Xulfiqar bro.. I need your opinion on another engine cold start up related issue.
Scenario 1 When i cold start my car (Toyota Altis Cruisetronic 1.6 model 2013. 80K on odo) in morning or after a long halt, I observe that the initial RPM surge is more than it should be, which means that it suddenly jumps up to little above 1.5 RPM and then gradually starts dropping down till the engine maintains NOT. The initial RPM surge feels as if the accelerator pedal was already pressed before the engine was cranked.
Scenario 2 I have another car Toyota Corolla GLI 2015 (MT), 60K on odo, which when started cold in the morning behaves differently. It has a smoother start up. No immediate RPM surge. after start up, RPM rises gradually but quickly to 1.5 RPM and then drops down slowly when NOT is maintained. No rough start up or rattle sound.
Questions related to Scenario 1
- Is this cold start RPM surge normal? by normal i mean, its intensity as compared to scenario 2 explained above?
- Could this also be one of the reasons for a rough rattling cold start up?
- Can this RPM surge be reduced / manipulated?
I hope i have been able to explain myself. Your worthy comments, please.
P.S. anybody who has experienced this phenomenon to please share his views. thank you