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Ally V8

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Ally V8 last won the day on December 30 2017

Ally V8 had the most liked content!

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About Ally V8

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  • Location
    Nr Bath,SW UK.

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  • Interests
    LR Independant,mostly diagnostic work.

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  1. You are quite right,I didn't look at the photo,only read the part listing - Which is clearly wrong.
  2. Sorry, my scopes are Pico 2 and 4 channel - bit much to do a single job. As much as I hate the parts shotgun, I think you might be better of in this case. I see Island 4x4 do a Bosch pressure reg for your car at £85+Vat.
  3. Ally V8

    Disco 2 or Disco 3 ..... Discuss!

    I think you will find that ZF revised their service intervals for these boxes well after they were out in service - and starting to give problems. Which is nothing compared to what is going on with some of their current 9 speed auto's.
  4. Without a scope you are just guessing. As I see it you either need to find a decent garage that really does understand Bosch common rail ,(Fail as we call it) maybe even a dedicated Bosch fuel shop ? Or you can just replace the regulator on the pump. From the symptoms you describe that is the most likely component. Unfortunately a multimeter is of very limited help with what you are diagnosing. Please use either OEM or genuine parts for these repairs,there are some horribly cheap and nasty parts on offer,these will either fail quickly or muddy the waters even more.
  5. Ally V8

    Disco cuts out

    It would help if you could confirm what car it is, you say a 94 TD5 . A 1994 Discovery would be a TDI, wheras a 1999 on would be a TD5.
  6. I think you are confusing yourself slightly. First off, the engine ecu uses the rail pressure sensor to dictate what to output to the fuel pressure regulator as closed loop control. So when you disconnect it the ecu just uses a default value based on other sensor values such as rpm,coolant temp,airflow and driver demand etc. You are measuring voltages I assume with a multimeter,so are seeing average voltages based on the fairly slow refresh rate of the meter. There are only really two ways to sort this out,firstly the parts shotgun, if I had no choice but to do this I would replace the pressure regulator first,its way more likely to fail than the sensor. The better way to sort it is to use an oscilliscope,with this you would be able to see the duty cycle of the square wave of voltage applied to the regulator, plus the varying output from the rail sensor.With a decent scope you can then freeze frame the waveforms and see what pressure a duty cycle of say 70% on time produces as a pressure reading at a given rpm. The rail sensor should show a voltage output of 0.5v key on,engine off. This should rise rapidly upon cranking,once above about 1.2-1.4v there is enough pressure for the ecu to start firing the injectors.The voltage should then rise to about 4.5v with a wise open throttle and immediately come back down on releasing the pedal. That is the theory,however when I had a problem with a non starting TD6 RR a few years back I found that the ecu would fire each injector 3 times whatever the rail pressure as soon as it was cranking.(Analog to digital converter unit was at fault inside the ecu in that case) But the principle is the same,0.5v raising to about 4.5v max. The reason you don't get a check engine lamp with the sensor disconnected is because the software in the ecu does not command it for that fault,I don't think LR ever listed,(As they do for later cars) a fault code list that shows command Mil yes/no, plus a detailed description of possible fault causes.
  7. In my experience its usually a cabling or connector fault. Rarely the sensor itself.There is even a replacement overlay harness as a fix from LR.
  8. Ally V8

    oil psi

    You won't achieve much by raising oil pressure on an old Rover V8, they simply don't need it to either work hard or do high mileages. Worn rockers,shafts,cam,big end and main bearings are your enemy. I've seen plenty of serp 3.9,4.0,4.2 and 4.6 engines with worn out valve gear,cams and bearings with only 100k or so under them. Can't think that the pump around the crank helped them much...
  9. Ally V8

    oil psi

    I think you would be lucky to ever see more than 40-45psi from an old 3.5. At idle with a hot engine there used to be a bit in the RR handbook that told the driver not to worry if the oil pressure lamp came on at idle,as long as it went out with a few revs on all was good. Think the oil lamp went out at 7psi. Old Rovers relied on volume,not pressure. Much volume used to be lost through worn rockers and shafts,replacing them would often quieten them down and make the oil lamp less friendly at low revs.
  10. The problem you are going to have is that a scanner is pretty useless during cranking.All you will get from it will be fault codes,which may or may not help.Best to clear them and start again,then view the codes after the first no start situation. live data from the scanner will help in terms of what the ecu can see with the ignition on,but not cranking - compare with your other car for good values. A scope is what you need to really see what's going on when cranking,something like a Picoscope. I say this because you can set it up,monitor whilst cranking and then replay the scope traces to see exactly what happened. Connecting the scope to sensor outputs at the ecu end,a close to the plug as possible always helps,and as close to actuators as possible. You have covered most of the usual suspects,but it might be worth checking the plug that connects to the end of the rail pressure sensor,these are prone to poor connections ,especially when the engine is rocking around while cranking. There is an official LR repair harness for this plug.
  11. Ally V8

    Discovery 2, headlight washers failed

    Sorry about the confusion, I wrote a post which was incorrect. Caused by a well known garage/tyre type chain failing a Disco on non working headlamp washers. They shouldn't have done,I checked on the Mot testers manual and they are only required to work after 2009 apparently. Job to keep up with Mot rules,even number plate lamps have had their rules changed...
  12. Ally V8

    disco to replace my old disco one

    And its also an honest way to earn a living,the owner of that car had no interest at all in doing his own repairs,it was a legitimate business expense to him. I'm finding its more rewarding than dealing with shi--y diagnostic jobs on newer LR's with huge parts costs and the high risk of of whatever warning lamp coming back on a week later...
  13. Ally V8

    D2 2001 Air suspension deflation method.

    Stabbing them with a sharp knife works well,you can then twist the knife to control the rate of deflation. I usually support the car properly to stop it from lowering. I then cut the bags right in half to make them very easy to remove. It also means nobody is tempted to try reusing them.
  14. Ally V8

    disco to replace my old disco one

    I recently had a customer in the same position as you,very rusty 300TDI Disco used for towing a horse box. Not many miles a year,but had been very reliable and he likes it. He chose to have it welded up, £2500 later he his chuffed to bits with it,couldn't wait to pay me and went off with a big smile. He now has no rust issues for probably another 5-10 years by which time his wife will no longer need to tow. He is happy because its simple and fixable. Plus the car was worth little as a scrapper and the £2500 would not have bought much of a replacement - Which would be an unknown quantity to him as well. Just saying...

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