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Discussion Starter #1
HI All,

Not posted for a while but been lurkin.... My 2000 P38 4.6 has developed a problem and I want to cure it. Starts fine and idles fine, Drives fine UNTIL.... I put my foot down at motorway speeds. Car seems to power up but then retards and does not accelerate properly. Seems like a blocked fuel filter but these do not have them. It does rev past the issue and all is fine but feels really lumpy if I press the pedal 3/4 down and does not pick up at all well. Seems like it won't rev. Then press all the way down and it does pick up but does not seem as responsive.

Some reads have lead me to the MAF but I have no diagnostic gear. Could this be disconnected and tested to see if makes a difference..??

Any help or advice wold be great.

Thanks
Ash
 

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comports said:
HI All,

Not posted for a while but been lurkin.... My 2000 P38 4.6 has developed a problem and I want to cure it. Starts fine and idles fine, Drives fine UNTIL.... I put my foot down at motorway speeds. Car seems to power up but then retards and does not accelerate properly. Seems like a blocked fuel filter but these do not have them. It does rev past the issue and all is fine but feels really lumpy if I press the pedal 3/4 down and does not pick up at all well. Seems like it won't rev. Then press all the way down and it does pick up but does not seem as responsive.

Some reads have lead me to the MAF but I have no diagnostic gear. Could this be disconnected and tested to see if makes a difference..??

Any help or advice wold be great.

Thanks
Ash
What do you mean Seems like a blocked fuel filter but these do not have them.Mine certainly has a fuel filter :think:
 

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1995-2002 Range Rover P38A
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You do have a fuel filter, but (and it's a big BUT) it's in the fuel tank on the Bosch. Absolute pain to do. It means dropping the tank or cutting a hole in your boot floor.
I replaced mine a while back, it's only a fine mesh filter and it was as clean as a flute, nothing wrong with it. But seeing as how I'd dropped the tank to do it, it made sense to change it whilst I was there!!! My problem ended up being plug leads!!!
Does sound possible that the MAF is playing up, trouble is, it could also be a host of other things. Fuelling, O2 sensors, plug leads. plugs, coil pack, air leak (you'd probably have an erratic tick over with an air leak) pity you can't get your hands on a fault reader, it may throw some light on the fault.
I have a spare, good, maf if you want to borrow it and try. As long as you pay postage both ways :thumb:
 

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Discussion Starter #4
Thanks Cornishman - I might just try to find someone with a code reader first. I also read that the MAF may not throw up any codes and the car has certainly not suggested anything via the dash.

IT does not have erratic tick over or idle and is fine at slower speeds around town. It just seems to bog down under load and then if I hold the throttle where it happens it stays bogged down. It will get past it on full kick down but It seems to be around the 70mph mark that it kicks and splutters along. No miss fire as far as I can tell but perhaps thats what the spluttering is. ;)
 

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Does soung very similar to the problem I had that turned out to be plug leads.
If I was holding her steady, she seemed to miss slightly and pick up wasn't clean. She lacked urgency, I bought a code reader and got lean on banks 1 or 2, (I think that's what came up!) leading me to replace O2 sensors and MAF, still the same.
Then replaced leads (as I'd only replaced the plugs weeks earlier), and my problem went away!!

As for removing the maf, I think you van just disconnect it a
 

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Discussion Starter #7
Thanks mate - I replaced the leads about 2 years ago for the blue ones and all was well but this has just started to happen in the last 2 months. I guess I should check them all now but if it was a (or more than one) dodgy lead, would it not be noticeable under most, if not all, driving conditions.?

Would a diagnostic check throw something up for this also.?

Thanks again
 

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I bought Magnecor Blue leads after buying cheap generics, that were rubbish. Lot of post's on here regarding cheap leads and how most buy Magnecors or OEM.
No fault thrown up re' leads apart from Lean codes, which could be a lot of things!!
Get a code reader on there and see what it says. What about a LR specialist in your area, NOT main stealer. They are USELESS......imo :thumb:
 

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comports said:
I guess I should check them all now but if it was a (or more than one) dodgy lead, would it not be noticeable under most, if not all, driving conditions.?

My problem only came to light under light throttle openings or coasting, when a slight misfire? or hesitation developed.
But she did seem reluctant to pick up and accelerate well.
 

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I do have the same problem on fuel only, not on LPG since 1 year. I don't think it's caused by my LPG single point install because the whole thing ran fine for nearly 10 years.

I can remember running Paris to French Riviera (almost 900km) non stop, on one tank of LPG (68 liters) and one tank of fuel at prohibited speeds.

Now running on fuel requires big concentration because a brutal stop can make it stall and not start for 15 minutes or so.
When i press the pedal fully, it misfires and i can hear some deflagrations in my air box. If i want to reach my maximum speed on fuel : 120 km/h, it requires minutes and minutes.

One code is always coming on my Testbook : 1178. Testbook says cracked headers.

The thing is if i reset adaptive values and run only on fuel for a week, i do not have the code but speed limits is something like 160kmh (it used to go well beyond 190kmh). So it looks like it's due to LPG.

I had my LPG tuned last month and no result at this point.

One other thing. On neutral, it revs freely up to 6000 RPM. On Drive, it depends how quickly i press the pedal. But it feels like it's running on 4 cylinders only.
 

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Hi had the same problem not long ago. Replaced the MAF sensor (3 minute job) ($130 AUD) and all was well, with another 100 bhp that was missing!!! Hope this helps?
 

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Hi Tonys - did you leave a zero or two off the cost of your MAF ? - if not, what sort is it and where did you get it, please?

Cheers

Andy
 

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There is a Lucas element which can be inserted into the existing tubular housing. Just be careful what you buy as I've had an LPG 4.6 Thor in recently which wouldn't run properly, and a local LPG guy had put one of these poor quality elements into the existing MAF. Needless to say it didn't work. :doh:

You can spot a poor quality version. There is something like the pins of a chip evident when you look towards the bottom of the element. Genuine ones don't have these. I as thinking that there is some sort of artificial data held on it to run an engine on data not taken directly from the MAF. Just a theory though. It would explain why some work and others don't... :doh:

Get a genuine part unit if you can. It'll save you time and money in the medium term.

Oh, and OP - I'd go with either poor HT leads or plugs. Maybe put it on T4 to check there are no fault codes stored for the Throttle Position Sensor etc... Again worth the money in the short/medium term.
 

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Guys,

If i had a bad MAF (mine is the stock one), wouldn't the Testbook tell it to me?

Is there a special test to do?

PS: i do have a chinese crap MAF in stock but didn't find time efficient to mount it. It may be worse than the stock one.

Thanks

Florent
 

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I too would like a definitive answer to Florent's question - will it throw a specific fault ? are there other specific diagnostic signs - I suspect mine is going but I wish I could know for sure without committing to the expense of a new one first. I have easy access to testbook etc - the only fault I regularly get is P1179 (from memory) - I have posted about this fault previously.

I haven't been able to find the MAF sensor only on the p38 spares website (Tonys post refers) - any other pointers?

Thanks

Andy
 

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I'm not sure about supply, but remembering that the Genuine Part is now over £800 for a GEMS AFM, Allmakes list one which should retail at around £135ish and my supplier (just called them) reports no returns under warranty.
 

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Thanks Rich - I can't find a link - can you assist with a link or the purchase?
 
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