I hear what you're saying about the light, but if you have no vacuum leaks (you say that you don't), and the engine is idling high, and then there is this:
It sounds like the blades aren't centered and seating properly, to me. This is what bjankuski is telling you. You need to loosen them and ply around with them to get them to seat better in the bores. If they are seating in the bores right, they'll close TIGHT and even lock/bind in the bore....there won't be any "pushing the lever back...and drop down"...because the blades will already be bottomed out in the bores.

YEARS ago, I bored my own TB's on a motorcycle cylinder boring bar, out to 53mm and bought 53mm throttle plates from Holley. When I installed them, the bore wasn't perfect, so I hand sanded the bores to get the final shape/finish that I wanted, and I had to do as bjankuski is telling you; loosen the plates and fiddle with them until the closed fully and centered in the bores...then tighten the screws. It took me several tries to get it right, but when it was right, it was RIGHT....and the car idled and ran right/good. Before buying a new TB, I'd fiddle around with the throttle plates. If it doesn't work out, I'd buy that no-good TB from you.

 

Back in the 90s, I got suckered into that one too. OMG! 1000 cfm. It must do something. My buddy has one and he swore up and down it worked. It has to be good. Reality bites. Some years later, I was reading about how it DID NOT do much so since my friend did the coolant bypass and a few other things, we took it to the track. He stood AWAY while I fiddled with it on the car. 3 randomized runs with, 3 without. His average was that he lost a little time with the big TB. Now, as an investment for future bigger gains, I'll put up with it when I am stock or slightly modified until I get to that point. I'll even bet I could have stayed with the stock TB on the Superram and headers on the F-body after tuning. So yes, I'm also guilty of buying into that hype.

I think what we seem to have an impasse with is that I don't follow why you are trying to make something work when I'm not seeing much of a gain. I'd ask you for a refund if you were the vendor.

 

Aklim, leave the guy alone here.
1. He already HAS the TB and he's told you that he wants to use it.
2. While a TB is not low hanging fruit or good BFTB, they DO consistently show a slight increase in HP. Your results are outside of the norm and I'd say that control was the down fall of your testing...just a guess, but TB's either do nothing, or add slight hp.
3. TB's definitely improve throttle response/tip in....and that can make a car more fun to drive.

So, I'd recommend actually helping this gentleman get his TB working right....what do you say? Let's leave the "Aklimmy-go-round" alone on this thread, and just help the guy...shall we?

 

Thanks , and yes I did loosen the blades about 5 times on off on off nothing the same push back the throttle leaver goes down to about 1000-800 RPM them back to 1500 . I say YEP the blades MM or too big , now this is a around $500.00 throttle body if I start sanding witch I think the blades need DA DA and it don't work I got a $500.00 paper weight so I guess I need another one .. I read BBK not good TPIS one now working ether so am going to look for another one am looking at the Professional Products one ?? a little cheaper .
Lots of work in this deal bolting on a throttle body shroud be the easy part guess not ..

 

Can you place the TB with the entrance facing UP, then pour in a liquid (oil, paint, something colored) and see where it's getting past the plates or shaft?

 

If got to push back on the throttle hard to get to ideal down something else groin on .I think the blades a little too big not allowing the blades to go back mm or two to ideal right seems to me it needs just 32ent 1/16 to close right . When pushing back on it can see the blades bending a little at this point it hits the throttle screw and is just right let go it comes off the throttle screw about 1/16 1/8 then goes to 1500 RPM .. I don't think the blades a mm or two ,to big ... Sanding on it and it does not work I got a real shinny door stop may have one now .. .. Thinking about setting it aside and finding a another one ..

 

Call TPIS, Warrenty?

 

1. OK. If you want to waste time on trying to use it, perhaps returning it for an exchange might be better.
2. Black from the Back? Not sure. With just the 2 of us, blind testing was all we could do with the limited time. I'd have double blind with a larger sample size but it wasn't my track.
3. Again, never saw TB change only data but if you have it, feel free to share.

Fine. Only if we get off the "Tommy Boy Go around". Lets go help this guy monkey with his TB. And if it works, great. If not, lets hope the vendor doesn't void the warranty since it was messed with. Go ahead, do what grandspt did and good luck returning it. I've had my warranty denied because the mechanic tried to make it work but maybe this time it will be different.

 

I can't be sure if this is radar502's issue but I hope it helps. Have a read here: https://ls1tech.com/forums/lt1-lt4-m...d-pp-tb-4.html
I know it turns into another; I know more than you pissing contest (I guess the Corvette Forum isn't the only one) but there is some really good information if you keep reading through it. I got my engine to run great after reading this. Look at the pictures at post #76 and then take a look at the back of your TB and see if it is similar. The factory LTx isolates the IAC passage (looks kind of like a triangle) from the throttle blades. The aftermarket stuff does not do this which is a big problem for idle issues. Apparently from what I read online aftermarket TB's used the early TPI L98 design which did not have a separate IAC provision in the intake manifold like the LTx's as shown in the picture I provided.
Also I adjusted my throttle blade screw to achieve the proper TPS 0.67volts. My IAC counts are around 30 after my mods. When I first installed the BBK new the IAC was 50-60 with a high and erratic idle.
Good luck and I hope you get yours running as good as mine!

 

And we're off...on the good 'ol "retard-go-round".

Help the OP with his TB Aklim. Make yourself useful.

GRANDSPT: I didn't read the whole thread, I started at ~post 70 or so, but it seemed like those guys' problem was getting the idle up high enough?

OP: I agree with bjankuski that if your TB is new/warrantied than you don't want to be sanding etc. HOWEVER, based on this:

Quote:

About 6 mounts back I got a TPIS 58 MM Throttle body off the forum looked new

...I didn't think that the thing had a warranty on it. The fact that "pushing back" on the throttle arm lowers RPM....from my experience that tells me that the TB blades aren't closing all the way w/the return spring alone. Something is wrong w/that TB and if it's got a warranty....I'd use that warranty. Have you called TPIS about it?

 

Tom, I agree that he has a high idle but the IAC can cause this as well at least in my case.
He may want to to make sure he has no vacuum leak. Is the throttle body gasket any good?
Has radar502 checked the TPS voltage with ignition on but engine off? The TPS is not adjustable on the LTx so to get to the correct approx. .67 volts you have to adjust the throttle stop. I think you guys have been calling it the idle screw adjustment which it is not.
Once the TPS voltage is set correctly the computer should be able to adjust for the correct idle that is written in the PROM.
Unless he has the IAC issue that I have been talking about.
Obviously he should check for binding as
I understand that if he pushes the throttle linkage back it causes a lower RPM. But doing this is also changing the TPS voltage.
Radar502 needs to check the TPS voltage first.
As for a warranty I contacted BBK about the idle issue I had, they were useless. The only thing they would do was to give me an RMA to return it and see if there were any defects. The defect was the design of the IAC circuit.
So it was a $375.00 door stop, that's why I performed the modifications.

 

I know it is against forum rules to personally insult and you seem like a nice guy so I must assume you are sharing a personal problem about you and yours. Believe me, there are resources. I have a associate that is a teacher so if it helps, I would be willing to ask him how to help you and yours.

Oh, I see. You define "useful". I told him to save effort and not do it or if he must, get an exchange and see if it gets better.

Oh, now you want to try the warranty angle. But why? Lets jack with it and eliminate all chances of a warranty then we ask if they will warranty it AFTER you jacked around with it. Makes sense to me. Easier to ask for forgiveness than permission. Good call. I'd never think of screwing with something that was giving me problems especially if it is unnecessary and then trying to get warranty. Good catch.

 

I can't guaranty 100% success but very often when you talk to your credit card company, they come looking for you. Case in point. A pair of light bulbs were bought over a year ago. 2 year warranty was in effect. Amazon couldn't find them and said "Oh well.". Told them I would consult with Amex about yanking the charge. The compromise was they would accept it back, less restocking and I don't need to send it and refund. Considering I used it most of the 2 years, I can live with that. Better than "Sorry. I can't help you.". Bought a helmet and it wasn't sized right. I bought the size they recommended. Told them about Amex. Problem solved.

 

 

 

Dog likes exercise. You advocate trying to fix a defective product instead of returning it for a refund or an exchange. I think I am beginning to see your thought process.

 

First off I can't return it ,it came for a person on the forum . I had it about a year just got around to in stalling it ,it looks new but had been installed on something short time . Just trying to figure out if it was me the throttle body adjustment or what the adjustment should be or what the hell is wrong with this thing '
First off looks like the IAC frozen up not moving . I put a meter on it I got a 6 ,tried to adjust it no not happening so I installed the ORG. Throttle body no problem unplugged the new one reinstalled the ORG. one fired up purred like a kitty ..
So installing a new IAC tomorrow and start over ..
Sometimes its hard to wrap ones head around that was ( said ) just took off my 93 ran great to not working right and should need nothing to not working right then you push it a little and it works . One has to sit back and think about things after all its a nice peace to just start filing on well I do have a big 20 LB hammer and it has got me out of a few binds for sure not this time..
Installing a new IAC.
The Marry -go-around deal if anybody thinks this BS is easy #-1 some people know nothing about working on the pain in the *** C-4s or just reading out of the manual ( I got one ) or know way too much about working on these pain in the *** C-4s and think anybody can fix one if the ladder come and fix mine or give me time ( don't know jack about the throttle body ) to try to use the info I got from some that relay know what the hell they are talking about to fix this deal.. From what I have read its not just me having problems with a 58 MM Throttle body... and some said just leave well-enough alone well I did drive it around the block and damn it will put you in the back seat with the 58 MM deal , just saying with the mods BIG difference for sure ..

 

Glad you got to the bottom of the problem.
I also feel that the 52mm TB made a performance difference for my car as well.

 

Hey Radar, the "Marry-go-round" wasn't directed at at you in anyway. Not at all. You did good finding your issue.

 

What ever you're "seeing"....it ain't enough and it ain't helpful to the OP....

And, this information was available right in post #1 of this very thread....