2G 1G Throttle Body Swap

[karbon]

Months after the swap I decided I wanted EGR again. I tried to follow RRE's suggestion to get the 2g EGR working on the 1g throttle body and it's still not working. I think it's a vacuum routing problem. Maybe I'm just not seeing this correctly, but RRE says that the 1g TB doesn't have vacuum at idle and the 2g does on the EGR line. The 2g EGR wants vacuum, so plumb it from the P line. Fine. Then hook everything else up as normal. Did that and it's still not working. Here's a schematic of how I hooked it up from directions from RRE and Taboo's site:
TB 'P' line --> EGR solenoid leftmost nipple
TB 'A1' line --> T fitting
T fitting one end --> EGR body nipple
T fitting other end --> rightmost nipple on EGR solenoid
EGR end/top nipple --> middle nipple on EGR solenoid
This is how I interpreted the schematic. Someone set me straight. After probably 1000 miles like this, no change in gas mileage nor does the EGR report a readiness state. It's definately not working correctly when it did before the swap.

 

[Empyrials]

i was wondering, i see a lot of 1g TB's for sell, some say they have sensors, others don't... do i need any of the sensors for this swap?

 

[FearceDSM]

i was wondering, i see a lot of 1g TB's for sell, some say they have sensors, others don't... do i need any of the sensors for this swap?

You only need to make sure you have the buterfly plate stop. The rest you can swap over from the 2g TB.

 

[blcknspo0ln]

just keep in mind guys... 1990 throttle bodies DO NOT WORK

91-94 turbo TB's are what you want, but you CAN use 91-94 nonturbo TB's but you eliminate your TB elbow, and will have to devise a new way to connect your IC pipes..

 

[D_Eclipse9916]

I dont know why but I only have 2 vacuum fittings on my car right now and it says 3 hook up to the 1g throttle body? I bought the car this way. I see three but theres no nipple fitting coming out of one of them. I bought the car this way, the car is stock. Someone heplk me

 

[eclipsegsxccca]

Post a pic so we can see what you are talking about. On another note; for whoever is wanting to do the swap, it is not very hard just follow the instructions from RRE. It only took me about a half hour and I noticed a difference immediatly. Get a good 1g t.b and just put your tps, isc sensors on the 1g tb, also you will have to get longer vac. lines and plug the one vac port that angles toward the firewall. You CAN get 1g tb gaskets at any part store

 

[VBGSX]

I dont know why but I only have 2 vacuum fittings on my car right now and it says 3 hook up to the 1g throttle body? I bought the car this way. I see three but theres no nipple fitting coming out of one of them. I bought the car this way, the car is stock. Someone heplk me

Out of curiosity, is your GSX an automatic?

 

[ZmanIV]

I also have two vacuum lines on my throttle body mine is an automatic gst I have a ported intake manifold and a TB waiting to be installed. how should I hook up the lines?

 

[xveganxcowboyx]

Someone mentioned a vacuum leak inside. Is this a common occurance and how difficult are the internal gaskets to replace? I have a vacuum leak that is comming from somewhere in the intake manifold area, but doesn't seem to be external at all. Wondering if this could be it.

 

[VBGSX]

I also have two vacuum lines on my throttle body mine is an automatic gst I have a ported intake manifold and a TB waiting to be installed. how should I hook up the lines?

Yep, this is why you only have the 2 lines

This shouldn't be hard to figure out.
1. What are the 2 vacuum ports on the TB labeled as?
2. What are they running to?
3. If you're not sure about #2, take a pic.

I've only done this on the regular 5 spd. It shouldn't be hard to figure out though.
Just give us all the info you have.

 

[VBGSX]

Someone mentioned a vacuum leak inside. Is this a common occurance and how difficult are the internal gaskets to replace? I have a vacuum leak that is comming from somewhere in the intake manifold area, but doesn't seem to be external at all. Wondering if this could be it.

The best way to find any leaks is to do a boost leak test.
http://www.vfaq.com/mods/ICtester.html

vacuum leak inside, well that could be taken several ways.
If you're talking about the TB shaft seals leaking:
http://www.ca.dsm.org/faq/tb-shaftseals.html
http://www.plymouthlaser.com/tbor.htm

BISS screw also can leak. Actually it's just an O-ring that's bad:
Very simple fix and I can give you directions on this.

Gaskets on both sides of the TB:
Again very simple fix

ICS can go bad(stuck open) which will allow more air to enter at idle and could cause an idle surge.
ICS goes bad(stuck closed) can cause the motor to die at idle, when the AC is on, decelleration to a stop, etc, etc.
Easy check and fix
http://dmtalon.v8eaters.com/ISC.html

The FAIV can also go bad letting in excess air(idle surge is one possible symptom):
Not to hard to replace: All 91 and newer FAIV's are interchangeable.
It's 5 screws and the removal of 2 water lines. You have to be careful not to tear the rubber gasket(same material as an O-ring. When you put it back together, I always you dialectric grease to relube the gasket(do not use motor oil). Put it back together.
These are just the basics. Maybe I'll do a larger/more indepth how to

These are the basic problems with any TB
Good luck

 

[ZmanIV]

Im currently at work and I will try and post a pic tonight. during a break I will go take a look and see what the hoses are labled as
thanks tor the help.

 

[ZmanIV]

the two lines are pluged into the E and A port. E looks like it goes to a solenoid valve near the firewall then down under the intake manifold. A goes to a hard line then under the intake manifold.

 

[VBGSX]

the two lines are pluged into the E and A port. E looks like it goes to a solenoid valve near the firewall then down under the intake manifold. A goes to a hard line then under the intake manifold.

I believe I have the answer for you

2g TB vacuum ports at idle:
A= routes to the IC pipe side. Not under vacuum at idle
E= routes to the manifold side. Vacuum at idle
P= routes to the manifold side. Vacuum at idle

1g TB vacuum ports at idle(1g NT TB)(1g turbo TB should be the same)
P= routes to the manifold pipe side. Vacuum at idle
E= Routes to the IC pipe side. No vacuum at idle
A1= Routes to the IC pipe side. Not under vacuum at idle
A2= Capped off with a vacuum hose per RRE's site. The one that sticks out at an angle.

Ok for you(automatic trani with different TB) hooking it up.
Your E hose(should be for the EGR) should go to the P port on the 1g TB
Your A hose should go to A1 port on the 1g TB.(****see below****)
put vacuum caps on the other open nipples

Make sure your 1g TB has the throttle switch. You will not hook it up but it will stop the throttle plate at it's proper position.

I urge you to verify what I've told you since you have the AT TB. This is how you verify it. This is quite easy and I recommend you do it.

1. mark each vacuum hose with tape as to which port it goes to on the 2g TB
2. Remove the 2g TB.
3. Find a small piece of vacuum hose
4. Put the vacuum hose on each port and blow hard.
5. Track where the air comes out on the TB and write it down(Manifold side or IC pipe side).
6. Do the same thing to the 1g TB
7. If it comes out on the manifold side of the TB it sees vacuum at idle. If it comes out on the IC side, it doesn't see vacuum at idle. Now wasn't that simple so far
8. If the vacuum hose you marked with tape wants vacuum at idle, hook it to the 1g port that see's idle at vacuum. If the vacuum hose doesn't see vacuum at idle, hook it up to the 1g port that also doesn't see vacuum at idle.

Very easy and I hope it helps

 

[xveganxcowboyx]

...

Thanks for the info. I'll save the diagnosis until I have my TPS replaced (think the guy I ordered it from scammed me) so I won't totally hijack this thread. It's strange though. i can hear the leak, but there is no change in idle from spraying carb spray all over the TB and intake manifold.

 

[RamenPride]

here's a pic...

 

[D_Eclipse9916]

Actually I have a 5-speed. Mine has three "ports" but only two have vacuum lines going to them. This is actually the same as my friend's 5-speed gs-t also so its not like it could have been a swap (I also bought the car stock, same with my friend) Ill get a picture tonight.

 

[droptopgst]

Anyone get any further on this? I just put the 1g t/b on my 98 gst spyder. My car had an automatic tranny but I did the 5 speed swap. Where is the 3rd line suppose to go on a 5 speed that the a/t would not need? I have the t/b hooked up and my car runs just not 100% sure its right? Would I benifit any by putting that 3rd line in there that the m/t's have now that I have a m/t?

 

[blcknspo0ln]

Is this picture correct? I was under the impression that the 2 vac sources were to be split on the TB and to 1 vac source on the EGR.

I also MSpainted a red tee on there, I suppose that it is a tee? I can't really tell from the picture.

thanks

 

[blcknspo0ln]

just to clarify, the green is the way I have mine routed right now

EDIT* I just rechecked VBGSX's post up top and it looksl ike i'm the one with the wrong setup. the 2g has 2 ports under vac at aidle and the 1g has one.. anyone can verify?