engine starting issue

[charlievoviii]

evo 8. everytime i refueling my evo. put the fuel cap back on. the car would stumble for liek 2-4 minutes and die. Also sometime if i come to a stop fast the car would stumbe and die. any help ? thanks

[Wroom]

It can be due to a faulty idle stepper motor.
The idle stepper has been an issue on the EVOs all the time through the models.
Record time for failure is a friend of mine that bought an EVO8 and two months later the stepper seized totally.

It can also be due to the mapping. It is easier to get a good and stable idle on the EVOs by setting the idle air screw a little higher. Say 5-8 turns from the bottom instead of 1-1.5 turns as standard, and then map the idle around that. This also improves emissions.

[charlievoviii]

It can be due to a faulty idle stepper motor.
The idle stepper has been an issue on the EVOs all the time through the models.
Record time for failure is a friend of mine that bought an EVO8 and two months later the stepper seized totally.

It can also be due to the mapping. It is easier to get a good and stable idle on the EVOs by setting the idle air screw a little higher. Say 5-8 turns from the bottom instead of 1-1.5 turns as standard, and then map the idle around that. This also improves emissions.


right now i'm idleling at 1000rpm set in the autronic. if i turn up the screw will that change the idle rpm even if the autornic still set at 1000rpm ?

[Wroom]

right now i'm idleling at 1000rpm set in the autronic. if i turn up the screw will that change the idle rpm even if the autornic still set at 1000rpm ?
Not until the idle valve is fully closed.

Thats the whole idea with an idle valve. It will keep the set idle rpm as long as it is not fully closed or open.
So by giving the engine more base idle air, you push the control range of the idle valve up in the rpm´s, and you eliminate the risk of stalling.
And the idle rpm´s can also be controlled by adjustments in the ignition table or by fuelling.
On the EVOs, an idle ignition ramp is very efficient. But the fuelling is best set flat around idle rpm.

Stalling on idle can also be due to incorrect setup of the regulating filter parameters for idle control in the ECU.

Also, setting a good idle on an Audi 5-cyl engine is quite simple. Just give it 15 degree ignition somewhat and enough fuel. But on an EVO engine it is much more complicated. That's one of the things you get when you pay an experienced mapper to tune the car.

I have some thousand of hours time put into my maps for the EVOs only for setting up a good idle that never stalls, and is stable in summer and winter, and with both hot and cold engine.

[charlievoviii]

i really apreciate your help. Being the fill US evo owners running Autronic, it's hard to get support. Well i will post my map up tomorrow. also can you break it down step by step what do i need to do to maybe fix my idle ? i don't want oto idle too high. so if i turn the idle screw up will my idle change from 1000rpm to more ? or the ecu will keep the idle at 1000rpm no matter what ? also is there a way to calibrate or synchronize the the engine idle with the autronic ? maybe the idle is lower than 1000rpm but the autronic is telling it to stay at 1000rpm.

[Wroom]

i really apreciate your help. Being the fill US evo owners running Autronic, it's hard to get support.
From where did you buy the Autronic ECU? The reseller should be able to give you good support.

Well i will post my map up tomorrow.
Yes, do so. That will make it easier to help.

also can you break it down step by step what do i need to do to maybe fix my idle ? i don't want oto idle too high. so if i turn the idle screw up will my idle change from 1000rpm to more ? or the ecu will keep the idle at 1000rpm no matter what ?
Well, the basic idea with an idle stabilisation is to keep the idle at a certain rpm. So if you open up the idle screw a turn, then the idle stepper will compensate by closing enough for the rpm to stay at 1000 rpm. And if you continue to turn up the idle air screw, the idle stepper will continue to close up, until it is fully closed. First thenafter the rpm will start to increase with you turning the idle air screw anticlockwise.

also is there a way to calibrate or synchronize the the engine idle with the autronic ? maybe the idle is lower than 1000rpm but the autronic is telling it to stay at 1000rpm.
I did not understand this part of the question. The Autronic, when correctly set up, will keep the idle at the rpm that is set in the ecu cal file.

[Madevelopments]

evo 8. everytime i refueling my evo. put the fuel cap back on. the car would stumble for liek 2-4 minutes and die. Also sometime if i come to a stop fast the car would stumbe and die. any help ? thanks

One question is the car stock or does it have diff cams or a larger engine.

Mark

[charlievoviii]

the car is fully builts. 2.0 liter with forge internals. hks 272/272, dual valvesprings and retainers, balanceshaft removed, and i'm running usa shitty 91 octane. lol

[Madevelopments]

What I have found once you put cams in them the base idle needs to be raised as the valve is open to much, and this causes idle/stalling problems check the idle valve duty on idle,
I drill a 2.5mm hole in the thottle plate to raise the idle this has a very big affect on the idle quality and you can make the idle stabilty almost as good as a stock car.

Mark

[MRMRacing]

Here is a doc showing idle set up for EVO cars. This is for stock engines but it may help.

[Wroom]

I drill a 2.5mm hole in the thottle plate to raise the idle this has a very big affect on the idle quality and you can make the idle stabilty almost as good as a stock car.
Should never need to do that on an EVO. The idle air screw is mostly sufficient.
And if one needs more air, one can adjust the throttle stop screw.
Those modifications are also fully reversible.

[Madevelopments]

Should never need to do that on an EVO. The idle air screw is mostly sufficient.
And if one needs more air, one can adjust the throttle stop screw.
Those modifications are also fully reversible.

The Evo 7/8/9 do not have a throttle stop screw and this is the only way to do it.

Mark

[charlievoviii]

did anyone take a look at my map yet ?

[charlievoviii]

Here is a doc showing idle set up for EVO cars. This is for stock engines but it may help.


in the pdf posted. what do they mean by "make sure the base fuel table are the same as and around the idle rpm ?

[charlievoviii]

also i dont see any selection for stepper setup in Menu 1

[Wroom]

in the pdf posted. what do they mean by "make sure the base fuel table are the same as and around the idle rpm ?
To maintain the values in the "base fuel delivery table" that affects fuelling on idle to be very much the same.

Say you idle around 900 rpm with a load of about 50 kPa and have one column of fuel cells at 800 rpm and another column at 1000 rpm. And that you have LOAD rows at 35, 50 and 70 kPa.

Lets also say you tuned cell att 1000 rpm and 50 kPa to be 63. Then start with copying out the value 63 to all the cells between 800 rpm to 1000 rpm within 350 and up to 70 kPa.

To achieve a totally flat response on fuelling from variations in load and rpm on idle can be a tedious work for an engine with low rotating mass, as the EVO 4G63. But to set the values of these cells to the same value is a good start.

Secondly, i disagree with that document in that one really should set an ignition ramp at idle to maintain a strong idle. Engine normally runs good at idle somewhere between 5-13 degrees depending on other factors. You can set a ramp with values between 0-22 degrees, so that the engine runs on 6 degrees on idle, and if the load increase, like a fan starting, or the AC starting, then the ignition ramp will force the ignition up and instantly counteract the rpm dropping. And also doing this much faster than the idle stepper can ever respond.

[Wroom]

did anyone take a look at my map yet ?
I have.

Have you tried turning up the idle air?

[charlievoviii]

yes i have turn the idle air screw up and it works. thank you so much. now all i ahve to do is figure why do my car stumble, every time i take the gas cap off or refueling and put the cap back on.

[Wroom]

Have you blocked the breather hose from the carbon cannister to the tank?

[charlievoviii]

Have you blocked the breather hose from the carbon cannister to the tank?


i don't have the canister anymore. I have a magnus intake manifold. and a one way check valve go towards the gas tank breather line fromt he intake to the gas tank line.

http://i142.photobucket.com/albums/r81/c-spec/a1.jpg
http://i142.photobucket.com/albums/r81/c-spec/a2.jpg

[Wroom]

i don't have the canister anymore. I have a magnus intake manifold. and a one way check valve go towards the gas tank breather line fromt he intake to the gas tank line.
You should have the breather line in open air. And preferably with some filter on.

There is a tip over valve on that line in the tank.


And i have a HKS Kansai plenum. ;)

[charlievoviii]

You should have the breather line in open air. And preferably with some filter on.

There is a tip over valve on that line in the tank.


And i have a HKS Kansai plenum. ;)

so the line that have show in the pix, just take off the factory oneway check valv off and put filter there.?/

HKS kansai, wow that's a very nice piece, too bad so expensive. I own a evo shop here in California, usa. I also have a Dyno dynamic, so i'm too broke. lol

[Wroom]

so the line that have show in the pix, just take off the factory oneway check valv off and put filter there.?/
If you mean the check valve that was connected between the plenum and the cannister from factory, then yes. The breather hose shall not be connected to the plenum.
You can plug it. But then you will have some slight pressure variations in the tank.

The pictures where quite dark. All i could see was a big shiny magnus plenum and a finger. ;)

HKS kansai, wow that's a very nice piece, too bad so expensive. I own a evo shop here in California, usa. I also have a Dyno dynamic, so i'm too broke. lol
If i where to look at what things cost, then i might go insane. :D
The induction in the Kansai is very good over the full range, and exponentially better with higher boost. Problem is the large volume affecting off boost response slightly.

[charlievoviii]

i will take a pix with my camera tomorrow.