jack7531 Posted March 28, 2015 Share Posted March 28, 2015 Hi all,l am new to this site and discos in general,my 300tdi starts and runs fine,idles at 950 nice and smooth,drives okay till l come to any sort of a hill,l then seem to lose power,kicking the autobox down helps a little but not much,l also have a check engine light on constantly,l cant find any problems,so l am wondering if maybe there is a sensor of some sort that maybe playing up??,other than that she is fine,saggy headlining notwithstanding,cheers all,jack. Quote Link to comment Share on other sites More sharing options...
Boydie Posted March 29, 2015 Share Posted March 29, 2015 Jack, What model 300Tdi ?? with or without EGR ?? with or without engine and gearbox electronics ?? Have you:- 1.) Cleaned out the intercooler recently, these have a nasty habit of collecting oil in them, this reduces their efficiency. 2.) Checked the intercooler pipes, if they are the original rubber hoses they sometimes delaminate causing a restriction in the air-flow. 3.) Do you have a turbo air pressure gauge fitted and if so what turbo pressure are you achieving? It should be around 14 psi when full bore up any hill in the correct gear. 4.) Looking out of the rear window climbing up hills what colour smoke (if any) is visible? 5.) When was the last time you replaced the fuel filter, every 6000 miles is a normal service filter change. The air filter is good for about 10,000 miles, no more. 6.) Have you checked the fuel sedimenter ? This is on the drivers side, under the fuel tank and on the inside of the chassis rail, again, empty any sediment out of it every 6000 miles. 7.) Does the water temperature rise when you're driving up hills? 8.) The engine light coming on is a real concern. This could indicate a low charge from your alternator. If you have a multimeter check the charge at idle and get back to us. Oh, and welcome to the forum Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted March 29, 2015 Share Posted March 29, 2015 The 950 rpm idle is too high,its a long time since I did much with EDC equipped 300 TDI's,but you may find the crank sensor has failed so the ecu defaults to the needle lift sensor on #4 injector.(This is why the high idle speed,the needle lift sensor is less accurate,the higher speed prevents stalling) Either way you need to stick it on Testbook to read which fault code is putting the lamp on.They are generally very accurate codes for the type/age of the system and will be a big help in diagnosis. Quote Link to comment Share on other sites More sharing options...
piper109 Posted March 29, 2015 Share Posted March 29, 2015 Have you checked the Turbo output ? See 3.) on Boydie's response. Quote Link to comment Share on other sites More sharing options...
jack7531 Posted March 30, 2015 Author Share Posted March 30, 2015 Hi guys and thanks for the responses,l dont have a turbo gauge anywhere l can see,so l guess there isnt one,l get a little smoke on starting from cold,this then reduces to practically zero,l have had it suggested to me that l should fit an egr removal kit-this is now on order,also a de cat front pipe-l dont seem to have a cat in the front pipe so assume a previous owner has done this already,where do l find the crank sensor?,l have had a look but cant see anything that looks like a sensor,or is it buried somewhere horrible?,if 950 rpm is too high what should it be?,iit sounds pretty good idling at that!!,l am about to give it a darn good service,and also change the lift pump,some of the bushes in the throttle linkage have a heck of a lot of slop and play which cant be helping,so l intend to rectify that asap,l have it booked in for a diagnostic this week,hopefully that will reveal why the light is on,she doesnt overheat or pressure up,oil consumption is zero as is coolant,fuel is another matter altogether!!,l dont expect a lot,but l have worked it out that l am averaging around 22mpg,l was kind of looking for around 25-30...will post the diagnostic results when l have them,cherrs for now all,jack Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted March 30, 2015 Share Posted March 30, 2015 A few things to consider, the idle should be around 750rpm,faulty egr will cause a lack of power - but black smoke as well.Dont worry too much about the slop in the throttle linkage,that lot is there for kickdown and cruise control,its not doing anything to the injector pump,the ecu tells that what to do from input coming from the throttle potentiometer.This is connected direct to the pedal inside the car. The crank sensor is bolted into the flywheel housing at about 11am looking from the front of the car.I wouldn't worry too much about that until you have had the diagnostic session done.Testbook allows you to view engine rpm as shown by the crank sensor and the needle lift sensor on #4 injector - both should read the same unless the engine is on overrun and therefore not injecting any fuel. 22mpg is not bad,about what I used to get from the one I had on local work, only my wife could get more than 30mpg on long gentle journeys. They just aren't very good on fuel. Quote Link to comment Share on other sites More sharing options...
jack7531 Posted March 31, 2015 Author Share Posted March 31, 2015 Hi again guys,well the diagnostic didnt flag up much,only two items-fuel temp sensor and air flow meter temp....fuel temp showed a minus value(0.37 l think),while the maf seems to think l am somewhere in death valley,showing a figure of +50 degrees,clearly both cant be right,the temp here in sunny south wales is barely into double figures,so it looks like l need to replace that at least,the guy who did the test tells me that the fuel temp sensor is inside the injector pump and cant be changed,l am having trouble getting my head around that??,just a few facts/figures l think l forgot to mention:-my truck is a 1997,automatic,300tdi,.......theres no real sign of smoke on hills,l am told that it wont start if the crank sensor is faulty,can the maf be repaired or do l just replace it?,thanks for all the help guys,it really is appreciated!!! Quote Link to comment Share on other sites More sharing options...
jack7531 Posted March 31, 2015 Author Share Posted March 31, 2015 Forgot to say,the turbo boost sensor is also suspect apparently!!!!!,cheers,jack Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted April 1, 2015 Share Posted April 1, 2015 OK, so the diagnostic check has given you 3 things to check out,there are or were at some time 3 things wrong. Before rushing to change any components you need to check the wiring to each of those 3 things.The readings seen on the diagnostic computer are what it thinks its seeing,for instance the ambient air temp of 50c is most likely a default reading because the sensor or wiring is open or short circuited. So firstly you need to get hold of the correct wiring diagram which you should be able to download somewhere on the net.You can then check out all the wires and hopefully do some resistance checks on the sensors to see if they match any expected values in the specs section of the "Rave" info.You have plenty to check before buying any parts. Unlike 99% of modern vehicles with a crank sensor, your car will run with it unplugged - try it,the plug is one of the two connectors just below the #4 injector, the other plug is for the needle lift sensor on that #4 injector. If you disconnect it when the engine is idling it should rev up,this indicates that the sensor is working and the ecu is using it. The ecu will pick up engine speed and just use the needle lift sensor for engine speed sensing.It has to do this as there is a risk of the engine stalling when engine speed drops on overrun as there is no injection.I cant find all the data I used to have about the 4 cyl edc engines,or I would copy and paste it.All I can find is my Bosch FI book which covers EDC theory.It clearly states that the only time the ecu will shut the engine down is if the fuel quantity actuator or its feedback pot fails,everything else has a backup - better,really than most current systems. Quote Link to comment Share on other sites More sharing options...
jack7531 Posted April 1, 2015 Author Share Posted April 1, 2015 Ok ally,if the current batch of wind/rain ever lets up,l will get to work with my trusty voltmeter,just noticed,your not far away from me,l am in chepstow,small world innit(l believe is the expression),while the guy was doing the test,l noticed she stumbled once or twice,just a quick hiccup then back to a smooth idle,not done that before,gone now,l plan to replace the lift pump anyway as it feels like the existing one feels like its not pumping,though l guess it must be doing something or she wouldnt run at all,cheers for now,jack. Quote Link to comment Share on other sites More sharing options...
Boydie Posted April 2, 2015 Share Posted April 2, 2015 Given the price of a new LR lift pump consider replacing it with an electric one, wired to the FIP fuel cut-off solenoid - it works better and priming the fuel filter is as easy as turning on the ignition Quote Link to comment Share on other sites More sharing options...
jack7531 Posted April 7, 2015 Author Share Posted April 7, 2015 hi guys,well l am no further forward,engine light is still on,l still lack power,the idle speed is 750 not 950,my bad,l have stripped and cleaned the maf sensor-how do l test that by the way?-the studs for the egr valve are siezed,so its off with the manifold/turbo,so l can get at them better,l have a tiny amount of play in the turbo,so l will have to get to that soon,l found the turbo boost valve,looks ok but l plan to change it anyway,alternator output seems to be fine,the truck feels like its holding back,-could l have a timing problem?,it runs okay otherwise,little or no smoke,starts fine (starter is lazy but l can live with that for a bit),l was going to fit a straight through centre pipe,till l found that they cost more than the centre muffler box!!!,not sure how that works,a straight pipe costing more than a built up box,not sure what to try next,l feel its something stupidly simple but l cant find it!,cheers all,jack. Quote Link to comment Share on other sites More sharing options...
Boydie Posted April 9, 2015 Share Posted April 9, 2015 Go back to my original thread and check the basics first. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted April 9, 2015 Share Posted April 9, 2015 Ignoring the faults registered by the engine ecu is not helping - its not going to perform with bad sensor info... Quote Link to comment Share on other sites More sharing options...
honitonhobbit Posted April 13, 2015 Share Posted April 13, 2015 Always found that the EDC lump goes better if set to the timing marks then moved forward on the pulley adjusters a tadge... But you need to get your management faults sorted first Quote Link to comment Share on other sites More sharing options...
lincsoldbird Posted April 13, 2015 Share Posted April 13, 2015 When mine did this it was fuel starvation and needed a new fuel pump. Quote Link to comment Share on other sites More sharing options...
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