10-31-2021, 05:40 AM
Something to keep in the back of your mind is that the e.c.u.'s as they have evolved over time have included " strategies " to deal with events like defect sensors, most sensors can be disconnected ( whilst setting fault codes which can be reset ) and the engine will still operate.
Customers appreciate the fact that a map sensor fail is not letting them stranded mid journey and gives the manufacturers a chance of selling the next model in the knowledge that customers won't shy away from their brand just because a connector was not secured, disconnected causing the engine to stop.
Not uncommon for intake sensors to be unplugged and the engine still operates, a diagnostic method to pinpoint a fault.
On the extreme end a temperature sensor in a ford car was indicating 120 deg celcius in a cold engine ( the sensor was broken ) and as a result the e.c.u. in the vehicle concluded that the start mixture was kept lean as per running condition and the car could not be started because the injectors were not providing a rich enough starting mixture necessary for the engine to fire up .
So be careful with conclusions regarding e.c.u.'s, step by step verification usually gets the wanted results and i am glad Dave is helping, he is quite the methodological mind plus has done it before, very hard to beat experience, keep us posted.
So the ecu has different strategies built-in for all possible failures.
Another thing may be the "throttle learning position", after disconnecting the battery some of the "learned values" in the e.c.u. may have to be re-learned, from memory this involves switching on the key and rotating the throttle grip fully-and-back three times and switching the key off again.
The maximum and minimum values for the throttle position sensor will now be "memorized" (because of this sequence) in the e.c.u., just something to try, see if it makes any difference.
Here is a video from one of our members showing how to disconnect the iacv to confirm if it was the cause of the high idle.
https://www.youtube.com/watch?v=uHxmxnRAYw4
Reason for you to try this is to connect the old iacv to verify the connector/wiring/ecu is operating normally ( step 1 ).
From rock climbing i learned to get to the top you make one move at a time, works for most climbers.
Customers appreciate the fact that a map sensor fail is not letting them stranded mid journey and gives the manufacturers a chance of selling the next model in the knowledge that customers won't shy away from their brand just because a connector was not secured, disconnected causing the engine to stop.
Not uncommon for intake sensors to be unplugged and the engine still operates, a diagnostic method to pinpoint a fault.
On the extreme end a temperature sensor in a ford car was indicating 120 deg celcius in a cold engine ( the sensor was broken ) and as a result the e.c.u. in the vehicle concluded that the start mixture was kept lean as per running condition and the car could not be started because the injectors were not providing a rich enough starting mixture necessary for the engine to fire up .
So be careful with conclusions regarding e.c.u.'s, step by step verification usually gets the wanted results and i am glad Dave is helping, he is quite the methodological mind plus has done it before, very hard to beat experience, keep us posted.
So the ecu has different strategies built-in for all possible failures.
Another thing may be the "throttle learning position", after disconnecting the battery some of the "learned values" in the e.c.u. may have to be re-learned, from memory this involves switching on the key and rotating the throttle grip fully-and-back three times and switching the key off again.
The maximum and minimum values for the throttle position sensor will now be "memorized" (because of this sequence) in the e.c.u., just something to try, see if it makes any difference.
Here is a video from one of our members showing how to disconnect the iacv to confirm if it was the cause of the high idle.
https://www.youtube.com/watch?v=uHxmxnRAYw4
Reason for you to try this is to connect the old iacv to verify the connector/wiring/ecu is operating normally ( step 1 ).
From rock climbing i learned to get to the top you make one move at a time, works for most climbers.