Bosch Diesel Injection Pump Disassembly

[MikeT]

I managed to find time to remove the last and most difficult bolt so pleased to say the armour is now off.

Kenny, I didn't understand what you meant about the hollow pin but now the immobiliser is revealed, I think I've got the same. It looks to me like an allen bolt with a strange crimp looking centre. My intial reaction is to try an allen key on the head but should I do something to the crimp in the centre first or will all be revealed as I progress?

Jim, I got a surprise visit from Toby today who found me staring blankly at a neighbours non-starting Pug, giving me the excuse to make a hasty exit.

He brought a boxed gift for me from you, thank you. I can't wait to delve in but not sure it'll be this year as there's a waiting list at the moment.

What did you do to him last weekend Jim? He wants a V6 and an Activa now.

[KennyW]

Mike,

Can you take a pic and post it, compare it to mine from earlier in the blog and see if it is the same.

As Jim said there are a few variations to the basic pump.

Since the weather forecast is dry , I'm going to refit all back together misus armour to test pump insitu. If car starts I will fit armour back on.

Kenny

[MikeT]

Hi Kenny, sorry it's not clear where it matters but I hope you can see what I mean. Two allen-looking bolts holding the immobiliser in place which interferes with distributor head removal.

I didn't notice anything similar to yours so I guess I've got yet another variant which makes me wonder what my MK2 pump has in store for me.

[KennyW]

Hi Mike,

No, the photo makes perfect sense. My pump is a later model and is a different design of armour over the solenoid.

But here's my news, it's not working but I think i mixed up my wiring.

On my pump there are 3 connectors Blue, Brown and Black.

On the black one 1,3 & 4 are used.

1 supplys 12V through the immob to stop solenoid
3 supplys 12V through the immob and returns to ECU via 4

On the older pumps the brown connector supplied the solenoid via the fuel pump relay wire 3.

I have ran the direct feed for the solenoid from wire 3 on the black connector hence the reason I believe the engine is not starting. IT should have been wire 1 but when i checked this wire no voltage therefore my conclusion is there is a break in the wiring between the relay and the black connector.

But, there is a connection between the unused feed (old feed for solenoid via brown connector) and wire 1 this maybe the problem spot.

If both of you understand what I am trying to say please let me know if you think I am correct.

Kenny

[MikeT]

Sorry, not with you old chap...

You say your stop solenoid isn't working...
a) because you ran a direct feed to the wrong wire and
b) there's no feed from the engine loom either - hence the reason for the fault in the first place?

But what sort of connection have you found between the brown connector (which feed my timing piston) and the black immobiliser connector?

I'd also be interested in more information about how you learnt which wire went where on the immobiliser.

[CitroJim]

He brought a boxed gift for me from you, thank you.

A pleasure Mike Do enjoy! (it is a Lucas DPC pump)

What did you do to him [Toby] last weekend Jim? He wants a V6 and an Activa now.

Just took him for a short spin in them, that's all

Kenny, I'll delve into your electrical question tomorrow. I'm too tired this evening to concentrate on it but I can recally what we did to lawrence#s 406 in that area.

The immobiliser in your shot Mike is the early one. It will simply unbolt from the stop solenoid via those two screws. Yours kenny, is the later one, encapsulated into the armour itself.

[KennyW]

Hi Mike and Jim,

I'm going to scan the wiring diagram I have which to the trained observer is french

It will make sense when you look at that and my,not very good explaination, of what I have found and done.

Kenny

[KennyW]

Hi Mike and Jim

Hopefully the diagram will make more sense

[KennyW]

Further to my problem I am going to test the solenoid insitu tomrrow if the weather holds.

I can now remove the armour insitu as I have torx bolts in place of the security bolts.

This does make life easier.

I am going to confirm if the solenoid is working or not and the supply is reaching the solenoid.

Kenny

[KennyW]

Hi Mike and Jim,

Well here's the latest in my saga .

I can now take off the body armour without removing the pump .
I checked the supply to the solenoid 12V and then switched the ignition on and checked the if the solenoid is working by placing the connection on and off the top and I could hear the click of the stop being activited and deactivted.

I then used the self primer, pumped fuel into pump until hard switched on the ignition to open stopper and cracked open the union on 4th injector.

I turned the engine over and no fuel came out of the pipe.

I can only conclude 2 things either i have not removed all the air in the system or the pump itslef has developed a fault.

I am arranging for a friend to call in and we will try the old push start so see if it will start.

Kenny

[MikeT]

Good progress being made there Kenny, well done. Shame you're not getting the result you'd hoped for.

Did you drain all the fuel out of the pump before working on it? They are self-priming if the tank is run dry as they retain a fair amount of fuel inside.

[KennyW]

Hi Mike,

No, I didn't drain all the fuel out. Hence the reason I think I have a problem with the pump itself.

Kenny

[CitroJim]

Oh dear Kenny, still good that the armour will come off with ease now.

One good test is to check that there is no blockages in the primary side of the pump by pumping on the primer bulb and seeing that fuel can be made to run out of the return. This shows that fuel will enter the pump body and will exit from it via the return line.

If that proves OK then it's a pump apart job. My suspicion falls on the lift pump having failed for some reason and thus not being able to make transfer pressure to allow fuel to fill the HP pumping element on the filling stroke.

This may be just a stuck pressure relief valve (the one detailed by Mike a few posts back) as if this is stuck open, the pump will fail to make pressure. Again, the lift pump can be tested by running the engine on the starter and watching for fuel flowing down the return line. Even turning it over by hand will generate enough flow for this to happen if all is good. Also, if the solenoid is open, hand rotation is enough to shoot jets of fuel out of the delivery ports.

The other possibility may be broken camplate springs (the big ones) if these break (and they do) the HP pumping element will not work effectively and may even break. If this is the case, both the pumping element and distributor head will need to be changed as they are a matched pair but the good news is they're identical across the pumps.

Luckily, Mike has produced an excellent stripdown guide to follow

[KennyW]

Thanks for the replies,

Will do the checks you have suggested Jim.

What kind of blockages can you get and does this require a pump strip down

If I have to stripe the pump, I might as well to do the complete thing.

Kenny

[MikeT]

Hi Kenny, in that case it won't be an air lock as these pumps will prime from the bulb or cranking.

I've not got enough experience to determine what does get blocked though in theory there are many points where even a restriction would cause serious starting/running problems. But to cause no output at the pipes is puzzling me.

Although you heard the solenoid clicking did you check the solenoid plunger itself wasn't seized?

Jim, can your broken high pressure plunger spring theory not be assessed via the timing hole or is that too dangerous?