All, I know this has been covered before but during these threads, the initial thoughts on culprit were fuel pressure regulator valve. However, reading further into these threads, when replaced, some still reported the same fault, therefore, all in all, was inconclusive. So, just starting this thread as a work in progress
So to my car: - 2.0 DTH, 2013, 67k mileage. First became aware of this about 6 months ago (circa 60k miles) but only for part of the warm up period and otherwise, the car drives perfectly - and it is still the same today.
I finally managed to get my op-com working in Windows 10, therefore do not now have to swap images with Windows 7 on my laptop (much more convenient for me now) and therefore decided to capture some engine data on Saturday from a cold start.
Data: -
No Fault codes stored on any of the car modules.
Foot totally off the accelerator pedal at all times during this test.
When the engine coolant temperature is below 18C, the idle is rock steady stable and always pretty darned close to the desired rpm but as soon as it reaches 18C, the fluctuating revs begin (between +50 rpm to -50 rpm of ECU's desired rpm) - from the data,you can also see the engine load fluctuate and the MAF data fluctuate in harmony with the different engine demands. As the coolant temperature rises toward 25C the idle steadies again and just as the glowplug command switches to off (I think they are in the 'afterglow' period at that point), the idle is once again rock steady and will be until the next cold start cycle. It is pretty repeatable that the rough idle begins spot on at 18C and evens out at Glowplug off point (i.e. does not look to be time related but rather temp related).
That is much as I have done thus far and fast becoming an old bugger, I like my creature comfort in the cozy house rather than be out in the cold, so unless this develops into a driveability problem I cannot see me doing much more until warmer days.
I wonder though, if one or more of the Glow Plugs is going slightly out of spec and demanding incorrect engine load. I did check the engine pressures with OP-COM when the engine was hot and they are fine, maybe will do the same check when it is going through this problem temperature range and see if it gives any cylinder imbalance.
So to my car: - 2.0 DTH, 2013, 67k mileage. First became aware of this about 6 months ago (circa 60k miles) but only for part of the warm up period and otherwise, the car drives perfectly - and it is still the same today.
I finally managed to get my op-com working in Windows 10, therefore do not now have to swap images with Windows 7 on my laptop (much more convenient for me now) and therefore decided to capture some engine data on Saturday from a cold start.
Data: -
No Fault codes stored on any of the car modules.
Foot totally off the accelerator pedal at all times during this test.
When the engine coolant temperature is below 18C, the idle is rock steady stable and always pretty darned close to the desired rpm but as soon as it reaches 18C, the fluctuating revs begin (between +50 rpm to -50 rpm of ECU's desired rpm) - from the data,you can also see the engine load fluctuate and the MAF data fluctuate in harmony with the different engine demands. As the coolant temperature rises toward 25C the idle steadies again and just as the glowplug command switches to off (I think they are in the 'afterglow' period at that point), the idle is once again rock steady and will be until the next cold start cycle. It is pretty repeatable that the rough idle begins spot on at 18C and evens out at Glowplug off point (i.e. does not look to be time related but rather temp related).
That is much as I have done thus far and fast becoming an old bugger, I like my creature comfort in the cozy house rather than be out in the cold, so unless this develops into a driveability problem I cannot see me doing much more until warmer days.
I wonder though, if one or more of the Glow Plugs is going slightly out of spec and demanding incorrect engine load. I did check the engine pressures with OP-COM when the engine was hot and they are fine, maybe will do the same check when it is going through this problem temperature range and see if it gives any cylinder imbalance.
Comment