Thread: 300TDI Injectors

I would think you would have to prime it , But then again when ever ive replaced my fuel filter on my 300Tdi i havent had to prime it
Id just try it and see if it needs to be primed

Originally Posted by andkat

Hi all, just picked up 4 new injectors from the UK, for under $400.00 air freighted to OZ!!!!
Now the question, once installed do I need to prime the system again by pumping the manual pump on the fuel pump, or as the TDI motor has a mechanical pump will it prime itself? Checked the Haynes manual and then the Rave Disc, dosn't seem to say much?
cheers
Crawf

The fuel should still be up to the injector pipes if you have only undone them at the injectors. iwould just leave one injector pipe loose and whir it over, it should fire up , re tighten pipe when it does.

Cheers Sumo.

crank any diesel engine long enough and it will prime itself.....

not that that helps the new injectors tho....

the longer you crank it without fuel in them the more likely you are to hotspot the needle.

carry out the full and correct bleed sequence, preferabley after youve fed a shot or 2 of dieso through them without having them in the head.

The other advantage of doing this is it lets you see the spray pattern of them to make sure that they all crack and spray about the same.

It depends on how long the fuel in the system has to drain/leak while the injectors are disconnected. Install the injectors as if you mean it but just nip up the pipe connections at the injector. Then back them off about half a turn.
Connect up another battery as if jump starting, then crank the motor over (assistant required) until you see fuel seeping from around the fittings. stop cranking, tighten the fittings and crank the motor over again. It should start. Check for leaks, it's not unknown for leaks to occur at the fittings with new injectors. It's also worth backing off the pipes at the injection pump end to release any tension in the pipes and make sure the clamps are evenly spaced to prevent the pipes from cracking-rare but it does happen.

$400. nice!, where did you get em from? im thinking mine will need to go soon.

ill 2nd what blknight says re the bleed/priming sequence. the better you treat em the longer it'll be till you have to do it again

Hi Andkat,

Can I ask how many kms your old injectors have done and how/why you decided to change them? Something noticable like reduced performance/more smoke/more consumption - or just because they've done a lot of kms?

Interested because my 300Tdi has nearly 240,000 up now on the originals. It still seems to go as well ever, but not quite as economical as in the past.

Planning to take mine out and look at the spray pattern when I organise the facilities to do so but I'm interested in others' experiences.

Thanks,

Don't touch the manual primer lever on the lift pump.

With a used lift pump, the diaphragm can fail because the manual lever can extend it beyond it's normal working stroke. When the diaphragm fails, diesel will contaminate the engine oil and can lead to bigger problems.

The lift pump can not produce pressure in the lines between the injection pump and the injectors.

At that price, were they genuine bosh injectors?

The non-genuine are a little cheaper than the genuine bosch at my local supplier.