I just finished replacing a reprogrammed factory ECU with a Power FC in my 93 FD. Everything seems to be working fantastically, but the car is idling way too fast (1600 – 1700 RPM). The PFC thinks that it is making the car idle at 750 RPM even though it is not. I know with the port job that I will not get it to idle at 750, but I should be able to get it to idle steadily below 1200 RMP or so. I would imagine that even 900 RPM should be fine. I just want the car to idle at what the PFC dictates.



I have already adjusted the AAS and TAS as much as possible. The AAS is closed all the way and I backed out the TAS until the car idle would fluctuate as though it was about to stall – but than catches itself and runs fast for a second before it dips back down again. I screwed the TAS back in until this symptom was relieved. However, the car is still idling way to fast in my opinion.



The engine is street ported and I have a free-flow intake, downpipe, stock main cat, and a catback exhaust. All secondary air injection equipment has been removed. I am pretty sure that I do not have any vacuum leaks anywhere as I checked all of this stuff when I installed my new boost controller. This includes everything under the UIM. I am also running the default maps for the PFC. I do not have the resources or the knowledge to be messing around with those maps at this point. If this could be the problem, does anyone have some maps that closely fit this configuration?



Can anyone get me pointed in the right direction? My FD has been garaged for about a month while I have been working on it and I am dying to get out and drive her again.

If you disconnect the negative terminal on the battery, will the PFC loose its mind and do the learning process all over again?

Nevermind, I think I have the issue sorted out. https://www.nopistons.com/forums/pub...#>/biggrin.png

sometimes it takes the pfc a good 1/2 hour or more to correctly lear things like idle

I dont see why your port size would effect the idle.

I set mine at around 700-800 rpm. I have larger street ports and I dont have any problems getting the idle down.

I managed to get the idle down to a reasonable 900 RPM with no electrical / AC load. I think the problem lies with the AAS and the TAS. With the reprogrammed factory module, the car was running way too rich. When I went to adjust the AAS, (turn it back in) I thought the damn thing was stripped it was out so far.



However, after I got the engine to settle down and run smooth at idle (I took 30 min.), I took it for a short spin. After I drove the car down the block and came to a stop, the idle began to surge mildly again (jump up 2 – 3 hundred RPM).



Another thing that worries me is that the knock sensor bar goes all the way across the display when I accelerate heavily. I know that the thing is extremely inaccurate, but I don’t know if I should completely ignore this or not.



I was doing some reading on another forum and I ran into a slightly different version of the wiring harness modification.

“The instructions have you cut the yellow/black A/C out wire, and splice the harness end of the cut wire to the A/C in wire. The ECU end of the yellow/black A/C out wire is left open.” (13brv3 – www.rx7club.com).

I did not do this and I am not sure that I want to. I have only cut the standard four wires out of the harness. Could this be causing a problem for me?



Finally, I came across some PFC maps that closely fit my modifications with the exception of the midpipe.

( http://rx7.homeip.net/pfc/pfc_view.php?FIL...ish007&SCALE=US )

I did the comparison with the base map and there is barely any difference at all. So few cells were changed that I think I should be able to go with the base map until I get it to a professional tuner. Anyway, I don’t think the issue is map related.



If you guys actually take the time to read this and respond with some ideas, I’ll owe you big time (guess it doesn’t count for much since most of you are so far away). Anyway, I have a great deal of respect and appreciation for those of you who don’t mind taking some time to go back and help the new guy. That being said, I don’t come here looking to have everything handed to me, but I do feel there are certain things that can only be gained through experience. This is something of which I currently have a considerable lacking.

Oops! The comparison might be useful.



http://rx7.homeip.net/pfc/pfc_compare.php?...ish007&SCALE=US

Plz don't let my thread fall off the stack. https://www.nopistons.com/forums/pub...O_DIR#>/11.gif

It sounds to me like you haven't let the car learn how to idle. The surging is normal and should go away. Get the idle close to what is set in the commander, and then let it surge for at least 15 minutes. Sometimes it can take longer than 15 minutes. Yes, every time you disconnect the battery the car will try to learn again. If you drive the car for a couple of days, and the surge doesn't go away, or comes back often, try this:



"First see if the idle smoothes out when you turn on the AC or the lights. If it does you have to dick around with the F/C A.E values in the idle settings. These #'s should be 200-300 higher than the idle settings. If the idle surges all the time no mater the elecrical load, AND you have driven the car around for a couple of days(sometimes it takes a while), try adding about 3% (ex. 1.21-->1.24) in the lower vacuum and lower rpm block. you find this by putting your commander on map trace function and seeing what blocks you are going through at idle. It should be the block that is lowest and farthest to the left. That would be the lowest vaccuum and lowest rpm you are hitting while surging. If the car idles, smooth after this, but is to rich, take fuel away from all the blocks around the idle block."

Thanks IGY,



But yes - I did let the car learn to idle. It was idling perfectly untill I tried to drive it. I let it learn for at least 30 min. I would add additional electronic load after it learned to idle with the current load. Then I did the same process starting with no load but with the AC on.



I wouldn't change anything until it idled smoothly for a while given the state of electric and AC load.



Roger