Non-Stop Serious Idle Surge (Video)

[Clinical]

Ok so I know what a bunch of possibilities are, but figured I'd post here to see if off the bat anyone knows what I should check first.

Just got my new 1g home today, and I need to source this bad idle surge issue it has. It idles fine until it warms up and then it'll do this constantly. It will never idle normal once it's warm.

I just want to see if anyone has perhaps had this identical problem or something so I can have an idea of what to pursue first. With negative temps I don't want to spend more time in my garage than I have too haha.

here's a video of the issue, any advice is appreciated - thanks
[ame=http://www.youtube.com/watch?v=EQ1Ugim901w]YouTube[/ame]

 

[Clinical]

Well it made the trip fine, it runs perfect and smooth while driving. Was a nice easy trip up here.

Though the weird thing, soon as I got into town up here and was on the offramp - my CEL started to flicker. Then by the time I came to a stop it was on solid, and it's still on solid now. I pulled up DSMLink soon as I got home and it's not telling me anything. It basically says there is no CEL. Baffled. It's not running any different, still drove fine and surging idle whenever not given throttle.

 

[Darksun280]

I don't know man. It may be a bad Idea to keep driving it while it's got an issue. Maybe theres a shop to can send it to?

 

[Clinical]

Really don't have a choice right now. I mean, it runs perfect driving around. I have no boost leaks. After messing with the tune, the Air/Fuel bounces a little bit but mostly stays around 14.3-15.3 so it's operating in the general area I want it too. The fact it bounces though really does tell me there has to be a leak. Any other one of my DSM's I've tuned via dsmlink that I had any kinks worked out of I could stay damn near rock solid 14.5-14.7 while cruising.

I can't really afford shop prices and I don't trust any shops to really work on my car except one back home now 3 hours away. I'm going to get some carb cleaner and spray around my TB shaft seal areas to see if they're leaking. As of now it's the last thing I can think of.

 

[Tyeler18]

What was your coolant temp when the CEL went full? You probably have the CEL lit during overheat on ecmlink so it's notifying you its above its specified temp.

 

[Riceburning101]

are you sure you put the tps on correctly and thats not why your getting weird readings? What i did to check my tps one time was pull the tps off the tbody and let it connected to the harness and messed with it to make sure i was getting good readings. That could be a fast easy way to make sure your not having resistance in the wiring also it would double check that you put the tps on the tbody correctly.

 

[Clinical]

Not sure about the temp, I eye my gauges and it never went above half but I'll have to log next time if it happens again and see.

Yeah when I put the TPS on I set it with a voltmeter to the correct readings and then it was a bit off in DSMLink so I adjusted it so the voltage was exactly what it's supposed to be. I can't imagine anything is wrong with it now. I did the same with the brand new one, but I returned the new one since it didn't change anything.

 

[Marchev]

Well it made the trip fine, it runs perfect and smooth while driving. Was a nice easy trip up here.

Though the weird thing, soon as I got into town up here and was on the offramp - my CEL started to flicker. Then by the time I came to a stop it was on solid, and it's still on solid now. I pulled up DSMLink soon as I got home and it's not telling me anything. It basically says there is no CEL. Baffled. It's not running any different, still drove fine and surging idle whenever not given throttle.

If there are no DTC recorded, link would throw a CEL for overheating and knock. Since yours has stayed solid for the remainder of that ride I'm assuming it might be thinking it's overheating even though its not. Looking at your log you have it set that the CEL light comes on at 201*F which is low, and if you idle your car without moving much it's normal for it to go to about 205-210*F, which would explain why your CEL came on. Usually people set that value to 234*F.

About your idle issue, if you are 100% sure you have no boost/vacuum leaks, you can try this. Since you say that when you disable the "idle switch operation" check box the car starts idling stable at ~3k, it is possible that your throttle plate is not closing all the way. It could be someone tried rebuilding the TB, before you got the car, and didn't put the throttle plate on properly OR your idle switch might be screwed too far in and preventing the throttle plate from closing.
Easiest way to check this is to take your TB off and shine a light through one side and see if you can see light out the other.

Hope this helps!

 

[92AWDHX40]

Clinical I had the same problem my cel stayed on couldn't figure out why no codes, must have the link setup so the cel comes on at a specific temp, car hasn't been driven in a while fixed my biss screw leak. I still need to do some more blt tests, car surge is better now, but working on it.

 

[Clinical]

now that I think about it, my throttle does have some space I can see through both top and bottom, very very miniscule but if I remember right the throttleplate is supposed to have like a hairline crack of clearance which is what mine has. I might pull it off and take some pictures of mine.

Also the CEL was for my temp, came on again yesterday and I noticed the gauge just barely sitting past its usual spot. I think I have some air bubbles in my system, no big deal.

 

[Clinical]

Giving an update to this.

I had my entire throttlebody rebuilt by a guy I know who does great work since I know it can be a tad tedious process and usually I don't mind undertaking it but being I rely on this car a lot right now for classes and this cold has been too extreme to ride my motorcycle yet much I figured I'd just let him do it over a weekend.
Using carb cleaner it did rev a bit when I'd spray all around the TB so it definitely had a leak somewhere.

However still idle surges like it was paid to do it. Really losing patience with it.
If it wasn't so god damn cold I'd try to spend some time inspecting my intake manifold close as hell, as it's the ONLY thing that I haven't looked over very well besides the upper side.

No boost leaks, air tight throttlebody, no vacuum leaks, coolant bypass mod.
In DSMLink if I remove "simulate idle from TPS" - it doesn't change it at all. However if I disable the idle switch entirely it's still just idling solid at 3000 rpms so it has to be getting excess air somehow yet.

 

[Clinical]

Figured I'd come back and update since I finally solved this since I know how much I hate it when a thread like this pops up in my searches and the person never says if they fixed it or not.

Was the FIAV all along. Whoever bypassed the coolant to the TB never blocked off the passages. I figured there was jbweld or something in there, ended up just blowing through one coolant line while blocking the other with my hand and sure enough air was going through. Whoever did it just never filled the hole or used a blockoff plate.

I bought a JMFab FIAV bypass plate, installed it - and she doesn't surge anymore! So damn happy. Still idles around 1000-1100 instead of the 950 I have it set at but I need to go back and properly set up my idle switch, biss, and TPS now that the main issue is taken care since everything is still a bit out of wack from all these attempts at fixes.
[ame]http://youtu.be/rqIwuNdNXZM[/ame]

 

[Kdouglas89]

Good stuff man. Love that feeling of finally getting something fixed, especially when it was so simple!

Kevin

 

[tbarmydoc]

Well done! I now know what a FIAV is, !

 

[pauleyman]

See post number 8. You could have fixed this then if you put you coolant hoses back.

 

[Clinical]

See post number 8. You could have fixed this then if you put you coolant hoses back.

Yes I'm well aware. I just assumed that when the person who bypassed the coolant they would of blocked off the passages. I have no desire to run coolant to the TB as it's a large annoyance whenever removing the TB or working in that region.

 

[pauleyman]

Fair enough. With dsm anything can happen. Also why I hate buying modded cars.