Replacing throttle pots

[trooperiziz]

I think I've narrowed down some dodgy running to my crappy, ten year old, throttle pots. Ordered a couple from Trackcar this week and intend to fit them this weekend.

Any pitfalls I should be looking for before I start? I have the software and shouldn't have any problems balancing them out to 17% each bank on idle should I need to. What i'm really hoping for is to be told that I can just take off the old ones, put the new ones on and it's done

[jonnie5]

You can just take off the old ones, put the new ones on and it's done

HTH

Don't listen to me, I know nothing...

[trackcar]

^^^^^^^^^ what he said ^^^^^^^^^^

[trooperiziz]

In that case, I might push the boat out and do it tonight instead!
What a wild and crazy life I lead...

[cossiemetro]

i thought it was a big job ??? that you needed to use a PC to set up
or have i miss read something ????

Edited by cossiemetro on Friday 8th September 22:59

[jensena]

Easy job to replace them, but you need the PC Diags to check them, and set them up.

[ancol]

what exactly are the throttle pots and are they expensive also where are they regards andy

[trooperiziz]

ancol said:

what exactly are the throttle pots and are they expensive also where are they regards andy

They are resistance potentiometers that send a signal to the ECU so it knows the position of the throttle. (I think )

Cost about £35 each and you will need a pair of them, they sit on the front of the fuel rail, one on each bank, with a cable sticking out the top.

Unless you are having uneven or "jerky" running problems, you don't need to replace them.


As an aside, replaced mine over the weekend, very easy job. Can't start the Cerb though Battery is flat due to a combination of not using it and the battery on its last legs and my jump starter doesn't pack enough punch to get the car running. It'll crank it for about 5-10 seconds before draining the jump battery, which isn't long enough to get the car running after it having been left for a few weeks. I'm hoping it just need a bigger jump and replacing the throttle pots hasn't screwed up my fuelling.

Ordered an Optima Yellow Top battery, which should hopefully get it going, other than that it will be a call to the AA man and pretend to be ignorant while he sorts it all out.

[cossiemetro]

as i said i'm sure you need to have them set up on a laptop.......

[trooperiziz]

cossiemetro said:

as i said i'm sure you need to have them set up on a laptop.......

I'm not adjusting the throttle though, just replacing the pots.

[ancol]

my cerb runs great but is jumpy on very small throttle opening like when you are hardly pushing the peddle when your cruising

[trooperiziz]

ancol said:

my cerb runs great but is jumpy on very small throttle opening like when you are hardly pushing the peddle when your cruising

The majority of Cerbs are, and common opinion is that "They all do that, sir", but i'm not so sure.

IMO it is possible to get a smooth Cerb, obviously not to Lexus standards (which, incidentally, I'm picking up an LS400 tonight, which will be a contrast!) but I think one of the Julians has a very smooth running Cerb.

The problem is, that it is likely to be a combination of reasons that all compound on each other. Dodgy throttle pots, worn throttle linkage, worn cable, worn throttle return springs, clogged injectors, screwed lambdas, etc... You could replace every single one of these parts in turn, but by the time you get to the end of the list, the start would need replacing again

p.s. In case anybody was wondering, I've decided to keep the Cerb for the time being (even though the bugger won't start!) at least until we are settled after our impending house move.

[trooperiziz]

trooperiziz said:

As an aside, replaced mine over the weekend, very easy job. Can't start the Cerb though Battery is flat due to a combination of not using it and the battery on its last legs and my jump starter doesn't pack enough punch to get the car running. It'll crank it for about 5-10 seconds before draining the jump battery, which isn't long enough to get the car running after it having been left for a few weeks. I'm hoping it just need a bigger jump and replacing the throttle pots hasn't screwed up my fuelling.

Ordered an Optima Yellow Top battery, which should hopefully get it going, other than that it will be a call to the AA man and pretend to be ignorant while he sorts it all out.

Well, that didn't go entirely as planned...

Realised that my MOT is due tomorrow so although I was waiting for the optima battery to turn up (couldn't get a yellow, ordered a red instead) I thought it best to get it running beforehand and switch the battery when it arrives.

Call the AA man, plug in his battery booster and connect up to his running van and she cranks into life first time! Yay!...

... then dies... Boo!

Turns out the battery is totally dead and won't hold any charge at all, so she will only start when connected to the AA van, which will make the run to the MOT centre tricky.
However, she is also running like a shovel of shite and the pots need adjusting (naughty people who said they don't ) Ordinarily not a problem, I have the software and know that I need to balance the two banks to 17% on idle (I think ) but not the easiest job in the world when she won't idle and the battery won't hold enough charge to restart the engine

When the new battery arrives I'm planning on pushing the pots all the way to the left (when looking back at the car from the front) to get it to idle, if a little on the high side! Then wind each one back while looking at the laptop to get them down to 17%, hopefully without it stalling too many times and flattening the new battery after a load of starts.

Does this sound like a plan, have I missed anything obvious?

My backup plan is to get the AA to take it to the local TVR place to sort it out I made sure the last visit was recorded as unfixable and needing recovery But i'd much rather fix it myself, ideally before we move house this weekend!

[toadusmodus]

trooperiziz said:

trooperiziz said:

As an aside, replaced mine over the weekend, very easy job. Can't start the Cerb though Battery is flat due to a combination of not using it and the battery on its last legs and my jump starter doesn't pack enough punch to get the car running. It'll crank it for about 5-10 seconds before draining the jump battery, which isn't long enough to get the car running after it having been left for a few weeks. I'm hoping it just need a bigger jump and replacing the throttle pots hasn't screwed up my fuelling.

Ordered an Optima Yellow Top battery, which should hopefully get it going, other than that it will be a call to the AA man and pretend to be ignorant while he sorts it all out.

Well, that didn't go entirely as planned...

Realised that my MOT is due tomorrow so although I was waiting for the optima battery to turn up (couldn't get a yellow, ordered a red instead) I thought it best to get it running beforehand and switch the battery when it arrives.

Call the AA man, plug in his battery booster and connect up to his running van and she cranks into life first time! Yay!...

... then dies... Boo!

Turns out the battery is totally dead and won't hold any charge at all, so she will only start when connected to the AA van, which will make the run to the MOT centre tricky.
However, she is also running like a shovel of shite and the pots need adjusting (naughty people who said they don't ) Ordinarily not a problem, I have the software and know that I need to balance the two banks to 17% on idle (I think ) but not the easiest job in the world when she won't idle and the battery won't hold enough charge to restart the engine

When the new battery arrives I'm planning on pushing the pots all the way to the left (when looking back at the car from the front) to get it to idle, if a little on the high side! Then wind each one back while looking at the laptop to get them down to 17%, hopefully without it stalling too many times and flattening the new battery after a load of starts.

Does this sound like a plan, have I missed anything obvious?

My backup plan is to get the AA to take it to the local TVR place to sort it out I made sure the last visit was recorded as unfixable and needing recovery But i'd much rather fix it myself, ideally before we move house this weekend!

You don't need to have the car running to setup the T-pots, just have the ignition switched on. Then you can take your time balancing them and just re-set the adaptive maps once you have started and warmed up the engine.

[trooperiziz]

toadusmodus said:

You don't need to have the car running to setup the T-pots, just have the ignition switched on. Then you can take your time balancing them and just re-set the adaptive maps once you have started and warmed up the engine.

Cool, didn't realise that, I've only ever played with the car running!
Currently the battery doesn't have enough power to switch the ignition on

p.s. What's up your end these days Mr Toad, you never call, you never write, you never email...

[trooperiziz]

Well, I realise this isn't in the same league as some of you on here, but i'm feeling chuffed with myself New battery fitted, new throttle pots on and balanced, car seems to be running like a dream!

Had a bit of a moment when the alarm went off after I removed the old battery, but as the electrics were so dead, it only did a few bips at full strength, then promptly started a HAL impression over the next 5 minutes... Daisy, Daiaaaaaissssyyyyy.............. beeeeeeeeeeep....<click>.

Could only get the new pots up to 16.5% on idle, so hopefully that will be enough to stop her stalling, otherwise I'll have to enlarge the screw holes to get a bit more play.

Should really book an MOT, anybody in the Newcastle area know of a "TVR friendly" MOT centre? I'd rather not have to put the cats back on if I can help it!