Throttle body mishap?

[luvmyc4]

I have been searching around as to various causes of rough idle and surging,
but problem occured after removal and cleaning of 85 l98 throttle body. Was careful not to scratch anything, removed iac with wrench to clean and noticed I may have bent 2 tiny tubes on side of iac. Would this cause rough idle. Really rough when cold,surges at redlites. Tried adjusting torx idle set screw no luck:ugh

 

[Schrade]

I have been searching around as to various causes of rough idle and surging,
but problem occured after removal and cleaning of 85 l98 throttle body. Was careful not to scratch anything, removed iac with wrench to clean and noticed I may have bent 2 tiny tubes on side of iac. Would this cause rough idle. Really rough when cold,surges at redlites. Tried adjusting torx idle set screw no luck:ugh

Surging? Like loping idle?

Probably a vacuum leak.

Originally Posted by Schrade
No one got the proper technique for vacuum leak detection... :confused

FIRST; block the pedal, or block the throttle linkage. YOU HAVE TO DO THIS TO GET A STEADY IDLE , around 1,250 rpms, or a little higher. If you don't, you can fish a propane hose, or WD40, or Krylon, or hair spray, or pee, anything, until you need a sweater in Hades, but if the motor is lopin' already from a vacuum leak, you ain't gonna' find any vacuum leak, unless it's so big that Little Jack Horner can stick his thumb in it and pull out a pineapple NOPE.

AFTER you get a steady idle, THEN, you can spray starting fluid everywhere - that's the best detector, because it's vapor pressure is very high - a LITTLE at a time, until you get the SURGE. Follow the vacuum lines to the EVAP cannister too. You might even have to follow the EVAP lines from the EVAP cannister to the gas tank too, but that vac leak will show up as a DTC 32 EGR fault, and won't normally show as loping idle, unless the EVAP cannister has been by-passed (been there, saw that uh-huh).

If you get a surge in a tight spot, and can't tell exactly where it is, light a book of matches, blow out the match heads while they're still burnin', and feed the smoke to the tight spot.

Fear not the starting fluid; you cannot put the can down fast enough and light the matches fast enough to catch the starting fluid, because the vapor pressure is so high.

Bookmark this post YUP.

Wrench Wizard OUT!

 

[luvmyc4]

Surging? Like loping idle?

Probably a vacuum leak.

Yep hose popped off was hiding from me. Thanks for quick reply.

 

[redvett]

I have been searching around as to various causes of rough idle and surging,
but problem occured after removal and cleaning of 85 l98 throttle body. Was careful not to scratch anything, removed iac with wrench to clean and noticed I may have bent 2 tiny tubes on side of iac. Would this cause rough idle. Really rough when cold,surges at redlites. Tried adjusting torx idle set screw no luck:ugh

That torx screw is not an idle screw it adjusts min air, idle is controlled by the ECM. All the min air adjustment will do is change the IAC counts which need to be 15-30 engine at 195F in drive and checked with a data scanner.

 

[KANE]

Yep hose popped off was hiding from me. Thanks for quick reply.

Glad you got it fixed!

 

[luvmyc4]

If it aint broke dont fix??

That torx screw is not an idle screw it adjusts min air, idle is controlled by the ECM. All the min air adjustment will do is change the IAC counts which need to be 15-30 engine at 195F in drive and checked with a data scanner.

Great and I messed w/ it. What is procedure for setting this screw? I guess u told me but Im used to "turn it all the way in and back it out 2 and a quarter turns" My first Vette. I need a data scanner cuz I messed w a screw lol. Thanx for the info!

 

[luvmyc4]

my 97 camaro was that color god I loved that car. Emerald green?{huh thought would reply to kane forgive the noob)

 

[luvmyc4]

How come my stupid pic aint under my name? help the noob lol.

 

[Schrade]

How come my stupid pic aint under my name? help the noob lol.

Another vacuum leak?











(after loadin' the pic, scroll down to the bottom of the page, and click 'Save')

 

[luvmyc4]

Yep hard drive making hissing noise...

 

[KANE]

Great and I messed w/ it. What is procedure for setting this screw? I guess u told me but Im used to "turn it all the way in and back it out 2 and a quarter turns" My first Vette. I need a data scanner cuz I messed w a screw lol. Thanx for the info!

luvmyc4- Here is a short thread on how to set your idle on an L98....

my 97 camaro was that color god I loved that car. Emerald green?{huh thought would reply to kane forgive the noob)

Thanks! Yep- it still has every inch of the OEM dark green metallic / code 43.

 

[aklim]

If you have access to a scantool, that is way easier. You get it hot and running. Shut off all accessories. Adjust the set screw until it gets 15-20 IAC counts. Each time you adjust something, rev it up and let it settle back before you make the next adjustment. Screw in, less IAC counts because you are opening the throttle blades. Screw out, more IAC counts

 

[luvmyc4]

Hmmmm

if you have access to a scantool, that is way easier. You get it hot and running. Shut off all accessories. Adjust the set screw until it gets 15-20 iac counts. Each time you adjust something, rev it up and let it settle back before you make the next adjustment. Screw in, less iac counts because you are opening the throttle blades. Screw out, more iac counts

i love this place!!