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98 GST Eclipse Spyder Turbo - Bad Idle

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Joshua T

Probationary Member
17
1
Apr 13, 2016
Trafford, Pennsylvania
Okay, so I have done a compression test. I got 182psi on all cylinders. Fuel pressure is spot on. I've tested each injector for clogs and pressure tested each one. All those things check out. So i know that the issue I am having has nothing to do with those things.

I have also replaced the spark plugs and wires in hope that it was the issue. Even checked both coil packs with no success. Now I am at a standstill.

Here is a video showing what is going on:
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Do you know if anyone has messed with the BISS screw on your throttle body? The previous owner had messed with mine, probably because he didn't like the higher idle in the cold, and it really messed with how steady the idle was after giving it gas then going into neutral, I would stall now and then but consistently have that rough initial idle. I ended up checking it and it had been turned counter clockwise a ton, I tightened it slowly, did half turns and tested as I didn't have the ability to log and set idle at the time. Eventually cleaned itself up.
 
I messed with it, but I have since turned it back to its orignal position. So you think its possible I blew the ica?
 
Yeah it is a possibility. I think the screw also has a little gasket like thing on it and if that has been pooched you would have to replace the screw as well. I had a friend who was having similar issues but his solution was unplugging the isc so it wouldn't try to fix the idle he had set with the biss screw. I wouldn't really recommend that but it worked for my friend.
 
Okay, so I tried to edit the screw. I took it out and looked at the o ring. It was fine. So i pulled the ica and set the screw. Running exactly the same. :/ starting to think its deeper than that.
 
That happens because the idle drops below 400rmp. Which trips the light. Its a common problem with such low rmps.
 
Is your bov vented to the atmosphere? If your running stock mas and your venting the bov then your going to be running rich when you left of the throttle causing idle to fall on it's face. Also have you done boost leak test? Check your isc for dead cell
 
How do you check isc? I forgot to mention, I did a leak test and it leaks from the throttle cable. That's the only place. Not enough to cause this mess.

I think that's where my p0170 code is coming from.

Also what is a bov bent?
 
Bov = blow off valve. It is recirculated from the factory for a good reason. Use the search tool and read up on it. Easier then trying to explain it. You can also use the search tool to learn how to test the isc. It's pretty easy. There is even a you tube video on the isc if your more of a visual learner.
 
Oh yeah, I don't have a blow off valve.
I swear I hear a vacuum leak. Other than the throttle body. That or it is the throttle body and I just can't tell because I can't get my ear over far enough to pin point the problem area. I sprayed carb clean to see if I could could find anything that way, Nothing was happening at all. So I'm a little confused

And i know that from the day that I bought the car it ran find at idle, never misfired or anything of that nature, but now all of a sudden a little over a year and 4.537 miles later the car is starting to run like this. It drives fine without any problems. But coming to a stop is when it happens.
 
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Check vfaq as well, it is a great source for info and pics they have a write up on testing iacv. Also just run through basics like mechanical and ignition timing, test your tps and coolant temp sensor. Are you sure no boost or vac leaks, get a can of starting fluid and spray it around vac lines and charge pipes, if your idle picks up you have a leak. You said you don't have a bov you should since it came with one unless someone removed it. When you say you have a leak from your throttle cable I'm assuming you mean from the throttle body shafts seal which are replaceable but a pain in the ass sometime so you may want to consider ordering spares in case one gets screwed up in the event that want to fix that leak.
 
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Okay so i attached some image files of the test with the ica. I think I did it right?! All seems okay. Also cleaned egr and blew on the hose and saw that it was moving. Also blew directly into the egr holes to see if it was stuck open, It wasn't. So I did another smoke leak test after all of this. I saw smoke coming from the oil stick hole. I did'nt realize vacuum could leak from there. The reason being is that I went to the junk yard & got a non turbo oil stick. All because the guy that owned it had a screw in the hole. So after some modifcations I was able to get the stick to stay down by cripping it with vice graps. Re-did the smoke test. Not leaking from there. I really thought it would fix the issue. Because I couldn't get not one psi of pressure for a second. Now it holds 6psi for about 8 seconds when I turn off the smoker. Slowly comes out of throttle body shaft seals and a little out of the biss screw. Besides that I really don't see any other leaks. But the car still idels on it's face. Any ideas?!!
 

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Wait...You DON'T have a BOV??? Is it a non-turbo car???
 
No, she has a turbo. Here are some pics of the engine setup.
 

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if you look at the pics you cant see the bov but the recirc pipe is in place so i would assume he has a bov and its recirculated properly, also if he didnt have a bov i dont think his turbo would last long when letting off the throttle after a pull.
 
To be honest, I don't see a BOV. Maybe it's just oriented very weird, but to me that white pipe off the intake goes down towards the charcoal canister past the bov, and there is only a black coupler connecting the two white intercooler pipes together. Can you verify if you have an actual blow off valve?
http://members.shaw.ca/dsm.1000q/Engineprimer/2G/bov.htm

I would also verify your mechanical timing isn't a tooth or two off, as that will greatly affect the idle and acceleration.
 
Okay guys, I finally got some time to look deeper I found the bov: I followed the line from the surge tank and found the bov.

Here are some pics. I have to find a way to test it without removing it. Any suggestions?
 

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T.B seals will drive you nuts.I would address the leaks, As petty as they seem,From my experience with my 3 dsms?.The small things will really hinder our dsm,s.High boost seals are very inexpensive in my eyes and give you a piece of mind.And don,t forget the NEW biss screw and o ring!!
 
Your idle is stumbling when you let off the gas, oil pressure could be the culprit, but itcould also be a BOV/boost leak causing air to escape from the system which could explain the stumble, You can test the BOV to see if it leaks under pressure... Here's a link to help you start looking for small leaks.
http://www.dsmtuners.com/threads/how-to-fix-your-idle-surge-problem.191137/

back to my original thought, One thing that really help my engine was a new PCV valve, this part is a regular maintence part and they could cause oil pressure related problems here's a link to help you understand
http://www.dsmtuners.com/threads/the-4g63t-pcv-system.366890/

hope this helps
 
I turned the key on & off.

IAC test:
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Is this right?
 
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