76 Datsun 280z throttle sticking

[TomoHawk]

BTW-   Somene mentioned elsewhere that you could also use a Cressida or Ford Aspire throttle/AFM as well, if you need something to ponder  after 17 beers..

[Captain Obvious]

Not to worry. The Sentra throttle body has not only the same mounting bolt hole locations as the original, but also has the identical throttle plate diameter. So no performance upgrade to "worry" about there. So... Since the throat bore and throttle plate is the same as stock, then one might ask "So why would you go through all that trouble to switch?" Valid question.

Answer - Because it has roller bearings and built in vacuum seals on the throttle shaft. Smooth as silk and absolutely no leaks. That's why!

 

[TomoHawk]

How did the throttle linkage connect?

I don't think I would notice a difference if it leaked that little bit.  I think an affordable OE fuel pump or a better AFM would be more important.

Edited August 19, 2018 by TomoHawk

[Zed Head]

25 minutes ago, TomoHawk said:

I think an affordable OE fuel pump or a better AFM would be more important.

Or new carpet....

[Captain Obvious]

11 hours ago, TomoHawk said:

I think an affordable OE fuel pump or a better AFM would be more important.

To each his own then. Haha! My fuel pump and AFM are working great. You're the one that that refreshed this antique post about a sticky throttle body.   

My throttle body was only sticky when the engine was warm and only when it was running. So needless to say that mine unfortunately mine wasn't as simple as the carpet being bunched up.

I also disassembled this part and made a new spherical bearing for inside. That took a lot the slop out of the linkage, but it didn't do anything to fix the sticky idle. Problem was in the throttle body itself.

[TomoHawk]

Well, the idle seems to creep up (higher) a little with a warm engine, but it wasn't as bad as having the carpet holding the pedal.  The warm engine col be creating a little air leak, which can be fixed, but the idle wasn't so high it makes things unsafe or requiring hard braking.

I was wondering why there is a spherical-looking bearing on that belcrank bracket.  I think it's to keep the throttle system from binding when the engine moves from torque effects, but an ordinary bearing shouldn't be a problem either, or any proficient driver.

Edited August 22, 2018 by TomoHawk

[TomoHawk]

On 8/18/2018 at 11:24 PM, Zed Head said:

Or new carpet.

Some carpeting is on my to-do list, but it's an easier job than finding OE parts that are affordable.

[TomoHawk]

On 8/19/2018 at 10:52 AM, Captain Obvious said:

I also disassembled this part and made a new spherical bearing for inside. That took a lot the slop out of the linkage, but it didn't do anything to fix the sticky idle.
 

I' like to hear your description of taking it apart. It seems to be welded together, unless there's a bolt on the back you don't see.

[Captain Obvious]

The reason they need a spherical bearing there is because the engine can move in any unpredictable manner, up / down / left / right. They account for all of that with the spherical bearing. Then they account for fore and aft with the shepherds hook which can extend and compress.

Between the spherical bearing in that piece of the linkage and the shepherds hook, they account for every direction of engine movement.

My description of taking that part apart? There is no nut on the back side, but there is a swaged (think rivet) joint holding the assy together. I cut off the flared section on the lathe and pulled the retaining ring off the back. The part I don't remember is exactly how I held it back together again once I was done.  It's back together, but I don't remember what I did there. I remember threading something....

I wonder if I have any pics of that process.  I'll check when I get a chance.

[TomoHawk]

I don't see any reason why you couldn't make the bracket a two-part deal, like a clamshell, with one half keeping the ball captured.  A glorified/modified washer  with a few small screws would work. 

But after driving it for a while, it's nicer, having smoothed-out the carpet.  The idle creeps a  little with the heat, but it's not a problem.  I think I'll add some Velcro to hold the carpet in place after the driving season ends.  I was thinking of possibly getting a professional carpet-job, but with some diamond-pattern vinyl over the transmission tunnel.  The current carpet was a cheap kit installed by an amateur.

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