Benser Posted October 10, 2009 Share Posted October 10, 2009 Hi all, wondering if anyone could help with this?? I 'm trying to figure out the fuel system of a 1998 P38 with 2.5 BMW diesel engine. I know the in-tank pump has not worked for some time, so I cant let fuel in tank drop below about a quarter full. Suddenly the engine wont start. My ques, what is the purpose of the black plastic assembly that the fuel filter screws into? I know it houses the pipe connections, but wires also?? Does the engine now only use the fuel injector pump to get fuel from tank to engine? Is it difficult to fit a new sender pump inthe tank? If anyone has any info I would really appreciate it? Thanks. Ben Quote Link to comment Share on other sites More sharing options...
sheltie50 Posted October 10, 2009 Share Posted October 10, 2009 Going to take a chance that you have had to give it several heats on the glow plugs to get the thing started and they have failed due to exesive use. Tank pump can be changed by cutting an access hole in the rear floor but you must be aware that the pipes and wiring are just below the floor and that the new access point should be sealed as per a real one. Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted October 11, 2009 Share Posted October 11, 2009 It's boring to keep writing this, but attempting to maintain a 38A without a copy of the RAVE Workshop and Electrical manuals to hand merely brands anyone as their own worse enemy. Google Green Oval RAVE and go from there. I see from looking at your previous post that you have used this forum before, to help with 38A problems. Surely you have seen that advice already? The wires in the fuel filter head unit are for a fuel pre-heater. (Shown in the ETM). The fail to start may or may not have anything to do with the failed in-tank fuel pump. I'm quite prepared to go with Sheltie's suggestion of failed glow plugs, but I don't associate their failure with the failure of in-tank pump. That said, very few people have sufficient experience to say what the side effects are of a particular failure are when it is ignored, EXCEPT to say that it inevitably makes diagnosis of a further fault more difficult. With any car, but particularly the 38A, don't ignore faults, fix them as they occur. Regarding changing the in-tank pump, why make things more difficult? The tank is easy to drop from underneath, but if you don't have the Workshop Manual perhaps you don't realise that. Normally I'd suggest running the tank down as low as possible, to reduce the weight, but now you can't start the engine you don't have that option. See what I mean about the benefits of NOT leaving faults until a second one occurs? With the failure of the in-tank lift pump, of course the High Pressure pump is now responsible for getting fuel from the tank to the engine. How else is the fuel to flow when the tank is below the engine? Again, the Workshop Manual takes the guess work out the analysis. As the HP pump is not a very good suction pump, your fail to start may be because the fuel filter is clogged just enough to prevent fuel flow at engine cranking RPM. I do appreciate everyone has to start somewhere, but help yourself by getting and reading the Manuals. Treating Manuals as a last resource, to be tried when all else has failed, is simply making life a lot harder than it need be, especially with the 38A (and probably later models of Land Rover). Good Luck. Quote Link to comment Share on other sites More sharing options...
Benser Posted October 21, 2009 Author Share Posted October 21, 2009 Hi guys thanks for both your replies. Sheltie, about the glow plugs, they were changed about 18 months ago, the engine always starts (started) on the first turn as soon as the heater indication on the dash goes out? Ps. when the tank pump failed, a local mechanic put a check valve on the fuel line after the filter, I didnt know any better and it did work? David, I take your point about manuals, ( and consider myself well told off ;o) I already have the Range Rover workshop manual. Its ok for instruction, but there is no troubleshooting/ diagnosis stuff in it at all? I tried to download the Rave manual but it seemed like a huge file and my computer gave up? I suppose stuff i was looking for was, I rigged up a temp fuel supply to the fuel line on the engine side of the filter/heater. Engine didnt start, then I wondered what pressure would the fuel normally be at, at this stage? Any hints/tips on testing any of the vital components without simply replacing them? Anyway thanks again for your replies, Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted October 21, 2009 Share Posted October 21, 2009 Hi guys thanks for both your replies.Sheltie, about the glow plugs, they were changed about 18 months ago, the engine always starts (started) on the first turn as soon as the heater indication on the dash goes out? Yes, that's what should happen. Ps. when the tank pump failed, a local mechanic put a check valve on the fuel line after the filter, I didnt know any better and it did work? The check valve trick is normal, although I think they normally get fitted between the filter and the tank, near the filter. That's where mine is, fitted during the first three years of the cars life. David, I take your point about manuals, ( and consider myself well told off ;o) I already have the Range Rover workshop manual. Its ok for instruction, but there is no troubleshooting/ diagnosis stuff in it at all? Came across a bit strong did I? Oh well, there was just plenty of opportunities presented :-) I tried to download the Rave manual but it seemed like a huge file and my computer gave up? Yes it is a big file, although I think it asks more of the download speed allowed by your ISP / local line than of the PC itself. In a similar exchange I had recently the other party said he wasn't to hot on converting Image files etc, but his 15 year old son said he'd do it in 10 minutes. I suppose stuff I was looking for was, I rigged up a temp fuel supply to the fuel line on the engine side of the filter/heater. Engine didn't start, then I wondered what pressure would the fuel normally be at, at this stage? Any hints/tips on testing any of the vital components without simply replacing them? The ETM has more explanatory text about the elements of the fuel management system than the Workshop Manual. No, I don't know what pressure the in-tank pump produces, the normal test is how much fuel it flows. From a Technical Bulletin (from the RAVE disc) 5. Remove fuse box lid and remove relay R12. 6. Connect an electrical feed from the battery to terminal 5 of relay R12 housing for exactly 10 seconds. 7. Note the quantity of fuel dispensed. A minimum volume of 180ml in 10 seconds confirms satisfactory fuel pump delivery. HTH. Quote Link to comment Share on other sites More sharing options...
sheltie50 Posted October 21, 2009 Share Posted October 21, 2009 There you go, get a rave on in your p,c Seriously though you will / do need it. It's not really the thing to do but have you tried a shot of aerostart to confirm that it will fire, maybe even start. Stupid question but is there enough fuel in the tank. Is the fuel shut-off wire still on and working. Black thing is a fuel heater, cant think it will make much difference in this country but open to persuasion. Pipe goes onto inlet manifold and should be on. Yes you are relying on the injector pump. The in tank pump requires tank removal to replace it, it can be done by cutting in from the top but unless your sure of location and exactly what your doing, do not go in from the top, fuel pipes and wires are just under the floor etc!! Have you checked that the immobiliser is off so that it can start, anything in the message centre. Its all questions but food for thought. Quote Link to comment Share on other sites More sharing options...
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