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Old 11-17-2004, 10:43 PM   #1
Pi7467mp
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Default Hydra Cold fast idle problem

Ok so I talked to phil the other day about my idle.. At first the idle was lingering at 3000 rpm after warm up.. ( this is after I first put the hydra in) he told me to reset my IAC by pulling the plunger out so it almost sits flush inside the Throttle body.. I did this and my idle dropped to 965 or so RPMs.. Now when I start my car when cold it will idle at 960rpm despite my car being warmed up or not. I have a brand new IAC so don't think it would be that? can anyone help me out. Here are my settings for idle.

Proportional=175
integral=150
derivative=20

max vacuum=651
ac step up=22.8
into drive step up=22
vehicle moving step up=10

PWM ISC VALVE:
min pwm duty=18
max pwm duty=90

STEPPER ISC VALVE:
10 valve steps
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Old 11-17-2004, 10:50 PM   #2
Darshu
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What's your idle speed target set at in the table under control 2? If your idle speed target table is OK and it's still not ballpark, you can try increasing the minimum ISC PWM duty. Looking at your ISC settings though I think it's just the idle speed table you need to adjust.
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Old 11-18-2004, 02:18 PM   #3
Pi7467mp
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Default idle target

My idle target table starts at 1648 at -20c and then goes to 984 at 70c
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Old 11-21-2004, 07:00 PM   #4
Pi7467mp
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bump
Still have the problem.. also I am running super rich at ldle and lean under boost help!
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Old 11-21-2004, 09:17 PM   #5
agnes
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Default isc prob

Does isc stepper click at key on? I heard some units were intended for pwm isc equipped vehicles and did not have a stepper driver chip installed. As for lean boost, sounds like you need a good dyno session.
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Old 11-21-2004, 10:04 PM   #6
Pi7467mp
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wel... I don't know if the iac clicks. but when key is turned on there are 2 clicks, and the fuel pump primes.. I agree on the dyno session.
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Old 11-22-2004, 11:45 AM   #7
Hitokiri
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I have the same problem on the unit I have been working on for RSEnigma!!!

So I am not crazy!!!!! Phil assures me that all my settings are correct. I have swapped out the isc with no change. As far as I am concerned the Hydra is not controling my ISC at all.

Sounds like you have the same problem!!! Has anyone gotten the hydra to control their ISC stepper motor????? Not the soloniod type! The stepper motor!!

It doesn't even try to move it at all. I have yet to take a voltmeter to the leads on the motor to see exaclty what signal it is seeing but I expect it's not even connected. I even had 1 motor connected to the wiring, and another installed in the car. We didn't notice any activity of the motor on the wire.

The reason your car idled at 3k (as did RSEnigmas when we first started it up) is that the hydra has no means of closing the gap the stock ECU placed the isc at. In pushing the plunger back in, you are essentially manually setting the idle speed because the hydra won't try to move it at all. RSEnigma's car currently idles cold at about 750 and warm at about 1250. The ISC does not move as it is warming up at all.

I was told by Element that the ISC needs to be set initially at a certain point for the hydra to control it. This makes sense I suppose as you tell the hydra the number of steps and it will try to move from the point you set it at that number of steps, but in my experience the hydra doesn't attempt to move the motor at all under any circumstances with a variety of control parameters.

can someone elaborate of the difference in the stepper motor / PWM ISC Hydras and if it is possible that some of the "RS Hydras" out there have the wrong "chip"?

I also noticed that there is an ISC output under th outputs section of the software that is not currently attatched to anything.... are they sure it controls stepper motors??

does anyones stepper motor work w/ hydra?

Darshu?
HOK?

thanks

Todd
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Old 11-22-2004, 09:51 PM   #8
Darshu
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Well, I have a MY98, and it works perfectly for me in my application. I'm not sure if it's the same type of unit as the MY00+.

FWIW, here's what I've been running with:
Code:
P: 160                        Min PWM: 12.8
I: 142                         Max PWM: 80
D: 15
Max Vac: 651
AC Step Up: 20            Stepper ISC Valve
Into Drive: 22              Valve Steps: 30
Veh. Moving: 16.4
I really couldn't say whether it has anything to do with hardware in the Hydra itself, I just know it works well for me. Also, my ISC stepper valve clicks like crazy when the key is in accessory.
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Old 01-05-2007, 05:46 PM   #9
qhatherly
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Back from the dead!

Did you guys ever find a solution to this problem, I'm having a very similar issue. Since i installed my hydra 2 years or so ago the idle has always dipped when I'm off throttle coming to a stop, or just free revving and its always been ignored as a "tuning" issue. Occasionally it did idle properly for periods of time but not very often. I'm fairly confident that it isn't now as my fuel and ignition maps have been professionally tuned. Once idle has caught, it stays there pretty rock solid.

When i say dip i mean free fall as soon as i come off throttle, all the way down to 400, barely catching, and rising back up to 1000 (just below where its supposed to be. It doesnt matter how much i play with setting at this point, i can max out moving steps up and it won't catch any sooner. I can also play with all the other settings with pretty much no noticeable change. My w/b is fowled so i can't give you a/f examples but it was professionally tuned and the cells it enters on the way down don't differ from when it catches or when it stumbles so i cant imagine fuel mixture being an issue. But just incase i tried playing with it and timing with no luck.

When its cold, the car idles low 800-900 when its set to idle at 1900 or so.

the car is a 99 rs (idle uses stepper motor) firmware 2.14v11 and these are my settings but again, thats just current settings, i've tried almost every possible combination of values. iacv is brand spanking new from subaru.

P-200
I-200
D-25
Max vac 651
moving steps up 22.8
valve steps 25
decel fuel cut is off

This is what happened when i manually reset my stepper motor (push plunger in by hand).

first startup idles at 4000, i change the D value to 255 so that my idle comes back down to where its supposed to, then i set it back to 10.

i go for a drive, car catches idle at 1600ish (moving steps up set to 22) when rolling and then kindly drops to 1080 (exactly where its set to idle) when i come to a stop. at this point in time the car is doing exactly what it should be doing.

i get bold at turn on decel fuel cut, car continues idle perfectly, turn it back off just to make sure this isn't contributing to the problem

this continues for a couple minutes but now idle is slowly catching lower and lower, eventually, after another 5 minutes or so it seems to just ignore the moving steps up and catch at 1080, dipping below this maybe once or twice out of at least 50-75 times coming of off throttle

go home, turn car off

start car, back to crappy idle right off the bat (1000rpm or so, always dipping off throttle)

drive around for a while, it doesnt get better

turn car off, key on, then off, then start again (so taht the stepper opens a little extra) and the car idles like its supposed to again

doesnt last long, 5 minutes later back to idle free falling off throttle all the way down until 400 or so, barely catching and going back up to just 1000 or so

I cannot find a correlation between this problem and coolant temp, ait, rpm/load cells the car enters on the way down off throttle up until the stumble, or anything else for that matter whether its logged data or changed settings.

If anyone can help, or at least lead me in the right direction id would really really appreciate it. I'm getting to the point where i'm debating just drilling a whole in my throttle butterfly. I just re-read this thread and i'm going to try and pull the plunger out rather then push it in.
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Old 01-06-2007, 03:46 PM   #10
gumby647
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Try raising your "Min PWM duty". if you go too high with this then the idle won't come down I think mine is at 18-20 if I remember correctly. Lowering the "Max Vacuum" could also help but once again if you go too low the idle will not drop down. Lowering the "Derivative" will also make the idle catch sooner. It might be a good idea to be sure your "Max ISC Integrator" is set high enough.
As for poor idle when cold that could be a problem with the temp compensation map but you would need to replace your O2 sensor to know for sure.
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Old 01-07-2007, 11:15 AM   #11
qhatherly
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I was under the impression that PWM duty did not effect stepper idle control. I've also tried playing with max vacuum, but when i log it shows that this isn't an issue. I've had the derivitive at zero with no luck, and Max ISC Integrator isn't in my ancient firmware. I do know the temp correction map isn't perfect and it is effecting the cold idle, but this happens hot too.

The big problem is, it barely reacts to changes in "ISC" settings, if at all, usually not at all. At this point i would LOVE if my idle was too high and didn't come down, that would be better than almost stalling every stop.

I'm not even worrying about finding balance between the idle reacting too fast/flaring up and being to slow/struggling, I'm simply doing everything i can to get it to react faster, but nothing is even giving me a hint of it getting better. After I'm able to do this, then i will make it a proper balance.

Why does it not get any better when i crank up the moving steps up, or even max it out? When its running properly after i reset the valve, this has the effect its supposed to, but after that short time is up, and idle is back to crap, this has ZERO effect on where idle catches.

What gets me is that after i reset the valve and bring my idle back down, it runs BEAUTIFULLY for a little while, so it shows me that it is capable of idling properly. It's almost like its loosing track of the idle valve steps, and thinking its more open than it is, but not likely since there would probably be more people with this problem.
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Old 01-07-2007, 12:06 PM   #12
gumby647
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So lets say if at idle you have a vacuum of 585 and you set your max vacuum to 580 it still will idle too low?

Does your setup have "Dynamic Enleanment Coefficient" under "Injection" ? Seems if this were set too aggressive it would cause the idle to not catch.
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Old 01-08-2007, 10:40 AM   #13
Element Tuning
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All the RS's Element Hydras I've tuned have had idles that are near perfect. With that said the customer's struggled to get the idle just right but I had no problem. I say this to everyone and 99% of the time it's a fuel tuning issue and not the ISC settings. In any event these as previously posted are very much in the ballpark for an RS using a stepper ISC valve:

P-200
I-200
D-25
Max vac 651
moving steps up 22.8
valve steps 25
decel fuel cut is off

Changing the valve steps requires a download to take full effect.

Thanks,
Phil
www.elementtuning.com
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Old 01-08-2007, 09:27 PM   #14
qhatherly
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Quote:
Changing the valve steps requires a download to take full effect.
Didn't know that, thanks a lot Phil, I'm really hoping its just an a/f problem too.

Do you sell the wideband o2 sensors that are a plug and play replacement for the ones andrew sent with the unit in the first place? I had some problems with the last replacement sensor i tried and want to eliminate my soldering as a possible problem.
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Old 01-08-2007, 09:55 PM   #15
qhatherly
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just gave valve steps a try, here's how it went:

started car, drove down the street, car's already at operating temp (90 degrees)

uploaded, viewed map, changed valve steps to 30

saved map, closed tuning screen, file-opened it again just incase, downloaded

started back up again, caught idle perfectly, drove around for 5 minutes, no sign of it getting worse again, everythings going well

park, turn off car, start up again 5 seconds later and the car is instantly back to not catching idle (dipping back down to 400 rpm coming off throttle)

i think the worst part of this is the little teases of it working properly once and a while.
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Old 01-09-2007, 11:01 AM   #16
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That's a fueling issue and not your ISC settings. You need to better tune your fueling in the lower vacuum areas. You do this by blipping the throttle and watching what load sites are hit as RPM drops. You will see it typically drops below normal idle load cells. You need to make sure under these conditions it's not too rich or to lean but very close to your idle AFR. This will fix your problem guaranteed as it's a transition fueling issue and not your settings. This is the third step I take when tuning a Hydra. First I typically tune the idle AFR at various RPM points, then turn on the AC and make adjustments to the next highest load cells and then I blip the throttle and work the lower load sites. Once this is complete I move onto tuning the rest of the fuel map.

I would have left your valve steps as they were originally.

Thanks,
Phil
http://www.elementtuning.com
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Old 01-09-2007, 11:40 AM   #17
qhatherly
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Alright one last question, does the hydra w/b need a resistor pack on the sensor wiring?

Thanks again Phil
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Old 01-09-2007, 11:44 AM   #18
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nm just answered my own question
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Old 01-09-2007, 11:51 AM   #19
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You can also detach pieces of your intake tract to alter idle vacuum levels. The same goes for blocking it off more.
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