not sure I should be adjusting it. :-/. I won't be running stage1 ecu anyway, so no big deal and didn't notice that issue on pfc map.