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Discussion Starter · #1 ·
can someone expain leak back in leymans terms, pretty please.

. Having some injector problems on a 98 auto p38. When i pull up a hill theres not so much power and over the brow when you let your foot off the accelorator the injector light comes on and it has been known to stall at higher speed. I know injector one needs re bedding and black death is visible but is cutting out expected rather than just power loss? After mulling over this for a few days i heard about leak back from a bosch specialist who confused me(on purpose i reckon).... any help would very much appreciated cheers
 

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Re: can someone expain leak back in leymans terms, pretty please.

i would imagine the injector pump needs a rebuild if its leaking back. i'm not sure about the RR diesel system, is there also a fuel pump in the tank?
 

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Re: can someone expain leak back in leymans terms, pretty please.

pull the plug on no. 4 injector and try it for a bit.
you will get a fault light but with no position signal it works fine on defaults, a false signal can confuse the DDE and cause it to shut off fuel. if it works better with the signalling injector disconnected you have your problem.

much better still is if you can get it on diognostics.every time the injector light comes on ilke that it logs a fault. thatnstays in memory even if it clears so you should point straight at the problem.
 

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Re: can someone expain leak back in leymans terms, pretty please.

and to answer your question leak back would normally mean fuel passing up the injector and out the leak past (the clear pipe).
some is normal to lubricate the injectors, it goes back to the system. very badly worn injectors will leqk more and get less of what should go to the pot into the pot.
other than no. 4 the injectors are not that expencive. price up a single TD5 injector and you will feel much better
 

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Discussion Starter · #7 ·
Re: can someone expain leak back in leymans terms, pretty please.

Thanks for your replies. Ill be trying that those avenues right away. Ill let you know the finding. This is no way to start a relationship.. (with the RR i mean) Cheers again
 

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Re: can someone expain leak back in leymans terms, pretty please.

ok, three repliesbut i found the site i was looking for
www.uniteddiesel.co.uk

they have far better explanations than me.

when i had to change an injector his price was very good and they loan a socket with a window for no. 4 with the wire.

try giving him a call, i will bet you money he knows a whole load more thqn your Bosch man
 

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Discussion Starter · #9 ·
Re: can someone expain leak back in leymans terms, pretty please.

So the fuel pump rebuild is so nearly had kittens about might not be as bad as i thought? Thanks, heart swallowed again! I know my luck though... number 1 injector is a mess with gunk and bubbling at its seat the others look to be fine visibly however like an iceberg, theres much more to it i cant see. Need to do an old fashioned bottle leak test too. I do like this car i just wish it didnt petrify me with this kind of thing. Gonna seem a bit thick here but is the bmw m51 a t5 engine?
 

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Discussion Starter · #11 ·
Re: can someone expain leak back in leymans terms, pretty please.

Ooh, there is a pump in the back but it seems to be priming fine if not more than i would expect. This may be me or due to the fault. Cheers.
 

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1995-2002 Range Rover P38A
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Re: can someone expain leak back in leymans terms, pretty please.

Hi

TD5 is the engine fitted to the Discovery vehicles and has nothing to do with BMW other then that the factory belonged to BMW when they were invented. These have electronic controlled injectors and are more modern then the type of engine that you have with the old fashion fuel injection pump and injectors.

Regards

Jos
 

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Re: can someone expain leak back in leymans terms, pretty please.

Hi

Is there any black smoke? Lack of power in a diesel is most likely because of fuel starvation caused by insufficient fuel supply towards the injection pump due to blocked filters or insufficient supply pump pressure. This can cause vacuum in the supply lines and air being sucked in. This starts to become most noticeable when extra power is demanded.

It can also be caused by problems with the turbo charger or charge air system. The last problem will cause lack of air and because of that the engine will emit black smoke.

Bad fuel injectors cause drips from the nozzles after the injection and result in high exhaust temperatures due to after burning and will also be visible as darker colour of the emitted gasses.

Regards

Jos
 

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Discussion Starter · #15 ·
Re: can someone expain leak back in leymans terms, pretty please.

No Jos, theres no real emissions of any kind and the car passed mot 2 weeks ago. I believe the turbo is fine as the car goes ok at times. It idles sweet. Just when i let my foot up off the accelerator it wants to cut out like fuel starvation. The filter is new and theres no bubbles and the pipes new from filter to ip.
 

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Re: can someone expain leak back in leymans terms, pretty please.

you definitly have more than supply issues if you are logging faults, you ned to find out what it has logged. your injectors dont sound ideal anyway hence the link.

trust me Jos, i a, well aware we dont have a TD5 and its not common fail, it is a BMw M51 as mentionedprice up a TD5 injector though and you feel a whole load better about buying a sex of six old fashioned ones even if no.4 costs more than the rest put togather
 

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Re: can someone expain leak back in leymans terms, pretty please.

*****in on my thread.... this is what i hate about forums. There are some very informative people out there but so much *****in like a bunch of girls out speakin eachother. And clever admin. Obviously a deisel or i wouldnt be doing a leak off test.. thanks for advice but if ya want to nit pick do it at home to the wife. Thats what ya get married for.....
 

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Re: can someone expain leak back in leymans terms, pretty please.

Hi

Back to your problem, You mentioned that it does not deliver the power you expect when it is pushed hard, and stalls sometimes when you let go of the accelerator, when it does it also shows the injector light in the cockpit.

When you have injector one leaking to the outside, start with repairing that. The principle from the diesel is that the compressed air in the cylinder becomes so hot that the injected fuel ignites the moment it is entering the combustion chamber. When there is a leak there is lost compression and the engine might be working on 5 cylinders explaining the power loss. The repair most likely only involves extracting the injector, cleaning and fitting with a new copper washer to seal properly.
A good way to test if the injector at idle is working is slacking up the high pressure pipe of the injector until it starts leaking at the connection the engine starts to run on 5 cylinders and a slight dip in rpm is normally noticeable. If you do this on all injectors you can determine if there is one that does not work properly.

From previous posts about diesels on this forum I have read that there were some problems with the leak off pipes cracking and causing air to enter the fuel injection system.

I do not have the Diesel P38 but a V8. I am however working with diesels for my profession as a marine engineer.

Regards

Jos
 

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Re: can someone expain leak back in leymans terms, pretty please.

*****in on my thread.... this is what i hate about forums. There are some very informative people out there but so much *****in like a bunch of girls out speakin eachother. And clever admin. Obviously a deisel or i wouldnt be doing a leak off test.. thanks for advice but if ya want to nit pick do it at home to the wife. Thats what ya get married for.....
where is your problem? Two people tell you basically the same thing and you call them a Bunch of girls!
Better than that: two Marine Engineers (I am a chief engineer) so people who really should know diesel engines.

Mods questioning if it a Diesel: most of the moderators and a good proportion of the forum members are US based and as such never had the diesel P38, I for one still very much value their comments on many subjects but asking if was a diesel seemed perfectly reasonable to me. Add it to your info and it would not be relevant.

Jos and I sound to have similar backgrounds and we are both saying more or less the same thing, if I were you I would listen before you cause damage and cost yourself a new engine. You said one injector is not right- fix it. Your engine has a fault, it keeps trying to tell you that - find out what it is.

Now a bit of specific stuff because I do have a diesel P38:
Jos`s suggestion on the HP pipes whilst valid is a ***** to do on that engine
Reason is to get at the injector you have to take the inlet manifold off (you then can't run the engine)
Once that is off fix the bad seat, if you suspect an issue try the link I gave you, a set of service exchange nozzles won't cost that much and then you only do it once.

You asked if was a BMW M51, I confirmed it. Look at the profile for Jos, do you think English is his first language?

If you do want to know about your engine as said it is a BMWM51, when LR developed the P38 they decided the tdi they had at the time was too agricultural and went looking around. The negotiations with BMW eventually ended with BMW buying LR but in the meantime they let LR use the M51 for the RR it it was modified, a very different sump to hold oil and maintain suction at extreme angles and it was down rated. One of the few engines I would advocate chipping (unfortunately the insurance companies don't agree) as it was down rated based only on marketing so the RR did not compete head to head with the BMW saloon cars, it had less power.

I do know a little bit, Jos clearly does as well. The fact that we both come back to see if you made progress shows we are willing to help, if you don't want to listen and prefer to call us (and the moderators) a bunch of girls then fine your problem.

Finally I did not marry my wife to "nit pick" if you did your wife has my sympathy





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