ashyers Posted March 7, 2022 Share Posted March 7, 2022 I'm with Croc on this, don't mess with the mapping. I think your TPS is toast. Here's what I'd do: * Record the voltage value of the current TPS at closed throttle with the engine off so you can reset it's position w/o messing up the mapping, or install a new one in the correct position once you've determined if it's dead. * Pull the TPS and run it through it's paces on a bench with the DVOM to ensure it's the issue. * If it proves to be toast figure out what obscure vehicle Caterham chose to pull the TPS from and pick one up, hopefully at your local parts store. * Install the new TPS and reset the voltage at closed throttle to match the old TPS. Hopefully it's not the harness!!!! Link to comment Share on other sites More sharing options...
JohnCh Posted March 7, 2022 Share Posted March 7, 2022 I believe that TPS is from Ford Duratec installations from the early 2000's. If that's the case, it should be easy to source in the US based on the part number. I don't have any experience with that specific TPS, but the Colvern units frequently used on Jenvey's do fail and exhibit similar, random behavior when that occurs. Rule out the easy fixes first. -John Link to comment Share on other sites More sharing options...
sltous Posted March 7, 2022 Author Share Posted March 7, 2022 5 hours ago, Croc said: Interesting plots. Just to clarify - this happens when engine properly warmed up? Does it happen cold? Does it happen with ignition on but not engine on? I would not play with Easimap settings yet as (assuming I understand the history here) it worked fine on those settings up to a point in time then you experienced the issue - do I have that correct? If so then changing Easimap would just mask the underlying source issue? Hi Croc, I have only collected a few data sets so far and can only confidently identify the problem with the engine running fully hot. However if ashyers' thought about the TPS wrapping around is correct this might be a problem all the time masked by consequence of not using much throttle during engine warmup. I think the problem is new but there has been enough fettling of small issues over the last year I cannot be sure it is a new problem. My thoughts on changing Easimap were to widen the range of the TPS (assuming this is an option) such that 0% throttle is at perhaps 5.0v or 5.05v rather than 4.95v. Again I have not opened this portion of Easimap so I don't know for sure if that's an option. 1 hour ago, ashyers said: I'm with Croc on this, don't mess with the mapping. I think your TPS is toast. Here's what I'd do: * Record the voltage value of the current TPS at closed throttle with the engine off so you can reset it's position w/o messing up the mapping, or install a new one in the correct position once you've determined if it's dead. * Pull the TPS and run it through it's paces on a bench with the DVOM to ensure it's the issue. * If it proves to be toast figure out what obscure vehicle Caterham chose to pull the TPS from and pick one up, hopefully at your local parts store. * Install the new TPS and reset the voltage at closed throttle to match the old TPS. Hopefully it's not the harness!!!! I think I'm leaning to replacing the TPS as a relatively cheap fix that may not necessarily fix the problem but will probably make diagnosis easier. My harness is a bit of a mis-mash as a prior owner did a Zetec -> Duratec swap so I'm hoping that's not the issue but if it is I'll just dive in further. 1 Link to comment Share on other sites More sharing options...
Croc Posted March 7, 2022 Share Posted March 7, 2022 1 hour ago, sltous said: I think I'm leaning to replacing the TPS as a relatively cheap fix that may not necessarily fix the problem but will probably make diagnosis easier. I think this makes a lot of sense. Fairly quick to swap and you gain a lot of progress at the same time to continue the trouble shooting. Link to comment Share on other sites More sharing options...
sltous Posted March 10, 2022 Author Share Posted March 10, 2022 (edited) An update while waiting for parts: I connected my laptop to the ECU via Easimap and my TPS was at 0.32-0.33v at rest. However occasionally while poking at the system the TPS would jump from 0.33V -> 5V as if (like ashyers thought) it was wrapping around or as if there was an internal short. This makes me feel very hopeful that the new TPS will reduce at least one of my issues. I have seen references to the TPS being at closer to 0.42v at rest, should I adjust my resting TPS position from 0.32V->0.42V to have a little more headroom, or is that likely to confuse my ECU maps? Edited March 10, 2022 by sltous Link to comment Share on other sites More sharing options...
Croc Posted March 10, 2022 Share Posted March 10, 2022 I'd suggest leaving the ECU as is until you have tried the new TPS. One change at a time makes it easier for diagnosis. Its slower I know but easier to isolate the problem. Is your MBE ECU unlocked? Or did someone give you the password? Link to comment Share on other sites More sharing options...
sltous Posted March 10, 2022 Author Share Posted March 10, 2022 5 hours ago, Croc said: I'd suggest leaving the ECU as is until you have tried the new TPS. One change at a time makes it easier for diagnosis. Its slower I know but easier to isolate the problem. Is your MBE ECU unlocked? Or did someone give you the password? Unlocked MBE. I am thinking of slightly changing the starting rotational position of the TPS, not any changes to the ECU. As it it, the rotational position is very close to fully closed at 0.33v (perhaps 0-5 degrees), I would be changing it to perhaps 5-10 degrees such that V_initial is 0.43v rather than 0.33v. Per Link to comment Share on other sites More sharing options...
fastg Posted March 10, 2022 Share Posted March 10, 2022 Most programmable ECU's have a TPS reset process. You initiate the process it asks you to close the throttle and press YES, then full throttle and press YES, so it know the operating range, or something like that. Electronic throttles can work it out themselves. Graham Link to comment Share on other sites More sharing options...
ashyers Posted March 10, 2022 Share Posted March 10, 2022 (edited) Be careful changing the TPS position w/o looking at the map. You could end up in a new column for fueling and ignition and give yourself some unintended headaches. Since you can view the fuel/ign maps, see where the breakpoint is for idle and note it before you mess with the TPS. That way you can see what you can get away with in rotating the TPS and can reset if necessary. Remember the TPS baseline is a reference point for the mapping. Were you able to find the P/N for the current TPS and order one? (Edit: Looks like you did, please list the P/N for future reference ) Edited March 10, 2022 by ashyers Link to comment Share on other sites More sharing options...
sltous Posted March 10, 2022 Author Share Posted March 10, 2022 4 hours ago, ashyers said: Be careful changing the TPS position w/o looking at the map. You could end up in a new column for fueling and ignition and give yourself some unintended headaches. Since you can view the fuel/ign maps, see where the breakpoint is for idle and note it before you mess with the TPS. That way you can see what you can get away with in rotating the TPS and can reset if necessary. Remember the TPS baseline is a reference point for the mapping. Were you able to find the P/N for the current TPS and order one? (Edit: Looks like you did, please list the P/N for future reference ) The TPS I have removed has part number PBT(GF20+GB20) molded in which Josh at Rocky Mountain Caterham identified as being the same as Ford part number 988F-9B989-BB which is apparently the same as the current 420 Duratec part Link to comment Share on other sites More sharing options...
ashyers Posted March 10, 2022 Share Posted March 10, 2022 👍 Link to comment Share on other sites More sharing options...
sltous Posted March 11, 2022 Author Share Posted March 11, 2022 Update after the mail arrived: The OLD TPS has No return spring resting voltage V_Initial_Old = 0.32-0.33v resting throttle site Throttle_Site_Initial_Old = 0.0 peak voltage V_Final_Old = 3.8v peak throttle site Throttle_Site_Final_Old = 14.6 The NEW TPS has Return spring requiring ~90 degrees of preload resting voltage V_Initial_New = 0.36v resting throttle site Throttle_Site_Initial_New = 0.0 peak voltage V_Final_New = 3.5v peak throttle site Throttle_Site_Final_New = 14.2 Thoughts? Safe to use the new TPS as is or do I need to make any changes? Link to comment Share on other sites More sharing options...
ashyers Posted March 11, 2022 Share Posted March 11, 2022 Looks like you're still starting at the same throttle site, so you should be OK to test things out. Does your map have throttle sites 0-15? Link to comment Share on other sites More sharing options...
sltous Posted March 11, 2022 Author Share Posted March 11, 2022 3 hours ago, ashyers said: Looks like you're still starting at the same throttle site, so you should be OK to test things out. Does your map have throttle sites 0-15? Yes, 0-15 throttle sites Josh asked me to measure the raw TPS voltages so I de-pinned the connector again and took some quick additional measurements. Old TPS has V_Initial_Raw_Old = 4.72v New TPS has V_Initial_Raw_New = 4.66v Link to comment Share on other sites More sharing options...
ashyers Posted March 11, 2022 Share Posted March 11, 2022 If you use Easimap you can check to verify you're covering throttle sites 0-15. If the orig. tune set the idle at site 0 then you just need to make sure you're getting to site 15 at WOT. Link to comment Share on other sites More sharing options...
sltous Posted March 12, 2022 Author Share Posted March 12, 2022 First 30 minutes on the new TPS are in and the data looks really clean, I tried to drive on similar roads to the ones I was having difficulties on previously and there is clearly no TPS percentage bouncing going on. More/longer data collection to come to see if this has actually solved my TPS problem and more/longer data collection to come to see if my TPS problem was also my kangarooing problem. Better take another drive! 2 Link to comment Share on other sites More sharing options...
sltous Posted March 13, 2022 Author Share Posted March 13, 2022 Another hour of driving data collected, still no evidence of TPS bouncing! Wet greasy roads out today so I wasn't able to push especially hard but I think I'm increasingly confident that the TPS data bouncing problem was a problem with the TPS and not with wiring. I didn't notice any kangarooing but I was a bit more focused on keeping the rubber on the road: water on the road, temp is somewhere in the 40s, and I did see a car flipped on its side. Link to comment Share on other sites More sharing options...
ashyers Posted March 13, 2022 Share Posted March 13, 2022 Glad to hear you have it fixed . Link to comment Share on other sites More sharing options...
sltous Posted April 24, 2022 Author Share Posted April 24, 2022 Fun plug identification game I have this plug in my car directly in front of the driver's footwell. It has 4 pins, two male and two female. The plug has a 12v, a 5v, a ground, and what appears to be the oil pressure output. Any ideas (a) what kind of plug this is (b) if I need to keep it (c) if there is a sensible way to purchase a mating plug What I am really looking for is a sensible place to tap into 5v in order to add a button to flag weird events to my ECU to my AIM Solo DL and I was hoping to use of the 5v reference feeds from the ECU at pins 4 and 22 on my MBE 9a4 so alternatives are accepted with gratitude Link to comment Share on other sites More sharing options...
sltous Posted April 24, 2022 Author Share Posted April 24, 2022 My current working theory is that this is a mini sureseal connector. It looks like Stack supplies sureseal connectors with their sensors so I am assuming that at some point this car had a Stack oil pressure gauge or sender or another sensor piggybacking on this portion of the wiring loom and this is a vestigial connector that it is safe to remove. Does this seem correct? Link to comment Share on other sites More sharing options...
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