MattB Posted June 7, 2022 Share Posted June 7, 2022 My 420 idles at around 1050rpm when warm. The Duratec in my 200hp MX-5 idled very happily at 800rpm.How do I adjust the idle speed on the 420?MattB Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 7, 2022 Share Posted June 7, 2022 You need to have the ECU remapped, either with a new unlocked ECU, or one of the tuners who can flash a locked Caterham ECU.1000RPM or so also gives a better idle on the 420R than earlier R400s that used 850RPM, in general due to the cam profile that Caterham uses. I'm assuming they increased the idle speed to overcome the idle and stalling issues when cold, I had to do this on my 2012 R400D and settled on 1000RPM idle with an unlocked ECU that I tuned myself. Link to comment Share on other sites More sharing options...
ChrisC Posted June 7, 2022 Share Posted June 7, 2022 Idle speed is controlled by the ECU, but if the throttle stop is open too far you can get hunting at idle as the ECU struggles to maintain the idle. The strange thing is the idle speed is normally set to 950rpm. Are you sure the idle is 1050, only reason I say that is I am not sure how accurate the tacho is around idle. EasyMap (or the good work this community has done decoding the can signal) is the only true source of information. Link to comment Share on other sites More sharing options...
GulfSeven Posted June 8, 2022 Share Posted June 8, 2022 Are you sure the idle is 1050, only reason I say that is I am not sure how accurate the tacho is around idle.If it's anything like my 310R, not accurate at all. You need to plug EasyMap in to see what it is. EasyMap shows my idle to be 800 rpm (which is the factory setting), but the rev counter shows 1,200 rpm! Link to comment Share on other sites More sharing options...
MattB Posted June 8, 2022 Author Share Posted June 8, 2022 I can only go by what the rev counter says as I have nothing else to measure engine speed with.Something else to sort at the first service ...MattB Link to comment Share on other sites More sharing options...
David_Long Posted June 8, 2022 Share Posted June 8, 2022 IIRC the minimum MBE ECU tacho pulse generated is 1200 rpm (1250 rpm?), so it is not possible to see RPM below that unless you use an external tachometer on the pulley, or use Easimap. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 8, 2022 Share Posted June 8, 2022 Although it may vary with different ECUs David, my MBE 9A4 ECU provides tacho pulses below 1,000RPM that exactly match the Easimap RPM values. The tacho needle also moves when the engine is cranking, so It seems like it is providing pulses at cranking speed, too. Link to comment Share on other sites More sharing options...
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