throttle bl**dy pots!
Discussion
Hi All
Spoke too soon the other day with reliabilty posting as car started miss firing this week. Thought it might be fuel or plug related but both seemed fine on checking so took it for a run and was still messing about so tried unplugging the throttle pot and hey presto started running normally again.
I changed the throttle pot when i first bought the car a couple of years ago and had problems with starting and poor running and seems a bit odd for it to be going again. Can anyone advise with whether it is worth giving it a blast of compressed air/wd40 or any other bright ideas to clear this up or alternatively a cheap source as the last one cost me about £90.
Thoughts appreciated
Stu
Spoke too soon the other day with reliabilty posting as car started miss firing this week. Thought it might be fuel or plug related but both seemed fine on checking so took it for a run and was still messing about so tried unplugging the throttle pot and hey presto started running normally again.
I changed the throttle pot when i first bought the car a couple of years ago and had problems with starting and poor running and seems a bit odd for it to be going again. Can anyone advise with whether it is worth giving it a blast of compressed air/wd40 or any other bright ideas to clear this up or alternatively a cheap source as the last one cost me about £90.
Thoughts appreciated
Stu
From memory the throttle potentiometer is a standard Ford item, £ 100 seems way to expensive.
Have a look at: http://bertram-hill.co.uk/tvrs3.aspx
They can last several years but sometimes just a few weeks. Ford replaced mine that only lasted a few weeks under guarantee.
In my experience once they start being intermittent not a lot you can do. I seem to recall some firm producing high quality pots no doubt someone on here will know?
Have a look at: http://bertram-hill.co.uk/tvrs3.aspx
They can last several years but sometimes just a few weeks. Ford replaced mine that only lasted a few weeks under guarantee.
In my experience once they start being intermittent not a lot you can do. I seem to recall some firm producing high quality pots no doubt someone on here will know?
The fact that it runs ok with the throttle pot disconnected doesn't necessarily mean that it was the TP at fault. Disconnecting the TP could put the car into "fail safe" mode so that it's not using the ignition and fuel maps, and therefore not relying on inputs fromn sensors including the idle speed control valve, the temperature sensor, etc.
So you might be masking the underlying problem, which could be in a number of areas.
Tell you where I'd start, though. There's a multi-connector on the loom on top of the right-hand rocker cover (under the coil). All of the sensors are connected to the ECU through that connector, and it gets wet / corroded. Pull it apart, clean the terminals and see whata happens.
One job on my list for the winter is to take that connector out and solder / heatshrink the wires together.
Also check the connections on to all the sensors on the engine.
So you might be masking the underlying problem, which could be in a number of areas.
Tell you where I'd start, though. There's a multi-connector on the loom on top of the right-hand rocker cover (under the coil). All of the sensors are connected to the ECU through that connector, and it gets wet / corroded. Pull it apart, clean the terminals and see whata happens.
One job on my list for the winter is to take that connector out and solder / heatshrink the wires together.
Also check the connections on to all the sensors on the engine.
I think Ford charge about £59 for a new pot, however the best thing to do is go to your local breakers yard and pillage any old rover 200/400 as they have the exact same pot on them, what I did was to get 2 of them 
and try them alll one at a time on the car so that I now know I have 2 working pots.
Cheers.....Tony..
and try them alll one at a time on the car so that I now know I have 2 working pots.Cheers.....Tony..
Edited by tozerman on Monday 14th December 08:24
tvrgit said:
The fact that it runs ok with the throttle pot disconnected doesn't necessarily mean that it was the TP at fault. Disconnecting the TP could put the car into "fail safe" mode so that it's not using the ignition and fuel maps, and therefore not relying on inputs fromn sensors including the idle speed control valve, the temperature sensor, etc.
So you might be masking the underlying problem, which could be in a number of areas.
Tell you where I'd start, though. There's a multi-connector on the loom on top of the right-hand rocker cover (under the coil). All of the sensors are connected to the ECU through that connector, and it gets wet / corroded. Pull it apart, clean the terminals and see whata happens.
One job on my list for the winter is to take that connector out and solder / heatshrink the wires together.
Also check the connections on to all the sensors on the engine.
`multi-connector on the loom` Agree with this. So you might be masking the underlying problem, which could be in a number of areas.
Tell you where I'd start, though. There's a multi-connector on the loom on top of the right-hand rocker cover (under the coil). All of the sensors are connected to the ECU through that connector, and it gets wet / corroded. Pull it apart, clean the terminals and see whata happens.
One job on my list for the winter is to take that connector out and solder / heatshrink the wires together.
Also check the connections on to all the sensors on the engine.
Had a very rough car for 6 months then had this sorted , cleaned off and hey presto, great running.
tozerman said:
I think Ford charge about £59 for a new pot, however the best thing to do is go to your local breakers yard and pillage any old rover 200/400 as they have the exact same pot on them, what I did was to get 2 of them and try them alll one at a time on the car so that I now know I have 2 working pots.
Cheers.....Tony..
If you have discounted the possible cause per TVRGIT's post and still need a TP, look t ebay for Lotus/Rover throttle... looks like the lotus boys swap their 48mm plastic throttle for a larger one so the old ones are often on ebay with no takers and you'll get one for a fiver complete with TP (same Intermotor part num) and try them alll one at a time on the car so that I now know I have 2 working pots.Cheers.....Tony..
Edited by tozerman on Monday 14th December 08:24
IIRC I read that when the Throttle itself is fully closed the TP is at about 16 degrees off the bottom but the rovers are at zero with the throttle closed, this means that the rover TP's are like new as far as the contacts are concerned... ( not easy to explain but imagine a clock with 12 being the "closed" position of the TP... when a Rover throttle is closed the TP is at 12 but a when a ford Throttle is closed the TP is at 10 past 12... )
HTH
K
ketvrin said:
not easy to explain but imagine a clock with 12 being the "closed" position of the TP... when a Rover throttle is closed the TP is at 12 but a when a ford Throttle is closed the TP is at 10 past 12... )
K
Hi KevK
Bloody hell dont tell me we have to set the timing on the throttle pot as well now
Edited by clarenceboddiger on Tuesday 15th December 06:23
Not sure wrt Kevin's post above, but when I compared my TP with my sons one on a rover 200 it was the same. S2Giles has also replaced one with one from a R200 based on my recommendation having used my spare (Ford one) for fault diagnosis and AFAIK his car is still running ok - these are available for under £10 on ebay and are plentiful so little harm in trying
HTH
Mark
HTH
Mark
FWIW I replaced mine first time it misbehaved. After that I took it out and had a look. Found that the plastic on plastic movement was a bit sticky, probably because of lack of use. Sometimes just some enthusiastic working the throttle would clear it, other times I'd use some rubber and nylon lubricant (got from Halfods, I'd like to make that clear 
)
Sorry of this has been said already, hope it helps.
)Sorry of this has been said already, hope it helps.
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