Why won't my diesel start instantly?

I bought a Renault Kangoo van 1.5 dci recently for bike carrying duties and as my main vehicle.
It’s only done 40,000 miles, but when starting it, it turns over for a few seconds before it fires up (worse when cold, and I let the glow plug light go out before starting it).
I can’t see any air bubbles in the fuel lines.
I have tested the battery and alternator with my voltmeter (all OK), and today I replaced the glow plugs- but the problem persists.
Help please, as I don’t want to end up stranded…

check the compression.

I guess it starts when warm ?

Have you checked for voltage at the glow plugs ?

Spill rail leaking letting fuel run back ? not familiar with the dci engine but is there a manual primer near the the fuel filter , try manually priming it before turning the key. If it starts good check the whole fuel system pre and post injector , either for leaks or could be letting air in .

After tat your moving into the realms of checking compression and doing a leak down test but requires special tools.

How old is it? Battery, or glow plugs?

Provided the glow plugs are working, then most likely something fuel pressure related.

IIRC kangoos use Bosch injectors which need over ~125bar to operate (Delphi are over 200bar, and not sure about Denso). Causes can be anything from a sticky injector (they can stick open, meaning they let fuel back through the leak-off pipe until pressure gets high enough and they’ll unstick and work perfectly fine), air getting in somewhere, the fuel pump itself, leaking fuel regulator seals (I can’t remember what regulator system Kangoo’s use, but only pressure regulating systems would suffer from this, as volume regulating systems it would actually make starting better), and that’s only if it’s a fuel pressure fault.
It could be something else like not cranking fast enough, faulty sensor….and lots of other possibilities.

If it’s a consistent time period to start, I wouldn’t worry too much, as you could spend lots of money trying to locate the problem. However if it was getting noticeably worse, I’d think about doing something to fix it.

Its French.. its bound to be temperamental

Daughter had a similar problem with. Fiesta 1.4tdci…..I had checked the battery etc and also thought it was an air lock issue…..turns out the battery was in fact in the process of dying, it would crank the engine over but not at the required rpm to satisfy certain sensors….sounded like it was cranking properly but wasn’t obvioysly…..new battery fitted, problem instantly vanished never to return. If you can get hold of another battery to try give it a go see if it cures the issue.

Or get the battery load tested

I recently gave my diesel Alfa’s MAP sensor its annual degunging and have noticed the car starts much better since. Possibly a coincidence…

partially clogged diesel filter?

Probably just the battery.

Also worth checking the starter and battery connections I guess. Wouldnt have thought it would be anything more sinister at that mileage. Unless it’s been clocked!

Seen this a few times… Battery or starter most recent few have been starter obviously check the main engine earth and live to the starter but the found the bearings in the starter partially seized causing slow turn over/slow rise in fuel pressure and slow starting. Worse when cold. But gradually got worse to the point it failed to start.

I had this with a 106 1.5 diesel it struggled to start from cold. It turned out to be the gap between the camshaft and shims were out (dunno why they went out, valve stem stretch??) measured for new ones and got them switched over, (quite a simple job really).

Have you tried warming up the glow plugs two or three times before starting? If that improves it then it’s a good sign it’s plugs.

Get the spotlight kid on the case.

I have tested the battery and alternator with my voltmeter (all OK),

while its cranking?

My Berlingo is taking increasingly long to start first thing. And when it does there is a cloud of white smoke. If I stop the engine and start again, it is instant.

I suspect it could be fuel running back when it is left over night, but the white smoke indicates that there is unburnt fuel in the cylinder(?). Perhaps an injector is leaky and letting the fuel rail pressure drop if stopped for a while.

A new fancy Varta battery was fitted last year. The starter could be reluctant. It is 10 years old.

I had exactly the same problem this week (on an admittedly old diesel) and my car eventually failed to start at all on Tuesday. Turned out to be the starter motor. Have you tried starting the car whilst soneone knocks the starter with a hammer, if you free it up momentarily this could be an indication it’s at fault.

The solenoid on my first car – a 1.9D Zx was like that. One whack, instant start.

Should be 350rpm on the tacho when cranking, I believe. If there is, then it’s not the starter or battery.

if your car takes that long to start that you can read the rev counter…..somethings borked.

have you tried priming the fuel system prior to starting yet.

cheapest thing to do and narrows it down to fuel delivery as oppose to compression.

as for the berlingo slow starting (assuming its turning over a full speed). i would try the same thing first – as its free .

failing that i would pull the glow plugs and bench test them – although iirc the inlet manifold has to come off first to pull the plugs it can be a pain in the chuff

Dci is common rail right?

The fact it runs well eventually suggests its a fueling issue and not compression

So it’s either delivery or timing of fuel. Common rail are timed electronic so could be a sensor on the fritz = ecu will just pick a starting map based on air/ fuel temp, so it’ll start eventually but not as crisp as it should be.
Or delivery = dodgy injector, ie it’s leaking back overnight. Not bad enough to cause a running issue, just in the morning. Could also be leak off pipes if it has them. Leaking doesn’t mean diesel coming out, more often just air getting in or one has collapsed. They cost about £5 for a metre of the stuff and you need about 30cm. cheapest and easiest thing to try before you start getting into injectors!

Tried priming but made no difference.
Doesn’t appear to be any air or leaks in the system.
I spoke to a mechanic earlier who reckoned it could be the glow plug timer relay.
If not this it’s going on a diagnostic.

Testing glow plugs is usually pretty simple and that’ll also rule in or out the relay. Does it turn over nicely, or is it laboured?

Turns over nicely and at the correct speed.

I don’t know anything about that engine but normally (always?) there is a camshaft sensor and a crank sensor.

If one of them is giving erroneous readings, the ECU will ignore it and use the other to start. One results in harder/laboured starting, the other can result in lumpy running and an engine management light.

It can also be a reason for an engine starting only when fed with easystart, apparently one of the sensors doesn’t receive a reliable signal whilst the engine is being started as the RPM is too low, with easystart it turns over faster and the signal becomes sufficient for the ECU to do its stuff.

I had the same problem on mine (52 plate Kangoo 1.5dci)after a bit of research found out that the crank sensor is a weak point on these and they fail over time, seems to be quite common on the 1.5DCI, changed it and happy chappy again.

Good thing easy they are quite cheap and easy to replace , 2 bolts and a multipin connector.

Tha hardest part is accessing it as it sits down the right hand side of the block above the gearbox bellhousing and its a little crowded down there.

Why does it need glowplugs to start? OR is that normal for common rail dervs? My direct injection starts immediately without glow plugs unless its well below zero or I’m running veg and its very cold.

Common rails use them not only to start but to run till it warms up a bit.

Thanks all massively for the suggestions.
Will look into the crank sensor next.

Brickman, it probably uses the glowplugs for every cold start, its probably just clever and turns them on when you unlock the car or as soon as the key goes in the ignition so you don’t need to wait for a light to go out.

OR is that normal for common rail dervs? My direct injection starts immediately without glow plugs

Yeah some engines need it more than others. Either by design or the condition of it.

Does it start straight away if the engine is warm?

If so, it is 99.9% the glow plugs. I had identical issues with an old XJ Jeep. Took an age to get going in a morning, but fine throughout the rest of the day. A new set of glow plugs sorted it out.

However, it could be “forced” to start by switching the ignition on and off for ages. When you turn the key, at least in the Jeep, you could hear the glow plug relay switching on and off. Turn key on, wait 20-ish seconds until glow-plug relay switches clicks off, turn key off. Repeat x10. Start engine. Drive off.