Measures of good idle
Posted: Sat Jun 21, 2014 8:57 pm
Check these three options with the following conditions
You have a good idle when ∆ rpm is < ±50 rpm
You have a fair idle when ∆ rpm is < ±150 rpm
You have a bad idle when ∆ rpm is > ±150 rpm
• free idle quality at all coolant temperatures starting with the lowest to the fully warm engine temperature
• at free idle first apply and then remove all possible external loads
• at free idle, engine warm or cold, press the break pedal with 1Hz
• at free idle, engine warm or cold with power assisted steering, turn steering wheel to full lock, release then apply full lock again
• at free idle, engine warm or cold, blip the throttle, reach various engine speeds then leave engine returning to idle
• previous point but with external loads
Check these three options with the following conditions
You have a good idle when ∆ rpm is < ±100 rpm
You have a fair idle when ∆ rpm is < ±200 rpm
You have a bad idle when ∆ rpm is > ±200 rpm
• from free idle, hot or cold engine, first and second gear, pull away with no throttle then abort pull away or de-clutch
• in idle drive, engine warm or cold, first and second gear (car should not feel incontrollable due to increasing engine speed)
Following conditions are time-dependent
• in idle drive, engine warm or cold, first and second gear, press brake to drop engine speed to 500 rpm then release, engine should not stall and recover quickly without overshoot, oscillations or surge
• at idle drive, engine warm or cold, apply external loads, there should be no disturbance
• in idle drive, engine warm or cold, after and while car parking manoeuvres engine should not stall and recover quickly without overshoot, oscillations or surge
You have a good idle when ∆ rpm is < ±50 rpm
You have a fair idle when ∆ rpm is < ±150 rpm
You have a bad idle when ∆ rpm is > ±150 rpm
• free idle quality at all coolant temperatures starting with the lowest to the fully warm engine temperature
• at free idle first apply and then remove all possible external loads
• at free idle, engine warm or cold, press the break pedal with 1Hz
• at free idle, engine warm or cold with power assisted steering, turn steering wheel to full lock, release then apply full lock again
• at free idle, engine warm or cold, blip the throttle, reach various engine speeds then leave engine returning to idle
• previous point but with external loads
Check these three options with the following conditions
You have a good idle when ∆ rpm is < ±100 rpm
You have a fair idle when ∆ rpm is < ±200 rpm
You have a bad idle when ∆ rpm is > ±200 rpm
• from free idle, hot or cold engine, first and second gear, pull away with no throttle then abort pull away or de-clutch
• in idle drive, engine warm or cold, first and second gear (car should not feel incontrollable due to increasing engine speed)
Following conditions are time-dependent
• in idle drive, engine warm or cold, first and second gear, press brake to drop engine speed to 500 rpm then release, engine should not stall and recover quickly without overshoot, oscillations or surge
• at idle drive, engine warm or cold, apply external loads, there should be no disturbance
• in idle drive, engine warm or cold, after and while car parking manoeuvres engine should not stall and recover quickly without overshoot, oscillations or surge