Bouncing RPM after cold start. Settles after ~30 secs.
Discussion
Hi guys,
Just bought a 63 plate Hyundai i30 1.6 Diesel Blue Drive Edition last Thursday, 57000 miles on the clock. Love the car and really enjoying driving it. I am however having a slight issue when starting the car from cold in that the RPM will bounce around for approx 30 seconds or so before settling. The engine sounds as if it is pulsing along with the RPMs but will also settle after approx 30 seconds. Once settled the car idles perfectly and will idle great in traffic etc as well as idling fine when started warm. Having had the car less than a week this is an issue I'd really like to resolve asap before the dealership put it down to wear and tear and refuse to repair it. Any ideas what might be causing this??
Just bought a 63 plate Hyundai i30 1.6 Diesel Blue Drive Edition last Thursday, 57000 miles on the clock. Love the car and really enjoying driving it. I am however having a slight issue when starting the car from cold in that the RPM will bounce around for approx 30 seconds or so before settling. The engine sounds as if it is pulsing along with the RPMs but will also settle after approx 30 seconds. Once settled the car idles perfectly and will idle great in traffic etc as well as idling fine when started warm. Having had the car less than a week this is an issue I'd really like to resolve asap before the dealership put it down to wear and tear and refuse to repair it. Any ideas what might be causing this??
MattOz said:
Might be the idle control valve or unit. Probably not a big job to replace.
When no such thing exists on a diesel like that...it'd be pretty hard to replace.Presumably the OP is asking, because the vehicle has just started doing this behaviour for no reason ? Or has it always been strange when cold ?
stevesingo said:
If it is purely cold start related and it is a diesel. I would be looking at the pre-heater circuit - Glow plugs and relay.
That’s what I’m thinking. It’s in under warranty with Hyundai this morning (dropped it off last night to allow for a cold start this morning) so will update once I hear back 
Picked up the car yesterday, further investigation still needed 🤨 for some reason they only scheduled the car in for an hour and so didn’t get much beyond scanning the car for codes.
Booked in the week after next for a couple of days when I can get a courtesy car to keep me on the road. Really hoping this doesn’t mean it’s something serious ..
Spent weeks deciding on a car, settled on the i30 for their reliability 😅
Booked in the week after next for a couple of days when I can get a courtesy car to keep me on the road. Really hoping this doesn’t mean it’s something serious ..
Spent weeks deciding on a car, settled on the i30 for their reliability 😅
Cap2018 said:
they only scheduled the car in for an hour and so didn’t get much beyond scanning the car for codes.
WTF? 'Scanning for codes' involves plugging a wire in and reading a screen. How the hell do you spend an hour on that? If they are able to reproduce the problem with access to live data then an hour is long enough to get a pretty good idea what is causing it.GreenV8S said:
Cap2018 said:
they only scheduled the car in for an hour and so didn’t get much beyond scanning the car for codes.
WTF? 'Scanning for codes' involves plugging a wire in and reading a screen. How the hell do you spend an hour on that? If they are able to reproduce the problem with access to live data then an hour is long enough to get a pretty good idea what is causing it.Cap2018 said:
she said they hadn’t even looked at them because they didn’t have time
To check they're getting power just needs a few minutes to back probe the connector. Checking the heater is intact just needs disconnecting and measuring the resistance. These are very basic checks which might not pin down the exact problem but should only take a few minutes to tell whether you're on the right track. I suppose they might need an extra ten minutes to take trim covers off the engine to get access, but I'd be very disappointed that they got basically nowhere in an hour.GreenV8S said:
Cap2018 said:
she said they hadn’t even looked at them because they didn’t have time
To check they're getting power just needs a few minutes to back probe the connector. Checking the heater is intact just needs disconnecting and measuring the resistance. These are very basic checks which might not pin down the exact problem but should only take a few minutes to tell whether you're on the right track. I suppose they might need an extra ten minutes to take trim covers off the engine to get access, but I'd be very disappointed that they got basically nowhere in an hour.
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