View Full Version : ME vs PowerFC vs Idle

03-24-2004, 07:13 PM
So we have finally got the car sort of running, except it won't idle at all.
I've got a red top motor with a blacktop harness and blacktop Power FC. I've also got the Q45 MAF with the FC set at VH41 MAF.
The biggest problem is that this thing will not idle when warm, not at all. It idles ok when cold, but as soon as it gets sorta warm it dies. It seems to do ok with some throttle but if you don't hold it it falls. Is the MAF just to big or does anyone know what I need to do to fix this thing. Anybody done a Q45 MAF on a power FC.
Also doesn't this thing find it's own idle if you let it run for like 10 minutes on its own? I need to reset it or something cause it just isn't working.

03-24-2004, 11:33 PM
yeh, reset it and let it idle for 10 mins, then turn a/c on an let it idle some more. My PowerFC had big problems idling with cams, 740s, and z32 mafs. it would idle, just erratic.

03-25-2004, 12:10 AM
Its probably too rich at idle. If its idleing fine while cold, then maybe it has a good amount of fuel for cold starting... but then too much for when its warm.

03-25-2004, 06:37 PM
So disconnect the battery for reseting it right, I had a base map put on by XS Engineering for the Q45 MAF and 740 plus cams but I'm curious what is your Fuel pressure at and your settings for injectors looking like through the commander?
I'm sure it is running rich, just not sure what to do to ease it back, have to excuse my ignorance, not so good with how the FC works just yet.


03-25-2004, 06:57 PM
You use a fuel pressure regulator to turn down the fuel pressure. You also need to hook up a gauge to set it.

03-25-2004, 09:51 PM
how far away from the turbo is your MAF? You need about 14" of ssmooth piping between your turbo and your MAF.

03-25-2004, 11:07 PM
Good to know, I'm alright though on that, I'd say I ave a little more the 14". I've got a Greddy gage and it is about 2.7 kg/cm^2 at idle when it is cold. Using a SX external FPR with Tomei 740cc/min injectors. HKS 264 step 2 cams as well. I"m really starting to wonder if something isn't right with the idle control valve.

steve shadows
03-26-2004, 12:15 AM
1. the power fc with the sr20 is insanely reliant on the IACV for proper drivablility, if this is not your goal then you should not have bought a power fc, which i also my idea...

2. Hugh, I would assume a lot of your experience with sr20/power fc combinations are with stock sr20 in the car already, or even in the jdm chasis.

one of the big things with the jdm motors from japan oil pours into the intake manifold http://forums.freshalloy.com/images/graemlins/tear.gif and fouls out the idle air control valve, thanks to burning oil on the sensor on inital startup...

This can be attributed to so many sr20 related idle issues.

Here are the main points to confirm, correct idle with the sr20 and the power fc. In this intance , we are assuming your using the base power fc map with a stock turbocharger, stock 370cc injectors, and a leak free piping system ( intercooler ) and leak free exaust, both equally important with this setup.

Set the base timing correctly, i have done a writeup as many others have on here about how to do this.

basically you need to 1st unplug the tps, use a timing light on the rear black diagnostic wire for the coil pack harness, aim it at the crank pulley and the sprong sticking out of the timing cover, and then adjust the cas accordingly to aquire perfect base timing, which initally will require you to adjust idle to factory spec using the Throttle body adjustment screw, which to if i remeber correctly in my haze right now is 850-900 rpms. Then line up the sprong with the 2nd "white" mark on the pulley as the light flashes from right to left or the 2nd mark from the exaust side of the engine. This simple thing is overlooked by a lot of people, and almost all of the tuning shops and import shops we have dealt with forget to do this, or dont do this correctly, we have even been blamed by a very few of our own customers of not setting the idle right after they have taken the car to other shops and had the shops tamper with the power fc and hardware in place...

try this first, then let the car idle correctly for 10 minutes and make sure the IACV is working properly...

next possible problem to check for sure on the IACV functioning , did you wire the IACV to power in the battery area. The old "popular" online schematic does not show it... use the new heavy throttle one that has been revised.

Are the coolant lines hooked up to the idle air control valve? Are they clogged, or is the heater core clogged, do you have your heater hooked up at all, or is your thermostat bad? Or do you even have a stock or clogged radiator. This sounds close to a temperature based idle issue, but it can also be attributed to an oil ridden idle air control valve. We think the overall problem lies somewhere in there. http://forums.freshalloy.com/images/graemlins/shocked.gif

make sure to reset the power fc after doing the IDLE. You should try setting up the idle on a stock ecu. If you are having initial idle problems. Remeber the power fc was SUPPOSED to be a plug and play unit for a well maintained stock car from japan...

-steve http://forums.freshalloy.com/images/graemlins/cool.gif

03-26-2004, 07:17 AM
So disconnect the battery for reseting it right? ...... have to excuse my ignorance, not so good with how the FC works just yet.

No, with PowerFC, unplugging the battery doesn't reset it.
"Initialize settings" is the closest thing to a reset.
It's in the Misc. menu.

03-26-2004, 09:23 AM
I wish I could intialize the Power FC, but I think I may lose my base map from XS Engineering. I don't have a stock ECU either, I only have the power FC....
Oil in the IVAC, that would be no good. I need to check it out I guess and get back to everyone. Not sure how I'm going to set the timing right, using the splitfire ignition which is missing that wire and the car doesn't want to idle to start with. Can I set it using the power FC, what should it read timing wise anyways, stock should be 15 right.

03-26-2004, 01:23 PM
whoa whoa... so you allready have an idle problem that is ignition related? Due to splitfire coil packs? Man, you have to solve the mechanical stuff first before looking into the PFC. Alot of times, problems you have on your motor go unnoticed with a stock ECU, when you put a PFC on, it brings out all the little things that aren't right with your motor. It's very sensitive and everything needs to be working right for it to work right.

btw... depending on if XS locked the settings in place, it may not reset their map... either way, it doesn't matter, go into Microsoft Excel and make 2 20x20 grids(if you have it, otherwise just make them with a pen and ruler)
Then go out to the car, turn key to ON, go to IGN map, start copying all the variables cell by cell.
Do the same with the INJ map.. copy it cell by cell.
I woudl suggest doing this anyway. This is the FIRST thing I do. From the very first base map, to all my maps I alter, I have them all copied somewhere, usually in Excel.

03-26-2004, 06:53 PM
ok I can do that.
When I look at the monitor it tells me an ignition timing value, is this right and can I adjust it there or do I need to adjust it mechanically? It should be 15 right?

03-26-2004, 09:07 PM
mechanical timing should be 15 at idle, yes.
That is set with timing light and adjusting the cam sensor.

Changing the values on the Commander at idle, won't do a thing. The IGN and INJ parameters around the idle cells, can't be adjusted with Commander, they are locked in. You can change numbers yes, but it won't do anything. (this is only in the few cells around where it idles)

03-31-2004, 09:34 PM
heh, without the base timing set, as in the aforementioned explanation, the pfc reading onthe commander will be incorect.



sorry i know only ahole's use caps


04-01-2004, 08:17 AM
hey guys sorry to break in on this but I just got my PFC and had a quick question. I see the self learning idle requires a few steps, what if I dont have A/C in my car? will that afect the idle setup?

dont worry I dont have it in my car yet http://forums.freshalloy.com/images/graemlins/tongue.gif gotta wire the car again and get a commander http://forums.freshalloy.com/images/graemlins/laugh.gif

04-01-2004, 11:46 AM
I certainly hope not, I have no AC as well.
Got everythign sweet on the Timing, and tested the IACV and it seems to be functioning. Looks like the wiring is good as well. So we reset the battery and fired it up, it idles good, but as soon as the gas is pressed it won't come back to idle. When you press the gas then let off blaa, it drops off. So what do you all think?, it will idle for days as long as I don't step on the gas.
Also what is this word "trailing" meaning in the settings menu?

04-02-2004, 07:12 AM
your PowerFC has a "trailing" map?
hahaha, thats for RX7's!!!!!!
(leading and trailing timing maps)

btw, like I said earlier, resetting the battery doesn't do anything with PFC! You have to initialize settings in the Misc. menu to reset.

Also, the reason you run it for a few minutes with a/c on then again with it off is just so it knows the load when A/C is on, that way it knows to give an allotted amount of fuel with a/c on or off. If you don't have it, it doesn't matter. ALSO... everytime you start the car, the PFC learns idle. If you make any changes like adding A/C later, then simply let it idle for 10 min with A/C on. (PFC works the same for boost, it "learns" boost duty cycles everytime you drive and can adjust the solenoid/fuel accordingly.

04-02-2004, 08:57 AM
oooh i forgot about the boost duty cycle thing. crap... now dilema to go with the boost kit or the HKS EVC EZII... damn http://forums.freshalloy.com/images/graemlins/smile.gif

04-02-2004, 11:20 AM
I guess it would be nice to have a translated SR20 commander manual, my bad.