Discussion
Back on the road again but the car is now hunting on idle.
When started from cold everything is fine. She starts at 1100rpm, however once warmed up the electronics drop the revs back and the engine then hunts between 900rpm and 500rpm. It's almost as if the throttle stop is wound too far back and the electronics are trying to catch it before it stalls. I've checked (and tried by adjusting) the stop but no change. The electronics just seems to learn and compenstae for this and it continues to hunt.
Anyone suggest what to look for/at to solve this?
When started from cold everything is fine. She starts at 1100rpm, however once warmed up the electronics drop the revs back and the engine then hunts between 900rpm and 500rpm. It's almost as if the throttle stop is wound too far back and the electronics are trying to catch it before it stalls. I've checked (and tried by adjusting) the stop but no change. The electronics just seems to learn and compenstae for this and it continues to hunt.
Anyone suggest what to look for/at to solve this?
A diagnostic software package that could monitor engine parameters and reset the adaptive maps was available in the U.S. See this thread for some discussion:
http://www.nobleforums.com/showthread.php?t=1315&a...
IIRC, it is also possible to do a reset by disconnecting the battery and leaving it disconnected for about an hour.
http://www.nobleforums.com/showthread.php?t=1315&a...
IIRC, it is also possible to do a reset by disconnecting the battery and leaving it disconnected for about an hour.
Noblescort said:
Back on the road again but the car is now hunting on idle.
When started from cold everything is fine. She starts at 1100rpm, however once warmed up the electronics drop the revs back and the engine then hunts between 900rpm and 500rpm. It's almost as if the throttle stop is wound too far back and the electronics are trying to catch it before it stalls. I've checked (and tried by adjusting) the stop but no change. The electronics just seems to learn and compenstae for this and it continues to hunt.
Anyone suggest what to look for/at to solve this?
This was posted by another member of nobleforums. I'm not sure what thread I got it from. It might help:When started from cold everything is fine. She starts at 1100rpm, however once warmed up the electronics drop the revs back and the engine then hunts between 900rpm and 500rpm. It's almost as if the throttle stop is wound too far back and the electronics are trying to catch it before it stalls. I've checked (and tried by adjusting) the stop but no change. The electronics just seems to learn and compenstae for this and it continues to hunt.
Anyone suggest what to look for/at to solve this?
"An oscillating idle is usually an indication that the throttle position is set too high. There is a voltage range (from the throttle position sensor) within which the ECU will control the idle properly (assuming that you have no vacuum leaks like I did). Once you set it in that range the ECU takes over the idle control. I believe that Mike said the range was 1.0-1.6 volts. Mine is now set at 1.3 volts and runs fine. Prior to that it oscillated like crazy whenever I tried to increase the idle speed with the idle adjustment screw. What I found was that anything outside of the 1.0-1.6 volt range and the ECU can't properly control the idle (the throttle plate is closed too far or too wide open and the idle air mixture gets screwed up). This is because the Noble spec engine does not use the idle air control valve that is on stock Ford Duratec engines. It uses the ECU to control the idle.
So, be careful thinking that just increasing the idle with the idle screw and then resetting the ECU will solve your problem. If you turn it too far, you will make it even worse. Make sure you don't have any vacuum leaks first. Then use the diagnostic program with a laptop and set the throttle plate sensor voltage in the proper range."
After you adjust the idle screw, you can reset the TPS by turning the key on and off 10 times. According to the thread referenced above, setting the idle should be done after verifying that the lambda sensor is working properly.
Great to have this info, thanks.
Now all I need to do is establish how to verify the lambdas are functioning correctly.
Can anyone tell me how?
I can look at them on the software but apart from whether they both read the same, Not sure what else I can do.
Will the values change at different rpm?
What should they read at idle (800 rpm?)
Now all I need to do is establish how to verify the lambdas are functioning correctly.
Can anyone tell me how?
I can look at them on the software but apart from whether they both read the same, Not sure what else I can do.
Will the values change at different rpm?
What should they read at idle (800 rpm?)
Edited by Noblescort on Monday 12th April 12:46
I've not used easymap but i'm sure it will be obvious which is working & which isn't, assume one will show fluctuation and the other faulty one nothing. Otherwise get a new one and start by changing the front one (nearest the bulkhead). To reset the Ecu just unplug the main fuse above Ecu for a couple of minutes.
Gassing Station | Noble | Top of Page | What's New | My Stuff