Throttle Position Sensor - Fitting a Colvern CP17
Discussion
Hi all,
I'd like to replace my 23 year old Lucas carbon wiper TPS, it does seem the the hall type Colvern CP17 is the go to item and is available from many sources, but the best price seems to be from Emerald at £50.
http://www.emeraldm3d.com/colvern-throttle-positio...
My question is, how have people who've used this Colvern CP17 on their TVR Chimaera connected it to the car's throttle spindle when the Lucas TPS looks like this...
And the the Colvern TPS looks like this...
Now I know I could buy the kit from ACT which solves the problem in a stroke.
The thing is by the time you've added the VAT and shipping you're looking at £190.00, now while I have no issue with people making a crust it does seem all you're actually getting for your £190 is....
1. A Colvern TPS - £50
2. A connector - £5 tops!
3. This little aluminium drive converter with bearing
As proved by a simple Google search the Colvern TPS and connector are £55 worth of parts, so that means you're being charged a whopping £135 for the above item
My guess is others have fabricated their own drive converter solution for a damn sight less than £135
Perhaps I'm missing something here but to me it looks like I just need to obtain a section of brass rod of the correct diameter and hand file the necessary flats, then fab up a simple aluminium converter block?
But maybe others have come up with a different solution, if this is you please can you share a photo of how you connected the Colvern TPS to your Chimaera throttle spindle?
Thanks, Dave.
I'd like to replace my 23 year old Lucas carbon wiper TPS, it does seem the the hall type Colvern CP17 is the go to item and is available from many sources, but the best price seems to be from Emerald at £50.
http://www.emeraldm3d.com/colvern-throttle-positio...
My question is, how have people who've used this Colvern CP17 on their TVR Chimaera connected it to the car's throttle spindle when the Lucas TPS looks like this...
And the the Colvern TPS looks like this...
Now I know I could buy the kit from ACT which solves the problem in a stroke.
The thing is by the time you've added the VAT and shipping you're looking at £190.00, now while I have no issue with people making a crust it does seem all you're actually getting for your £190 is....
1. A Colvern TPS - £50
2. A connector - £5 tops!
3. This little aluminium drive converter with bearing
As proved by a simple Google search the Colvern TPS and connector are £55 worth of parts, so that means you're being charged a whopping £135 for the above item
My guess is others have fabricated their own drive converter solution for a damn sight less than £135
Perhaps I'm missing something here but to me it looks like I just need to obtain a section of brass rod of the correct diameter and hand file the necessary flats, then fab up a simple aluminium converter block?
But maybe others have come up with a different solution, if this is you please can you share a photo of how you connected the Colvern TPS to your Chimaera throttle spindle?
Thanks, Dave.
Edited by ChimpOnGas on Wednesday 14th August 09:11
Well you're also paying for the fact that someone has measured it all up, done a drawing, paid for a batch to be made etc etc .. and profit to actually make it all worthwhile ..
For what it's worth I wouldn't go hand-filing a converter, I'd go for something made to a good standard if that is the route you're choosing.
However ..
The original Tpot is a spring-return item and as such is very good at always tracking the spindle position crucially at the point of changing direction (ie foot on throttle, then off throttle, at light throttles).
The colvern is not a spring return Tpot and as such the fit of the D shaft into the pot, and more importantly the blade into the end of the RV8 spindle is absolutely critical in my experience, especially at very light throttles where you might be using a close threshold for things like idle position mapping. Any play at this point results in poor manners at very light throttles even on the lucas setup.
This is not a good area to be trying to take short cuts, and as such I still maintain a good used original Tpot is the best way to go and will always be the way I go until I can't find any more to use.. if you do want to go the colvern route though then the ACT kit is very well made, and not expensive when you consider what's involved to do it yourself to a similarly high standard.
For what it's worth I wouldn't go hand-filing a converter, I'd go for something made to a good standard if that is the route you're choosing.
However ..
The original Tpot is a spring-return item and as such is very good at always tracking the spindle position crucially at the point of changing direction (ie foot on throttle, then off throttle, at light throttles).
The colvern is not a spring return Tpot and as such the fit of the D shaft into the pot, and more importantly the blade into the end of the RV8 spindle is absolutely critical in my experience, especially at very light throttles where you might be using a close threshold for things like idle position mapping. Any play at this point results in poor manners at very light throttles even on the lucas setup.
This is not a good area to be trying to take short cuts, and as such I still maintain a good used original Tpot is the best way to go and will always be the way I go until I can't find any more to use.. if you do want to go the colvern route though then the ACT kit is very well made, and not expensive when you consider what's involved to do it yourself to a similarly high standard.
Thanks, makes sense.
A friend is suffering Lucas TPS issues so we're exploring options together, personally as my original seems to be working acceptably perhaps I'm better leaving my Lucas TPS alone then
As I said I've no issue with people making a quid and I get the tooling up and machining costs, I guess its up to each individual if they think that little converter block & bearing is worth £130.00 to them?
The spring return point is a good one as I can see how see how this ensures good contact with the D shaft, but I'd been interested in a range of experiences and feedback on this one.
Has anyone else fitted a Colvern TPS?
I've also read some reports that the original Lucas item is the carbon track type while the Colvern is hall type, so the suggestion is it gives better resolution, I'm interested if this is indeed the case and if it offers any worthwhile benefits in real world operation
Given the TPS on my Canems system is just there for a some idle valve and transient enrichment authority I'm not overly convinced the TPS signal needs better resolution than I'm seeing from my Lucas one anyway... but I'm happy to be corrected on this point.
Thanks all, Dave.
A friend is suffering Lucas TPS issues so we're exploring options together, personally as my original seems to be working acceptably perhaps I'm better leaving my Lucas TPS alone then
As I said I've no issue with people making a quid and I get the tooling up and machining costs, I guess its up to each individual if they think that little converter block & bearing is worth £130.00 to them?
The spring return point is a good one as I can see how see how this ensures good contact with the D shaft, but I'd been interested in a range of experiences and feedback on this one.
Has anyone else fitted a Colvern TPS?
I've also read some reports that the original Lucas item is the carbon track type while the Colvern is hall type, so the suggestion is it gives better resolution, I'm interested if this is indeed the case and if it offers any worthwhile benefits in real world operation
Given the TPS on my Canems system is just there for a some idle valve and transient enrichment authority I'm not overly convinced the TPS signal needs better resolution than I'm seeing from my Lucas one anyway... but I'm happy to be corrected on this point.
Thanks all, Dave.
Am I right in thinking you can re calibrate the original TPS position using after market Ecu ( not sure about CUX ) so moving it’s starting position along slightly sort of thing.
I was told they wear just at that point off idle so you re configure the signal starting from a higher voltage and avoid the worn part that sends the signal.
Excuse the lack of technical speak.
I might start buying up every second hand TPS
I was told they wear just at that point off idle so you re configure the signal starting from a higher voltage and avoid the worn part that sends the signal.
Excuse the lack of technical speak.
I might start buying up every second hand TPS
I’m going to replace our throttle pot at some point and I will be machining up the required hardware.
I can’t see it being that hard to make an extender whose TPS spigot is a mild interference fit into the Colvern TPS, and fit a return spring to the extender.
I also do not have a problem with businesses making a profit but I do see too much of people “adding value” by marketing parts whose identifying numbers or references are deliberately absent/redacted from websites etc so you cannot make a value judgment on the price they charge. Im a bit cleverer than that and can normally research it and work it out, but it is annoying to see people charging double for a standard part, and relying on the fact that most people don’t know they’re being overcharged...
Still, that isn’t relevant to this adapter, but it is expensive for what it is.
I’ll make my own, I might even use a RVDT. Now they are extremely accurate and have extremely low hysteresis as well as no sliding electrical contacts.
I can’t see it being that hard to make an extender whose TPS spigot is a mild interference fit into the Colvern TPS, and fit a return spring to the extender.
I also do not have a problem with businesses making a profit but I do see too much of people “adding value” by marketing parts whose identifying numbers or references are deliberately absent/redacted from websites etc so you cannot make a value judgment on the price they charge. Im a bit cleverer than that and can normally research it and work it out, but it is annoying to see people charging double for a standard part, and relying on the fact that most people don’t know they’re being overcharged...
Still, that isn’t relevant to this adapter, but it is expensive for what it is.
I’ll make my own, I might even use a RVDT. Now they are extremely accurate and have extremely low hysteresis as well as no sliding electrical contacts.
ChimpOnGas said:
Good post Ed Crouch, to be honest this is something thats an ideal little project for someone with a 3D printer.
The days of paying through nose for this type of thing are over, anyone with a hobby 3D printer and some open source software could make a spacer like this.
I agree anyone with a 3d printer could make a spacer that would fit, but the problem comes with the application. Most materials will not withstand engine bay temperatures and will become unstable or just plain melt. You need some pretty specialist materials to get away from this problem, and typically those cannot be printed with a run of the mill hobby 3d printer because the nozzle temperatures required to melt the filament are higher than they are capable of. There are some materials you can print at home that are border line in terms of ability to withstand engine bay temperatures, but results would be hit and miss.The days of paying through nose for this type of thing are over, anyone with a hobby 3D printer and some open source software could make a spacer like this.
Yeh I don't think SLS machines have come down quite that much in price 
Edit: other thing that occurs to me is the Honeywell RTP range of position sensors. Designed for automotive/industrial environments, and get this, they are true non-contact. The sensor body is positioned close to the magnetic rotor, whose rotary position is detected accurately without any contact between the rotor and the sensor body. They therefore don't wear out.
Edit: other thing that occurs to me is the Honeywell RTP range of position sensors. Designed for automotive/industrial environments, and get this, they are true non-contact. The sensor body is positioned close to the magnetic rotor, whose rotary position is detected accurately without any contact between the rotor and the sensor body. They therefore don't wear out.
Edited by ed_crouch on Wednesday 14th August 14:39
lancelin said:
I have an old TPS. I wonder if it possible to recondition them? Will have a look tonight.
Failure is often due to hardening and subsequent fracturing of the wire insulation which causes localised fracturing of the copper wires. This generally occurs just inside the TPS housing. I have repaired one by cutting back the TPS to expose the soldered track connection. Replace with heat resistant cable and Bob's your uncle
ChimpOnGas said:
The spring return point is a good one as I can see how see how this ensures good contact with the D shaft, but I'd been interested in a range of experiences and feedback on this one.
Has anyone else fitted a Colvern TPS?
Dave.Has anyone else fitted a Colvern TPS?
Yes, I’ve fitted a Colvern and Jenvey TP11 to the standard plenum and both worked perfectly with my own spindles that I had machined from an 8mm brass rod. They are a tight fit and worked perfectly without spring loading but the output voltage has to be setup correctly via RoverGauge, where as I assume the ACT ones are quick and easy plug & play.
Let me know if you get a Colvern or Jenvey and I'll post you a spindle free, for the greater good of the Rover V8, and also an alloy end plate for the Jenvey if required, the Colvern should come with its own end plate.
You can see some pictures of my effort here on the dark side.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
ChimpOnGas said:
I've also read some reports that the original Lucas item is the carbon track type while the Colvern is hall type,
The Colvern is not hall effect.You may remember this thread
https://www.pistonheads.com/gassing/topic.asp?h=0&...
where I’m using a true halls effect throttle POT sensor, but previously wasn’t total happy as I had to power it via voltage stabiliser. However, good news I’ve now deleted the voltage stabliser by wiring it direct to the battery via a standard 12v relay, I guess the original TVR +12 volt wiring supply I used was loosing too many volts on route which caused the throttle pot to drop out while cranking.
ChimpOnGas said:
Given the TPS on my Canems system is just there for a some idle valve and transient enrichment authority I'm not overly convinced the TPS signal needs better resolution than I'm seeing from my Lucas one anyway... but I'm happy to be corrected on this point.
The 14CUX is exactly the same, the throttle position is only used to switch between open and closed loop idle control and momentary fuel enrichment/leaning with sudden throttle movement, other than that the throttle position does NOT effect fuelling.RV8 - I'm doing my bit for Global warming
Wow, great work Steve 
We live so close to each other perhaps I could pop over your way and we could discuss this one over a pint, my round in exchange for your excellent spindle and cover plate solution.
I can show you my Canems software and how simple it is to calibrate the TPS with this system.
Actually all I'm doing here is future proofing my currently working TPS, I'm on a mission to replace every engine sensor as my Canems installation came with some dubious quality components like a no name MaP sensor that clearly had poor resolution from new.I replaced it with a Japanese quality NTK MaP sensor that cost me just £28 and the car was transformed, my Lucas TPS was reused in the Canems installation but its 23 years old now and has suffered the harsh and hot environment of my Chimaera engine bay all that time so I'd like to renew it as my ongoing program of preventative maintenance.
In addition to the preventative maintenance point and now I've solved my earth loop and looping priming pulse issue the installers we're unable to correct, I'm also preparing to reinstate the PWM idle valve.
Much like the poor quality MaP sensor the installers gave me a no name and dubious quality platern part idle valve, this dreadful idle valve gave very inconsistent behaviour. It made the engine impossible to map and achieve consistent AFRs which proved super frustrating until I worked out what was happening.... at which point I removed the damn thing and again the car was transformed.
So with my earth loop and looping priming pulse issue issue eliminated I'm about to return to the PWM idle valve setup this time using quality German made item from a respected ISO9001 manufacturer, this will alow me to remove my temporary manual extra air valve which has proven to work brilliantly but is of course not fully automatic in operation.
Here's the valve I'll be fitting...
But to ensure my new PWM idle valve has the very best chance of working perfectly I need a quality high resolution throttle position signal to the ECU, hence my further interest in replacing my old Lucas TPS.
However, a good mate of mine (also with a Canems system) is in more urgent need of help than me as he is definitely suffering a partial TPS failure that manifests itself as the engine bay gets hot.
PM me so we can make arrangements to meet up
Many thanks, Dave.
We live so close to each other perhaps I could pop over your way and we could discuss this one over a pint, my round in exchange for your excellent spindle and cover plate solution.
I can show you my Canems software and how simple it is to calibrate the TPS with this system.
Actually all I'm doing here is future proofing my currently working TPS, I'm on a mission to replace every engine sensor as my Canems installation came with some dubious quality components like a no name MaP sensor that clearly had poor resolution from new.I replaced it with a Japanese quality NTK MaP sensor that cost me just £28 and the car was transformed, my Lucas TPS was reused in the Canems installation but its 23 years old now and has suffered the harsh and hot environment of my Chimaera engine bay all that time so I'd like to renew it as my ongoing program of preventative maintenance.
In addition to the preventative maintenance point and now I've solved my earth loop and looping priming pulse issue the installers we're unable to correct, I'm also preparing to reinstate the PWM idle valve.
Much like the poor quality MaP sensor the installers gave me a no name and dubious quality platern part idle valve, this dreadful idle valve gave very inconsistent behaviour. It made the engine impossible to map and achieve consistent AFRs which proved super frustrating until I worked out what was happening.... at which point I removed the damn thing and again the car was transformed.
So with my earth loop and looping priming pulse issue issue eliminated I'm about to return to the PWM idle valve setup this time using quality German made item from a respected ISO9001 manufacturer, this will alow me to remove my temporary manual extra air valve which has proven to work brilliantly but is of course not fully automatic in operation.
Here's the valve I'll be fitting...
But to ensure my new PWM idle valve has the very best chance of working perfectly I need a quality high resolution throttle position signal to the ECU, hence my further interest in replacing my old Lucas TPS.
However, a good mate of mine (also with a Canems system) is in more urgent need of help than me as he is definitely suffering a partial TPS failure that manifests itself as the engine bay gets hot.
PM me so we can make arrangements to meet up
Many thanks, Dave.
Dave,
I’m pleased you've sorted your earth looping issues.
You’re always vey welcome to pop over for a beer or coffee and biscuits as you’ll be driving and you’re very welcome to have the spindles and back plate free to help future proof the Rover V8. I’ve currently lent my ready made up Colvern and Jenvey TP11 to another TVR enthusiast for comparison so I currently can’t give you a working demo but nevertheless you're welcome to come over, I’ve got your mobile number so I’ll give you a call or you can call me if you have my number.
I must point out to everyone the Colvern adjustment travel is severely limited once fitted due to the adjustment slots being below the centre line of the spindle which you can see in COG's Colvern picture and therefore requires a little persuasion with a hand file to get the correct closed throttle voltage, this explains why ACT mount the Colvern on an adapter plate with offset screw.
I recommend the Jevney as its much better quality and has a slightly higher output voltage at WOT which is better for the 14CUX in LRs plus the adjustment slots are not restricted once fitted, but the Jenveys are more expensive.
I forgot to mention in my previous post the throttle pot is also used to trigger the 14CUX's full throttle enrichment which occurs at 80% for TVR tunes or 91% for Land Rover tunes.
I’m pleased you've sorted your earth looping issues.
You’re always vey welcome to pop over for a beer or coffee and biscuits as you’ll be driving and you’re very welcome to have the spindles and back plate free to help future proof the Rover V8. I’ve currently lent my ready made up Colvern and Jenvey TP11 to another TVR enthusiast for comparison so I currently can’t give you a working demo but nevertheless you're welcome to come over, I’ve got your mobile number so I’ll give you a call or you can call me if you have my number.
I must point out to everyone the Colvern adjustment travel is severely limited once fitted due to the adjustment slots being below the centre line of the spindle which you can see in COG's Colvern picture and therefore requires a little persuasion with a hand file to get the correct closed throttle voltage, this explains why ACT mount the Colvern on an adapter plate with offset screw.
I recommend the Jevney as its much better quality and has a slightly higher output voltage at WOT which is better for the 14CUX in LRs plus the adjustment slots are not restricted once fitted, but the Jenveys are more expensive.
I forgot to mention in my previous post the throttle pot is also used to trigger the 14CUX's full throttle enrichment which occurs at 80% for TVR tunes or 91% for Land Rover tunes.
Well, for one-off parts it is indeed a ballache and certainly no quicker than turning handles, especially if you are writing the G code manually. Most CNC shops will have delCAM or the like which makes the process hugely quicker, for a cost.
It is a mistake to think that these parts are machined up as one-offs though. Most likely a large billet of aluminium is clamped to the mill table, and an array of these parts is produced from one op, either fully automatically or with an X/Y offset punched in between each part.
You're right, but no-one worth their salt would produce them as one-offs.
Edit: In fact, having looked at it again, the part is largely just a profile so could be very easily and cheaply lasered out. That sorta thickness would need a 2-3kW flatbed laser. then CSKs and counterbore for the bearing, threading and tumble finishing. Easy in any kind of volume.
The downside is of course that if you're going to commission a production run, you have to be confident you'll sell them all and until you hit your break even sales figure, it has cost you. That bit there can drive the price up because you'd want to amortise the production/design costs ASAP.
It is a mistake to think that these parts are machined up as one-offs though. Most likely a large billet of aluminium is clamped to the mill table, and an array of these parts is produced from one op, either fully automatically or with an X/Y offset punched in between each part.
You're right, but no-one worth their salt would produce them as one-offs.
Edit: In fact, having looked at it again, the part is largely just a profile so could be very easily and cheaply lasered out. That sorta thickness would need a 2-3kW flatbed laser. then CSKs and counterbore for the bearing, threading and tumble finishing. Easy in any kind of volume.
The downside is of course that if you're going to commission a production run, you have to be confident you'll sell them all and until you hit your break even sales figure, it has cost you. That bit there can drive the price up because you'd want to amortise the production/design costs ASAP.
Edited by ed_crouch on Friday 16th August 08:41
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