TB removal and then some!!!
 

Thought I would start a new thread for Throttle Body removal. Although the seasoned ZR-1 owners know this all too well, this is basically intended for an owner who may be apprehensive doing this for the first time.
With many suggestions, advice, text, and returned PM's in the last 24-48 hours from different members that I contacted, a big thank you to all...:thumbsup::thumbsup:
I also searched Cliff's Solutions, and maybe missed the thread for pics or detailed info that I was looking for....you could read his info for hours....:)

So here we go.....disconnect the battery, just in case....
here are the tools you will need for removal....
I used 3/8" drive....breaker bar, ratchet, extensions and Torx socket set. Also good to have a pencil or long magnet on hand. You will also need a "mallet" hammer just to tap the throttle body loose after the bolts are removed.
http://i127.photobucket.com/albums/p...428_131645.jpg
1-air cleaner assembly removed
2-air horn removed....there are 4 T-25 screws that hold the air horn on the inside, and 2 T-25 screws that are on the outside on the top at opposite ends. The bolts on the inside are made so they stay attached to the air horn when removed. Only problem with mine, is that one bolt comes completely out. That a good reason for the magnet, just in case.
3-undo the 2 T-15 screws on top of the plenum that hold the throttle cable to the top of the plenum. I used blue painters tape to mark the cable so I would reinstall in the exact position.
http://i127.photobucket.com/albums/p...428_122458.jpg

Re: TB removal and then some!!!
 

4-now that the cable is undone you can remove the 5 T40 screws with a breaker bar to get them loose and then use your lightweight hammer to tap the TB loose.
http://i127.photobucket.com/albums/p...428_130125.jpg
http://i127.photobucket.com/albums/p...428_130118.jpg
5-Pay attention to the size of the bolts that come out of the TB, lay them out in the rotation that they were removed and take note. That way upon installation, they will go back in the same location. 4 are on the paper towel, from R-L and the 5th bolt is to the left of the pic, you can barely see the thread, that is the bottom bolt.
http://i127.photobucket.com/albums/p...428_131322.jpg
6-My finish on the TB is peeling off, I just may undo the cable now that I can see how it is attached and refinish the TB myself or send it out to Marc for a complete overhaul, don't know yet.
http://i127.photobucket.com/albums/p...428_130819.jpg

Re: TB removal and then some!!!
 

7-now is a good time for the little things too....such as the clips...already sanded and 0000 steel wool used and ready for paint...
http://i127.photobucket.com/albums/p...428_122827.jpg
http://i127.photobucket.com/albums/p...428_123139.jpg
http://i127.photobucket.com/albums/p...428_123703.jpg

Again, thanking everyone for their quick responses to my inquiries and an especially big thanks to Yun (secondchance) who has always answered my text at any time whenever needed
Appreciating all of the input received......:dancing

Re: TB removal and then some!!!
 

:dancing Now that you feel comfortable time for the stainless bolts upgrade

Re: TB removal and then some!!!
 

Oh i always feel comfortable, lol, but with my luck you never know what is going to happen next....the stories i could tell....lol
We did the stainless on the plenum when we did the pull, except one got lost in never never land....but will check into the others.....

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Re: TB removal and then some!!!
 

Tom,

First, your erratic idle rpm may be due to intermittent vacuum leak.
As for the TB corrosion, this is caused by galvanic corrosion - electric current plus steel bolt and aluminum TB, both exposed to water base coolant. Even if refinished will return unless the cause is resolved. In my case, bypassing coolant through TB, was the fix.

Re: TB removal and then some!!!
 

I noticed that. Jerry has all those stainless bolts ready to buy ;)

Re: TB removal and then some!!!
 

I imagine that everyone else is having the same problem with the forum. Don't know what I did, but I may be able to post......lol


Yun,
I found the problem apparently the smoke test was correct. I don't think I have an intermittent vacuum leak, rather it is indeed the primary blade. The TB bypass may be an option for me in the future...I will probably need your expertize for that mod as I know you have something different that you do from reading previous threads.

Did the light test recommended by G8nightman (George) with a flashlight shining through the throttle body blades. I can tell you when you turn out the lights in the garage, it gets dark real quick!!!:sign10:
But the results are in and correct. When shinning the light through each secondary blade, there is no light what-so-ever coming through. When holding the light up to the primary blade from the back, you can see a good amount of light and also see how far the blade is open. I would venture to say that is my idle problem, no doubt.
Thanks George for the tip and btw, your PM box was fill as of early this AM.
Here are the pics....
light through the primary blade...
http://i127.photobucket.com/albums/p...428_201249.jpg
light turned off...see what I mean about it being dark.....
http://i127.photobucket.com/albums/p...428_201303.jpg
flashlight back on....
http://i127.photobucket.com/albums/p...428_201255.jpg

Now I have to decide and figure out the correct way to accomplish the task. I am not touching the secondary blades, except for a light clean up...hmmmm
maybe not!!!
Have to determine if both the min air adjustment procedure from Dominic and the application of the dry lube will correct the problem. Or just try to adjust the idle stop screw as it is in its present state, and also add the dry lube to help seal the perimeter of the primary blade.

Also looks like I need to sand the TB as some of the finish has cracked off and the top is bubbled, so it needs a refinish. Just might attempt to do it all in the engine compartment and not remove the throttle cable at all.


Yes, for sure....that is where the first batch came from....:)

Re: TB removal and then some!!!
 

Tom,
Thanks for sharing with the group. Here are a couple of photos of the difficult to adjust Allen set screw exchanged for a M5 x 0.8 25mm cap screw and full size nut. If you do this mod be sure to massage the contact end like shown in the bottom photo.

http://i540.photobucket.com/albums/g...psllwfj7hx.jpg

http://i540.photobucket.com/albums/g...psov4lvkwp.jpg

Re: TB removal and then some!!!
 

Gap on the primary certainly looks greater than .002".

Re: TB removal and then some!!!
 

Phil,
Glad to anytime I can...
Thanks for the pics, no success in getting a 7mm screw as mentioned in the other thread. So the spec you gave will help me get the correct cap screw.
Going out to the other car tomorrow will see if we can massage the contact end as you have shown after I get one.
Thanks for the tip....appreciated...


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Re: TB removal and then some!!!
 

In my experience when using a bright light the opening clearance appears much bigger than it actually is when measured with a feeler gauge.

Re: TB removal and then some!!!
 

phil,

I understand what ur saying but that still looks bigger than the thickness of a paper strip. Due to the contour of the bore, I don't rely on a feeler gauge. A paper strip gets it close as a start.

Re: TB removal and then some!!!
 

Need an engraved billet throttle body plate to clean things up.

Re: TB removal and then some!!!
 

Did the paper strip test as posted in the other thread, but would like to know how much of an opening it really is...


Sounds good to me, what are the choices???

Re: TB removal and then some!!!
 

You've seen my billet throttle body plates on many, many Z here and in the newsletter in my sponsor section. Email me if you have ideas for something else.

Re: TB removal and then some!!!
 

The paper strip is about .002". Its a place to start not a final. That will be based on IAC counts and desired idle rpm. The paper should have a slight drag to it.

Re: TB removal and then some!!!
 

Can't send you an email as of yet because of the forum problem.
I do have an idea for something else....

Copy that....thx...

Re: TB removal and then some!!!
 

FYI, as per Phil's recommendation....went to HD and purchased the following...
Cap screw, hex bolt & nuts...originally purchased a 7mm bolt, but was too big...also could not locate a full size nut as of yet!!!
http://i127.photobucket.com/albums/p...6b115b6380.jpg
now my grinding abilities are not the best....lol so what I did was used a file to smooth and "flatten" out the bottom of the screw for a full contact with the linkage. my grinding skills on the left....lol the file work in the middle and a screw as is on the right...as you can see with the screw in the middle the outer edge is removed for a totally flat surface. also did this with the hex bolt...
http://i127.photobucket.com/albums/p...429_144550.jpg
now you can have a choice as to what type of screw or bolt to use as to if you will ever need to do the min/air adjustment as per Dominic on the vehicle. the Cap screw uses a 4mm Allen hex wrench which I have is almost 4" L.
the Hex bolt uses a 8mm combo wrench which I have is almost 4 3/4" L for adjustments... (your sizes may vary)
each one will reach outside of the linkage area making adjustments on the vehicle easier. (although IMO and what Phil has shown, the Hex Bolt would seem the way to go)
http://i127.photobucket.com/albums/p...430_123044.jpg
http://i127.photobucket.com/albums/p...430_123124.jpg
for the original idle screw, I found that either a 2mm or 3mm Allen will fit that opening, but the keys are way too short to reach in and make any on car adjustments....

Re: TB removal and then some!!!
 

Yes I would advise against the Allen bolt. SOOOOOO much easier w the hex head. Its a small throttle plate, so tiny changes make a BIG difference.

Re: TB removal and then some!!!
 

You have a PM.....:dancing

Re: TB removal and then some!!!
 

Read and replied.....:D

Re: TB removal and then some!!!
 

Back at ya.......:cheers:

Re: TB removal and then some!!!
 

http://i127.photobucket.com/albums/p...428_130819.jpg

I would consider Carter's Billet Clips and Billet TB Cover.......:thumbsup:

:happy1:

Re: TB removal and then some!!!
 

I would consider doing a bypass of the throttle body coolant.

Re: TB removal and then some!!!
 

I would consider..........Oh........the list is too long for this post :D

Tom already suggested "and then some" :sign10:

Re: TB removal and then some!!!
 

Already have on the cover, will check out the clips....:thumbsup:

Don't know if I trust myself to do the throttle body coolant
bypass...:dontknow:


Cliff,
You may as well post the long list, as I will probably take the Z out of service for awhile. After speaking to another member for a length of time, I am finding out that the primary blade is not to be completely closed and is supposed to be opened slightly. So it looks like that is not the source for my idle issue. So what I thought was to be was and is not!!!
Their feeling is that there is a slight vacuum leak that happens when the engine warms up. Could be a number of items. So I think I may take the Z out of service and do a plenum pull. I have to start from the beginning and go through everything to find the issue. As was pointed out, the min/air adjustment may not fix the idle issue. Feeling was the idle air stop was not touched and you didn't have the idle problem in the past, so the theory again turns to a vacuum leaks as others have pointed out. And the fact that the test Yun and others suggested to me about blocking the TB and the results being that the idle came down from being high to "normal" but did not kill the engine. And as Yun and others have said in the past, this leans towards vacuum. The other member also agrees with this theory.
And once again I appreciate everyone's input and welcome additional thoughts on the issue.
So I imagine the best way to do this is start at the pull and go from there.
To be continued........lol

Re: TB removal and then some!!!
 

Tom,
You have yet another PM....;)


Cliff,
Thanks for the kudos :-D

TB removal and then some!!!
 

Thanks for sharing all these details and nice photos Tom! I have been having some idle issues since I got this 95, but time to address it. I have this NIB TB and might as well put it to use instead of on the shelf for the last 14 years or so.

https://uploads.tapatalk-cdn.com/201...ab5fe39d97.jpg

I'll add the Carter Bling Special while I'm at it and get the stainless fastener kit from Jerry. Thanks Phil for the adjustment screw tip and I'll do that while I'm at it. I'm waiting on my ported plenum and IHs from Corey so I can do this all at once. I would be better off sending the old TB to Marc to work his magic, but can't afford the down time right now without a garage. I have to do the coolant bypass too. Best wishes to get your issue squared away.


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Re: TB removal and then some!!!
 

Marc offers a very simple coolant bypass solution utilizing a bent aluminum fuel line that passes under the plenum and connects the throttle body coolant hoses to each other.
The solution I have seals the coolant passages at the injector housing (both sides) and includes a small valve to bleed the coolant system.

Re: TB removal and then some!!!
 

Carter,
Another PM answered.....:)

Craig that TB looks great, now only if I could persuade you to let it go for some :pray Philly Cheesesteaks & Hoagies and $$$.....lol just had to try!!!

Just going to take my time and get this idle issue fixed. A learning experience for sure. Also will wait and see what the results are with mine before thinking about sending the TB out to Marc for a check-up.

Glad you enjoy the pics, I enjoy taking them!!!:D
Keep us posted on your progress too...

I did see that before, elaborate more on your solution when time permits...
I guess my concerns are winter driving, (which I don't use the Z that much), so not a concern....lol The other one is air being trapped in the system....and I assume your bleeder valve would solve that problem. I know there are a lot of members to have done the bypass in different ways, so it is something to be considered.

TB removal and then some!!!
 

Tim I had the exact same symptoms you describe. I sent my TB to Marc for his repair

Had my TB back in two days...problem solved


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Re: TB removal and then some!!!
 

Tom,

Here's one way to eliminate coolant flow. Different than mine.

https://www.corvetteforum.com/forums...post1581460754

You might also ask Marc for the "helper spring" he sells for the TB. That may be enough in your situation.

Re: TB removal and then some!!!
 

Dennis, I'm already in this far, so the plenum will come off. Then will check for vacuum leaks and see if any hoses popped off.
TB is last resort.....

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Re: TB removal and then some!!!
 

Dom, will give it some thought, I'm still not feeling too comfy to attempt this mod...
Thanks for the link, and the info for the "helper spring". :thumbsup: Will contact Marc.

Re: TB removal and then some!!!
 

Latest update.....success!!!!
After I used my 5 lb sledge and crow bar, removal was easy peasy....lol
Having a cold one in celebration of my first plenum pull myself.....woohoo!!!

Used a hand siphon for the antifreeze, what a treat that was....I won't go into detail and yes it makes for the case to do the TB coolant bypass....

Just looking at everything at a quick glance, all seems fine. The one thing I was concerned about was when I pulled the plenum up the "curly" line (I imagine a PCV line) came out of its connector. But I can't tell you if it was already out or not. Will check more within the net few days. A lot going on, even with the 74, can't loose sight of that project...:nono:

All-in-all, everything went well so far!!!
Looks like I'll continue to freshen up parts as time goes on. Now is a good time to repaint the plenum. And maybe even more....

Here are some pics and a question or two.....
Another "famous" block(s) of wood....lol...they come in handy!!!
http://i127.photobucket.com/albums/p...502_210942.jpg
http://i127.photobucket.com/albums/p...502_211007.jpg
You may be able to see some of the connectors that need to be undone before plenum removal....the crow bar really comes in handy here....I didn't really say that, did I??? just kidding, must be the brew.....
IIRC, there must be 5-6 connections that need to be unplugged and one unbolted. Take your time when doing these, as patience is a must...
Again, directed to those who may want to attempt this for the first time...
http://i127.photobucket.com/albums/p...502_211028.jpg

Re: TB removal and then some!!!
 

One of the also "famous" curly lines under the plenum. This one came out of its connector when I pulled up on the plenum. Did it pop out before, that I can't tell you.....
http://i127.photobucket.com/albums/p...502_214445.jpg
I imagine this is the PCV "pig tail" that Yun has referred too on numerous occasions. Have to see if this can be replaced, just to be sure....
http://i127.photobucket.com/albums/p...502_214532.jpg
not tapped....
http://i127.photobucket.com/albums/p...502_213717.jpg
tapped, no foreign objects allowed here....
http://i127.photobucket.com/albums/p...502_214219.jpg
had enough for the night....lol the LT5 is feeling nice and cozy all covered...
http://i127.photobucket.com/albums/p...502_214926.jpg

Re: TB removal and then some!!!
 

Looks like the old original plenum gaskets were re-used when the plenum was pulled last. I'm not a fan of re-using gaskets, they're not that expensive compared to the problem of chasing vacuum leaks.

Re: TB removal and then some!!!
 

Yes they were....I have a set of thin gaskets, but may just order the thicker ones, plus a few other items....
Do you carry the part where the hoses connect into??? the bottom hole in the connector is the "curly" line connected to the LSF of the plenum.
http://i127.photobucket.com/albums/p...a66fd5b087.jpg

Re: TB removal and then some!!!
 

You need my billet EGR plate to replace that nasty black piece you have there......;)