T350 sticking throttle bodies

T350 sticking throttle bodies

Author
Discussion

TerryB2

Original Poster:

10 posts

67 months

Sunday 19th March 2023
quotequote all
Started my T350 the other day after a prolonged 6 month layup - for reasons I won’t go into here. She is on a trickle charger and started first time as usual, however when tickling the throttle to keep the revs around 1200 for a few seconds as she was a bit lumpy revs started to rise much higher, this was with my foot removed from the throttle, when they reached 2k + without any help from me I switched the ignition off. Suspecting a sticking / frayed cable I removed the pedal box cover but no frayed cable, the cable was stuck with the pedal moving freely along the cable. Seems the cable wasn’t returning. So removed air box, removed clevis pin and cable separated cable from throttle bodies and cable moves freely, nice smooth action and returns OK. Have lubricated cable and it is working smooth and free. However trying to move the throttle pot linkage is extreme stiff as though they are sticking and tight. When I open the butterfly valves they stay open as if stuck.
I would expect them to spring closed quite freely, or are they dampened by the front and rear TPS modules? What should I expect.?
Have I just got gummed up throttle pots that need cleaning or is there an underlying issue . Have sprayed some WD40 on the linkages and they move a bit easier, but don’t spring closed, and intend to clean the throttle bodies with some carb cleaner, over the next few days. anyone on here had this issue and can offer any advise.

Thanks

nawarne

3,098 posts

267 months

Monday 20th March 2023
quotequote all
The main return to closed assistance for the throttle bodies and all the associated linkage is the "vertical" 'ish, spring that is concentric with the throttle cable.
You mention that the action of the linkage seems stiff - even with the cable disconnected. I would concentrate on doing some more checking in this area to get everything working smoothly.

Nick

mk1fan

10,651 posts

232 months

Monday 20th March 2023
quotequote all
Have you had the TB modified to swap the spindle bushings to bearings?

The bushings weren't great for maintaining balance. A couple of people offer the bearing conversion.

It could be the bushings or the spindles have 'rusted' slightly causing sticking. Or become damaged.

If the TB have been modified to be bearings then they could be damaged in a similar way.

Are the TB firmly fixed in position? Worth a check, if one is loose they could bind.

If all fixed in position then try a bit of easing oil along the spindle and see if this helps.

Check the throttle cable runs smoothly too and may as well lube at the same time.

Some easy checks before taking it all apart!

TerryB2

Original Poster:

10 posts

67 months

Monday 20th March 2023
quotequote all
Thanks for the replies,

1/ The throttle cable has been disconected. There is no resistance in the cable it all runs nice and amooth, i have as a matter of course lubricated the cable anyway.

2/ As far as i am aware the TBs are all original and unmodified, I am thinking like yo mk1fan that they have rusted slightly and as you say and why they are sticking, In cannot see any other reason.. I will check the TBs are all firmly fixed but nothing seems loose. She was running fine the last time I used her, throttle action was smooth she just went away into the garage as normal.
I have spreayed WD40 onto all the spindles and between the linkages and the TBS and will cleani the TBs , butterflies and spindles with some carb cleaner. The spindles have eased off a bit, maybe i just need to take some time to let them soak in and ease off..

I will let you know.

Many thanks






rfisher

5,024 posts

290 months

Monday 20th March 2023
quotequote all
I posted this on the last thread relating to this problem ...

It's frequently (like always) the last 'linkage' that turns the speed potentiometer right at the front of the engine.

You need to loosen one of the cross-head screws and squirt WD40 between the pot and the engine.

It's hard to get to the top screw but not necessary anyway.

Move the throttle from closed to fully open a few times after treatment, then fire her up and hit the road (assuming it's ok).

TerryB2

Original Poster:

10 posts

67 months

Monday 20th March 2023
quotequote all
Thanks rfisher I will have a go.

BTW I did try and search for a similar problem but all I could find were posts relating to throttle cable issues.


Granturadriver

629 posts

268 months

Monday 20th March 2023
quotequote all
Even after not starting the engine during winter for over 4 months I had not such issue.

The 3 throttles on the left (rear) and the other 3 in the right (front of the car) are linked. You might be able to narrow down whether all 6 are stuck or just 3 on one side. Than you could try to find out if it is just one or all the 3.

rfisher

5,024 posts

290 months

Tuesday 21st March 2023
quotequote all
TerryB2 said:
Thanks rfisher I will have a go.

BTW I did try and search for a similar problem but all I could find were posts relating to throttle cable issues.
https://www.pistonheads.com/gassing/topic.asp?h=0&t=1994231&r=47163076&hm=1193&mid=1193#47163076

beer

TerryB2

Original Poster:

10 posts

67 months

Tuesday 21st March 2023
quotequote all
Many thanks

TerryB2

Original Poster:

10 posts

67 months

Tuesday 21st March 2023
quotequote all
So have been liberally applying WD40 throughout the past few days to the TB linkages and I now have free moving linkages mechanism that spring back nicely from being fully open. Hurrah 😃 Many thanks for everyone’s help and advice.

mk1fan

10,651 posts

232 months

Thursday 23rd March 2023
quotequote all
Eggplant.

Now get on and sort the other 473 faults biglaugh

TerryB2

Original Poster:

10 posts

67 months

Thursday 23rd March 2023
quotequote all
at least.....

TwinKam

3,169 posts

102 months

Thursday 23rd March 2023
quotequote all
Now oil it, because W**0 is not a lubricant.
Shortly, the solvent and fish guts that you have just dispensed will dry out and leave you back at square one.

TerryB2

Original Poster:

10 posts

67 months

Thursday 23rd March 2023
quotequote all
TwinKam, dont worry already done I'm not having this problem again, and ill check regularly, mind you its the first time in over 5 years of ownership!

lancepar

1,042 posts

179 months

Friday 24th March 2023
quotequote all
WD40 comes in a variety of different types..........

Just get the right one for the job..........

"Whether you need the original blue and yellow can with thousands of uses, or a penetrating oil, lubricant, cleaner, degreaser or solution to protect against or remove rust, we’ve got you covered. Get the Job Done Right with a range of products from WD-40"

clap

TwinKam

3,169 posts

102 months

Friday 24th March 2023
quotequote all
lancepar said:
WD40 comes in a variety of different types..........

Just get the right one for the job..........

"Whether you need the original blue and yellow can with thousands of uses, or a penetrating oil, lubricant, cleaner, degreaser or solution to protect against or remove rust, we’ve got you covered. Get the Job Done Right with a range of products from WD-40"

clap
Many far better products available since 1950s!