1G tb on a 2G help

[red_devil]

I have installed a 1G throttle body and I am experiencing some idle issues.

When starting the car cold the idle does not rise to warm up the car and in fact will run at about 600rpm. It has trouble keeping constant and will sometimes stall when I press the gas then let of. When the car is warmed up it seems to run fine.

Is this a TPS or IAC issue? When I installed the tb I used the 1g IAC but installed my 2g TPS getting it close as possible to the original adjustment. Should I have used the 2g IAC?

Vfaq only explains TPS adjustment on a 1g. My manual says set point 1 and 4 to be 5ohms at 0% and point 2 and 3 at .9ohms at 100% throttle. Some threads on here seem to say different though

My logger says around 3% at idle while my safc says 0%, throttle progression seems to work just fine.

 

[Talesin]

I'd more guess a faulty FIAV, or an intake leak somewhere behind the MAS. Had a similar bogging problem in the morning when my EVAP line to the intake hose was just hanging there, disconnected. The ISC could also be at fault... did you check to make sure that the coils are good, and that it actuates strongly enough?

 

[red_devil]

Could I replace my FIAV and my IAC with the one on my unused 2g one?

But if the FIAV is not working properly doesnt that mean that I should have high idle and some surge? which im not getting

 

[Talesin]

No, the FIAV is integral... you can't repair it. I don't believe the ISC (Idle stepping controller, don't think we have an IAC) is not backward-compatible either.

Stupid check.. have you tried adjusting the BISS? Really don't think the TPS is the issue.

 

[ZmanIV]

ISC is the same from 1G to 2G
is the throttle stop in the correct position?

 

[romeen]

Could I replace my FIAV and my IAC with the one on my unused 2g one?

But if the FIAV is not working properly doesnt that mean that I should have high idle and some surge? which im not getting

As ZmanIV said, the IAC's are interchangeable. Even though they may look slightly different (earlier ones have a metal case with light tan colored plastic at the electrical connector end while the later model ones are all a dark brown colored plastic) they are interchangeable.

As Talesin stated, the actual FIAV is incorporated into the bottom half of the TB. However, you can switch the entire bottom half of the TB between 1G and 2G TB's. You have to remove the TB from the car of course. Then just remove the 5 Philip's head screws and pop the bottom half off. The only real difference is that the connections/nipples for the water hoses stick out at a slightly different angle for 1G and 2G so you might need to slightly alter the length of the coolant hose that attaches to it. It may be a good idea to also replace the FIAV gasket that goes between the top and bottom halves while you're there.

If you haven't done a boost leak test since the install it would be a good idea to do one since a leak could be causing your idle issues.

I don't know if you used the RRE instructions but it talks about how to adjust the TPS near the bottom of the page here:

http://roadraceengineering.com/2gtbswap.htm

 

[red_devil]

How can I interchange these?
left is from my stock 2G and right is from my replacement 1G

 

[Auto RS T]

You actually took the ISCs apart. You need to put them back together with the two bolt metal case and swap the ISCs complete with plunger, as a whole.

 

[red_devil]

ok thanks doh moment for sure.

Put my 2g ISC back in now it idles fine...thanks

 

[smores114]

you may also want to check ## 1gTB itself since its off the car. Make sure you rebuilt it, in case u got it from a junkyard. The rebuild kit is rather cheap.