Does anybody know if the trottle body sensors are compatable with the 730 ECM? It's a 75mm single bore from a 2000 and later Northstar.







Any information would be greatly appreciated!


EDIT : Oh yeah, it has the Caddy sensors on it that are supposed to be backwards compatable for 1996-99 engines if an adapter is made.

 

Not sure about the IAC but the TPS should be ok. You may want to use a DVM just to make sure and measure the hi-lo resistance and compare to your current one. The IAC in use on the older motors is the stepper type. If the current one is a solenoid type, then your SOL. How many pins does the IAC have?

 

I'll find out and get back, thanx for the response. I'm looking to get one from another site, the guy is selling them for $50.

 

This is what he sent me.
Hopefully you can determine with this information.

 

That pin-out looks like the same as a stock TPI IAC, but the connector itself would need to be changed on a TPI harness. The Coil A/B high/low is the normal IAC wiring for a 165 ECM or 730 ECM. Does it come with the sensors for $50? New GM sensors would probably be $50 or maybe more. I think you can buy the connectors from www.rosesandwrenches.com for less than $20.

EDIT: Is the throttle linkage on the wrong side? The area of that TB equates to a V8 TPI TB with 53mm bores...not bad. My LT1 intake EFI TB has the same style IAC connector as the one in the picture. The LT1 TPS connector looks the same as the one in the picture. I use both with a 730 ECM. I would be surprised if the Northstar TPS sensor resistance is different than the stock 730 TPS resistance (not sure though).

 

Thanx, junk. Haven't seen much of you lately.

 

And why couldn't the TB be used upside-down? The guys using them on the transverse V6's are putting them at a 15* angle from stock. Yes, they come with the sensors (worth 50 buck themselves).

EDIT : The V6 throttle cable is on the driver's side (same as V8's?).

 

I have been busy working on the turbo truck I was supposed to have done over a year ago. The deep freeze came and I got tired of working in the cold so I am doing ECM stuff to take a break from it.

I don't see any reason why you couldn't run it upside down. It would just look a little strange with the IAC on top. You would need to make up some cable brackets(maybe?).

The V8 has the cable on the driver's side. In the pics, the first couple have the throttle on the pass. side. The last pic has it on the dirver's side. They are two different TBs. The one with the sensors has the throttle on the pass. side and I think that is the one you are asking about. Why not just run the cable to the pass. side?

 

I could. The main concern was weather or not the sensors would work with my ECM. Yes, I'm getting the one with the sensors.
My next challenge is getting my UIM to accept the larger bore, 74mm is the OUTSIDE dimension of the TB neck. I wish I could afford the Trelio intake for this TB (they're almost $1000).
I'll give a link for these, the guy has 20 or so more.

EDIT : Almost forgot the link...
http://60degreev6.com/showthread.php?t=34483
Also, I think that might be a reverse negative picture (mirror image) because the water pump is "backwards" of mine (unless they're different on transverse engines).

 

Here's a pic of the Trueleo:

 

That intake doesn't look bad, but I like the one Dave12secV6 made more.

That add says 75mm TB, but it doesn't look like the throttle blade is 75mm. If it is not 75mm at the blade, then I think they are being mis-labeled. The housing looks like 75mm and the blade looks like 50ish mm. In other words.....tiny TB. Am I wrong?

 

Well I'm helping Dave with his UIM's so he said he'll give me a discount on one, but it still utilizes the MIM and LIM which can be very restrictive. The Trueleo has been flowed and above IIRC 2000 RPM has zero resistance (it flowed the same as bare heads).
As far as the bore on the TB, the one in the pic that is mounted on a 3500 so it may seem smaller when looking at it installed. The guys using this on the 3500 are having to make an adapter that tapers insider the TB bore to make these work (which they are still being restricted by the inside bore of the neck/plenum). The stock TB on the 3.1 is 54mm (measured it so I might be a little off) and the intake measures 68x76mm (inside). I don't think GM would put a smaller one on the latter 3900 (a 260HP 3900 at that).

 

The Dav12secV6 has a larger plenum for the intake pulses. From a free flow point of view the tubular looks fine, but the plenum is small.

So the TB in the pic has a 75mm blade. The TB intake diameter must be like 3.5" or 4" then. This TB sounds good to me. Maybe worth a try on a V8 too. It is better than the dual 48mm LT1 unit I have now.

 

Did you check out the link? The explaination is in more detail and if you sign on there, you can talk to him yourself (as long as you tell him I sent you there, lol).

 

few things,that truelo intake is so dam ugly,the one car i know of that has one on it actually slowed down with that intake lo.
#2 i can put that tb on one of my manifolds,but i would need the tb to do it,so i can prperly locate the throttle and tv cable linkages.
#3 the throttle cable hookup on that tb is diff from what we have stockso it will prolly reguire a throttl ecable swap.or atleast a swap of the linkages on the shaft
#4 trans tv cable, this ones up in the air,would have to measure distance out from center to see if it has enough pull/or to much from closed throttle to wot .
if its off the trans wont shift right

edit i still think ur better off with a ford style tb

 

1. Really, was it a stocker? I agree on the ugliness I was looking at functionality.
2. When I get my hands on the TB and mock it up, probably could just have you leave a square "plate" bigger than the TB and I'll take care of boring it for the mounting holes and the intake opening.
3.&4. These are minor problems, just will take some time to get them right.

Are you using a Ford TB? Which one? I'm thingking this TB was only $50shipped and if doesn't work, I'm sure I'll be able to get rid of it for that.
2.

 

It looks like it is 75mm at the blade. The throttle linkage looks like it needs the cable coming from the front of the TB. A stock 3rd gen takes the cable coming from the rear. What cable do you plan on using? I wonder if the Northstar cable is really long.

 

That TB was already modified to fit on a FWD (actually a transverse RWD) and one of his posts explains that it does pull from the rear which would be beter for RWD vehicles.

 

You lost me. I read the post about the throttle pull but I think the guy meant FWD and not RWD.

I have a northstar TB like the new one in the pic in my hands and the cable bracket bolts onto the front of the TB. The cable pulls from the front. The 5.3 TB pulls from the rear.

 

It came today!
I believe if I can adapt the pull on my 3.1TB, this one is going to be perfect. The TB's both pull in the same direction, on the same side, and are almost the same size in depth.
Here's a pic, I'll get some more later...

Not to mention, the sensors are in the right place AND have the right connectors!

 

nice i might have to get me one of those,whats the outside diam on that thing anyways,hopefully its not some oddball size that u will have trouble getting a silicone connector for
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its not the mim and lim thats restrictive, it is the uim,and the truelo still usues the stock lim,

 

By the looks, I would think the MIM is restrictive. Although it still needs gasket matching, cause they're WAY off.
And the outside measures 4".

 

no the mim is pretty much a stright shot to the lim - minus the slight bend at the top.but by removing the stock uim u have cut that bend in more then half.
from just behind that minor bend in the mim, is a straight shot to the intake valve.
when u combine the stock uim and mim that bend is approx 167*
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stock bend

and with my manifold

 

Nice pics. Yeah, I see what you mean now, I was looking down inside as I took things apart. I'm sure opening up the intakes to gasket match would improve quite a bit compared to stock.
.
How often have you seen a 4"to2.5" reducing coupler?!lol.

EDIT: What stopped you from using the stock pulling straps and bolt a new bracket for your chain to pull the motor?

 

u have to make ur own.roll a cone thats 4 inch on one side that tapers down to 2.5 inch on the other,then weld a 1-1.5 inch long pice of 4 inch tubing on the one end so u can get a coupler on it.
though 4 inch to 3 inch reducers are common and u could do what i did on my setup 2.5 inch from turbo to intercooler,and 2.5 - 3.0 coupler on the intercooler outlet.with the 3 inch pipe all the way to the tb

 

Gotta get the TB working first,lol. The inside bore is bigger than the neck/plenum on the UIM.

 

i can take care of that easily,but it will require u to relocate the throttle cable bracket possibly,though it prolly just need u to change the up/downward angle of the cables depending on how high/low the linkages end up.
though id need u to send me that tb when i build u that manifold though
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lol i didnt have a chain that had a hook on the end handy that would fit
so i just bolted my engine cjain to the front of one head and the back of the other

 

I don't think anything is going to have to change on the linkages. As long as the center of the pull mechanism is in the same place as the stocker, I think I'm going to be able to use all the stock stuff.
.
If you grab one of these TB's before they're gone, hmmmm....
Or like I said before, just leave a plate on there for me, the only issue I've come up with is that your manifold appears to be less than 75mm tall so the neck would have to be "oval'd" a little bit. Just trying to save on some shipping.

 

i dont know if i can grab one,funds are getting scarce fast specially with the baby due shortly.nope wont have to oval it at all,ive got another way to do it.
the problem with just leaving a plate on there is without having a tb is i may not be able to get the inlet/plate exactly in the right spot,which will just make more work for u in the end.in the end if i cant get one ill knock a lil more of the price off so u can ship me that one just so i can make sure everything is right the first time.since it will cost less to ship me the tb then for u to have to ship me back the manifold if something dosent line up right

 

You say that they pull in the same direction, but that isn't true in terms of how GM designed it. Look at the very first pic posted in this thread. The round part of the throttle cam is on the back side of the TB. Therefore, it pulls from the front. The throttle cable bracket bolts to the front.

Of course, you can make anything work and just pull from the rear without the cam, but it puts a lot more load on wearing the shaft. To do it right, you need to rotate the cam 90 degrees or more to do it right when pulling from the rear.

The connectors are the same as a 2.8 TB. They are what is referred to as the "new style" TPS and IAC connectors (GM metri-pak) instead of the "old style (GM weatherpack). The pipe inlet measures close to 3.8" and the slight lip on the end measures about 3.9". The surface behind the lip is just wide enough to fit a Clampco T-bolt clamp. It is boost friendly with the lip on it. There shouldn't be a problem with pipe blow-off, but a 4" silicone coupler does fit loose.

I noticed all the adapter plates on the V6 site do not have cut-outs for the IAC and port areas. Notice how the rubber gasket blocks off the port and IAC from the main air inlet hole.

 

I'm thinking I can just use the entire cam set-up off the V6 TB (my 3.1 TB is different than the 2.8 TB) and adapt it to fit the 75mm. Yes I noticed that about their adapter plates also, don't worry mine will be right - unless they just cut the small piece of AL that seperates the bore and IAC controls?
EDIT: I read that thread again and now see what you are talking about. I got confused on the post that actually shows TWO TB's, one for the 5.3L and this one from the N*. They actually said the 5.3TB would work better for RWD applications, but for $50 including sensors, I'll make this one work. As far as the IAC's, they are using a remote mount set-up and eliminating the N* location.

 

Maybe I should just get one for you and put it towards the manifold? That way you would have one to mock up and be able to keep it for yourself.

 

OK, had a few minutes to go out into the garage and was able to get the cam off the N* TB. The pin was juast flat on the end with the cam and washer pressed on then "mushroomed" on the end to holt it together. I just filed the end of the pin flat and used the vice on the drill press to allow the pin to fall through and tapped it out with a hammer and punch. Now the cam can be rotated 180* and used on a RWD easily, although I think I'm just going to hack up the stock cam to be used on the N* TB. I'll post some pics later with an explaination of how it was done. It took maybe all of 15min to flip the cam, just have to figure out a way to put stops on there.

 

Yes, that is what needs to be done to the Northstar TB for use on a RWD (rear pull cable). I know what you mean about pulling the locator pin. I plan on pulling the throttle blade and sliding out the shaft. Then cut/grind off the staked end of the pin, pull the cam, weld a bracket on the back side of the linkage and install a new pin/bolt. The only reason to pull it apart is so that the cam doesn't melt when I weld the linkage. Nothing that I will get to soon, but that is the plan.

Did you pull the blade and shaft out or just punch out the pin with the shaft in the TB?

 

I pulled the blade, then the TPS. There was a snap ring holding the shaft to the TB. Used a file to file the staked end flush with the cam washer, and drove the shaft out of the cam. Then I filed the shaft so the cam will go on easier.


I noticed the high quality of the unit, it has needle bearings even for the shaft to ride on. I thought about welding also, but might drill/tap (or thread the outside) the shaft and cut the stock cam to go on the flattened end and use a bolt or nut to hold the stock cam on.

 

Yes, the shaft was pulled first to avoid damage to the TB.

Here's some more pics,
Close up of the shaft filed flush with the washer/cam:

And I'm unhappy with the marks in the blade, but some were already there from the tight fit in the shaft: