Throttle sticking

[cb4798]

My throttle is sticky and gets stuck when on full throttle. It's not the cable but rather the spring on the throttle body.

Can anyone suggest how to loosen this? This is a recent issue. It has been fine for 9 months but I haven't used it that much recently. 

When I last used it, it got stuck open while overtaking someone, which was fun!

thanks

 

[Jonathan Kay]

Does it happen every time when you work it by hand after disconnecting the cable?

Suggestion about retainer springs.

Can you add a description and photo of your set-up?

Happy New Year

Jonathan

[Mort]

A few suggestions:-

1) Check spring manually as Jonathan has suggested.

2) If you have a plastic throttle body then check that the jubilee clip holding the air filter on isn't too tight, as this will prevent the butterfly valve from turning within the throttle body.

3) Check the cable for free movement (it may be frayed) and lubricate well with WD40.

4) With the cable disconnected, check that the pedal moves freely

I had a similar problem, which took ages to identify.  Strangely, it was fine when the car was warm. But awful when the car was cold, and it was always worse in cold conditions.  It turned out that the throttle pedal had been greased, and the grease had congealed and solidified.  When the engine/footwell was warm it melted a bit and all was OK, but when it was cold it was very stiff and prevented the return spring from doing its job.

Hope this helps.

[cb4798]

This is the offending item. (sigma engine)

If I manually move it to its maximum position then it sticks. It also doesn't feel smooth when moving it.

I'm sure that it isn't the cable. I'll see if WD40 helps.

[Jonathan Kay]

See Nick's second point: can you disconnect the external lever bit from the bit in the intake to see which is sticking?

Jonathan

[cb4798]

I will try tomorrow morning. Thanks Guys.

 

[cb4798]

So, the spring that is stiff is the one that isn't directly attached to the throttle cable. That one and the cable itself move freely.

It looks like it is all held in place with a grub screw. Has anyone taken this apart before. Am I going to have trouble putting it back together?

 

[Jonathan Kay]

How do you know it's the spring that's stiff rather than any other moving bit?

Jonathan

[SM25T]

Spring may seem strong ..... but it is designed to return the throttle butterfly to the closed position after you apply your size 10 clog to the pedal. Unless it is catching on something, it won't be the spring. You do need to remove the cable from the throttle lever at the engine end and see exactly what is sticking /catching.

[cb4798]

I have removed the throttle cable and it's not the pedal. 

I then removed the join between the two levers so they move independently to see which is stiff, the one that connects to the throttle cable moves freely and always returns to the close position. The other one, when push open remains open, I then have to give it a push before it releases, so I know it is that mechanism/spring. 

It doesn't appear to be catching on anything, which, is why I think I need to take it apart, but I'm a bit reluctant to do that since I'm not entire sure what is holding it all together. 

[Blue C7]

Are the screws tight in the butterfly spindle? If not can allow disc to move and jam.

[tbird]

I have had exactly the same problem a BlueC7 above On a CSR as well ) , loose screws attaching  butterfly to spindle causing butterfly to foul body and Jam, although mine jammed just before closing so not quite as dramatic, to re centre I made sure both screws were very slightly loose, allowed butterfly to close fully and using finest feeler guage just put tip of gauge between  barrel and bottom of butterfly then nipped up screws . all ok afterward

 

Tim

[gileshudson]

Chris,

One of the guys in my area meet approached me tonight and asked me to get in touch with you about this, as he can only read BlatChat and not reply because he can't login to the new site.

He said that is very keen to get in touch as he has had exactly this issue in the past on the same engine and no post on this thread to date has pointed you at how he sorted it.

I've just pinged you his email in a private message and so hopefully you can liaise with him that way and get yourself sorted with a bit of luck.

Hope this helps... keep us posted.

Cheers
Giles

[cb4798]

Thanks for the message, Giles.

I will keep you updated.

[cb4798]

Giles, Tom was spot on.

Just incase someone else has this issue. The problem is with the two bolts on the opposite side of the spindle. A half turn on these was enough to free it.

This picture shows the throttle stuck on, and I have circled the bolts that needed adjusting.

Thanks all for you help! 

 

 

 

 

 

[Jonathan Kay]

Well done. How far did you have to disassemble to isolate the stickiness?

Jonathan

[DJ.]

Thanks for posting the update with picture, I am sure this thread will be very useful to members in the future

Duncan

[cb4798]

Jonathan, about a half turn or so on the bolt you can see in the picture was enough. I screwed them out and back in so they were tight but not causing it to stick. Then I added a dot of loctite and marked them with a pen so that I can check them to see if they are moving.

[Jonathan Kay]

Thanks... all done with the external actuating bits still connected?

Jonathan

[cb4798]

Yes

[Jonathan Kay]

Thanks. As above, this is going to help someone someday.

Jonathan

[Mort]

Interesting. Quite different to my K-Series setup.

[gileshudson]

I'm glad you're sorted Chris, and congratulations to Tom Arundel of our Bear 7s (Warwickshire North) parish for knowing what the problem was and how to fix it.

If you're reading this Tom, get that BlatChat login issue sorted (Try a half turn on the two bolts on the keyboard) and come say Hello on this thread to prove it's working...

[richd13]

I'm the someone, cheers guys!!

[Jonathan Kay]

:-)

Jonathan