X300 TPS Replacement Alternatives
#1
05-06-2021, 03:30 AM
X300 TPS Replacement Alternatives
Hi - new to forum in AUS. I see that there has been some discussion regarding replacement TPS for the X300 4.0l - but has anyone managed to find a decent $ alternative to the JLM12074 which sems to be out of stock in most places and mighty expesnive for what it is. Mine has the usual Ford name stamped on it but no part number. Someone said that a similar unit is the Ford Scorpio 2.9 TPS but I am not sure ? TVR Cerbera has a simlar TPS also but without getting a look at the drive (Blade D or other) its hard to tell. Does anyone know whether all TPS use a 5v base or are some different voltage ? Looking at some of the possible repalcements thay seem to be made by Intermotor (TH417) or Stark Automotive (SKTPS-0380011). Any help appreciated on an alternative. Thanks Matt
The following users liked this post:
jagy4321 (05-06-2021)
#2
05-06-2021, 05:30 AM
Hi Matt,
Welcome to the forum.
If you have a browse around the various threads on the forum, you will quickly see that the TPS is a recurring problem area (in fairness, one of very few) where several forum members (including yours truly) have gone through a similar thought process to you.
The TPS units do wear out, the problem most commonly manifesting itself as a high idle speed. The OEM part does seem outlandishly expensive for something which originated in Ford's parts bin. There has been talk of a Scorpio unit working, although I have yet to see any definitive confirmation that it does. An added wrinkle is presented by the fact that the workshop manual states that there is a need to go through a throttle adaption process to make the TPS function correctly with the ECU. It has become increasingly difficult to find anyone with the equipment to do this, although some experience, including my own, suggests that fitting an OEM replacement can be successful without the adaption being performed.
All of which leaves your basic question still out there and unanswered. It strikes me that the TPS is essentially a rheostat which outputs a range of values which change based on its position. If a known working TPS can have its outputs measured (I think this data is out there already) It would seem that a match could be found, or perhaps achieved by modifying another unit. There are some packaging considerations, especially on the XJR, but where there is a will, there may be a way.
In my own case, the immediate availability of the OEM part proved too tempting, and the cost, although high, was not in the end a deterrent to achieving a "pukka" solution in this mission critical area. I have a feeling however that availability will continue to diminish, and the cost will continue to increase, so the search for the answer to your question is likely to continue.
I am sure others will have thoughts to add, as there is a large body of shared suffering on this topic!
Welcome to the forum.
If you have a browse around the various threads on the forum, you will quickly see that the TPS is a recurring problem area (in fairness, one of very few) where several forum members (including yours truly) have gone through a similar thought process to you.
The TPS units do wear out, the problem most commonly manifesting itself as a high idle speed. The OEM part does seem outlandishly expensive for something which originated in Ford's parts bin. There has been talk of a Scorpio unit working, although I have yet to see any definitive confirmation that it does. An added wrinkle is presented by the fact that the workshop manual states that there is a need to go through a throttle adaption process to make the TPS function correctly with the ECU. It has become increasingly difficult to find anyone with the equipment to do this, although some experience, including my own, suggests that fitting an OEM replacement can be successful without the adaption being performed.
All of which leaves your basic question still out there and unanswered. It strikes me that the TPS is essentially a rheostat which outputs a range of values which change based on its position. If a known working TPS can have its outputs measured (I think this data is out there already) It would seem that a match could be found, or perhaps achieved by modifying another unit. There are some packaging considerations, especially on the XJR, but where there is a will, there may be a way.
In my own case, the immediate availability of the OEM part proved too tempting, and the cost, although high, was not in the end a deterrent to achieving a "pukka" solution in this mission critical area. I have a feeling however that availability will continue to diminish, and the cost will continue to increase, so the search for the answer to your question is likely to continue.
I am sure others will have thoughts to add, as there is a large body of shared suffering on this topic!
The following users liked this post:
Mkii250 (05-06-2021)
#3
05-06-2021, 05:54 AM
Senior Member
That is a Sierra TPS and looks identical to the Jag one. I don't think anyone ever tried it, we've discussed it here a number of times and I will definitely try it myself if noone else will and when the time comes and I'll have to replace my own one.
PS
You should be able to set it up without doing a full TPS adaptation when replacing TPS, just make sure to check before removing it what's the TPS voltage with the throttle closed and make sure to fit the new one in in exactly the same position, showing exactly same TPS voltage with throttle closed. This of course can be checked under OBD live data with key in position 1. Any difference in that base voltage after TPS replacement and you'll have high idle voltage. There is enough slack in the TPS bolts to change that base voltage by 0.1V and anything over 0.02V will cause idle issues.
Last edited by katar83; 05-06-2021 at 05:59 AM.
The following users liked this post:
Mkii250 (05-06-2021)
#4
05-06-2021, 10:25 AM
Trending Topics
Thread
Thread Starter
Forum
Replies
Last Post
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)