Throttle body wear

[G Winter]

I think I finally figured out why my 90 idles to fast most of the time and now and then searches.
I noticed the other day that coming to a stop sign it hardly dropped below 1600 rpm. I burped it and it settled down to it's near normal (for this car) idle speed.
Back in the garage I played with the throttle shaft and I do have some noticeable play. I took the air tube off and put my finger against the shaft on the inside and could feel it there also. I had always checked it with the engine running, apparently you can't move the shaft against the pull of the engine vacuum when it is running.
Is this my problem? How much will this effect idle speed ?

Glenn

 

[gmjunkie]

I think I finally figured out why my 90 idles to fast most of the time and now and then searches.
I noticed the other day that coming to a stop sign it hardly dropped below 1600 rpm. I burped it and it settled down to it's near normal (for this car) idle speed.
Back in the garage I played with the throttle shaft and I do have some noticeable play. I took the air tube off and put my finger against the shaft on the inside and could feel it there also. I had always checked it with the engine running, apparently you can't move the shaft against the pull of the engine vacuum when it is running.
Is this my problem? How much will this effect idle speed ?

Glenn

Yeah,It can suck enough air to change the idle if it's worn enough!Also take a look the butterfly's and see if there hanging up on the inside of the housing!!Thats usually what is happening when you can burp it and is straitens up!! I've had to de-burr a few!!

 

[G Winter]

Couple months ago I cleaned the TB and didn't notice any burrs. Even if there are burrs hanging the throttle and I take them out, I still have the problem of fast idle and hunting?

If I need to replace the TB I would like to try repairing one before I buy a new one. I work as a machinist and have some pretty nice equipment at my disposal to bore out the shaft bore and install a bushing.What I would need is a worn TB and some prints.

Glenn

 

[gmjunkie]

Couple months ago I cleaned the TB and didn't notice any burrs. Even if there are burrs hanging the throttle and I take them out, I still have the problem of fast idle and hunting?

If I need to replace the TB I would like to try repairing one before I buy a new one. I work as a machinist and have some pretty nice equipment at my disposal to bore out the shaft bore and install a bushing.What I would need is a worn TB and some prints.

Glenn

You shouldn't have any problem doing it Glenn!!
I've pulled them apart and hillbilly engineered small A/C o-rings on the shaft with use of a drill bit to make a small seat in the throttle body at the shaft!!:L:L:L

 

[G Winter]

I know an O ring would seal it but still would like to have one that the shaft don't wiggle.
So the search is on for a super cheap throttle body.

Thanks for the replies.

Glenn

 

[Schrade]

Couple months ago I cleaned the TB and didn't notice any burrs. Even if there are burrs hanging the throttle and I take them out, I still have the problem of fast idle and hunting?

If I need to replace the TB I would like to try repairing one before I buy a new one. I work as a machinist and have some pretty nice equipment at my disposal to bore out the shaft bore and install a bushing.What I would need is a worn TB and some prints.

Glenn

Hunting / loping idle is a dead giveaway for vacuum leak.

Grab a book of matches, light 'em up, blow 'em out while the heads are still burnin', and see if the smoke will feed thru' the shaft bore where the TB linkage connects.

If the shaft is exposed on the passenger side (I don't think it is), try over there too with another book.

 

[Schrade]

Did you do the vac leak test in the other thread post #14?

 

[G Winter]

It only searches occasionally. Have tried carb cleaner, and propane both, just couldn't get it to show up. Will try the match trick. The idle is usually high enough that I don't need to block the throttle. Monday after work I will check it some more.
Overall it runs pretty good , plenty of power and economy is good. Average mileage was on 26.9 when I pulled into the garage a bit ago. One 50 mile run and 4 16 mile runs, with a mile of each in a small town, couple stoplights and stop signs.
On the flat I can even pass cars at 60 mph without taking it out of 6th.
thanks for the replies.

Glenn

 

[Schrade]

It only searches occasionally. Have tried carb cleaner, and propane both, just couldn't get it to show up. Will try the match trick. The idle is usually high enough that I don't need to block the throttle. Monday after work I will check it some more.
Overall it runs pretty good , plenty of power and economy is good. Average mileage was on 26.9 when I pulled into the garage a bit ago. One 50 mile run and 4 16 mile runs, with a mile of each in a small town, couple stoplights and stop signs.
On the flat I can even pass cars at 60 mph without taking it out of 6th.
thanks for the replies.

Glenn

You'll have to catch it when it IS loping, and you'll THEN HAVE TO block the linkage, or the pedal, to raise the idle to get it STEADY. THEN, AND ONLY THEN, can you find where it's suckin' air, like around the TB body/shaft, as is suspected.

This is EASY to do, but it HAS TO be done right.