525 TDS fuel lift pump query ?

[Nickhlx]

I have narrowed my problems with starting down to a likely two problem issue.
As a reminder, the car is a 1995 E34 525 TDS touring...

Can anyone confirm whether the pump on top of the fuel tank has / should have a non-return valve in it, so each time the ignition is switched on it doesn't push a pipeline full of air towards/into the injector pump, which then tries to inject it into the engine, which doesn't start except after two or three minutes of cranking, which is very bad for battery, starter motor and my nerves ?

I think the air is getting into the supply pipeline from an injector which is sticking open (sometimes) after switching off, and I think that is the other part of the problem.

I await with interest........


Nick

[High Compression II]

The lift-pump is fitted inside the tank, as far as Im aware, there is no NRV fitted If you are getting air in the system its a leak somewhere, or maybe the transfer-pump within the main injection pump on the engine has worn allowing drain-back of fuel when standing--This is common on the mechanical VE Injection Pump on which the EDC pump is based, and uses the same Transfer-Pump components.--If this is the case, then the Injection pump will require overhaul and the transfer pump components replaced, and the pump recalibrated. (Been there, Done That with many a VE!)

Does the fault happen more when the vehicle is parked facing uphill with little fuel in the tank?

Also, Is the elec. pump supplying any pressure--Should be around .4 bar, around 7 PSI or thereabouts, Tee in a fuel-pressure guage just before filter on the rubber pipe to check lift-pump pressure.

Worth also replacing fuel-filter It may be partially blocked and causing the IP to draw air in through its front seal even though the elec pump is operating correctly.

Check ALL hoses at their connections from tank to IP for leaks and loose fittings.

These are the transfer pump components....

Wish I had this fault instead of the one Ive got!

[Nickhlx]

Hi, Thanks for the reply - answers / comments in RED

Nick
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The lift-pump is fitted inside the tank, as far as Im aware, there is no NRV fitted If you are getting air in the system its a leak somewhere, ( injector sticking open ?) or maybe the transfer-pump within the main injection pump on the engine has worn allowing drain-back of fuel when standing--This is common on the mechanical VE Injection Pump on which the EDC pump is based, and uses the same Transfer-Pump components.--If this is the case, then the Injection pump will require overhaul and the transfer pump components replaced, and the pump recalibrated. (Been there, Done That with many a VE!) [COLOR=Red] Oh dear-oh dear - megabucks then ? hope its a sticking open injector?
Does the fault happen more when the vehicle is parked facing uphill with little fuel in the tank? Yes, and yes.
Also, Is the elec. pump supplying any pressure--Should be around .4 bar, around 7 PSI or thereabouts, Tee in a fuel-pressure guage just before filter on the rubber pipe to check lift-pump pressure. Yes - recently (2 weeks) replaced and fills a bottle on top of engine quite meaningfully, so seems good (it's new)
Worth also replacing fuel-filter It may be partially blocked and causing the IP to draw air in through its front seal even though the elec pump is operating correctly. Replaced about 1000 miles ago - genuine part.

Check ALL hoses at their connections from tank to IP for leaks and loose fittings. All checked and vacuum and pressure tested - all OK
These are the transfer pump components....

Wish I had this fault instead of the one Ive got! what is your problem then ?

[High Compression II]

Nickhlx,-

Guess Ill answer your questions in order as above to avoid confusion.

1-Tis not really possible for an injector even if stuck open to allow air to enter and drain the whole pump back to tank as they are on a completely different hydraulic circuit within the IP, and the delivery valve on the HP line at the pump effectively seals the injector from the pump just like a NRV Most of the time, the line to the injector is closed off by the action of the pump plunger within the high pressure rotorhead as well--If for some reason an injector was stuck open, you would get a heavy knock on that cylinder with maybe smoke etc. as it would not be atomising correctly.

2- You are experiencing worse starting under low tank contents/parked facing uphill, It really looks like transfer-pump component wear allowing the fuel to drain back from the pump past the worn transfer pump vanes/rotor/liner. Unless you are brave, I would recommend you take the pump to a Diesel Specialist and tell him the faults. It is possible to do the job yourself IF you can get the components,--Sometimes not easy as diesel specialists dont like to sell components for pumps--The main dealer will be even worse wanting to supply a complete pump only, as they dont stock internal pump parts.

3-By all accounts the tank lift-pump will cause poor power on hills and not give the fault you have

4- It may be worth changing the fuel-filter again, before you suspect the main IP, as its the cheapest optoin, seeing you have covered all others except the injection pump itself.



On a different tack--My problem was just the elec windows not working--BUT now it wont start on the key as well--Crossing the solenoid will start the engine, but Ive no idea what Ive done to upset the starting Just checked fuses, etc and checked out the rear mounted power dist box to find some animal in the past has put some kind of remote alarm system in rather badly--Wires cut in to others etc a right nightmare!--It was getting late and wet yesterday, when I finished so this afternoon Ill check out K1 relay wiring etc and then look for that 'Comfort Relay' as others have had problems with that one, causing the window fault.--Hopefully all that bollox the animal fitted isnt causing my problems!.

[iainand]

if i had an injector that was not atomising corectly, would the knocking problem be less at higher revs?

the reason i ask is because my engine knocks at idle but is much less noticable as the engine revs increase, much quieter at 2,000 revs for example.

it has been like this since i bought car at 120,000 miles, now 144,000.

its not coming from the timing chain, i'm assuming problem might be down to injectors or worn valvegear??

Another annoying problem along with my warm starting problem too!!!!!!!!!!

[High Compression II]

You may have a worn nozzle or six not atomising well, and at those milages I would replace them without even thinking about it--My 525TDs which I just had a week ago, although does not knock--In fact its very quiet--will have a set of new nozzles, as I run vegetable oil as fuel where the whole injection system needs to be perfect--even if it was on derv as fuel, I would replace at 100K as these things are subject to wear just like the rest of the engine--Use GENUINE Bosch Nozzles and have the pressures correctly set by a good diesel expert--There are many poor diesel places that will put cheap nozzles in your injectors and dont even set them up properly!.

You MAY have hydraulic tappet noise/cam wear--apparently quite common on older M51's--Take a peek with a torch through the oil filler-cap you may see some wear in the cam lobes--Hope not though.......

Timing chains do wear, but generally rattle not knock, More likely its hydraulic tappet/cam wear

Is it mechanical noise or definately diesel-knock? Is it on one cylinder only or all? Can it be isolated by slakening each injector line while idling?--(Take care, diesel at high pressure can enter skin)

You could try 20% veggy oil/diesel from Asda (cheapest home brand stuff), as this % will quieten combustion knock and reduce emissions to boot and will cause no harm--At least this will prove whether its combustion knock or mechanical noise..............

You mention you have hard starting when hot?--Could be IP/injector wear.

BTW-- Does the de catted exhaust make much difference to the power? and what type are E39 wheels?

[iainand]

many thanks for reply, i think injectors 3 & 4 seem to be main culprits, noise seems most evident in that area.

i have had rocker cover off, and all looks OK in there - thankfully!

if those injectors were at fault would the noise tend to quieten down as revs increase, my engine seems so much quieter at 2,000 upwards. and if i rev it stationary i can hear noise come back again as revs fall.

De-catted i could feel an immediate improvement in throttle response, certainly lets turbo spin up faster, not sure how much of a power increase i have. i was surprised how low the exhaust emmissions were at mot time too!

E39 alloys were just off a 1998 525 SE, so nothing special, still 15", but to me improve look of car, im still on the look out for some 17" alloys off a E39 though

[High Compression II]

Yes when you raise the revs, things can quieten down as there is a much faster rate of delivery of fuel and even a worn injector will atomise OK, but at idle it may well mearly dribble fuel in, in a squirt rather than a spray.

Sounds like mechanically your engine is quiet if when revving and allowing revs to fall, the time before revs reach idle there will be NO fuel supplied and hence no diesel knock. As the engine approaches idle, then injection will begin slowly and maintain idle speed.

Time for new nozzles maybe, although if your emissions are low, there shouldnt be much problem apart from the annoyance of noise, which I know can be a real pain................

As yet, I havent ventured too far under the car to see if mine has a cat or not. Guess Ill take a peek when I change the ATF/filters in the week, and maybe remove it and crack out the ceramic core.............

The wheels on mine I know are not the correct 'cross-hatch' type, but are multi-spoked, and quite large--16 inch I think--They are BMW wheels but I dont know what model.-- the guy I bought it from says they are from a later model--He made quite a fuss about them, but I couldnt make out why..............

[iainand]

i got these wheels on ebay for £200, had Pirelli tyres on with approx 6mm tread on each (worth about £120 each new), tho the front have not lasted well (7,000 miles) i would not recommend soft pirelli tyres for the front of the diesel 5.

i will look into cost of replacing all 6 nozzles on injectors (dont think i will like cost though)

[High Compression II]

i got these wheels on ebay for £200, had Pirelli tyres on with approx 6mm tread on each (worth about £120 each new), tho the front have not lasted well (7,000 miles) i would not recommend soft pirelli tyres for the front of the diesel 5.

i will look into cost of replacing all 6 nozzles on injectors (dont think i will like cost though)


The Incoming cost to diesel specialists not including VAT, fitting and setting of your average Pintle type DN0SD style nozzle is around 8 quid each for Bosch originals.

Be prepaired though, These prices are what the specialists DONT want you to know, and keeps them in Jaguars!--Ive been quoted upwards of 25 quid for a single genuine Bosch nozzle for a tatty old Citroen BX! ( DNOSD 299A)--The cost of that one from a suppliers was just 7 quid!--You can easily get them yourself from somewhere like Merlin Diesel Systems, (on the 'net) BUT you will need to strip one of your existing ones to find the nozzle number--or maybe they can cross reference from the KCAxx.xxx number on the injector body, and unless you have spare shims and an injector tester, you cant set them up..........

--Your diesel specialist may baulk at your 'Electronic' injector, and try and charge more for changing the nozzle in that one--If he does, go elsewere, as hes ripping you off--There is NO difference for the purpose of changing and setting up an electronic 'needle-lift' type injector nozzle to the others,in the KCA type holder--They are otherwise identical and use the SAME nozzles, Its just the upper body that contains a coil and needle lift monitor pin.

Pity you havent got a set of used old injectors, I could do them for you, but they are not the sort of usual spare guys keep hold of as they are generally exchange/rebuildable items...........

If you can wait a week or so, Ill be changing mine, and can tell you the numbers I find inside those,--I need to change the seal on the top of my IP too, Another thing I discovered today, Leaking something horrible! Still no joy with my elec windows though........... :(

[Bill R.]

http://www.bimmer.info/%7Ebill/Dieselnozzles.jpg
The Incoming cost to diesel specialists not including VAT, fitting and setting of your average Pintle type DN0SD style nozzle is around 8 quid each for Bosch originals.

Be prepaired though, These prices are what the specialists DONT want you to know, and keeps them in Jaguars!--Ive been quoted upwards of 25 quid for a single genuine Bosch nozzle for a tatty old Citroen BX! ( DNOSD 299A)--The cost of that one from a suppliers was just 7 quid!--You can easily get them yourself from somewhere like Merlin Diesel Systems, (on the 'net) BUT you will need to strip one of your existing ones to find the nozzle number--or maybe they can cross reference from the KCAxx.xxx number on the injector body, and unless you have spare shims and an injector tester, you cant set them up..........

--Your diesel specialist may baulk at your 'Electronic' injector, and try and charge more for changing the nozzle in that one--If he does, go elsewere, as hes ripping you off--There is NO difference for the purpose of changing and setting up an electronic 'needle-lift' type injector nozzle to the others,in the KCA type holder--They are otherwise identical and use the SAME nozzles, Its just the upper body that contains a coil and needle lift monitor pin.

Pity you havent got a set of used old injectors, I could do them for you, but they are not the sort of usual spare guys keep hold of as they are generally exchange/rebuildable items...........

If you can wait a week or so, Ill be changing mine, and can tell you the numbers I find inside those,--I need to change the seal on the top of my IP too, Another thing I discovered today, Leaking something horrible! Still no joy with my elec windows though........... :(

[High Compression II]

Great!--At least we know the nozzle type now without removing the injector-DN0SD300, set at 150 bar

Does the listing include the year of the vehicle or does the whole range use the '300 nozzle?

BTW, where did you find this list?

[Bill R.]

factory service manuals that i have.





Great!--At least we know the nozzle type now without removing the injector-DN0SD300, set at 150 bar

Does the listing include the year of the vehicle or does the whole range use the '300 nozzle?

BTW, where did you find this list?

[Nickhlx]

...will have a set of new nozzles, as I run vegetable oil as fuel where the whole injection system needs to be perfect--even if it was on derv as fuel, I would replace at 100K as these things are subject to wear just like the rest of the engine--Use GENUINE Bosch Nozzles and have the pressures correctly set by a good diesel expert--There are many poor diesel places that will put cheap nozzles in your injectors and dont even set them up properly!.

You MAY have hydraulic tappet noise/cam wear--apparently quite common on older M51's--Take a peek with a torch through the oil filler-cap you may see some wear in the cam lobes--Hope not though.......

Timing chains do wear, but generally rattle not knock, More likely its hydraulic tappet/cam wear

Is it mechanical noise or definately diesel-knock? Is it on one cylinder only or all? Can it be isolated by slakening each injector line while idling?--(Take care, diesel at high pressure can enter skin)

You could try 20% veggy oil/diesel from Asda (cheapest home brand stuff), as this % will quieten combustion knock and reduce emissions to boot and will cause no harm--At least this will prove whether its combustion knock or mechanical noise..............
You mention you have hard starting when hot?--Could be IP/injector wear.




I was very interested to see you comments on "veggy oil" - I was in Tesco and saw some veggy oils at 42p / ltr and (jokingly) said to my son " get me 60 litres of that for the car please" but what are the ins and outs and excise duty implications ? can a proportion of 28 second central heating oil be added before things start going bad ?

Thanks, Nick 1995 525TDS SE Auto