throttle body

[jimmers]

Lately my throttle body has been sticking. What i mean is that it will stay at a certain rpm and not go down. I can manually push the level down and the idle will go down. I decided to clean it to maybe loosening everything up. I got carb cleaner and soaked it all. Today it still did it. I was driving home and all of a sudden the rpms got stuck at 3000. When i got home i pushed the lever back down and the idle went down. Any ideas what would be causing that? I assumed it was dirt but i guess i am wrong.

 

[Nitronick]

You will probably get a bunch of people telling you the bore for the shaft is worn and you need a new throttle body.:eyerole

While that may very well be the case, you need to check all other possibilities first before spending that money.
With the MAF pulled, open the throttle plates and with a light look and see if there is any carbon buildup behind the plates.
If that's not it, unhook all cables attached to the throttle arm. Start the car and see if it still hangs. If the idle comes down normally, start reattaching the cables one at a time, checking after each one. Mine turned out being the cruise cable causing the hangup.
If everything else checks out ok, there is a guy online that rebuilds the throttle bodies, mills and inserts roller bearings for the shaft.

 

[582Boat]

Sticky Throttle

Before I would go to to much work, check the TBS (Throttle Body Sensor) Put in a new one, set it propertly and see if this doesn't help. Autozone carries them for my 1985 Vette. Doc

 

[grumpyvette]

Id say 60% or greater of the time I see that on C4 corvettes its the throttle cable or the trans cable that needs lubracating, if the throttle body itself is already been,cleaned and lubed correctly

 

[jimmers]

the throttle body is completely clean inside and out. No dirt anywhere. Would the TBS stop the throttle from closing all the way? And how would i go about lubricating the cable? The cable goes into one of those black plastic tubes. I can only see a small bit of the cable showing. Thanks for the replies guys!

 

[grumpyvette]

to lubracate the cables

the cable assemblys can be uncliped from throttle body linkage and the bracket bolted to the side of the plenum, held vertically and that new liquid wrench super penetrating oil with the teflon can be sprayed into the sheath as the cable is worked back and forth, then they get replaced in the braket ,that may not be the correct method but it works just fine

http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&CNTKEY=misc%2fsearchResults.jsp&keyword=Liquid+Wrench&cm_ven=hd_over&cm_cat=Search&cm_pla=D-25X&cm_ite=bid10067073-liquid_wrench&ovmkt=RRHSQV1MO3BS19VV9KJKO4DLIK

 

[582Boat]

Throttle Body

If all else fails take the TPS loose from the throttle body by removing two small mounting screws and check the TPS pick-up lever for movement. By playing with the TPS while the screws are slightly loose you will notice a change in the rpm 's of the engine, it is best to set this with a volt meter, but I have set it by ear. Doc

 

[jimmers]

Thanks guys for some solutions. I will lubricate the cables and see what i can do with the TPS. Wish me luck!

 

[Moonunit 451]

If all else fails, David Koldos at this e-mail is probably the rebuilder mentioned above and is well respected. He also sells rebiults on ebay dkoldos@ameritech.net

 

[Drjohn]

Check the TPS.

If you can't get it to work, please feel free to upgrade.

 

[Nitronick]

Lubricating the cables is a good idea. You should also visually inspect each cables entire length for fraying of the cable jacket, especially where it runs through something, ie. firewall.
As I said before, mine was the cruise cable, where the cable jacket mounts to the diaphram bracket. I have seen a case where the throttle cable had frayed coming out of the firewall.

 

[Ken]

I had a brand-new throttle body hang up the TPS switch. A little gentle filing on the offending piece and I was good to go.

That's not to say it's the cause of your problem; I just thought I'd throw that out there as an example of what could go wrong.

 

[jimmers]

well i tested my tps and it read at about .5 volts. With WOT it read only 2.5 volts. So it must be faulty because should it be at about 5 volts, right?

 

[jimmers]

right??

 

[Ken]

As to whether it's faulty or not I can't say. I imagine if the readings don't move when you move the sensor, then it's bad.

 

[Jeb]

well i tested my tps and it read at about .5 volts. With WOT it read only 2.5 volts. So it must be faulty because should it be at about 5 volts, right?

The TPS should be near 5V at full throttle from what I've read on the subject.

 

[gsmi837]

Ken, Maybe you can help me out. I've got a 04 z06 with AFR heads, comp cam, 3:90 gears, and I would like to have a better throttle body installed. Can or would you suggest one that would get me the most bag for my BUCKS! Tanks, gsmi837

 

[Vettefan87]

You might get some better feedback from someone in the C5 section. There are a few modded Z's on here that I know about. Good luck.

 

[Ken]

Justin's right. The C5 owners would know more about the LS1 than I do.