lumpy tickover, no go till 3k revs

[simond001]

Anyone got an idea. Got to use the cerb tomorrowto go from Sussex to Peterborough (crashed Range Rover, andBMW is in the garage having a service) and didn't realise how rough the Cerb was till i took it for a wash.

Got an empty garage a free evening if anyone hasan idea what i ca do....

[purpleheadedcerb]

Has it been laid up for a while?

[simond001]

driven once or twice in the last year.

[purpleheadedcerb]

I'd start with some fresh fuel. I've had similar symptoms with my older cars that have been left a while. Its suprising how quickly the petrol can go off.

Hopefully, someone else might have some better suggestions.

[Extra 300 Driver]

I would sy fuel too, maybe a pressure problem.

Try some fresh first.

It could also be water in the fuel. I know if you leave aircraft over night, you get water at the bottom of the tank, I see no reason why this shouldnt happen in cars too.

>> Edited by Extra 300 Driver on Monday 24th April 22:01

[simond001]

Appreciate the help. I have filled it to the top, (it actually ran out totally) and have run about half tank through it.

Once i hit the 3,500 rpm, it takes of like a bat outta hell but not much below that.

[purpleheadedcerb]

You might have sucked some crap from the tank in when it ran out totally, although you would think that it would be lumpy throughout the rev range. Could be electrical. Is it running on all 8 below 3500rpm? Not what you want to hear but get it plugged in and checked out.

[kojak]

Drive it more.

[trooperiziz]

purpleheadedcerb said:

You might have sucked some crap from the tank in when it ran out totally, although you would think that it would be lumpy throughout the rev range. Could be electrical. Is it running on all 8 below 3500rpm? Not what you want to hear but get it plugged in and checked out.

Yup, when mine had these symptoms it was due to a coil failure and wasn't firing on all cylinders at low revs.

[simond001]

anyone know what the coil is from? i will go and get one and try it

[rmaurer]

simond001 said:

anyone know what the coil is from? i will go and get one and try it

Just posted a thread along similar lines (how to change the coils on a 4.2?)...
Here's the link I found for coil packs, I ordered one this morning: www.pistonheads.co.uk/gassing/topic.asp?t=244616&f=6&h=0

>> Edited by rmaurer on Wednesday 26th April 16:09

[trackcar]

the symptoms sound like a lambda sensor connection waterlogged and generating it's own voltage .. ecu thinks engine is running rich and keeps weakening off the fuelling .. at 3500rpm the lambda control is disabled, the trimmed values are blended back into the base map from there to 4k rpm .. hence the reason your car goes ok after that 3500rpm point i would guess.

[simond001]

Thanks Trackcar. I will get the car in the air this afternoon and try and get to the connector. It looks like a devil of a job to reach it.