Hello all,
Its been a while since I posted last, and yes this is a follow-up on my last post of the p0505 code. I drive a 95 Eclipse GST, Ok I changed out the ISC motor once again cleared the computer (unplugged the battery). My problem is that I dont have any problems with my car except that the CEL light is on and if I let the car idle for 15 minutes it starts to raise in rpms, up to like 2000-2500, but for the first 15 or so minutes it will just hug 750-800 without a problem. After the car does this I will drive around for a little while and the car will be just fine for another 15 or so minutes. If anyone has any ideas let me know, I have a 95 Talon TSI as a parts car so if someone suggests I change something I will do that.

 

a little while ago, my car did something similar. it threw the p0505 code. i changed out the ISC and the RPMs jumped up to 2k and surging. i just messed with the BISS while the car is runnin at the normal temp. and it fixed the problem and it idles around 750rpms now.

just something to try...you never know.

 

tj I have also changed the o-ring on the BISS screw and have also done what you have infact I have my BISS screw 1 1/2 turns out from bottomed out. At one point in time I have had the BISS screwed almost all the way in and still didnt help. I can drive the car and not have a problem, but if I let it idle for 15 min it starts creeping up. One thing I did not mention was if I go out and drive my car and shut it off for like 30-45 min, and then start it, it will right off the bat start at like 2000rpms.

 

ok so let me get this strait, you start up your car and it shoots up to 2k. you'll drive it around and it'll idle normal and then some time later while idling it shoot back up? is this right?

is the idle surging when it shoots up to 2k or just stays there?

 

When I start the car first thing in the morning it idle just like it is supposed to. But after I drive the car for a little it will still be fine but after that if I let the car idle for 15 or so min it will creep up. Then if I drive the car around when it starts doing that it will eventually start to act right again. If I shut the car off and wait for about 30-45 min then try to start it that is when it will shoot up to 2000. No the idle doesnt surge it just stays there. But if I tap the throttle (while it is doing this high idling) just a bit the idle will drop down from anywhere from 200-400 rpms. And yes I have a Haynes and a Chiltons! and dont forget I have a spare Talon TSI parts car. (whole car)

 

did you do a boost leak test? because its getting extra air from somewhere thats why the car will idle high or surge.

 

Not yet I am planning on doing that when it gets warm outside. but I am kinda stumped because I figure if I have a boost leak then shouldnt the car be idling high like that all the time?

 

you would think that.....then again we own a DSM....lol

i dunno it could be several things causing it such as a crack that expands when its hot and lets in extra air...blown gasket...computer glitch.....who knows. oh yea, did you put a new ISC or a used one in?

 

Yup, do a boost leak check and spray the intake manifold/TB down with soapy water. Doing this can do two things, find a boost leak and find vacuum leaks. Ok, you're not applying vacuum, but the theory is that where air will get sucked in, it will also get pushed out...do you follow?
Idle issue is common with DSM motors and everyone at some point will have an issue like this if not the same. I've had it too. I just removed and blocked my FIAV, re-ringed the BISS, removed the EGR system, removed the ISC (I have DSMLink to keep the CEL from coming on), and I live in Hawaii and I don't have to worry about temperature changes.

...but first things first, check for leaks. It's free and will only cost you time. There is another thread in here (still new) that deals with idle surge. The Advocate posted a couple of helpful links that can apply to you also because in the DSM world, idle surge and high idle can equate to the same issues.

 

Tj I have put in 2-used ISC that I personally tested the coils on, they did change from what my original symptoms were on the car but now these above symptoms developed. I even went to the extreme of using the ISC out of my wifes 96 Talon TSI and that didnt even help.

Silver I planned on doing that this summer and I was just wondering would the boost/vac leak throw a p0505 code? Another question I have is, lets say just out of curiosity I would unhook the BOV dump tube while the car isidling with the return tube pluggedjust to see the valve inside the BOV. Now here is my question should the valve be partially open and blowing out air without the throttle being pressed and the car just idling? Its even does this at normal idle.