[Sam7Clover]

Hi all,

I wonder if anyone could shed insight into a recent issue with my 2008 i30 1.6 CRDI diesel.
Both local and dealership mechanics are mystified.

The car, which is in very clean condition and treated well, but has high KMs, will start on a cold engine fine, but rough idles under 1000RPM and dies almost immediately on a warm start.
This is obviously the inverse of most temperature-related startup issues, so quite puzzling.

. Full servicing completed, inc. fuel filter, etc..
. OBDII scans completed, yeliding no results.

Any thoughts or suggestions would be greatly appreciated!

Sam😊

[The Gonz]

Hey local Sam,

all that occurs to me is some error in how it's reading temperature. There may be a sensor that regulates fuel based on temperature and if that's out in some way, it could behave as described. It could also be temperature related in that some air leak occurs in the warmer circumstances.

[sundiz]

Gonz pretty much nailed it. Temperature sensor issue or air leak would be also mine first suggestions. It would be interesting to see fuel pressures with cold and with warm engine. Especially in the start ups.

If you prime the fuel filter from the pump over the filter, will it start any better? Local dealership mentioned that they saw couple of cases where the fuel heater element had cracked. It allowed air to be sucked in the fuel system causing low fuel pressure. Small leaks could be worse with warm engine due heat expansion. Low fuel pressure should still create error message. Have they been able to have these starting issues in the workshop or are you only one who have experienced it. If my car gets low fuel pressure issues the codes are only visible when the engine is still running. After restart message disappears also from the history data.

[mrexcitement]

Wow I have the exact same issue on a 2010 CRDI with 225,000 on the clock.

I started a topic on it ages ago but I never had any responses with any idea's or suggestions so I though it was very rare , good to hear I'm not the only one.

Still have no idea why , a mechanic friend suggested maybe a leaky injector and when it's warm the viscosity of the diesel is less so more leaks into the cylinder before startup , does this make any sense to anyone ?

It starts perfectly every time when it's cold , almost instantly , so definitely the glow plugs are ok.

But now we are getting into the warmer months , it has started doing it again , it will run real rough when it does this delayed start and continue for about a minute or two before it clears itself while idling (I always warm the car for a few minutes before driving)

So sometimes it will take me two crank cycles , I never sit there just continuously cranking the engine , I only do it for about 5 - 10 seconds max then stop and go again , on the second attempt it will always start like normal , it's only ever on the first attempt to start when warm it will do this.

Also when this happens there will be a lot of unburnt diesel coming out from the exhaust but never any sign of this when it's cold air temp.

It's almost guaranteed it will do it when the temps are higher eg Air temp < 15c no sign of this issue and starts first time every time , Air temp > 15 getting closer to 18c - 20c definitely will do this delayed start.

This issue has pretty much been there since I purchased the car at 80,000kms , it hasn't got any worse or any better and only happens when it's warm weather.

Any tip or suggestions would be greatly appreciated.

[mrexcitement]

Oh and this is only from a cold engine start , once the engine is warmed up it never does this.

[sundiz]

Unburned diesel might have something to do with leaky injector. Or some sensor gives wrong values so ecu wants to spray more fuel than it actually should. Not sure how diesel will affect catalythic converters, but in petrol cars unburned fuel can cause damage to the cat.