Sticky Throttle

Sticky Throttle

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Discussion

Jarcy

Original Poster:

1,559 posts

282 months

Saturday 2nd May 2015
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Hoping for some help please..
I've just returned from a track day, and the throttle started sticking wide open.
It was quite alarming the first time it happened - on lift off at the end of a straight prior to braking, and the car didn't start to slow as you'd expect. yikes I was therefore 10m late braking and missed the corner.
It kept on sticking on the way back to the pits, but corrected itself once back.

The same happen on the next 3 sessions, after perhaps 5 or 6 laps would stick open again.
Absolutely fine for the drive home, so I'm guessing it only happens when wide open.
I tried WD40 at both ends but to no avail. No sign of fraying or kinking of the cable.

Has anyone experienced this? Could it be in the throttle body or is it more likely cable related? Operating the throttle at the throttle body, it springs back nicely. But the peddle did feel sort of dead when it stuck making me think it's the cable.
Is the cable easy to change - can you pull it through the tunnel or does the floor need removal.
Didn't want any drama before Rockingham frown

Thanks for any suggestions.

AMG Merc

11,954 posts

260 months

Saturday 2nd May 2015
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Sounds like the know problem of the throttle cable outer sheath melting and locking the cable up. Same thing happened to me at brands noble day. After a few runs, and the associated extra heat, mine was sticking at 3000 revs - not a good plan on the m25 going home so I had it trailered to mv from the infield.

This ocurred with cars that had the cable routed centrally over the forward turbo. The fix was to reroute a new cable to the right side along the top chassis rail. Of course, not sure if this is your issue but sounds mighty familiar.

Ps - no floor removal necessary.

spec1976

63 posts

136 months

Saturday 2nd May 2015
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I did have this shortly after I got my car but mine was a simple fix. One of the rubber pipes near the throttle body had somehow wedged itself onto the cable and jammed it open. Needless to say it is very well tie wrapped now.
Your problem sounds a bit more serious that mine though

Jarcy

Original Poster:

1,559 posts

282 months

Sunday 3rd May 2015
quotequote all
AMG Merc said:
Sounds like the know problem of the throttle cable outer sheath melting and locking the cable up. Same thing happened to me at brands noble day. After a few runs, and the associated extra heat, mine was sticking at 3000 revs - not a good plan on the m25 going home so I had it trailered to mv from the infield.

This ocurred with cars that had the cable routed centrally over the forward turbo. The fix was to reroute a new cable to the right side along the top chassis rail. Of course, not sure if this is your issue but sounds mighty familiar.

Ps - no floor removal necessary.
Thanks Rob, I'll look for any evidence of melting.
Then sourcing and fitting a new cable... Thnx

TuxMan

9,011 posts

245 months

Sunday 3rd May 2015
quotequote all
AMG Merc said:
Sounds like the know problem of the throttle cable outer sheath melting and locking the cable up. Same thing happened to me at brands noble day. After a few runs, and the associated extra heat, mine was sticking at 3000 revs - not a good plan on the m25 going home so I had it trailered to mv from the infield.

This ocurred with cars that had the cable routed centrally over the forward turbo. The fix was to reroute a new cable to the right side along the top chassis rail. Of course, not sure if this is your issue but sounds mighty familiar.

Ps - no floor removal necessary.
Perfect answer , I would go so far as to advise anybody with the throttle cable running over
The front turbo to change it and run it down the passenger cill !!!!
It's pretty dangerous fitted near the front turbo !!!

Jarcy

Original Poster:

1,559 posts

282 months

Sunday 3rd May 2015
quotequote all
It seems that the cable is at fault. It runs over the turbo to intercooler pipe, so keeping it away from the actual turbo and heat shield so it doesn't get any closer than about 5cm from the turbo. I can't see evidence of melting, but either way it needs replacing, and fast.
I understand the advice to route the cable down the sill, but I need a quick fix. Is this an at-home job or do I need a garage and a ramp. I guess I'll be on the phone to Jetstream for advice and hopefully supply of a cable, but need to fix it locally.

Just seen your thread from 2010 Tux, when your cable melted. Do you recall how you got the cable down the sill? Did you remove the sill floor panel? It seems that the difficulty if getting the cable from the front bulkhead into the sill. The exit at the rear is fine.
I'm thinking that I might try to fix it the standard way through the tunnel and the do the sill mod at a later date. That way I might make it to Rockingham...

TuxMan

9,011 posts

245 months

Sunday 3rd May 2015
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Don't remember it being too bad , remove drivers side rear wheel and wheel arch inner to allow access to sil , connect cable to peddle ,loop around and clip along bottom of the front wheel arch .
Drill hole through to cill and push new cable into cill and along until rear wheel . Then connect up .





Best photo I have but if you need more just shout .


Tux

simonx50

818 posts

167 months

Sunday 3rd May 2015
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am I right in saying if you can see the cable behind the drivers front wheel its ok and not going to melt?

TuxMan

9,011 posts

245 months

Sunday 3rd May 2015
quotequote all
Yep .

Jarcy

Original Poster:

1,559 posts

282 months

Monday 4th May 2015
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TuxMan said:
Don't remember it being too bad , remove drivers side rear wheel and wheel arch inner to allow access to sil , connect cable to peddle ,loop around and clip along bottom of the front wheel arch .
Drill hole through to cill and push new cable into cill and along until rear wheel . Then connect up .





Best photo I have but if you need more just shout .


Tux
Thanks Tux, I looked hard and then could see the cable as you describe.
Where did you drill the hole into the sill? There's a removable shaped panel to the rear of the front wheel arch - did you go through there?

On reflection it looks like the sill routing may end up easier than through the tunnel.

Blu3R

2,379 posts

206 months

Monday 4th May 2015
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Just make absolutely sure that the wheel won't catch it on full lock! Ask Andy about that one....
Clip it at close intervals and go as low as possible before it turns through the new hole.

Jarcy

Original Poster:

1,559 posts

282 months

Monday 4th May 2015
quotequote all
Blu3R said:
Just make absolutely sure that the wheel won't catch it on full lock! Ask Andy about that one....
Clip it at close intervals and go as low as possible before it turns through the new hole.
Noted! eek It did cross my mind, especially as there's evidence that the wheel has rubbed the inner arch higher up.

Jarcy

Original Poster:

1,559 posts

282 months

Saturday 9th May 2015
quotequote all
Job done. I found it easy to feed the new cable through the sill, and I imagine much simpler than trying to route through the tunnel. This solution only required a small hole in the fibreglass inspection panel on the inside of the front wheel arch. Filled the resulting gap with sealant, and routed the cable low down in the wheel arch with P-clips. I found that the cable was just the correct length too. Was worried initially as it appear too short for this route, but was OK in the end. Good job it wasn't 5cm shorter.







The old cable was easy to pull out through the tunnel once disconnected. On close inspection I found that the damage was not great. No real evidence of melting - I think that the outer sheath has just worn over time, and then the elements have got in.



And this section was under the rear section of the tub and was also rubbing (not actually melted).




All fixed now, so Rock-on Rockingham! smile

P.S. I wish my car was as clean as Tux's - and thanks all for your help with this job.

Edited by Jarcy on Saturday 9th May 09:53

Quantum Steve

153 posts

128 months

Saturday 9th May 2015
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Nice looking Protechs! Hope all goes well at Rockingham JC.

Jarcy

Original Poster:

1,559 posts

282 months

Thursday 11th June 2015
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OK, so it now seems that my offside handbrake cable has also gone the same way. Sticking so now that only the near side wheel will lock under the handbrake. To be honest, it could have been like this for a little while without me noticing. I think this because the adjuster bar in the tunnel is bent where the adjuster locknuts sit, suggesting that it has been pulled unevenly by the canterlever bar that attaches the cables, for some time.
Do I presume that this is a Noble only part, or does anyone have an aftermarket solution?

And a different problem, I've had a turbo coolant hose split - the one running from a T near the expansion bottle to the front turbo. Any suggestions as to what to replace with, and should I do the lot for good measure (I think I know the answer). BTW I don't want blue silicone hoses - they'd look rubbish in my engine bay. I see ACT do a full kit of blue silicone hoses, but I don't want to replace the air hoses and blue looks really naff (in a red car, at least).

I'm thinking of changing the expansion bottle while I'm at it, as the plastic one has cracks forming on the top (there must be quite some presure in there!). If I go for the ProAlloy one, did I see somewhere that you need to source a special high-pressure cap for it?

Thanks all.

Blu3R

2,379 posts

206 months

Thursday 11th June 2015
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Jarcy said:
And a different problem, I've had a turbo coolant hose split - the one running from a T near the expansion bottle to the front turbo. Any suggestions as to what to replace with, and should I do the lot for good measure (I think I know the answer). BTW I don't want blue silicone hoses - they'd look rubbish in my engine bay. I see ACT do a full kit of blue silicone hoses, but I don't want to replace the air hoses and blue looks really naff (in a red car, at least).
ACT do the hoses in black (what I have) or red but I think you'll have to buy the entire kit. I don't believe they offer individual hoses.

Jarcy said:
I'm thinking of changing the expansion bottle while I'm at it, as the plastic one has cracks forming on the top (there must be quite some presure in there!). If I go for the ProAlloy one, did I see somewhere that you need to source a special high-pressure cap for it?
You don't have to use an uprated cap, if the standard one is fine now then it'll continue to be. If you find you're venting through the cap then you should really be checking the whole system as simply replacing the cap for a higher pressure one will put extra strain on the rad and hoses. I don't know what sort of spec your car is but be careful you don't let high pressure find the next weakest point.
Oh and one last point - the PA header tank is a work of art and won't split like the Ford tank, this is true. What's also true though is you can buy around 15 Ford tanks from ebay for the price of the PA....

TuxMan

9,011 posts

245 months

Thursday 11th June 2015
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I hate silicon water hose , it always seems to leak , the best stuff I have used is the std high temp water hose from Perteck , cheap but works really well !! and yes I would change it all !!

Jarcy

Original Poster:

1,559 posts

282 months

Thursday 11th June 2015
quotequote all
TuxMan said:
Perteck - cheap but works really well !!
Interesting, thanks Tux.
Presume that's Pirtek - there's a depot near where I'm going tomorrow so will look in.
Does anyone know the diameter of the turbo cooling hoses, or is it standard stuff?


Rob_W

1,070 posts

221 months

Thursday 11th June 2015
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9.5mm

TuxMan

9,011 posts

245 months

Thursday 11th June 2015
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Lol yeh sorry Pirtek 😉 9mm bore reinforced .