4 replies to this topic

[kommander]

My Jap Spec SPi mini has an erratic idle at startup (cold engine). This symptom however, disappears once the engine is warm. Any attempts at driving the car before the engine is warm results in it cutting out, and having to be restarted. There's definitely a misfire. Scans with my SP hasn't returned any error codes. I have replaced plugs, leads and coil. There's a K&N filter installed and the injector seems to be spraying fine.

The coolant temperature sensor was replaced last year.

 

The following are vids I made at startup

 

https://youtu.be/1d72EWVp6R8

 

 

https://youtu.be/OCfHw4XaMss

 

 

Any suggestions will be appreciated.

[BlakeSarrington85]

on a typical ecu when the engine is cold it runs on closed loop settings which are set by factory. the car takes no readings from sensors apart from coolant temperature. once the coolant reaches a certain temperature it will move onto open loop circuit which will give the ecu readings from things like air temperature,O2 sensors and throttle position sensors etc. they will adjust accordingly to engine temperature, ambient temeraturte etc. typically on closed loop a car will run fast idle to gewt heat in the engine quicker. hope this gives you slightly better understanding.

Edited by BlakeSarrington85, 08 August 2017 - 12:38 PM.

[bigchief3679]

Was this sorted? It may likely be the ceramic manifold heater at the base of the intake manifold or its wiring.

[pete l]

on a typical ecu when the engine is cold it runs on closed loop settings which are set by factory. the car takes no readings from sensors apart from coolant temperature. once the coolant reaches a certain temperature it will move onto open loop circuit which will give the ecu readings from things like air temperature,O2 sensors and throttle position sensors etc. they will adjust accordingly to engine temperature, ambient temeraturte etc. typically on closed loop a car will run fast idle to gewt heat in the engine quicker. hope this gives you slightly better understanding.

 

Is the MPI the same ?  I ask because mine is very hard to start and runs like a pig from the word go. 

[kommander]

Turned out to be the crank angle sensor.