SNsLude

Hey guys, so as I searched and searched about the dreadful idle surging problems, I thought i had narrowed it down to the fitv. I did the whole "finger" test and sure enough, there was suction in the lower port of the tb that led to the fitv. So, basically I blocked off the fitv and that part is fixed.

However, as I thought my surging idle would be gone, it still lingered around. Turns out, when I put my finger over the top port in the tb, there is that same suction as from the lower port, and then my idle also goes down.



that port ^^^



port leads out through this area.

I looked on my IM, and there is a little opening for that port, what is it for? My gasket doesnt block that opening.

Is it safe to just simply block it off? What can I use to block it off while still keeping a clean tight fitting when I put the tb back on the IM

SNsLude

Okay, so people have informed me that that port is responsible for getting air to the IACV. Can I just simply block off the IACV as well?

SNsLude

Hm, I blocked off the IACV, but there is still suction from that port and that is def what is causing the idle fluxuation. When i block off the port with my finger it goes away. I have the iacv blocked though, so what else is it. No vacume lines can lead to that port or cause the problem right? It's just strictly the iacv?

Blamo

yes, this is an old thread but this is my situation too. When I block the top port my Idle surging stops, and car drives perfect! I pugged it for a short while with a rubber cap, drove it for a week and it was perfect. That was only a temp fix tho, the cap was not going to stay much longer so I took it out. Im aware this goes to the Idle air control valve, but as he stated is there anywhere else it goes too? In the second picture, at the top left part of the chamber, there is a small hole about the size of the point on a pen. It heads in NW direction, where does this lead? Im guessing this might be my problem since I have already replaced my IAC. Anyone shed some light on this? Thanks

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94 Si

marcucci

The top port goes to the IACV, it provides fresh air for the IACV to bypass the TB and control the idle (other port on the IACV goes directly into the manifold). Blocking this just eliminates the IACV.

Check the sticky at the top of the GD forum for idle issues. My guess is that the issue is either that the base idle is set too high (the IACV will run to the end of it's adjustment and start over, causing surging) or that the IACV is bad or clogged and ineffective (causing it to run out of max adjustment and go back to minimum and surge).