Idle control on specific conditions

[AVP]

Thanks Gintis

after a bit of search, i did find a torn vaccum hose which i replaced. Now i setted up the DC reference curve as mattias suggested.

However i still get the idle speed getting higher as the IATs get higher, and even with the refpos in idle general settings disabled.

why is that happening?

[AVP]

what Hz is best used?

when i try to run the car with the ign.table disabled, the idle valve cannot keep the idle speed low enough. Even at 30% it is still running. Surely there is no other boost leak now!

[AVP]

here is my big question:

reading from the wiki as well, it appears that when the IAT is going higher, the idle should usually go lower!

in my car, the opposite happens!!! i get higher rpm speed as IATs get higher!!!

[GintsK]

Did you try block IAC hose? Still runs? Then you have a leak. Legal (trough trottle) or illegal (hoses, O-rings, seals etc).

Usually rising IAT leads to lower rpms. Simply because of less O2 molecules passes trough same area.

[AVP]

it is dark outside, so i couldnt block the IAC completelly.

the Throtle valve may not block the area of the TPS 100%, but from memory it is a very narrow opening that remains, less than 0.1mm

if usually rising IAT causes lower rpm, then why is the opposite happening in my engine?

[AVP]

went at it again. Definitelly not visible leaks from hoses etc

when i tried to remove one of the vaccum hoses from a T piece that connects the rear of the inlet manifold to the dump valve and the hose goes into the ECU in the car, the car momenteraly almost died!

i quickly reconnected the hose and the idle speed was reached once again.

[peter_jensen]

Hi

You could try my settings.

Fit a diode near the IAC
use highest frequency
Her is a log: http://vems.dk/vems/v3.3_n002087-2010.12.24-11.16.23.zip
 

Peter

[AVP]

Diode is fitted already between the oem plug and the is valve

[AVP]

peter, i cannot open the log file, can you try and resend it??

[peter_jensen]

Try this then http://vems.dk/vems/v3.3_n002087-2010.12.24-11.16.23.vemslog

Peter

[mattias]

Do the test that Gints told you about, and set the min limit DC % for the valve to 30% to prevent it moving into limp-home mode.
You must let the valve control the idle completely to make the best use of the adjustments.

[GintsK]

went at it again. Definitelly not visible leaks from hoses etc

when i tried to remove one of the vaccum hoses from a T piece that connects the rear of the inlet manifold to the dump valve and the hose goes into the ECU in the car, the car momenteraly almost died!

i quickly reconnected the hose and the idle speed was reached once again.

Most probably from that T-piece goes hose to the MAP sensor. Otherwise it require deeper inspection.

How it becomes that you can't block IAC hose? You always can!  

There is no matter to try different settings until too much uncontrolled air goes to the engine.

BTW 0.1mm could be enough. What about stop screw?
Engine has no more MAF. So easy way to check flow trough throttle is block it. I usually do it by palm. But it is bit painful. So you could prefer some similar alternative.

Regarding frequency. Valve works quite good on different frequencies since true PWM involved. I use lower frequencies like 75, 100Hz. Then valve has less chance to stick. It vibrates a little.

[mattias]

Also very important to add, since I failed to notice the comment about the T-piece earlier :  You must never connect the MAP sensor hose anything but directly to the plenum. Sharing signal line with the dump valve or wastegate is not practical, those devices require flow while the MAP sensor is basically static, which can cause false readings in the MAP sensor signal.

[GintsK]

And also it is important for your turbo that dump valve has direct, well breathing connection to plenum. Valve should work as sharp as possible. But any additional volume (MAP sensor hose in this case) in dump valve hose works like a damper. As result valve get lag.

[AVP]

Guys thanks for the answers.

to get something clear because you have been telling me a few times without reading my posts:

TPS plate screw has been adjusted to the point where it cannot be adjusted any more!!!!!!! OK?

now that we have that clear, i will change the vaccum hoses to ECU and dump valves ( i have 2 of them) so that they do not interfere. However, even motronic picks up the signal from the plenum this way( throuth a T piece) and there are no problems there.

The reason that i cannot easily block the IAC valve hose is because of the position of the valve in the engine which makes it very difficult to fit my hands in there to manipulate it. Did you see the pictures i posted? Yesterday in the dark i could not do it. I will try and do it today.

The T piece that i momenteraly removed, if that was the problem and it is leaking, then why did the car almost died? Shouldnt it increase the idle speed once i took it to the air completelly? By removing it i basically generated a larger boost leak! But instead of the idle to go higher, it almost stalled. Is that what is supposed to happen?

@Mattias: you never connect a vaccum hose from the plenum or ECU to the wastegate anyway. But most of the times you do connect a boost gauge for example to the hose that goes to the ECU without problems.


Unfortunatelly i have 4 vaccum exits from my plenum and i need to connect to those: FPR, x2 Dump valves, ECU, Methanol injection, Carbon canister.  Can you advise which are OK to connect together so that i use the T pieces there and eliminate probable malfunctions?


In any case today i will try these:

1) block the IAC hose to the plenum: if the car still idles but does not reduce any idle speed, then this will most likely be a leak after the plenum.Correct?

2) If the throttle plate leaves a small amount of opening regardless of the adjustment screw there, then there is nothing i can do than to order a new throttle plate which seals better, correct?

3) Since i now have 30%Dc on my settings to keep the idle speed as low as possible, and 100Hz on the speed, it seems that settings wise, this can no longer be adjusted anymore. It looks like i either have any of the 2 problems above to solve.