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Renault Clio 1.5 DCi 2003 - Hard start when hot - Fixed #

Posted by Phil Dunmore on March 17, 2010, 10:50 am

Year of Manufacture *: 2003
Engine Code or CC *: K9K
( Optional ) Scanner Used: Launch

Have searched forums and found Dave Hill's excellent post on this very subject.
My vehicle has one significant difference. The non start is very temperature specific, above 75 no start, 74.9 down and off it goes. With temp well above 75 it will start if temp sensor disconnected.
When it dosn't start intial cranking is laboured as if injecting early. This is only momentary, rapidly reaches a good cranking speed

Looking at live data fuel pressure is reaching target. Leak tested injectors anyway, OK.

We have just fitted a used engine with injectors & pump, also new turbo. Injector codes programmed ok. No other problems or fault codes.
Original engine was in a very poor state due to ruptured air filter and inhaling soil. Turbo was destroyed. However it would start. We think it had the same syptoms on hot start but put it down to excess crankcase pressure and turbo passing lots of oil.

Could this be a software issue similar to Mondeo?

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Dave Hill <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2783' width='330' height='300' border=0 style='border:none;'> on March 18, 2010, 9:37 pm, in reply to "Renault Clio 1.5 DCi 2003 - Hard start when hot #"

Hi Phil

I don't know about my Excellent post, I merely posted things as I found them (but thanks anyway

)

I am not sure about that very specific temperature threshold issue, but I would dismiss it to begin with & take some time to explore the basics of high pressure fuel development & rail pressure holding ability.

The subject is too complex to discuss in a short post, but the basics should be eliminated before you dive in too deep.

Are you a scope user?

Cheers

Dave

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Phil Dunmore <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5515' width='330' height='300' border=0 style='border:none;'> on March 19, 2010, 7:36 pm, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"
Philip Dunmore

"Are you a scope user?"

You make it sound like an addiction

Truth is, I dabble when time permits or there is a need.

Follow your thinking on this, probably is a pump issue. Actually sick of looking at this van. It has had so many major issues, would be nice to just get it out the door. Today switched pump for vehicles original, does seem a little smoother at idle. Temperature problem remains.
By fitting a 100ohm resistor in place of temp sender(115c on scanner) engine will start cold.

Will have a go at scoping pressure decay cold & hot tomorrow if people will leave me alone long enough.

The guy who carried on driving this until turbo fell to bits is back from holiday on Monday. Will try interrogation techniques to find out if this was a prexisting fault. It's actually quite trivial compared to the state van was in when it arrived under its own power with following smoke screen.

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Dave Hill <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2783' width='330' height='300' border=0 style='border:none;'> on March 19, 2010, 8:35 pm, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"

Hi Phil

You don't know how true that "addiction" comment is!

The thing I enjoy about using the scope is that it gives you an unparalleled view of events as they happen at the sharp end & not after the ECU has interpreted them. Although it has to be said that it is not always necessary to go in so deep. Many times I find serial "live data" can reveal things that are not evident in a scope trace. For example, petrol injection fuel trims & CRD injector flow rates can be far more useful. Knowing what tool & when, is something else to learn hey!

In your last post you mention that you swapped the HP pump. That is not a five minute job for sure & it is something that I would try to avoid doing & instead prove its efficiency by other means. What if your replacement is no better?

When I tackle these kind of jobs, I tend to spend time proving the serviceability of each major component until I eventually uncover the culprit. Once you have clear evidence that the pump is good & then the injectors are good & then the crank speed is good etc etc, you can then move on with confidence.

I don't claim that clever scoping will give the answer to all the points I mention, but with good understanding of how each system works, you can certainly tick many things off your check list. & if you are not "up to speed" on a system, then you can put some R & D time in & learn a lot about how a system works by studying the cause & effect relationships.

If I come across like I think I know it all, then I have to come clean. I am as clueless as the next man very often. I just like to do play the "detective" & the scope is my best ally in the role.

Sorry if I am preaching to the converted.

Regards

Dave

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Phil Dunmore <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5515' width='330' height='300' border=0 style='border:none;'> on March 19, 2010, 9:10 pm, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"
Philip Dunmore

These type of things are often a puzzle to begin with. Considerable time has to be invested to gain a clear understanding of what is happening. The hope is some of that time can be recouped on the next one. Sometimes it works.

I could easily become an addict and spend all my time testing & measuring. How stuff works has and always will fascinate me. Like many who post here my fascination has become my livelyhood and in turn led to the employment of others and the responsibility that goes with it. Time is the enemy.

The pump was fitted by the tech who did the engine transplant. He was available, I was not. The logic in my desicion was to fit the vehicles original pump that we presume did not have this fault...but maybe it did.

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Dave Hill <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2783' width='330' height='300' border=0 style='border:none;'> on March 20, 2010, 6:55 am, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"

Hi Phil

""I could easily become an addict and spend all my time testing & measuring. How stuff works has and always will fascinate me. Like many who post here my fascination has become my livelyhood and in turn led to the employment of others and the responsibility that goes with it. Time is the enemy. ""

That is my role too & with seven guys to keep busy I know all about time & pressure. I am not saying it is easy & you must choose your subjects carefully. After all it would be pointless doing a full R & D session on a dying or ageing technology, that you won't reap a reward from.

However, when you consider that this Delphi CRD system is possibly the most common type seen on cars, spanning many makes i.e Jag X type, Ford TDCI Mondeo/Focus/Connect & Renault too. It doesn't take long to appreciate the benefits that will come from some real investment of your time.

Cheers Phil

Dave

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on March 21, 2010, 10:51 am, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"
Mark Carter

Hi Dave, speaking as one of the addicts who started off taking things apart as a kid just to find out how they worked, and then found employment in the industry so I could learn more (some 25 years ago) and now share my time between running my business(still fixing vehicles) and teaching the subject, I could not agree more with your last two posts.

Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Simon Dean <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5221' width='330' height='300' border=0 style='border:none;'> on March 21, 2010, 3:51 pm, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"
Simon Dean

Hi Phil

Delphi crd....prove the integrity of the spur gear/vac pump.(in line gauge back of pump)proof test it by restricting fuel line to see a good vac pressure/or pull if you like

.

5/sec per division on pico time base(50 secs of time).
5 Volt scale/monitor the rail pressure sensor signal wire KOEO PLAUSIBILITY VOLTAGE/START/IDLE/FULL WOT/IDLE/OFF/DECAY.

Better still be ready with this test when fault occurs

use a 2sec per division if you wish.
the IMV on pump controls volume of fuel which has direct effect on pressure generated. Don't forget the 'time'it takes to generate pressure correctly is within 1 second...you may 'see' your fault when in non start situation.

IMV can be prone to sticking!
Not a scope guru but r&d and learning.
Above may not be right totally stand to be corrected

.

HTH
Simon

Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #

Posted by Phil Dunmore <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5515' width='330' height='300' border=0 style='border:none;'> on March 27, 2010, 7:21 am, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"
Philip Dunmore

Taken it all on board guys. This engine has now developed a nasty mechanical noise. Will continue when that is sorted.

Fixed #

Posted by Phil Dunmore on April 18, 2010, 9:53 am, in reply to "Re: Renault Clio 1.5 DCi 2003 - Hard start when hot #"
Message modified by board administrator April 19, 2010, 12:00 pm

Guys who supplied the used engine have supplied and fitted a replacment. Hot start problem is solved. Pump and injectors were changed with the engine. Unfortunatly no one has time to do an autopsy on the old engine.

My feeling is that Dave was on the right lines with this, either pump failing to build presure fast enough or injectors not holding it. As the engine would fight the starter on first hot crank I suspect the latter. Could this have been the cause of mechanical failure?

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