Loss of Power

Hi guys,

I'm a bit new to Range Rovers - I've got a 94 P38 4.6HSE - and I'm very new on here.

My Range Rover was without a battery for about 24 hours and after a new one was fitted it runs rough and has lost a lot of power. I've checked the plugs and leads and it's running on 8 cyclinders OK, but it's as if the timing has gone to pot. I'm guessing that the ignition timing is controlled by the ECU - and if so could it have lost the mapping whilst the battery was out and defaulted back to a factory setting or am I way off the mark here?

Should add that it's got an LPG conversion and has the same symptoms running on petrol or LPG.

Thanks

When i had probs with my gas i was told to take the battery off my 99 4.0 so's it lost its memory and what i was told to do was start the car after reconnecting the battery and drive it for about 20 miles (no less) on petrol only and then stop, turn off the ignition and the petrol map would reset. Which it did fantastically. The problem i have now is that the gas screws up the petrol everytime i try to use it, but that is not related to disconnecting the battery!

Hope that helps.

Cheers, Nick.

Hi Nick,

Thanks - that sounds like sound advice. Although I get the same symptoms on both petrol and gas - as it switches automatically over to gas just after stariting it's probably never run on petrol long enough to reset the mapping.

I'll give it a go this morning and let you know the outcome.

Cheers

Colin

Does anyone know if there ss there a way of determining if the ECU is faulty without connecting it to Rovacom?

The only solid test is to swap it with a known good one, some land rover specialists do keep them for this purpose so you need to speak to your local fella. Did you try what i suggested or did it not work? Where in the world are you?

Cheers, Nick.

Nick,

Opps - I edited my first posting with the results but they obviously got lost.

I did what you suggested, drove for about 25 miles on petrol then switched off and started again and unfortunately there was no difference. It's running rough, as if it's only running on 6 or 7 cylinders and little power when you put your foot down. That's what made me think the ECU might be shot. Having said that though I didn't disconnect the battery first so maybe the mapping had already been reset with a grotty one caused by running on LPG.

I think I'll disconnect the battery tonight and try again in the morning. How long do you have to disconnect the battery for - do you know?

I live in Leicester - oops again just edited my profile.

Thanks

Colin

Just reading this i think i have similar probs

i had a flat battery & charged it etc, but i keep getting "blips" (short drops) in the revs when i use the LPG, but runs fine on petrol. I will try the 20 mile run on petrol & see what happens.
Will let you know how it goes.

I've just disconnected my battery so it'll be off for about 9 hours or so. I'll also post results tommorow after another 25 mile run.

Hi both.
Firstly there is apparently a distinct difference between going flat and disconnecting the battery. Secondly you MUST disconnect the battery overnight before you drive the 20 odd miles, and you can't let it change to gas. Don't forget there will be no alarm!!! If the battery goes flat the low voltages seem to confuse the various brains on the car. Thirdly mine is a '99 4.0 on motronic mangement and all that is affected is the petrol map, windows need resetting and the radio memory. Hope this help's.


Cheers, Nick.

No joy still the same. I guess I'll have to get someone to look at it.

Hi Colin.
My car has the issue of running rough, knocking when started from cold (brand new engine) and poor performance so i got it booked in on t4 and it said low fuel pressure. After much ummng and ahhring i changed it, no better. New air flow meter, no better, already has new temp sender and stat. Out of curiosity i stopped using gas for three weeks and it had returned to normal. So used gas for 15 odd miles on Saturday and on Sunday it was awful again.
Turns out that my all singing, all dancing, "Specificaly for that model, adaptive, sequential Italian Electrickery" monitors my petrol map for thirty seconds from cold, changes over seamlessly and then spends the rest of the journey buggering up my petrol map, if i met Mr Zavoli this morning i think i'd just shoot him!!!!!!!! (Allegedly)

However i might just take it back (again) to the gas fella who says that he can program (takes about three hours of me driving him around) the gas by reading the petrol map and altering the bad spots in the gas map.......i am definately losing the will to live.

Have a good day.
Cheers, Nick.

Zavoli - well there's a coincidence!

I bought my RR, already converted, a year ago and everything was fine until I had to remove the battery for 24 hours for Halfords to confirm that it was nackered! New battery in and rough running and power loss ever since. As I get the same symptoms on petrol and LPG I've been concentrating on the petrol side but I suppose that the LPG system itself might be screwing things up.

It's due the 140,000 mile service in a few hundred miles. I think I'll bite the bullet and speak to the local Zavoli man - hopefully he'll be able to service it as well. Just cost loads I expect - and that on top of a new Cat that I've just put on. Still, I managed to get 1 for £1,300 less that Land Rover was charging!!!!

Cheers for now.

Colin

Update.

Took it to the LPG man today to sort out and service the LPG at the same time. However, it seems that it's more of a problem than I thought as it's got very low compression on 3 cylinders (and he hasn't checked the other bank yet).

Hmm - I think my days of Range Roving might be over!