A battery question!

scott02464 · Jan 18, 2011

Just been trawling through a few posts but cant really find diffinative answers to my specific problems....

1. Iv read that you can fit the biggest battery you can fit under your bonnet but the threads iv read are regarding Diesel engines, but is this the same for petrol engines? (4.0 V8)

2. My battery this morning read on the voltmeter 12.00 volts before i started the engine and then 14.65v when running, is it time for a new en? (battery)

3. Would this kind of voltage make my V8 run like ****e when first started? ie, not supplying enough voltage/spark?

Regards, Scott

lowfat · Jan 18, 2011

It applies to all P38s.
But 12v is what you would expect a battery to produce and 14.65v is what you would expect as a healthy alternator output.

whats your problem?

scott02464 · Jan 18, 2011

lowfat said:
It applies to all P38s.
But 12v is what you would expect a battery to produce and 14.65v is what you would expect as a healthy alternator output.

whats your problem?

Cheers mate.

Problem is that when started from cold, it idles rough as a dog. A blip of throttle andthen the revs drop to nearly stall.

Then when i go to accellerate it just stutters with no power for about 4 seconds then picks up and goes fine until i come to a stop again.

It does this until warm.... Really doing my head in now mate!

j the range · Jan 18, 2011

when you blip the throttle you is knocking off the choke, thats why is running to nearly a stall. if you can get a live read on the engine..

scott02464 · Jan 18, 2011

j the range said:
when you blip the throttle you is knocking off the choke, thats why is running to nearly a stall. if you can get a live read on the engine..

Is that normal then?

Also why would it start doing the same when i get to a junction? (splutters for around 4 seconds before getting any power?

Engineer1964 · Jan 18, 2011

I guess the cheapest option would be to change the fuel filters and see??

Take a read of this thread on fuel problems http://www.landyzone.co.uk/lz/f10/p38-2-5dt-fuel-starvation-issues-81360.html

scott02464 · Jan 18, 2011

Engineer1964 said:
I guess the cheapest option would be to change the fuel filters and see??

Take a read of this thread on fuel problems http://www.landyzone.co.uk/lz/f10/p38-2-5dt-fuel-starvation-issues-81360.html

Thanks for that, iv just read the thread and the symptoms on mine are slighly different. The thread discribes a fuel vacuum problem, but mine has 'no power and spluttering' only when cold. It doesnt do this when warm?

So does any one know what works (or should work) when cold that doesnt work when warm/hot?

Because its as though something is not telling the engine it is cold???

JellySpanners · Jan 18, 2011

scott02464 said:
Thanks for that, iv just read the thread and the symptoms on mine are slighly different. The thread discribes a fuel vacuum problem, but mine has 'no power and spluttering' only when cold. It doesnt do this when warm?

So does any one know what works (or should work) when cold that doesnt work when warm/hot?

Because its as though something is not telling the engine it is cold???

Have you checked the engine coolant tempature sensor, that tells the ecu that the engine is cold and increases fuel and idle speed, I would also check and clean your throttle housing and Idle valve if you havent allready?

scott02464 · Jan 18, 2011

JellySpanners said:
Have you checked the engine coolant tempature sensor, that tells the ecu that the engine is cold and increases fuel and idle speed, I would also check and clean your throttle housing and Idle valve if you havent allready?

Thats one of the things i havent checked yet as it happens....

Iv cleaned the throttle housing, it was clean to start with.

Where would i find the temp sensor? Its a Gems 4.0 V8.

Also is it a different sensor to the one that runs the temp gauge on the dash?

sandyt · Jan 18, 2011

Have you cleaned your MAF

JellySpanners · Jan 18, 2011

scott02464 said:
Thats one of the things i havent checked yet as it happens....

Iv cleaned the throttle housing, it was clean to start with.

Where would i find the temp sensor? Its a Gems 4.0 V8.

Also is it a different sensor to the one that runs the temp gauge on the dash?

Engine temp sensor is usually around the thermostat area, Not too sure if you have one or two sensors on a Gems, you may have just one multi sensor which does fuel injection and temp gauge...just because your temp gauge works doesent mean its telling the fuel injection the right temp...Eightinavee is your man to ask...

scott02464 · Jan 18, 2011

sandyt said:
Have you cleaned your MAF

Yes mate, i cleaned it, it looked clean to start with. i used the electrical connection cleaner?

JamesBB · Jan 18, 2011

scott02464 said:
Cheers mate.

Problem is that when started from cold, it idles rough as a dog. A blip of throttle andthen the revs drop to nearly stall.

Then when i go to accellerate it just stutters with no power for about 4 seconds then picks up and goes fine until i come to a stop again.

It does this until warm.... Really doing my head in now mate!

Mine (1996 4.6 HSE) started doing exactly this and now the local LR dealer has it for a diagnostic. MAF and IAC valve was cleaned as it was idling low - 500rpm or so.

I got it from them 3 months ago with a very limited 3 month warranty, had it a week and still diagnosing. I said they can take their time if it is for a free fix. I was advised to get my long term fuel trims / adaptive values reset, but the dealer says it is not that, the P38s have a closed system (unless there is a fault I guess).

I know they are supplying a new battery as all the repeated cranks for starting have pretty much killed this already ageing battery. Aiming to get it back Friday.

sandyt · Jan 18, 2011

on the off chance have a look at the fuse box under the bonnet they corrode and are pretty much useless after 8-10 yrs when mine went could smell burning but more importantly it would not start when warm and it also idled roughly it can be the cause of lots of probs worth a look

JamesBB · Jan 27, 2011

scott02464 said:
Yes mate, i cleaned it, it looked clean to start with. i used the electrical connection cleaner?

Did you manage to get this going?
Mine was a dodgy wire to the MAF, and also a dodgy wire to the temp sensor.

scott02464 · Jan 28, 2011

JamesBB said:
Did you manage to get this going?
Mine was a dodgy wire to the MAF, and also a dodgy wire to the temp sensor.

Hi mate, yes it was finally diagnosed as a O2 sensor fault. After replacing them both it runs fine again now

The full write up with problems/symptoms is in this thread http://www.landyzone.co.uk/lz/f10/running-bit-rich-129824.html

The thread is a bit long but basically the oxygen sensors wasnt switching (Could see on the live data)

I also got the fuel trims reset, im getting a good fuel consumption now, for a V8 anyway lol!

Let me kow how you get on!

Scott

JamesBB · Jan 28, 2011

scott02464 said:
Hi mate, yes it was finally diagnosed as a O2 sensor fault. After replacing them both it runs fine again now

The full write up with problems/symptoms is in this thread http://www.landyzone.co.uk/lz/f10/running-bit-rich-129824.html

The thread is a bit long but basically the oxygen sensors wasnt switching (Could see on the live data)

I also got the fuel trims reset, im getting a good fuel consumption now, for a V8 anyway lol!

Let me kow how you get on!

Scott

Great stuff, mine was fixed too in thread http://www.landyzone.co.uk/lz/f10/rough-idle-after-maf-clean-124650.html

All seems good

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