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Discussion Starter #1
Sorry for all the questions but it's all coming together at once and I have so much to ask!!!

I drove my p38 4.6 HSE yesterday for the first time, it hasn't moved for nearly 18 months. I just took it a couple of miles but it wasn't quite as smooth as I had expected, the engine was running lovely it was more the gearbox. I haven't gone far so it's difficult to say, but trying to drive slow it felt a bit sluggish and gently pressing the throttle didn't make a huge amount of difference and gearchanges seemed a bit jerky. If I put my foot down a bit more it went like a rocket and gear changes seemed quite smooth.

So really it seemed a bit all or nothing with the power - is that how you would descibe it? Or is there something I should be looking into? I have no faults on the message centre, all warning lights clear from the dash once I start driving. Is it something which needs a little time to bed in?
 

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LEGACY VENDOR
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Rich998a said:
Probably needs a good service..?
And a reset of adaptive values
 

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needs more than a couple of miles!! :naughty:
you can't expect it to be in peak operating range unless you have driven about 12-15 miles (20-25km) under steady conditions to bring it up to proper operating temperature... then make your observations...and it has been dormant for 18 months :shock:
 

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2002-2005 Range Rover MkIII / L322
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Agreed with above.

Also, to me, the P38 has the smoothest shifting tranny of any auto box I've ever driven. It's rare when I even feel a shift...although I can hear it since I cut out my rear silencer boxes. :doh:
 

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Not to thread jack, but it picked my interest when you said the p38 had the smoothest shifts of any autobox you have driven. I have 265/75r16 tires on my rover (dont know if that makes a difference) and my shifts are sometimes very hard, and on hills, the truck doesn't always seem to know what to do. Any ideas?
 

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2002-2005 Range Rover MkIII / L322
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NikeCheck246 said:
Not to thread jack, but it picked my interest when you said the p38 had the smoothest shifts of any autobox you have driven. I have 265/75r16 tires on my rover (dont know if that makes a difference) and my shifts are sometimes very hard, and on hills, the truck doesn't always seem to know what to do. Any ideas?
The one time my truck wasn't shifting smoothly was when it was low on tranny fluid (my fault).
 

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1995-2002 Range Rover P38A
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Fresh fuel.......just one liter of nasty old fuel can knock the cetane value of fresh fuel for a 6 so dont fill up to much, then drive and toss in a bit more fresh fuel....

18 months, engine oil needs changing proberly tranny oil and filter too as you say its sluggish
 

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Discussion Starter #9
Fuel is 18 months old and nearly empty so a good tank full should help, but the engine itself is running smoothly I would say it was more the gearbox, fluid level is a little low due to the cooler leaking when it's running - so hopefully that will help once sorted, and hopefully it will adapt a little over time. I had an Auto Disco 300tdi a few years back and that was lovely and smooth was that a similar box?
 

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Perhaps it would be best to start with a fresh batch of ATF in the tranny. It's been sitting, and has it possibly been apart? You may have some moisture contamination. Start fresh and go from there.

My P38 shifts very smooth at all operating speeds/loads. Other than the change of engine noise you really wouldn't even know when it shifts most of the time. Smoother than my Jaguar.

And Congrat's on getting her up and running!!! Well done....
 

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Discussion Starter #11
Took it for a quick drive today to put some fuel in,

Engine seems to be running nice and smooth but the gear changes are awful.

If I tootle about at slow speeds it seems great, but if I need to accelerate it's awful. Just trying to accelerate a little makes it rev loads then you can just about feel a gear change and the revs back right off for a second or two then the revs go back on, you do gain speed but it's not nice!

Once upto speed say 50mph it seems to drive nicely as you back off the throttle,

Switching to sport mode seemed to improve it slightly but only because it took a little longer to change gear I think?

I don't really understand the whole adaptive values thing.

Engine oil is fresh, car behaves the same on LPG or petrol

Could it be anything mechanical such as where the throttle cable pulls?

Still getting no errors on the dashboard
 

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JACK'S GRANDAD
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Test your TPS first off.
If sat it needs a filter/ATF change IMHO.
Before looking into other "cures" get it back to square one first.
The adaptive values should also be reset if it needs a TPS for sure, and I would probably do it after it sat for so long myself. A decent Indy shop should be able to do it for very cheap (10 minute job).

Martin
 

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Discussion Starter #14
I'm going to test the TPS voltages to start with but having read the section in Rave I don't think it's detecting a TPS fault as the kickdown function seems to be operating, having read more on here though it does seem it can mess up with out actually triggering a fault.

The Rave Manual suggests that Adaptive Values resets isn't neccessary, and that there is something in place which will relearn over time.

I am also going to inspect the plugs

It idles perfectly so I don't think the iac needs looking at,

I did notice that the mechanical linkage at the back behind the TPS was a bit sticky so I'll give that more of a clean and see if I need to adjust
 

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JACK'S GRANDAD
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Oh well, if Rave says so then skip everything I said. Does Rave Know it was sat for 18 months too? :think:
What I suggested, and what others have suggested, are cheap starting points. Trying to save YOU money is what we are trying to do.
Will it relearn all adaptive values? Sure it will, after something like 50 drive cycles... :roll: That or you can have someone click a few times on a mouse pad and get it over with. Problem with letting the rig relearn everything, is that you will be chasing ghosts in the meantime. How Rave knows that everything is out of whack due to 1.5 YEARS of sitting around is a little beyond my comprehension unfortunately /:(
If it were me, I would be changing ALL fluids and filters off the bat. Then you can see what is wrong and what is right.

Martin
 

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Discussion Starter #16
Sorry didn't want to sound like I'm not taking your advice, I'm taking it all in and searching for further info around what you suggest,

My problem at the moment is that I can't get to anyone with a diagnostics machine due to it not being MOT'd yet, and I need it to be good enough to get through the MOT before I can go there - bit of a catch 21.

I had a bit of a fiddle today. I had a litre of ATF so I dropped a litre out and put that in. I started with the level right on the top marker on the dipstick and ended up with it right in the middle.

I also cleaned up the throttle bit that operates the TPS and adjusted the throttle to reduce the idle point - was about 900rpm now it's about 650rpm

I also checked each spark plug and they all look identical.

I then took it for a quick run and it was loads better, it wasn't doing the strange gear changes - felt loads better. It still felt a little flat low down as if it's still not 100% right but it's driveable now.

Not sure what helped but I will be getting a couple of gallons of ATF and will look into getting a filter too.

Few more problems appeared though,

Big box in exhaust is rattling big style
Throttle body appears to have sprung a leak
Still got leak from T peice in coolant hose (which goes to LPG)

Brake Accumulator seems to run a lot - not sure how much is too much though?
 

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As said, start by changing the ATF and filter. When you check the level, make sure you do it with the transmission cold, engine running and after cycling through all the gears standing still.

The brake pump shouldn't run more then once every 5 presses of the pedal. If it does, the easiest fix is to replace the accumulator and hope the pump itself is still OK. I had one fail on me a few weeks ago, had to drive it home without brake-assist, not pleasant in a heavy car, especially with an autobox.
Before it goes, you should notice the brake and ABS warning lights coming on when starting (and staying on for some time) or when braking hard.

Greetz,

Filip
 

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Discussion Starter #18
ABS light comes on, on startup but disappears when driving off.

You can hear the pump running everytime I go to start up for quite a while, then I think it runs with every press of the pefal. Brakes seem to work well but I'll have a closer look - don't fancy having no brakes 8-0=
 

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sotal said:
ABS light comes on, on startup but disappears when driving off.

You can hear the pump running everytime I go to start up for quite a while, then I think it runs with every press of the pefal. Brakes seem to work well but I'll have a closer look - don't fancy having no brakes 8-0=
The ABS light remains on to inform you the system will only arm when going over 5mph. It's the red brake warning you should keep an eye on.

Running at start up is normal, but it shouldn't come on with every press of the pedal.

Don't fear too much either, your brakes WILL work without the accumulator/pump, but you won't have power assist, so you'll need to put quite some weight on the pedal.
 
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