Idle setting

[carmined]

What is the normal idle setting for a 2006 Viper? I just put a roe billet throttle body and bought a programmer. I have the idle down to 800 on startup and it seems like after I warm it up, the idle seems to stick around 1100. The throttle is closing all the way to the detent. Should I just close it more?

 

[Nader]

Looks like the idle hang is not just with x-metal TB's. I look forward to hearing the responses.

You are not alone...

 

[Racer Robbie]

I would check to see if the throttle butterfly's are perhaps sticking after the engine has fully warmed up. this would cause a high idle condition.

 

[VicTxV10]

The Roe is a single blade like X-Metal's. I ordered the BBK twin blade from DC Performace so i'll report if I have any troubles.

 

[mjorgensen Woodhouse]

The blade and the IAC is not working the same way as factory. The blade either is open still too much or closed so much the IAC can't provide enough control. We have seen the same effect with cars in the shop that have these mods.

 

[Roadrunner]

Base idle is meant to be 700 rpm... if it is higher due to too much shut throttle airflow, the engine computer will be doing things to attempt to lower speed (ie reducing spark and fully shutting the IAC).

You need to make sure that the minium opening barely allows the engine to run at all (~450rpm) with the IAC bypass plugged shut. That amount of airflow then allows the computer to control idle speed over the full operating temperature.

When the engine is cold it requires more air (which is why you get 800rpm cold), and as it warms it normally cuts down airflow for warming to full warm engine. (which is why since it can't close the air passage you get 1100+ idle).

 

[Nader]

Mark that is interesting. Have you adjusted them? What is the best adjustment? The throttle stop set screw?

The blade and the IAC is not working the same way as factory. The blade either is open still too much or closed so much the IAC can't provide enough control. We have seen the same effect with cars in the shop that have these mods.

 

[Nader]

Interesting also. I cant believe it took this long for someone to post a plain english explanation.

Base idle is meant to be 700 rpm... if it is higher due to too much shut throttle airflow, the engine computer will be doing things to attempt to lower speed (ie reducing spark and fully shutting the IAC).

You need to make sure that the minium opening barely allows the engine to run at all (~450rpm) with the IAC bypass plugged shut. That amount of airflow then allows the computer to control idle speed over the full operating temperature.

When the engine is cold it requires more air (which is why you get 800rpm cold), and as it warms it normally cuts down airflow for warming to full warm engine. (which is why since it can't close the air passage you get 1100+ idle).

 

[mjorgensen Woodhouse]

Mark that is interesting. Have you adjusted them? What is the best adjustment? The throttle stop set screw?

We have tried everything and although some work better than others none have been cured to my liking. I have even removed a couple at the owners request. As you may know there are compromises with almost any mod and if you feel the "increased" performance is worth a little hiccup now and then so be it, if you are not happy with something and cannot adjust to your liking just get rid of the problem parts. The actual gains from some things are just not worth the trouble they may come with, this is why I don't try and sell everything under the sun for the Viper or any of our cars really.

 

[Nader]

Point taken. Thanks Mark.

We have tried everything and although some work better than others none have been cured to my liking. I have even removed a couple at the owners request. As you may know there are compromises with almost any mod and if you feel the "increased" performance is worth a little hiccup now and then so be it, if you are not happy with something and cannot adjust to your liking just get rid of the problem parts. The actual gains from some things are just not worth the trouble they may come with, this is why I don't try and sell everything under the sun for the Viper or any of our cars really.

 

[carmined]

I closed it from what was recommended, on startup it hangs around 700 then after running, it is 900-1100. The throttle is going all the way back to the detent, so it does not seem to be a case of expansion. I don't see any real problems with it around 900 with the six speed. What does everyone think? Can any harm be caused due to this?

I will say that with the large opening and the reprogram, you can feel it breathing better. Probably would help if the exhaust was changed as well.

 

[viperbilliam]

It shouldn't be doing that. I have the Xmetal and I'm not having any of the problems mentioned here. It idles the same way the stocker did; about 700 rpm when warm.

 

[carmined]

That figures, I always have these unique problems.