Idle surge, not a noob

[MattratfTSI]

I just got my new motor in my car this weekend and it has an idle surge. I went through all the vaccume lines and found that when I took off the egr block off plate, and put the egr valve back on, the car idled fine. later on that day, I started the car again and it was back to surging again. I had not changed a thing. so i guess this rules out a vaccume leak. only thing i noticed was that the small wire connection on top of the throttlebody was just about broken with the wire showing. My question is does this wire have anything to do with the idle control?

 

[shawnc16]

You need to hook that back up. Its a closed throttle switch. That should fix it. If it still surges, you can also adjust that switch. The nut loosens and you can turn the plastic part with a screw driver..

 

[1995gsx20g]

if you took the battery out to change the egr plate then it would reset the ecu and it wouldn't surge for a little while.

 

[MattratfTSI]

You need to hook that back up. Its a closed throttle switch. That should fix it. If it still surges, you can also adjust that switch. The nut loosens and you can turn the plastic part with a screw driver..

thanks alot man, you know im not talking about the TPS right? the black sensor on the front of the throttlebody. I mean the small one that has a metal prong that sticks strait up. This is the closed throttle switch? or is the closed throttle switch and the TPS the same thing? just dont want any confusion.

<a href="http://s174.photobucket.com/albums/w103/mattratf/?action=view&current=dsmthrottlebody.jpg" target="_blank"><img src="http://i174.photobucket.com/albums/w103/mattratf/dsmthrottlebody.jpg" border="0" alt="Photobucket"></a>

this is the connection im talking about.

 

[anteversion]

Yes, this is the idle throttle switch. It will tell the ECU that the throttle plate is really closed, and that the engine should be running at idle. Fix this wire and let us know about the result

Does it surge when cold , or even at the normal engine running temp??

 

[dsmmatt28]

My car surges with it plugged in. Idles fine with it unplugged. I have swapped 3 sensors
and still does the same thing I cant figure it out. I left it unplugged cause its got me confused.

 

[AutoMods]

Sounds like FIAV issue. Easy fix is get rid of it with a JMF FIAV bypass plate so you can retain your ISC motor. Import Evolution

Pretty simple instal and easy fix. This is assuming it is not your ISC motor causing the problem.

-Colton

 

[92gs_918]

i did the same thing. mine was idling like shit with a bad surge. unplugged that sensor and hmmmm, no more surge

 

[MattratfTSI]

Seems to surge weather cold or warm. I'll bet if I fix that wire it will be fine. Just have to fix a coolant leak first.

 

[steve]

My car surges with it plugged in. Idles fine with it unplugged. I have swapped 3 sensors
and still does the same thing I cant figure it out. I left it unplugged cause its got me confused.

i did the same thing. mine was idling like shit with a bad surge. unplugged that sensor and hmmmm, no more surge

Seems to surge weather cold or warm. I'll bet if I fix that wire it will be fine. Just have to fix a coolant leak first.

If the IPS is disconnected the ECU doesn't do the tests that cause the surging, it also never tries to manage the idle speed or cut off the injectors on deceleration or open the ISC to emulate a dashpot.

Surging is caused by too much air bypassing the throttle butterfly and causing a high idle. It can be from a misadjusted BISS, dirty throttle body, bad ISC, bad FIAV, bad PCV, ECU damage, or other vacuum leaks.

Disconnecting the IPS to fix surging is like plugging in a 50A fuse where a 5A fuse goes to stop it blowing.

 

[MattratfTSI]

I repaired the frayed IPS wire (the one circled in my picture) and the surge stopped. It now idles fine at 800rpm. I feel like I have a pretty good grasp on what idle surge is all about by now, so heres a checklist for anyone trying to fix an idle surge... this along with "terrys trouble shooting guide" should get you idle surge free and ready to rock.

-Start at the MAF and check every connection on all intercooler piping for vaccume leaks, including BOV. Make your way all the way to the Throttlebody.

- Now check all 4 of the little nipples on top of the throttlebody and wherever they may lead. Its easy if you have your emissions removed.

-Check that the small connection on top on the Tbody and the TPS are secure.

- check that there is no air leaking between the Tbody elbow and the Tbody itself, as well as between the Tbody and the intake manifold. You should have good gaskets between these.

-There are still 4 vaccume sources on the intake manifold itself. Brake booster hose on the back, FPR, BOV , and PCV on the front. check to make sure these are all good connections with good lines.

- another place that you can have a leak is at the injectors where they go into the manifold. You would probably have a fuel leak if the seals were bad here too.

-EGR valve, or blockoff plate if you have one.

- PCV valve (take it out and plug both the hose and the valve cover with your finger to test)

-I guess if you had just had your intake manifold off, a bad gasket seal to the head would cause a vaccume leak.

-now if you have gone through this whole list and still have a surge, it is likely that you have a bad IAC motor or connection. You'll have to do a search on how to test this but I know you take an Ohm reading on it.