Hunting Idle when hot - L SERIES DIESEL

Hi folks...

Tiny is back with a minor but irritating "feature".
When cold she idles perfectly...starts fine etc.
When warmed up the idle goes all chuggy and thrummy like she is hunting.
Sat at lights and it sounds like she has a hot camshaft

"Thrum, Thrum,Thrum,Thrum"

No other symptoms. Any one got any ideas?

Ming - fuel filter d'ya recon?

I can't understand it...she is not exactly high milage or anything....

fuel pump?

aussielander said:

fuel pump?

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it do's sound like a fuel issue, but check basics first ,air filter, fuel filter , engine vac breather, all rubbers ta inlet turbo are sound,check yer egr valve is not all clogged wiff ****e, un that the in your case ,the egr solinoid is working, failing that ,take o/p orft pump [should **** out doozle]wiff ign switched on ,no foam or low pressure [have plenty er rags handy ta mop up ]and again in your case re-prime low pressure doozle [using yer squeeze fingy] and follow bleed procedure. . .

Cheers folks - will replace fuel filter at the weekend.
EGR already blanked so not an issue but will check all hoses etc.

On a petrol engine hunting is too much fuel or I suppose not enough air. My L series hunts at tickover but thats because I have upped the fueling with the Rover Ron gadgett

Here's another strange thing too - she does not seem to be using any fuel! (good innit?)
So far I have done 310 miles on half a tank and the needle has hardly moved... before you say it - nope - the fuel guage and sender are working fine (1st thing i tested)....lumpy idle I can cope with if I can run on fresh air!!

tinytdi said:

Here's another strange thing too - she does not seem to be using any fuel! (good innit?)
So far I have done 310 miles on half a tank and the needle has hardly moved... before you say it - nope - the fuel guage and sender are working fine (1st thing i tested)....lumpy idle I can cope with if I can run on fresh air!!

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I WANT YOUR FAULT. . . .

ming said:

I WANT YOUR FAULT. . . .

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Can yer passit over t me when yer finnished wiv it ming !

check wirring to tank. punp and gauge are in the same unit. sounds like this could be your problem, erattic idling caused by pump in tank not working and apparant lack of fuel use due to sender net working-- wirring issue--. me thinks anyway

Well filter came today so will fit it later.
So far 320 miles on half a tank...needle does move but only noticable in a matter of days rather than hours..
Mad as a box of frogs I tell thee!
If replacing the filter sorts the idle and makes the consumption normal I may sell the old filter on ebay as a magic one! LOL.

Right folks - update on Tiny.
Filter replaced and economy still verging on the good side of amazing...ignore that though - dont want to "rectify" that "issue"!!!
Checked all hoses, EGR has been blanked since day one and she still has a throbbing idle when warm. This does not happen from startup but the hotter she gets the worse it becomes. Almost sounds like she is going to stall at times.
Now casting my mind back to my Mini days....induction leaks used to cause similar symptoms. Would spraying WD40 about (like you do on a petrol car to find an induction leak) work on Tiny do you think???

Its injection so its difficult to see how a leak could affect the mixture/idle. Unless it's post turbo. In which case you are looking for a positive pressure not a negative, so WD may not help. but soapy water and a paint brush might?

Thanks for the advice so far.

WD40, soapy water, checked all pipes...everything okay.

Clueless.

I've had this exact same problem for a couple years now. Have you found the cause?

kumanyoko said:

I've had this exact same problem for a couple years now. Have you found the cause?

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Holy thread revival.

Does it start well?

What year is the car?

1996 Freelander with L Series turbo diesel. The problem is exaclty as TinyTdi describes. After it warms up the idle is 'thrum, thrum, thrum'. It's starts no problem at all. Thanks.