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Throttle body butterfly armature rigidity & stiffness
#1
Here's a quick question (yeah right).  In order to check properly, you have to remove the air filter box, so some of you may rely on memory for your own cars, but is everyone's throttle body butterfly armature, which is connected to the throttle spool via the miniature ball-jointed control link bar, tight?

What i mean by this question, is:  is it "waggle-able" from left to right quite freely, or is it held rigid in place by the staver nut which holds that whole sprung loaded assembly together?

I'm asking, because for a while now, i've been suffering a "sticky throttle".  

In fact, ever since i disassembled the VOD in 2015.

The situation is improving all the time, with a tweak here and an adjustment there, but coming down the M6 three weeks ago, the problem exhibited itself again.
Not badly, but persistent.  It seems it only becomes an issue when the car is fully warmed up and been running for a while (something expanding with heat?).

What's happening is the throttle is getting stuck around the 2k rpm mark, and i can only get it to return to idle by stomping down on the accelerator quickly a bit, and letting go immediately.  Then it returns to idle.  The idle speed micro switch, as far as i can determine, is always being clicked, at least when the throttle spool returns to the resting idle point (which isn't with the tab on the spool resting against the vertical pin.  which i guess is another question.  Is it supposed to?  It hits the pin at full acceleration on the other side, but not when idling.  I tried to make it do both, but couldn't win with that.  I ascertained that even in this resting position, both butterflies are fully closed inside the throttle valve, so i'm convinced it's ok).

I'm finding that by releasing that staver nut (which i think is the only one on the entire car out of interest) another "notch" at a time, is slowly improving the situation, but it's starting to get that armature quite loose feeling and waggles quite freely.  In fact, the threaded push bolt which clicks the idle speed switch is now over to one side, only just meeting with the metal of the switch, rather than sitting nicely in the middle of it.  Others have demonstrated with their car that their armature is solid feeling and works fine with the idle speed returning, but if i tighten up that staver nut to produce the same result, then the throttle becomes really stiff and sticky.  Back in 2015, immediately after my VOD work, when we were driving round the Lotus test track, my throttle got jammed at 4,500rpm!  and i had to get out the car to push it back to idle.  That was before i started loosening off the staver bit by bit.

I'll admit that when i had everything apart doing my VOD, i disassembled that whole assembly to clean it all up, including the springs throughout that whole throttle area, and realised that the original rubber on that armature pinion had all perished and was crumbling, so i had to devise a replacement setup using nitrile o rings etc, and i'm wondering whether my rushed, under pressure effort to get me going ready for Lotus, was simply not good enough.

Sorry for such a long explanation.  A video would have been better than all these words i guess.  Anyway.  Any help or ideas or comparisons of what your car does around that area?
Rissy
Chris M. Morionem qui loquitur multus sine cogitatione.
(Forum Member 288)
(DOC Member 663)

May 1981 vin#1458
"LEX" aka "Wonkey" - Officially used in Britain's Greatest Machines (80's episode) with Chris Barrie.
Grey Wheels
Grooved, flapped Bonnet
Black Leather Interior
Chassis: #1073
Engine: #2839

Main Car(s):

2005 BMW M3 E46 Shape 3.246 Straight Six in Velvet Blue
1999 Honda Civic MB6 Shape 1.8VTi VTEC in Pirates Black
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