Anyone know where we can get ls4 tb connector pigtails, both male and female? Could then make up a wiring adaptor pretty easy.

 

I got mine from bmotorsports.com

 

Found a truck throttle body on an 2003 silverado and it has the 8 pin connector on it. Junk yard wouldn't sell the tbody though, goes with the motor. SMC whom I mentioned in a few posts below sells the truck throttle bodies new for $80. I might pick one up on Monday. GM part number for 4.8, 5.3, 6.0 03-07 truck t-body = 12570800.


Now one other item I need to modify below is a pic of the PCV hose connector tube that is on the LS2 valley cover by the back of the intake manifold. To route the PCV hose correctly I need to find a 90 degree bend version of this. Anyone know where I can find one? Thanks!

 

What about this tb? would it work? its an 8 wire.
gm # 12590211 It is supposed to be for GM LS! LS6 , chevy truck , supposedly taken off a new 5.7L crate engine
I looked around and found in a Corvette forum that this throttle body was also used on 97-04 LS1 corvettes. Its a 78mm tb. Anyone know about its 8 pin wiring? same as ours??

 

Same connector, different pining, but you can get a removal tool to switch around the stock one.

 

Is the pinning difference what you had posted before on this thread?

TRUCK tb / LS4 WIRE HARNESS
A = E
B = C OR H
C = F
D = C OR H
E = G
F = D
G = A
H = B

 

I believe so. Let me dig up the link for the truck wiring...

http://chevythunder.com/drive_by_wire.htm

As you can see it's probably also possible to use the 1998-2005 corvette ones with the two wiring connectors. Both of those tbs will bolt up to the ls6 manifold.

The truck one is the newer design and would be the best option other than making an adapter plate for the manifold.

One of these.
http://www.bmotorsports.com/shop/pro...oducts_id/1084

One of these. The 03-06 Truck Throttle Body Pigtail.
http://www.eficonnection.com/eficonn...omponents.aspx

Eight each of these.
http://www.bmotorsports.com/shop/pro...roducts_id/559
http://www.bmotorsports.com/shop/pro...roducts_id/628

If you wanted to keep it stockish.

 

Thanks a lot , that helps, I picked up a 2005+ truck/corvette tb last night on ebay for cheap. Now gonna make a conversion cable to fit LS4 wiring. Don't wanna move pins and rewire my tb cable, I don't wanna take a chance of ruining it or breaking it.

 

You could cut down the pigtail wires and put a little bit of split loom or heat shrink around it to really minimize the appearance. I recommend getting one of those crimpers and pin removal tools.

 

Ok, got the 2003 & up 78mm throttle body (8 pin) on ebay. Got some of the connectors, need to buy the pigtail. I will wire the pigtail to new connector to make a cable adaptor and be good to go. Only thing I will need to do is get a new silicone 45 degree elbow connector tube for my home made cai box. The truck tb has a 4" opening leading to 78mm butterfly, our stock tb has a 3 1/4" opening. I need to go from 4" tb to 3 1/4" maf. The only reducing 45 degree silicon elbow I find is 4" to 3.5" so I will need to bush the 3.5" end down to 3 1/4"

 

interested in hearing more about this!

 

Once spring hits here I might be messing around with some stuff. Still have a few more months of driving my truck around for the winter.

 

Here's a pic of the OPSU adapter from SMC on my LS2 valley cover.



and truck throttle body on the ls6 manifold:

 

Does it work?

 

I won't know until I put my other motor that is being built in the car. It won't be until around April. I'm hoping someone else get's around to wiring the tbody up to see if it works before then.

 

I thought I'd add this little bit of info I got a while back. It's an email from a guy who swapped an LS4, with an LS2 intake and throttle body, into his fiero. The first paragraph is me asking questions and the second is his response.

"I'd like to learn more about your LS4 swap. More specifically the LS2 intake mod. I read your web page where you covered most of the swap. From the looks of it you used an LS2 intake, TB, the valley tray and the fuel rail. I have a couple questions regarding this swap. How did you get the LS2 TB to work with the LS4 connector? What else did you do to complete the LS2 intake/ TB swap? I'm sure there is something regarding the OPSU and MAP sensor. Any help is greatly appreciated."

"The LS2 intake and throttle body are unmodified. The lifter valley cover is modified in two areas. It has a crankcase vent line that is cut off flush and welded shut. Also, the OPSU boss was cut off and a new one made from aluminum rod welded on at an angle to clear the TB. The LS4 MAP sensor fits the LS2 intake. I replaced the TB connector with one from an LS2, there are two wires un-used. The LS4 has two separate sets of 5v ref and ground circuits, on the LS2 they are combined. The LS4 injectors are too short, you must use LS2 type injectors. The car has not been fully tuned yet, but I started by importing the LS2 injector flow rates and ETC settings to get it running."

 

Ok, here is where I am , too cold to work outdoors, so I am doing everything inside I can to get ready. I got an LS6 intake manifold, another LS4 DOD valley cover , a truck LS6 throttle body and a spare LS4 fuel log from ebay, all pretty good prices. I have modified the intake manifold by removing the vacuum/map mount from the rear. I punched out the whole thing with a metal rod through the manifold rather then cut it off. I sealed the 2" hole with a fender washer, a dime, (yup) and some JB Weld epoxy. I also ground some plastic just behind the bottom corner of the TB mount where it would interfer with the OPSU tower. I cut the OPSU tower on the LS4 valley cover at 15 degrees just above where the oil feed comes in and rotated it 180 degrees so it slants 30 degrees outward and had it welded, looks perfect. I redrilled the oil feed hole to clean it up. There is a vacuum nipple on the neck of the LS6 manifold which will interfer with OPSU, I will cut it off and seal it. I also want to thank neilownz for his help with wiring the TB. See a few posts above. I used the links to obtain the wiring components and made an adaptor cable to mate LS4 wiring harness to LS6 truck throttle body. It was pretty easy they are both 8 pin with same connectors, just have to switch wire positions. The truck throttle body has a molded opening with a open passage to the manifold neck that we do not want or need, it would make a huge air leak. I expoxied that up too which made for a smoother opening anyway. (not all of the LS6 TBs have this open passage but mine did)
I plan on drilling and tapping the upper right hand face of the throttle body for a screw in brass hose connection for vacuum rather then try to drill the manifold neck and attach a vacuum source to that. The LS6 manifold and TB has that funny open channel in the mating face, I am going to use it for vacuum source. I will post pictures soon of what I have done so far

 

Oh! The fuel rail!!! I am going to try and persuade it to bend enough to clear the LS6 manifold. May have to cut it a little at the 4 mounting tabs and the tab that holds the fuel feed. If it won't budge ..........

 

Updates anyone?: I am almost there just trying to sort out the fuel rail issues. I might just cut my alt bracket and use the LS6 injectors and rail with the harness adapters, but I'd really like to use my stock stuff. Has any of you guys tried aftermarket fuel rails with stock injectors?
Here's where I am. LS6 intake, Throttle body adapter, power steering pump res extension, map extension harness and an LS3 valley tray with the vent tube removed and plugged. I also plugged the oil pressure port for now. I will get the right valley tray later with the adapter. (I bet headers and intake will be 30hp at the wheels!!)I should be around 275-280 right now. Also... with headers and intake, cam upgrades will become much more rewarding! especially a single patter design with a tighter lobe separation. I'm thinking of a 212/212@.050, 112-114 L/S with about .580"/.580" lift using 1.8 rockers. I'll have to ditch my Crane rockers so I'll probably go with Harland Sharps. I need to find out what our stock heads flow and at what lift. I wanna keep our stock intake closing point the same. These are just general specs but I'm going to go with a custom grind. Will definitely go with 3.69 gears when this trans decides its had enough.

 

Did you make the throttle body adapter? Have a pic?