1997silvia

i did some searching and found this is a common problem but anyways i have a power fc djetro with inj/turbo/etc and i am running a steve shadows tune. my problem lies when the car is totally cold it will start run for about 5 seconds then die out and it will do this about 3 or 4 times til it starts to get warmer then it will drive. but only once the water temp is about 65 celsius or above will it drive good? does anyone know what the cold water temp correction values should be?

also tip in throttle response is bad
air fuels are good at cruising speed and rich at wot like 10:1 ish

any help is greatly appreciated

steve shadows

Are you using data logit?

If you are I can adjust the .dat file for the temp to see if that helps

Also something you need to check is the condition of your Idle Air Control valve, these are critical on cold start and to prevent idle dip. Setting up the idle properly means adjusting the throttle plate screw and the IACV together to find the best idle with the least amount of drop off or dying off throttle or at cold idle.

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1997silvia

i am pretty sure that my iacv is in great working condition, i have been playing with that and it is make a difference, i know that i can adjust the coolant temp correction values on the commander but i dont know what to set them at?
no i dont have datalogit yet i may soon though
i do have a wideband and at wot my air fuels are super rich like 10:1

1997silvia

does anyone have any idea on what normal correction values are for coolant temp in the power fc?

also i am going to try and lean out the fuel map also, can someone let me know the increments i should adjust in? such as .01 or .10??? because its way to rich and i think thats why its runs bad when cold and stalls out before its warm

thanks in advance

mrphams

Don't touch the fuel map....

Do you have a hand controller? You might just need to adjust the "Water Temp Correction Table" settings.

The settings allow you to increase fuel at certain water temperature ranges. Definitely check it out.

jspaeth

This is common, I have the EXACT same issue.....when the car is cold, it won't hold idle, but I can put it in gear and drive (of course I don't rev it past like 3K or so till it gets warmed up) and it is fine, but during the process, if I try to let it idle on its own, it usually ends up dying unless i tap the throttle as the revs go down.


^I think what steve said here is exactly correct. For example, my car has the same problem you mentioned.

When I put the car in gear, and drive (while it's cold), my AFRs are nearly the same as they are when the car is fully warmed up,

At 30C, I am only using 1.04 and 1.07 correction for fuel.


Based on the AFRs being reasonable even at 30C while driving, I don't think the issue lies in the fuel.


I think the IACV (an old, shitty, possibly sticky-when-cold one) is a huge culprit in a lot of idle issues.


Also, in my case, I have pretty big cams (264/264) and as you know, the PFC likes to default to 15* when it goes into "idle mode"

15* with cams like that makes the car want to die kinda easily, it just needs more timing down there, but you can't really do anything to fix that (aside from changing your base timing so that 15* to the ECU actually equals 25 or 30 mechanical, but let's not get into that.)

In summary, try cleaning up your IACV and adjusting the set screw at the throttle plate, like steve said.

I find that the cold water temp enrichment that comes stock on the power FC is COMPLETELY excessive. Like I said, at 30C, I use only about 1.04 and 1.07 and at 50C, I use like 1.02 and 1.04 or something.


In the end, I can't really get the problem to completely go away, so I just deal with it....it means that I can't really turn the car on and leave it to warm up, but I don't care enough to go out and spend $300 or so on a new IACV.

I just start the car up, and drive it under VERY light load until the water temp and engine temp get up to the point where it WILL hold idle.

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1997silvia

thank you very much for your reply, and i will take a look at my cold fuel correction values, also the iacv and tb
i am still wondering however why my wot af's are soooo rich? is that steves safety factor? and yes i do have the commander
i also have sti 550 injectors and in the original tune they should have been at 66% but i had to bump the duty up to 80 to get it to idle hot or cold, should i take them back down and try messing with the idle with the iacv more? and or set idle rpm in the pfc? thanks

riptor

see im haveing the same issue..i just installed my pfc ( it was a referb) and i dont think it got the factory defaults. i have step 1 procams and nismo 555s, s-14 thorttle body, stock turbo, on a l-jetro pfc. hope im not a thread jacker..lol.

riptor

ok never mind...i had the boost control turned on...runs and idles fine now! good luck bro!

ShadowMan

I too have the exact same problem running the power fc, does not idle at all when cold. I have to blip or feather the throttle as she starts to die to keep her going, if i try to put steady pressure on the throttle she just falls on her face. I was thinking my fuel pump/regulator were effed up which I'm still going to change. She has all new o-rings, fuel filter, and fuel lines. I'm going to check to see if my boost control is turned on as well.

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riptor

if you dont have it tuned it would be best to try and get a base tune done. that way your fuel trims can be set and what not...also check to see what your off a/c idle is set at.

WhipsGoneWild.net

yeah im playing around with mine trying to avoid getting dyno tune until i have all my parts on but im sure the water correction is a factor ive noticed how different my car runs at certain temp ranges

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Kingtal0n

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In the power-FC D-jetro, usually there is a TPSvsIGN box. Set it so that below X% Throttle position you have an additional XX* of timing.

Kingtal0n

Possible causes:

1. Not enough air
2. Not enough fuel

Diagnosis #1: Open the bypass on the IACV using a screwdriver, or hold the throttle open manually when it would normally die.

Diagnosis #2: You have a Commander? Add fuel to that part of the map or jack the CoolantvsTempeature enrichment up. If there is a bug and the coolant enrichment is a failure, just bump the fuel map temporarily for diagnosis.

Once you narrow the problem down to air or fuel, attack it directly. Even if the solution to #2 is manually adding a bit of fuel when you need to start the car, at least it presents a reliable solution to the problem until something else can be done. There is a temporary adjustment option in the PFC for exactly this reason: non saved data about ignition and injection compensation.

Seraphim38

I just had a Power FC installed and custom tuned for my built SR20 by the best tuner in the NW states. Under WOT it's right on, but cold starts get the same surge to 2k rpm for about 3 or 4 seconds, then it drops to 1k and dies.

thanks for the tips in the thread: I will see if it can be adjusted out, (or at least improved by adjustment).

RACETUNE

If you have access to the open up the the calibration of the ecu, there is not enough fuel during the cold start compensation table. All you need to do is ask your tuner and have him make the changes and everything will run perfect.

- Frank Siharath

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Kingtal0n

Hi. There is another problem to consider. Some (I am not sure about ALL) Power FC models on the sr20det have a problem controlling the IACV. I can say for certain that at least four of my cars have had this issue.

The fix that I have generally agreed upon is to open the IACV completely, then use an external ball-valve (such as from home depot) to control the inlet airflow. If you adjust this correctly, so that the engine idles hot-neutral right where you want it (with OEM cams about 800rpm) and open the power-FC Setting up to about 950RPM or more, then during a cold start all is well.

So far, rocking this setup for 3 years, no inconsistency no problems on an S13 D-jetro @ 400whp

cotbu

That fix sounds familiar!

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