moorsd123 Posted June 13 Share Posted June 13 (edited) Trying to get to the bottom of why my R400D has an issue where it seems to idle higher when it gets hot? This only seems to happen when the engine is really hot like sitting in traffic for a while etc, before this occurs, it idles at around 1000rpm nicely but seems to creep up to more like 1500+rpm when really hot? I've replaced the TPS sensor and looked on Easimap, which shows that when idling from cold and when warm, the Throttle Site is showing as 1.0 (Throttle Angle increasing is 1.20), however as the engine gets really hot the Throttle Site showns as 1.2 - 1.4 at idle (Throttle Angle increasing still shows 1.20) and the idle rpm increases? Should this happen and if not, any ideas on possible culprits? Edited June 13 by moorsd123 Added more detail Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 13 Share Posted June 13 Is your throttle cable too tight? Needs a bit of slack when the engine is hot. It will tighten up slightly as the engine warms up, but may already be too tight on a cold engine, as it should be at between throttle site 0.0 and 0.4 when at idle. Link to comment Share on other sites More sharing options...
moorsd123 Posted June 13 Author Share Posted June 13 No the Throttle cable has plenty of slack to be honest and rests on the stop when cold and hot. I've tried adjusting the idle screw and the Throttle Site doesn't seem to go down to 0.0 and just stays at 1.0?...unless I'm not doing it right? Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 13 Share Posted June 13 1 hour ago, moorsd123 said: No the Throttle cable has plenty of slack to be honest and rests on the stop when cold and hot. I've tried adjusting the idle screw and the Throttle Site doesn't seem to go down to 0.0 and just stays at 1.0?...unless I'm not doing it right? Did you try moving the TPS within the holes? There is only a fraction of a mm movement between 0.0 and 1.0 sites. If the TPS is not below 1.0 at idle, it probably won’t do any idle control through ignition advance, so you won’t get an accurate idle speed. If the idle was correct before TPS replacement, I would try to return the stop to its position from then and move the TPS around slightly within the constraint of the holes. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted June 13 Share Posted June 13 Possible slight air leak on the manifold flange due thermal distortion. I wonder if the idle conditions on the map are correct, in order to correctly adjust the idle speed in relation to temperature Link to comment Share on other sites More sharing options...
moorsd123 Posted June 16 Author Share Posted June 16 (edited) OK, played about with the TPS position (slotted the holes slightly) and experiencing something unexpected... I can get the "Throttle Site" to show 0.0 - 0.8, however this seems to always reset itself back to 1.0 once I've isolated the battery etc. To test this I tried altering the tps position and held it in place at at below 1.0 and it still crept back up to 1.0 on it's own in real time without any other movement or adjustment?? Also noticing that when started from cold and warmed up it idles OK but when you blip the throttle it starts to fluctuate between 1.0 and 1.2 throttle site and the revs then creep up? However when the fan kicks in it sits nicely at 1.0 rather than fluctuating between 1.0 and 1.2? Any ideas as this is slowly driving me mad!! Edited June 16 by moorsd123 Link to comment Share on other sites More sharing options...
StevehS3 Posted June 16 Share Posted June 16 The Sigma TPS on my car is different to yours but that must not be over tightened. In fact it needs just enough tightening to hold it in place and no more. I presume the TPS voltage is varying too? Link to comment Share on other sites More sharing options...
moorsd123 Posted June 16 Author Share Posted June 16 (edited) The TPS voltage stays the same even when the Throttle Site slips back to 1.0?..but the voltage does change when making adjustments to the idle screw. The throttle site and tps voltage go up as the throttle is opens as it should do. I've tried varying how tight the TPS screws are from tight to loose ansld doesn't seem to make much difference? 🤷🏻♂️ Edited June 16 by moorsd123 Link to comment Share on other sites More sharing options...
StevehS3 Posted June 16 Share Posted June 16 (edited) That is strange. I don’t know why the throttle site should change when the voltage doesn’t. Also, I would have the Target Idle Speed (what it is aiming for), Idle Speed Error Term (the difference between target and actual) and Idle Ignition Term Prop Degrees (the amount of ignition advance/retard to achieve the idle RPM). This is my screen setup with the info I use highlighted. When hot it achieves the target RPM with little fluctuation and needs almost zero ignition advance to achieve it. NOTE THIS IS FOR A SIGMA, I don’t know much about Duratec so please keep that in mind. Edited June 16 by StevehS3 Link to comment Share on other sites More sharing options...
moorsd123 Posted June 16 Author Share Posted June 16 Thanks Steve, I'll see if I can add those to the screen on Easimap. It is strange to be fair, it's like the car wants to default to throttle site 1.0 all the time. Like I say I moved the tps to get below 1.0 (lowest I could get with the available adjustment was 0.5 - 0.8) and the throttle site resets to 1.0 with the TPS voltage remaining the same both when battery is isolated, but also in "real time" after blipping the throttle?? Link to comment Share on other sites More sharing options...
StevehS3 Posted June 16 Share Posted June 16 It is almost as if the ECU is recalibrating! I would add Idle Speed Status (you can see it on my screen towards the bottom left in Green.) When Active the ECU engages Idle control. It needs to be Active at idle to control the idle using ignition advance. I am not sure it would be active at throttle site 1.0. Link to comment Share on other sites More sharing options...
moorsd123 Posted June 16 Author Share Posted June 16 Yeah totally, that's a good way of describing it...like it's recalibrating each time! I'll add the dials to Easimap and report back bit probably won't be until next weekend now 🙄 Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 16 Share Posted June 16 Looking back through old ECU configs (haven’t got an unlocked one for the 992, though), I can’t see any function for dynamic TPS site mapping. The voltage should always map to an exact TPS site. Have you tried completely removing and restoring power to the ECU to see if the TPS site going to 1.0 no matter what the TPS voltage at idle still happens? Also, does the TPS site transition consistently with the TPS voltage all the way up to full throttle? To me it seems more like a software corruption issue, as opposed to a calibration function. Link to comment Share on other sites More sharing options...
moorsd123 Posted June 16 Author Share Posted June 16 I'll double check when I next get chance, but I think the transition of throttle site and TPS voltage is consistent all the way to full throttle...it's just this weird resetting to 1.0? Haven't tried fully unplugging the ECU, just using the battery isolator, so will try unplugging it, but not that confident it will make a difference. Hoping it's not a corrupt ECU, as that'll mean £££ and other than a new ECU with custom map, not sure how it could be fixed?? Link to comment Share on other sites More sharing options...
StevehS3 Posted June 16 Share Posted June 16 4 hours ago, aerobod - near CYYC said: Have you tried completely removing and restoring power to the ECU to see if the TPS site going to 1.0 no matter what the TPS voltage at idle still happens? James (sorry) 😀 1 1 Link to comment Share on other sites More sharing options...
moorsd123 Posted June 18 Author Share Posted June 18 (edited) Had another look tonight and I'm still none the wiser? Steve - I can't see those additional tiles in Easimap? I've searched for Target Idle and "idle" and none of the tiles you have highlighted are listed? Also looked in the menu but can't see anything listed (or anything that sounds similar?). Tried unplugging the ECU and cleaned the contacts and earth straps etc just in case....still have the same issue! I've attached a picture of my ECU in case this means anything to anyone...assume it's standard Caterham? Edited June 18 by moorsd123 Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 18 Share Posted June 18 It looks as though the firmware version 992ab94p that you are using is quite limited in idle control. It dates back to either late 2006 or early 2007, going by the notes in the file properties. The only idle control is based on the fuel at the idle throttle site, it is then only modified by ignition advance changes made relative to coolant temperature when the throttle is at the idle site. It is not possible to see what the idle throttle site is configured to or the ignition advance vs coolant temp map at idle with the locked 992 ECU. The only idle related panel you can add is "Idle and Start Temp Site", search in the real-time channel panel selection tree for "idle" and it will appear as a selection. Link to comment Share on other sites More sharing options...
moorsd123 Posted June 18 Author Share Posted June 18 Thanks James, appreciate you looking. Bit of a dead end with this one then? I emailed Northampton motorsport about the cost of a new ECU and custom map...and the the "all out" option of Jenvey's and carbon airbox while they're at it! 😁. Very tempted, but not sure I can stomach the nearly £5k cost right now. However it might be a favourable option over just a new ECU with custom map at £1.2k? Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 18 Share Posted June 18 Just now, moorsd123 said: Thanks James, appreciate you looking. Bit of a dead end with this one then? I emailed Northampton motorsport about the cost of a new ECU and custom map...and the the "all out" option of Jenvey's and carbon airbox while they're at it! 😁. Very tempted, but not sure I can stomach the nearly £5k cost right now. However it might be a favourable option over just a new ECU with custom map at £1.2k? I would still check a few things, as Neil mentioned, check for air leaks around the intake system and any attached hoses. I would also confirm that the TPS voltage doesn't always correlate to the same TPS site (it certainly always corellates in the current 9A4 ECU implementation on a Duratec). You could log the TPS voltage and site when driving the car, then output the values to a spreadsheet or look at them on the graph. If the values don't always map 1-to-1, then there is some inaccessible modifier in the ECU that is changing them. If the values do always map 1-to-1, then either TPS site 1.0 has been used as the base idle site in the ECU config, or there is still a mechanical adjustment to be made to get it to site 0.0 (or at least below 0.5). If the TPS site stays at 1.0 as the TPS is adjusted such that the voltage drops but the site doesn't, it may just have reached a "floor" value, which can be set in the TPS config that you can't see due to the locked ECU. If everywhere else the same TPS site maps to the same voltage (from the logged info), then TPS input to the ECU is as-expected. Link to comment Share on other sites More sharing options...
StevehS3 Posted June 18 Share Posted June 18 After the checks above I would email Caterham and ask for instructions on how to setup the TPS and idle for your car. You shouldn’t really need to buy a new ECU and rolling road session although I appreciate that might be a last resort. They should have a set of instructions as they will have set it up in the first place. Link to comment Share on other sites More sharing options...
Rich Goddard Posted June 19 Share Posted June 19 (edited) If you do choose to contact CC (and get a reply) I’d be very interested. I have the same TPS issue (unable to get it to permanently achieve < Site 1.0). I can’t vouch for the accuracy of this (think I tried a year or so ago but it didn’t work) but seems there’s a school of thought the ECU can be reset/rebooted: https://home.purplemeanie.co.uk/index.php/2019/07/30/millwood-flat-floor-stalling-ecu-reset/ (SuperSport R with 210bhp upgrade, standard plastic plenum, MBE 992 ECU with map loaded by Williams) Edited June 19 by Rich Goddard Link to comment Share on other sites More sharing options...
John Vine Posted June 19 Share Posted June 19 17 hours ago, moorsd123 said: I've attached a picture of my ECU in case this means anything to anyone...assume it's standard Caterham? Yes, that's the MBE 992 as supplied by CC, and the same as on my 2008 R400D: The 992 is now no longer available, having been superseded some years ago by the 9A4. JV Link to comment Share on other sites More sharing options...
moorsd123 Posted June 22 Author Share Posted June 22 Thanks all. Just tried the turning the ignition key 10 times suggestion and still the same. Although interestingly (but may just be coincidence) the throttle site briefly reduced to 0.8 and then went back to 1.0 the same as when I manually try and do it? I've emailed Caterham asking them for advice and the correct throttle stop adjustment procedure...so let's see of they respond!! 🤞🏻 1 Link to comment Share on other sites More sharing options...
moorsd123 Posted June 23 Author Share Posted June 23 (edited) Going to run a log on Easimap when I get chance, however took the car for a run this weekend and decided to turn the throttle stop screw down a bit regardless...which has actually helped a bit. Although can't turn it down any further as it won't idle from cold any lower. Don't know if this will mean anything to anyone or narrow the cause down, but I've found that when it starts to idle higher than normal, when stopped in traffic, if I lift the clutch when in gear and load the engine so the revs drop, it then settles and idles properly....weird!? Edited June 23 by moorsd123 Link to comment Share on other sites More sharing options...
Eriedor Posted June 27 Share Posted June 27 I had a very similar issue to this, especially your last part about being able to "pull the idle down with the clutch". The cause for me was my inlet manifold gasket was gone so it was letting in extra air 1 Link to comment Share on other sites More sharing options...
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