Idle issue after 1g tb in 2g

[bob123131]

So i did the swap today and ported the inlet on my intake mani. When i got everythign together and started it up it was idleing at 4k so i tighted the biss screw all the way now its at like 2500. Not only that it hesitates like fuel cut once i get it to about 3500 rpms. I switched all sensors with worked on my 2g on to it. It isnt sticking either. What could this be? i have researhed and only thing i kind find that i havent checked is the o ring on the bliss, which i really dont think could be doing this. ### any help would be greatly appreciated due to this is my daily driver.

 

[WatchItExplode]

The o-ring on your BISS could definately be the problem, so check that. You say the throttle isn't sticking, but are you sure it closes completely? I had a similar problem as you, everything seemed fine, no sticking, but my idle was way too high and I couldn't adjust it. Turns out the intake manifold side of the throttle body was all gunked up from EGR gas, which caused my throttle plate to stay open just a hair. I removed the throttle body, cleaned the hell out of it, replaced the gaskets, and my problem was solved.

If none of that helps, do the resistence test on the ISC. You want 30 ohms of resistance between terminals 1&2, 2&3, 4&5, and 5&6 as described by the VFAQ.

 

[TurboSportAWD]

Are you sure you didn't just put too much tension in the throttle cable when you tightened it down? This would cause it to hold the throttle open.

 

[Screamin Eagle]

Sounds like to much tension on the throttle cable.

You do want a little slack in it when you re-install it.

Other than that, the throttle plate might be sticking because of dirt or something.

 

[CanadianTSi]

Yep, check the throttle cable and make sure there's some slack in it, you don't want it to be tight.

 

[Splitpi]

Did you use the feeler gauge to position the sensor correctly? From RRE webpage:
http://www.roadraceengineering.com/2gtbswap.htm
Closed TP Switch and TP Sensor Adjustment [2G]

1. Disconnect the connector of the TPS.
2. Connect ohm meter between terminals 3 and 4.
3. Insert a feeler gauge with thickness 0.45mm (.0177 in.) between the throttle stop and the throttle lever.
[Fold a piece of paper in half 4 times if you don't have the feeler -Ed.]
4. Loosen the TPS mounting bolts. Turn the TPS all the way counter
clockwise.
5. Check for continuity in this condition.
6. Slowly turn the TPS clockwise until the point where continuity and
non-continuity is found (pins 3 and 4).
7. Tighten the TPS mounting bolts.
8. Check the voltage between pins 2 and 4 of the TPS with the ignition
switch on, but the engine not started.
9. Standard value: 400 - 1000 mV
10. Remove the feeler gauge.

 

[Syndicate13]

I'm going to put money on the FIAV. They deteriorate with age and the newest 1G TB is 12 years old.

http://www.dsm.org/how-tos/tttt/tttt3.html

Go through everything in that list and I bet you'll probably end up at the FIAV, just like I did. Block it and remove the water lines, it makes taking it off if you ever need to a whole lot easier. My car idles rock solid at 750. The ISC will still hold a higher idle point, around 1200 for me when you first start the car.

 

[paul s]

Make sure the "close switch" is adjusted properly, look to see if the throttle plate is closeing properly.

 

[RamenPride]

I'm going to put money on the FIAV. They deteriorate with age and the newest 1G TB is 12 years old.

I concur. I had a high idle problem at startup after swapping in a 1G TB. I then put a 2G FIAV on the 1G TB and the problem went away.

 

[paul s]

Or you can just plug up your old FIAV.

 

[bob123131]

ok now for the dumb question. I have done every suggestion besides the FIAV. Hate to sound to dumb, but where is it located?

 

[bob123131]

i thought the FIAV was the lower assembly on the TB, but if you are just blocking that off then where do u put your ISC, and if your are runnign without an ISC does that screw up idle whe nusing ac etc?

 

[Syndicate13]

i thought the FIAV was the lower assembly on the TB, but if you are just blocking that off then where do u put your ISC, and if your are runnign without an ISC does that screw up idle whe nusing ac etc?

The FIAV is only part of the lower half of the TB. The way it works is this, you know those two coolant hoses that are mysteriously running to your TB? Well the FIAV consists of a passageway and a wax pellet. When the car is cold the wax collects and solidifies causing a bypass around the throttle plate so the car will idle higher. As the car warms, the collant flow melts the wax pellet and it seals off the passageway thus bringing down the idle. I live in FL and have never had a problem with the car stalling when cold but YMMV. Here is a Wayback link to the VFAQ for it, some of the images may not work.

http://web.archive.org/web/20050205125429/http://www.vallotton.com/fiavblockoff.asp

 

[bob123131]

it was the FIAV, thanks alot

 

[-DSM2NR-]

I seem to have the same problem. Only on startup my RPMs are on 2500 or so. Once the car warms up the rpms drop to 1000. They are NOT moving around though (ex: from 2000rpm-1000rpm-2000rpm-1000rpm etc...). So I guess I don't have idle surge.
But the thing that freaks me out is that whenever I build boost and then shift (as to change gears) the rpms drop way too low. The car even dies sometimes.

What could my problem be? Might my FIAV be messed up as well?