AuthorTopic: Intermittant rough running fault  (Read 1867 times)

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Offline gt.jacko

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Intermittant rough running fault
« on: June 30, 2009, 15:44:24 »
Hi I have a defender fitted with a 4.2 lse engine and auto box, the last couple of times i,ve driven it it has a really bad running fault, it will suddenly start to run really rich clouds of black smoke from exhaust and I can almost see the fuel gauge going down :'(. If you stop it and restart it seems ok again until revs get up above 2000 rpm , this morning i drove into stockport which is 15 miles away from me on the way there it never missed a beat then coming back it did it nearly all the way home on and off bloody thing anyone any ideas please.

Cheers
            gary :help:

Offline Rossko

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Re: Intermittant rough running fault
« Reply #1 on: July 01, 2009, 11:14:44 »
Dried leaves or sock in air filter box, faulty oxygen sensor, faulty coolant temp sensor (the EFi uses a different one from the gauge, don't let that confuse you), faulty Airflow Meter, chafed wires (check where your loom has been put through the bulkhead), split vacuum pipe to fuel pressure regulator or duff regulator, pinched fuel return hose.
« Last Edit: July 01, 2009, 11:19:35 by Rossko »
GLASS

Offline Bowie

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Re: Intermittant rough running fault
« Reply #2 on: July 01, 2009, 11:20:28 »
Coolant temp sender?

Loose air flow meter connection? These corrode slowly over time and make running 'interesting'.

Lambda probe.

Pretty much all it can be -if it all looks OK, then try the Hotwire diagnostics in the back of the Haynes manual -it's a lift straight from the LR workshop manual.
1980 SIII Lightweight 2.25 Petrol - completely standard.
1991 Range Rover Vogue SE 3.9 V8 - now on LPG (sorted!), 2" lift, mud tyres, and more to come...

Offline gt.jacko

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Re: Intermittant rough running fault
« Reply #3 on: July 01, 2009, 22:12:05 »
thanks guys will have a look a those as i need to get it sorted it drinks fuel at an alarming rate when it goes off on one cost me £20 to do 32 miles yesterday and of course it wont idle at junctions etc so it,s apain in the backside to drive like that :evil:

Offline Range Rover Blues

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Re: Intermittant rough running fault
« Reply #4 on: July 06, 2009, 20:05:28 »
Quick question, did the installation include ALL the engine sensors, road speed, gearboc etc and what tune select resistor is fitted?
Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.

Offline gt.jacko

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Re: Intermittant rough running fault
« Reply #5 on: July 07, 2009, 20:55:18 »
It did n,t include the rd speed sensor but everything else is fitted it has been running fine this fault has come on recently, oh and I dont know what tune select is fitted without having a look as i cant remember.

Offline Range Rover Blues

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Re: Intermittant rough running fault
« Reply #6 on: July 07, 2009, 22:35:45 »
Road speed sensor doesn't make a massive differnence on it's own.

Does sound like either an air blockage or sensor fault.
Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.

Offline gt.jacko

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Re: Intermittant rough running fault
« Reply #7 on: July 11, 2009, 16:30:29 »
Looks like it might be air mass sensor as when fault appears if you disconnect air mass sensor it makes no difference to the running of the engine , any ideas best place to get one at the right price?

Cheers  :)

Offline Range Rover Blues

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Re: Intermittant rough running fault
« Reply #8 on: July 12, 2009, 01:25:29 »
Someone said new ones were £50 on E-Bay.

Just check but I think the 4.2 uses the same as the 3.9, 3am and 5am are interchangeable too.
Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.

Offline gt.jacko

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Re: Intermittant rough running fault
« Reply #9 on: July 12, 2009, 12:35:16 »
Just looked at my air mass sensor to get part no of it and it has no identifying no,s on it at all :huh: any ideas what part no could be most of the sensors advertised on ebay ask for part no of your old one typical :evil:


Offline Range Rover Blues

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Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.

Offline gt.jacko

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Re: Intermittant rough running fault
« Reply #12 on: July 15, 2009, 21:56:12 »
Looks like it was air mass sensor , borrowed one of a mate and tried it ,seems ok now going to give it a longer run tomorrow, oh one question which tune select resistor should be fitted to this, it has o2 sensors but no longer has cats fitted.

Cheers
            Gary

Offline Range Rover Blues

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Re: Intermittant rough running fault
« Reply #13 on: July 17, 2009, 00:50:04 »
Then you can run it with either of the UK market ones, I'd need to check but I think therer were 3 fitted most of the time.

One is for a cat equiped car, one obviously non-cat, thing is whilst the cat equiped might be slightly thirstier (had to run stoichiometric whereas non-cat can run lean) the cat equiped is definietly self-tuning whereas the earlier non-cat and non-lambda cars were not, so if there is a TSR for non-cat lambda cars, that's what you want, otherwise stick with the one for cat equiped, if that makes sense :-k
Blue,  1988  Range Rover 3.5 EFi with plenty of toys bolted on
Chuggaboom, 1995 Range Rover Classic
1995 Range Rover Classic Vogue LSE with 5 big sticks of Blackpool rock under the bonnet.

 






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