Won't start when hot

Cityfinal
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Joined: May 20th, 2010, 6:24 pm

February 4th, 2017, 12:28 pm #1

For the past two /three months my 35S12 has been taking longer and longer to start when hot. This morning, after a run of 20 miles or so it failed to start after several attempts. Eventually the battery faulted, so I called Greenflag, who got it started with a jump and some easystart.
Some say it's the immobiliser losing communication with the key, though I can't find why it would lose communication only when the engine is hot. Any ideas???.
The other thing I've noticed is that it'll start when hot quicker if there's a full tank or close to it.
Sender unit??
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Spooky_b329
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Joined: November 22nd, 2009, 8:39 pm

February 4th, 2017, 1:47 pm #2

Immobiliser fault will give a keycode fault on dash.

I am short on time today, but if you search, I think (from memory) that either a faulty crankshaft or camshaft sensor can cause hot starting problems. Easy fix if that is the culprit!
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yiannism
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Joined: November 4th, 2011, 3:39 pm

February 4th, 2017, 7:55 pm #3

Hello,

Not starting when hot could arrise because of many problems..

As spooky said, check the sensors, if they are working properly.
Also i don't understand why when fuel tank is high, it will start ? right away ??

Did you feel the LP pump working ? ( sometimes it will fail when hot )

Also a good idea is check the injectors. ( after checking the above )

My friend has a 2.3 Iveco F1A which had a non starting issue when hot..it turned out to be injector problems.( the seals were gone )

I hope your symptom is one of the easy fixes and not the injector one.

John
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diddley
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diddley
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Joined: January 4th, 2013, 9:00 pm

March 1st, 2017, 7:16 am #4

I too have had a problem with starting when warm so after being on here and reading up I have changed the crankshaft sensor and it didn't seem to work immediately however after a a couple of days it seems to have worked. ?
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Cityfinal
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Joined: May 20th, 2010, 6:24 pm

March 11th, 2017, 10:17 pm #5

Changed the camshaft and crankshaft sensors, LP pump checked and working, but still no start when it's hot.
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gaz2313
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gaz2313
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Joined: January 23rd, 2012, 9:09 pm

March 12th, 2017, 12:49 pm #6

my mate had this same problem started fine cold but intermitent on hot many was the time he left the van on a job till it cooled again on his it turned out to be a connector after many months of investigating but unfortunatly i cant remember which one but the problem was a loose wire on a connector right at the back of the engine when it got hot it broke the cct
might have been in the immobiliser wiring to ecu but not sure it was a bugger to get too but soldering a jumper wire across the connection cured it and its been perfect since
sorry i cant remeber its exact location
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Cityfinal
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Joined: May 20th, 2010, 6:24 pm

May 16th, 2018, 8:27 am #7

Solved it!!
Changed the cam and crankshaft sensors, but no change. Someone said pour cold water on the water temperature sensor when it’s hot. So I sprayed it with a hose pipe for a few minutes and tried to start it....It started! Great I thought, so I bought a new water temp sensor and fitted it. Went for a drive, turned off, then tried restarting it, but same old thing....turns over, but not firing.
So a squirt of easystart, which got it going, then home. On the way back, I realised the high pressure fuel pump was directly underneath the water temp sensor, so it would have got cold when I sprayed the water. Next day I bought a seal kit for the fuel pump (about £40) and set about replacing the seals on the pump. Not easy, front of the van needs to come off.
Anyway, job done ✅ It starts when hot and starts quicker when cold.
A couple of points to note, the bottom pulley has four bolts holding it on. Undo these and get a puller on it, don’t touch the large bolt in the middle.
Use three of the bolts to clamp the fuel pump drive wheel in place while the large central bolt is removed.
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