Need a pic of the FIAV blocked off

[niterydr]

This is on my white one. 91 tsi, auto, stock. I can't do a boost leak test til I come back home to MN which is in 2 weeks. The car does run lean at idle. I'm pretty sure I need a new fuel filter cause at light loads (driving up a hill) I'll feel a big loss of power and the wide band goes to about 17.5 a/f. Or I was thinking it's the fpr. But that is a different problem. I can't really do anything til I boost leak test it otherwise I'll just be going in circles. And I don't know if base timing is set correctly but the car idled fine before, except it idle surged as it warmed up. But once it was warm it was absolutly perfect. Now that I blocked off the FIAV it does the opposite..

Check your base timing. If the ICS was stuck open it could have been letting in enough air to overcome the fact that the base timing is way off. Now that you've closed up that leak the car does not have enough air to run (If I am reading your problem correctly the car will start then die?) Another problem could be a very large vacuum leak.

The fuel filter can cause a blockage in fuel flow overall. A fpr failure would be a lack of fuel under load. If the vacuum line isn't hooked up to the FPR you will not have a rising rate of fuel pressure delivery under boost.

[4g63tcrazy]

So my leaning out problem is probably my fpr. The vacuum line is hooked up. I have another one from my red talon to put on it i've just been lazy. Maybe I'll do that today. I did test the ISC yesterday and it's good. The car starts fine, it doesn't die. Once it starts to warm up it begins to idle surge. Before I blocked off the FIAV it would idle surge as it warmed up but once it was warm it stopped and idled perfectly. I don't have a timing light to check base timing so once again I'll have to do that when I get back to MN where I have access to one.

[niterydr]

So my leaning out problem is probably my fpr. The vacuum line is hooked up. I have another one from my red talon to put on it i've just been lazy. Maybe I'll do that today. I did test the ISC yesterday and it's good. The car starts fine, it doesn't die. Once it starts to warm up it begins to idle surge. Before I blocked off the FIAV it would idle surge as it warmed up but once it was warm it stopped and idled perfectly. I don't have a timing light to check base timing so once again I'll have to do that when I get back to MN where I have access to one.

You still have the ICS working? The biss does not do anything? Did it function before?

[4g63tcrazy]

Yup the ICS is still working. I only blocked off the FIAV. The biss no longer really does anything. It did function perfect before.

[niterydr]

Yup the ICS is still working. I only blocked off the FIAV. The biss no longer really does anything. It did function perfect before.

Then you have a large leak. Does unplugging the ICS do anything? The idle surge is because you have to much airflow and cannot control it. The computer is trying to pull timing or close off the ics but is not doing it successfully so you are constantly hunting to try to control the idle air.

You can try to unplug the ICS and see if you can adjust the airflow with just a BISS.

You can also try to ground out the timing plug on the firewall to lock in the timing to a base setting, this would eliminate the computers ability to change timing (dont drive like that though as it locks in the timing at base setting if I remember correctly).

[4g63tcrazy]

Yeah that's what I said earlier. It's acting like I have a large leak more than a sensor problem. I've had too many idle surge experiences with other cars and now I'm getting the hang of the symptoms. Haha. But I did unplug the ISC and it did nothing, played with the biss and it did nothing. So I know for a fact I have a big leak somewhere. Last night I swore I heard a little whistling around the throttle body area and I can garentee it's the leak I'm hearing. And I haven't driven the car cause it's too embarassing and probably wont until I drive home in 2 weeks if I havent found the problem by then.

[4g63tcrazy]

Just went outside to play around with it. Can't really do much with only a $20 tool kit from autozone. Only thing I really tried was unplugging the maf when it was fully warm and it stopped idle surging. I really need an air compressor......

[Dundars]

I personally like having the ISC, especially in a DD.

[4g63tcrazy]

FIXED IT! Used an Amp can and cut it for a block off plate. Still using the ISC too. Now I just have to adjust the idle a little bit since it's way different with that blocked off. I played with it a little and got it to idle at 850 which I will probably just leave it at.

[Halon]

Awesome. Way to be resourceful!! And why not set the idle the correct way while you're at it? You ground two spots which sets the ISC in a middle neutral position, then set the BISS screw to the correct RPM, then unground and the ISC takes over.