marmieej

iTrader: (3)

I have a problem getting my throttle or butterflies to close fully when I slowly release the gas pedal. The butterflies will stick slightly open. But, if I rev the engine up real quick and just let off the gas pedal, they will close.

Watching the linkage, it appears like the throttle spring is too weak to close the butterflies fully when letting off the gas pedal slowly.

Can I just replace this spring or is the problem something else entirely? If the former,, where can I get a new spring? I have searched and had no luck.

Any help is greatly appreciated!!!

articwhiteZ

iTrader: (56)

dont know if you can take it apart (rivet)?

but you can always install a return spring. like on a carb.

also make sure it's not all nasty in back of the plates..(clean it up)
should close when clean..

battman

iTrader: (2)

I repaired my sticking throttle body blades by removing the tb and cleaning the bores with some good carburetor cleaner and then hold the tb blades open and lightly sand the bores with some 400 grit sand paper until the blades no longer bind. worked wonders on mine. its been several years since I have done it and it still works like new

AC

iTrader: (3)

I did this:

Take TB off
Take butterfly plates off / out ( I believe they're are 2 screws each?)
They should slide out of the bar they're in
Take some green scotch brite and run around the OD of each plate lightly but enought to clean them off and take off any burrs / scratches
Clean the SH*T out of the innner bores, again running a little green scotch brite around the bores of the TB
Reassembled but only thread the butterfly plate bolts in halfway
Close the throttle body and they plates should center themselves in the bores and in the bar
Tighten bolts

vetteoz

iTrader: (13)

The fact that it closes when you hit it hard means there is nothing wrong with the spring tension.The problem is with the TB binding up somewhere
Check the butterfly shaft for slop on the hole where it goes through the TB housing also.
When it wears out of round with age ( common ) the vac pulls the butterflies off center so they bind up on the bore and not close fully back on the stop
If any noticible slop then you can get TB housing rebushed

uemf

I'm betting it's the play in the butterfly shaft.
I just swapped in one from a doner car because mine had so much play.
I notice the most play in mine when I pushed the drivers side of the shaft towards the front of the car.
My idle is much more reliable now. sometimes it would idle at ~800 other times at 1500 with the original TB. A blip of the throttle and who knows where it would be.

Tony

p.s. I've never seen anyone sell a TB rebuild kit but there are a few guys that will rebuild it for you out there on the web, but you have to send it to them... (if anyone know different, I'd love to be able to go back to my original TB, it looks better )

vetteoz

iTrader: (13)

The housing requires boring oversize so new shaft bushes can be fitted.
Some places will bore the TB out at the same time
http://cgi.ebay.com/ebaymotors/54mm-...Q5fAccessories
You send your old TB back for the core credit after you install rebuilt one;
no down time

BOSS 357

iTrader: (1)

Had this problem after I removed and cleaned my TB. A good couple shots of WD40 on the pivot shaft where it connects to the sides of the body fixed me right up.

camaro1185

Just wondering, how many miles are on your car? Maybe i should pull mine off and clean the crap out of it as some preventative maintenance.

vetteoz

iTrader: (13)

If you don't know when it was last cleaned ; well worth the effort. Normally lottsa gunk in there

Reset IAC and TPS when finished
http://www.corvetteactioncenter.com/...and+Idle+Speed

jack harrison

greese the tb spring up and check for exhust leaks! ive got an adjustable borla exhust and with the smallest holed plate in my throttle wouldnt close! must be something to do with vacum. i changed the plate and its never happened since.

vetteoz

iTrader: (13)

The spring is not the problem; it closes correctly if he snaps it shut fast.It is only on slow closing it binds up

Too much backpressure ; exh can't get out

Sandman22

Glad to see it all worked out at least, I will keep it in mind if I have any sticking issues in the future.... Thanks much

franqc

Glad I found this blog, I am having a big problem with TPI throttle sticking open, something about vacuum for sure. I see here a similar problem and it was exhaust!! Having a hard time trying to figure out what we where talking about?
Someone please elaborate for me if you can, Thanks Franqc.

Tuned Performance

iTrader: (92)

read post #5 , are you throttle blades sticking open or do you have a vacuum leak or both. A visual inspection and feeling play in the throttle shaft by moving the lever to check for play would be a start.

franqc

Thanks for your reply, I have checked the TB and butterflys no problem there. How do I check for vacuum leaks?? I can actually watch as the throttle retracts when I turn off the engine!! Thanks once again.

Tuned Performance

iTrader: (92)

you throttle blades are not fully closing until you turn off your engine ? If thats the case the return spring is weak or the throttle shaft is worn or sticking.

franqc

Spring is fine, had the whole thing off the car, closes like a rat trap with engine off, but sometime is causing it to stay open with the engine running, has to be another cause

franqc

I noticed some small hairline cracks around the headers, would this contribute!!!!

Apeiron

franqc

I have examined it from every angle, have taking it off, no play or slop and it snaps shut, but not with the engine running!

Apeiron

Yes, because the shaft is worn.

It's not round anymore and the vacuum sucking on the back side of it at idle keeps it from closing. It'll close just fine when there's no vacuum, and you won't notice any play.

Tuned Performance

iTrader: (92)

Please do not pm me asking me to call you. The information is all provided for what you need to look for.

franqc

Sorry if I was out of line, I was working on the car and needed to get it finished before dark! My bad.

Tuned Performance

iTrader: (92)

franqc

I see some advertised @ 52 and 54 mm, is it marked on them? or is it by the year and model?

Tuned Performance

iTrader: (92)

stock is 48mm, you can have yours bored to 52mm and or rebushed. aftermarket you can get 54mm and 58mm. The linkage style you need is 89-92. This is a little large but is a good price but you need to buy a ACCEL 74192.

http://www.ebay.com/itm/New-ACCEL-TP...c5bff6&vxp=mtr
http://www.autozone.com/autozone/par...96537&cmpid=cj

Tuned Performance

iTrader: (92)

or this

http://www.summitracing.com/parts/sum-227705/overview/

or place a ad in the wanted classified section

franqc

Sweet great deal and brand new! Thanks, can't go wrong with this. Thanks once again.

Tuned Performance

iTrader: (92)

I believe the second one will either fit both linkage styles if not it will come with 2 levers one for 85-88 and one for 89-92. The application listing shows all years though. The throttle maybe alot stiffer with this throttlebody I know bbk's atleast are a pretty stiff return spring.

franqc

So the two eye ports and all the hardware bolt on to TB listing you sent me!

Tuned Performance

iTrader: (92)

a new throttle body will come with the gaskets you will need to swap over your coolant/iac housing. It is common for the bolts to break when removing the lower iac plate soaking it down with pb blaster helps remove.

franqc

Great stuff, I am all over it.

franqc

OK, I finally got my throttle to close and eliminate my high idle, It was mentioned above but not fully agreed upon! This is what I think happens, as I said I examined my TB from every point of view and found nothing out of the norm. What I did find was some small cracks in my headers! So I set about repairing them with exhaust repair, let it dry, and presto, every worked as it should. This is what I think happens, when there is an exhaust leak above the O2 sensor the car takes in air and passes it down to the sensor which picks it up and tries to compensate with the IAC, thus making the car idle higher than norm! This is why it only happens when the car is running but when its not the plates close freely!! Sometimes wear might be attributed in other cases, but not in my mine, my car is running as it should!
Let me know if this is a possible scenario.

Tuned Performance

iTrader: (92)

if there is a exhaust leak bye the o2 sensor the o2 sensor reading will be false. The o2 will think the engine is running lean due to the additional air and will run the engine rich to compensate.

franqc

Would this cause the throttle to stay open a little at idle?

Tuned Performance

iTrader: (92)

No it wouldn't keep the throttle blades open. The ecm controls target idle speed based off coolant temperature and the park neutral switch selection. The iac is a controlled vacuum leak that the ecm uses to control the idle speed through the passage in the center of the throttle body.

franqc

Wow thanks, so it was just coincidence that my problem went away after I repaired the leak! Would the IAC letting more air into the plenum cause the blades to stay open a smidge!

Tuned Performance

iTrader: (92)

I have no idea why your throttle blades were open a little.

franqc

Thanks so much, you were right, got if fixed. But came back from vacation and I have another problem, when I start the car in the mornings from cold it runs high (like a choke) @ about 1000 rpm which is normal. It use to drop after a blocks but now it stays high! the only way I can get it to normal idle is to turn off the engine and restart it, happens every time, very frustrating! Any ideas as to the problem? Thanks once again. Franqc

devilschariot

Pop the cap on your idle adjust screw on your tb, back out the screw. The butterfly is connected to an arm that hits this screw. Does your butterfly go back as you back out the screw?

If a gap opens up between the valve lever arm and the screw end as you back that screw out, start your car and push in that arm lever towards the screw end to lower idle. Does idle stay down with the lever arm touching the screw end? Does the arm go down but idle remain the same or higher?

Keep in mind, by down, I mean pushing the butterfly lever towards the drivers seat.

devilschariot

Whats the lowest your idle will get by backing out the adjustment screw is basically my question. And if you can keep backing it out but the idle still stays high, does closing the butterfly with your hand lower the idle?