Dicky Posted November 18, 2016 Share Posted November 18, 2016 Had intermittent operation problem caused by incorrectly positioned brake pedal switch. When testing its operation I set it to 30mph on a flat road and it ran no problem......BUT....when I came to a down hill stretch followed immediately by a uphill stretch I noticed the car maintained 30 mph down the hill but when it started to climb up the hill the speed dropped off to about 25 mph before the car realised and started to increase the speed again to 30. Is this normal operation on the 370 or should it be a bit faster to increase the speed? Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted November 18, 2016 Share Posted November 18, 2016 I do not know about a 370, however when CC is applied on other cars, then a constant speed will be maintained. 1 Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 18, 2016 Share Posted November 18, 2016 Sounds normal to me. Auto might be a bit quicker to react as it can change gear, but a manual can't. Every car with CC I've ever driven will drop a fraction on the uphill and rise a bit on the downhill, as it has no idea how steep the hill is and can only compensate retrospectively. What gear were you in? 1 Quote Link to comment Share on other sites More sharing options...
brillomaster Posted November 18, 2016 Share Posted November 18, 2016 yeah id agree with dan... the car can only react, it has no idea a hill is coming. and especially coming from applying zero throttle going downhill to applying lots of throttle to go up the other side. but sure when it is used on a faster cruise with gentler gradient changes it'll be absolutely fine. 1 Quote Link to comment Share on other sites More sharing options...
Dicky Posted November 18, 2016 Author Share Posted November 18, 2016 I've looked into how CC works. The system inputs are a switch on the brake and clutch pedals, the controls on the steering wheel, a speed sensor ( on the gearbox I believe) the accelerator potentiometer, and a feedback sensor on the throttle valve control feeding back position. The only control output as far as I can tell is the throttle valve drive motor to position the throttle disc to regulate air intake. As I say the speed when climbing the hill drops off slowly down to around 25 mph when the control system seems to wake up and starts to apply more power. The only things I can think would cause this sluggishness are a dodgy speed input signal (but the speedo would probably show signs) a slow processor in the ECU (which I doubt) and the throttle valve drive motor. Has anyone come across problems IE stiffness, dirt ingress etc that could slow this arrangement down.? If it's a common problem then maybe it is just the ECU with a slow processor or something. I'd like to tine it up if poss because my 350z doesn't do this. Any further feedback welcome. Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 18, 2016 Share Posted November 18, 2016 Auto or manual? Quote Link to comment Share on other sites More sharing options...
Dicky Posted November 18, 2016 Author Share Posted November 18, 2016 Auto or manual? Manual Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 18, 2016 Share Posted November 18, 2016 What gear were you in? Or have you tried it in multiple gears? Quote Link to comment Share on other sites More sharing options...
Dicky Posted November 18, 2016 Author Share Posted November 18, 2016 What gear were you in? Or have you tried it in multiple gears? Good question! If I'm not mistaken it was 3rd possibly 4th but think 3rd Quote Link to comment Share on other sites More sharing options...
Wayne370Z Posted November 19, 2016 Share Posted November 19, 2016 I don`t recall ever seeing so much of a drop when cruise is on. Seems to keep pretty steady at the speed set to within a couple of mph above or below. 1 Quote Link to comment Share on other sites More sharing options...
Richf Posted November 19, 2016 Share Posted November 19, 2016 I've looked into how CC works. The system inputs are a switch on the brake and clutch pedals, the controls on the steering wheel, a speed sensor ( on the gearbox I believe) the accelerator potentiometer, and a feedback sensor on the throttle valve control feeding back position. The only control output as far as I can tell is the throttle valve drive motor to position the throttle disc to regulate air intake. As I say the speed when climbing the hill drops off slowly down to around 25 mph when the control system seems to wake up and starts to apply more power. The only things I can think would cause this sluggishness are a dodgy speed input signal (but the speedo would probably show signs) a slow processor in the ECU (which I doubt) and the throttle valve drive motor. Has anyone come across problems IE stiffness, dirt ingress etc that could slow this arrangement down.? If it's a common problem then maybe it is just the ECU with a slow processor or something. I'd like to tine it up if poss because my 350z doesn't do this. Any further feedback welcome. Throttle discs dont control airflow on the 370z thats not how the VVEL works 1 Quote Link to comment Share on other sites More sharing options...
Dicky Posted November 19, 2016 Author Share Posted November 19, 2016 BUGGAR Rich ! I Just get used to how one engine works and then they go and change it ! I'm sure this is a Jap conspiracy against us Geordies, me in particular! I'm now going to have to watch this lots of times to get my head around it. Wish I'd been born clever instead of just good looking. As it happens i stumbled across this vid clip last night and could'nt get my head around it at all. So what do the two throttle valves do these days. Have the Japs just left them in just to confuse me even further.?? Quote Link to comment Share on other sites More sharing options...
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