TD4 fuel pump issues.

Oh well. here we go again.

TD4 once again failed to start..usual symptoms. no whirring from the in-tank fuel pump under the rear seats. Eventually banging the cover, and the rear doors and waiting a bit resulted in the correct whirr and a functional car..

Now..what are my options here?

A new pump plus labour is going to be about £350, and frankly at this time of year I dont feel like doing it myself.

Before I pass my credit card to the local rapists, is it possible that there is another reason other than a defunct pump for this?

It's supposed to have been properly serviced..so I assume fuel filters are OK.

It's also gutless when cold, and seemingly using more fuel since its last service, though this problem predates that service..could be the new brake disks/pads fitted explain that..

So, I conjecture that its
- a failing pump
- a bad conection
- bad relay? I do always get a definite clunk on switching the ignition on..
- some sort of safety interlock stopping it starting?

Oh, its the BMW model with an auto box.

check the fuel pump fuse and relay first. . . . .with ign on [dont start it] the pumps rear and front run for about 12sec then stop as the high fuel sensor detects the increase pressure. . . .if they keep running then its never reached the correct pressure or the switch is fooked. . . .then you have to decide is it the in tank or the other one. . . .the only way to find out is to dissconect pipe before second pump and it should **** out, no foam or glugging,if that is good then do same operation on the second pump. . . . . .yes its a ****e design, but i never designed it. . . . best oh luck

ming said:

check the fuel pump fuse and relay first. . . . .with ign on [dont start it] the pumps rear and front run for about 12sec then stop as the high fuel sensor detects the increase pressure. . . .if they keep running then its never reached the correct pressure or the switch is fooked.

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No, when its working, that's exactly what happens, when it doesn't work, I just turn the key to get the idiot lights, there is a big relay that goes clunk somewhere up the dashboard/firewall area, but NO PUMP running in the tank. It's running now, so fuses and realys must be at least partially OK..its done this three times now..slamming rear offside door eventually fixes it..it just took 45 minutes this time..

. . .then you have to decide is it the in tank or the other one. . . .the only way to find out is to dissconect pipe before second pump and it should **** out, no foam or glugging,if that is good then do same operation on the second pump. . . . . .yes its a ****e design, but i never designed it. . . . best oh luck

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What second pump? you mean the actual injector pump by the engine? That is DEFINITELY OK because when I was cranking occasionally there was enough fuel to fire..just the odd cylinder occasionally.

No, the symptom is that the in-tank pump doesn't run at all. If it whirrrs and stops, the engine starts. If it doesnt whirr, it doesn't. I just want to know if that there is a possible cause beyond 'a fooked pump'

I.e. is there any way that a perfectly good pump might not run, due to something else? Obviously bad connections are worth checking and I'll do that tomorrow, but I dont want to fork out £300+ to NOT solve the problem.

The car has only done about 55k miles, BUT we do take it off road rather more than perhaps a Gaylander should - mainly looking for love lorn dogs gone to play the balcony scene with neighboring Juliettes..so there is probably a load of muck and wet round the electrics ..

Well yer neffer said wot model /year [i aint a mind reader] so from 200-2003 td4's had in tank pump and a lift pump in engine bay both low pressure pumps after that the second pump was under wheel arch at the rear i fink , and after that i don't know. . . . .anyhows wot i told you still holds ,but without going through fault finding and your sure the filter is good, then yer rear pump is intermittent, so its down to you really

My first post clearly stated 'in tank pump'

Give me credit for having checked...where it was.

All I want to know is where the feed for that comes from.

I know that if it gets bashed, it starts eventually. But is it reparable or is it a straight swapout.

Does it have an internal relay for example?

vintage1 said:

My first post clearly stated 'in tank pump'

Give me credit for having checked...where it was.

All I want to know is where the feed for that comes from.

I know that if it gets bashed, it starts eventually. But is it reparable or is it a straight swapout.

Does it have an internal relay for example?

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FFS old un i'm tryin ta elp ya [yer dont wanna be goin to the tweetmint room]. . . .the relay is in yer cab fuse box and the fuel pump fuse. . . . . and no its not a repairable pump and it comes complete wiff the fuel level sender. . . . .and it costs a fortune. . . . . . .and i niffer give any Eartlings any credit cos there all thick. . . . . .

ming said:

FFS old un i'm tryin ta elp ya [yer dont wanna be goin to the tweetmint room]. . . .the relay is in yer cab fuse box and the fuel pump fuse. . . . . and no its not a repairable pump and it comes complete wiff the fuel level sender. . . . .and it costs a fortune. . . . . . .and i niffer give any Eartlings any credit cos there all thick. . . . . .

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.................:amen:

If its a 2003 MY or later the secondary LP pump is just forward and inside the offside rear wheel and because thet are relatively close its not too easy to tell which pump is not running from the sounds. Slamming the rear door will certainly give this pump a jolt so make sure which one it is. At least the secondary pump only cost £175 if it is this.

BMW engine, registered June 2003..?

Couldn't see any pump inside the wheel arch tho.

Is it hidden?

vintage1 said:

BMW engine, registered June 2003..?

Couldn't see any pump inside the wheel arch tho.

Is it hidden?

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remove the wheel-arch liner..........assuming you don't have an under-bonnet fuel pump and filter?

well if I do, its not the problem.

As I said, the failure of the car to start is 100% correlated with zero pump noise, from the back..

So, which is the pump that makes the noise? the in tank, or the wheel arch?

I am coming to the conclusion it is the in-tank bastard. Now there may be (electrical contact) corrosion there, as the thing appears to also do the fuel gauge sensor, and that has changed a bit recently.

If I lift the cover, is it easy enough to unplug and check the wiring contacts?

vintage1 said:

well if I do, its not the problem.

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? if you do (have the under-bonnet pump) you won't have one under the rear arch.

So, which is the pump that makes the noise? the in tank, or the wheel arch?

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both, depending on which you have.

I am coming to the conclusion it is the in-tank bastard. Now there may be (electrical contact) corrosion there, as the thing appears to also do the fuel gauge sensor, and that has changed a bit recently.

If I lift the cover, is it easy enough to unplug and check the wiring contacts?

Click to expand...

removing and checking the in tank assembly is a piece of **** so why not have a look?

Think it was late 2003 that the pump was moved from front to rear wheel arch [not 100%sure] any how if it aint in the front rhs under the leccy black plastic fing then its at the rear, dunt go fiddlin bout with leccy bits in fuel tank ,less you really understand the dangers and procedures, like slapping an avo on it or anything. . . . . . . .youve bin warned