14CUX inner workings
Discussion
Anyone know a good place to find out how the 14CUX translates sensor input into injector openings?
I'm trying to diagnose a long term intermittent problem on my car. I know the throttle pot is misreading and remains wrong despite replacing it and then changing it back again. I know it occasionally cuts the fuel and when it does so the throttle pot is reading less than idle on Rover gauge.
Rovergauge is a start but knowing what the 14CUX is doing with these readings would really help as I have a number of niggles that might be all one big problem or might just be completely separate.
I just looked at a Rovergauge log for this morning's commute and for about half of my morning commute throttle pot was reading closed but the car was running fine! I also got a few short total loss of power events associated with less than idle throttle pot readings (ECU cutting throttle as it thinks the car is at idle but revs are too high?). However, I also noticed that after the service the car just had the idle was ~2k while it warmed up but now is back to normal and the long term lambda was set to 100% and 98%. Not re-checked these after this morning's run though.
Anyway any detailed technical links for the 14CUX would be appreciated and any ideas also appreciated.
Ta
Rob
I'm trying to diagnose a long term intermittent problem on my car. I know the throttle pot is misreading and remains wrong despite replacing it and then changing it back again. I know it occasionally cuts the fuel and when it does so the throttle pot is reading less than idle on Rover gauge.
Rovergauge is a start but knowing what the 14CUX is doing with these readings would really help as I have a number of niggles that might be all one big problem or might just be completely separate.
I just looked at a Rovergauge log for this morning's commute and for about half of my morning commute throttle pot was reading closed but the car was running fine! I also got a few short total loss of power events associated with less than idle throttle pot readings (ECU cutting throttle as it thinks the car is at idle but revs are too high?). However, I also noticed that after the service the car just had the idle was ~2k while it warmed up but now is back to normal and the long term lambda was set to 100% and 98%. Not re-checked these after this morning's run though.
Anyway any detailed technical links for the 14CUX would be appreciated and any ideas also appreciated.
Ta
Rob
P.S. I'm wondering about an intermittent connection in the harness possibly messing with the ECU's self learning of the throttle pot reading versus throttle opening.
It would also be helpful to know what a "normal" throttle pot reading is from rover gauge with throttle closed (both corrected and absolute).
It would also be helpful to know what a "normal" throttle pot reading is from rover gauge with throttle closed (both corrected and absolute).
For test purposes we want the absolute range to represent the percentage change the ECU sees between a fully closed and full open throttle position. So a throttle position sensor that is within the correct range will show:
Throttle shut 0.085-0.545v 2% to 10%
Throttle fully open 4.2-4.9v 84% to 98%
Throttle shut 0.085-0.545v 2% to 10%
Throttle fully open 4.2-4.9v 84% to 98%
Thanks, gives me a reference to check against.
Logs show 0.159 for "normal" throttle closed.
0.115 for an error condition (flat line despite me driving at that point and air flow clearly varying)
0.028 when it momentarily cuts the throttle when driving along (not a nice feeling)
Time to get the DVM out
Logs show 0.159 for "normal" throttle closed.
0.115 for an error condition (flat line despite me driving at that point and air flow clearly varying)
0.028 when it momentarily cuts the throttle when driving along (not a nice feeling)
Time to get the DVM out
Edited by Rob_the_Sparky on Tuesday 3rd May 17:17
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