D5 (D5244T to 2005) Injector leak back test results - what does it tell me?

[Yosser]

Ok, I've run another test and this time only for 1 minute.

It was quite difficult to measure the amounts accurately as the measure I was using only went up in 5 ml steps.

That said, all injectors were well under 40 ml;

1: 8 ml
2: 7 ml
3: 11 ml
4: 7 ml
5: 8 ml

These could be out a little due to spillage and misreading.

Does this mean I should just leave the injectors alone?

[Clan]

yes i would leave them for now , but it doesnt mean you don't have a faulty spray pattern , anything is possible at your mileage ! A leaking intercooler wont upset the idle smoothness .

[5cilinder]

Originally Posted by Clan

yes i would leave them for now , but it doesnt mean you don't have a faulty spray pattern , anything is possible at your mileage ! A leaking intercooler wont upset the idle smoothness .

Spraypattern can affect smoke and cilinderbalance
A vida cilinderbalance test at the dealer is alot cheaper than testing injectors in a bench and renewing pipwork

[Yosser]

I've picked up a used injector at a good price and will fit it in no.3 position when time allows (hopefully tomorrow evening).

After that I'll do another leak back test for comparison and post my results.

Thanks for your continued advice and interest.

[5cilinder]

your leakback results where in tollerance
More important is if your engine runs better with another injector than leakback results
In theory (and) practice it could be a different inctor or no injector at all
So if if you change the injector use the old pipework to check a running engine a few drops leaking wont hurt for the moment in case of no improvement exanche the new injector with the old pipework with another injector until engine runs good and than renew the pipework

[DieselDoNicely]

Originally Posted by 5cilinder

your leakback results where in tollerance
More important is if your engine runs better with another injector than leakback results
In theory (and) practice it could be a different inctor or no injector at all
So if if you change the injector use the old pipework to check a running engine a few drops leaking wont hurt for the moment in case of no improvement exanche the new injector with the old pipework with another injector until engine runs good and than renew the pipework

Cant you use washing up liquid whipped into bubbles to do a leak test on the injectors?
If they are blowing there will be bubbles blown from the liquid surrounding the leak.

I used this method to check for leaks around my glow plugs, and indeed a couple did leak. I didnt have a deep socket after after rebuilding the head so couldn't torque them straight away.

[5cilinder]

No ;-)
"Leaktest" regarding injectors is commonly referred to the diesel return flow from the injector to the tank its internaly leaking up to a point needed as cooling but when too much leaking is caused by enjector needle wear

Leaking injectors in the sense that the cilinder isnt sealed off completely can be easily spotted with the black "tar" in the injector hole

[5cilinder]

Beware that bubbles are not always leakgasses but can be boiling due to the heat

[Yosser]

Originally Posted by 5cilinder

your leakback results where in tollerance

I should have probably listened to you.....

Last night I set about changing number 3 injector for the used one that I bought.

The original injector was quite easy to remove, so I was pleased about that. Next step was attaching the new mounting kit to the replacement injector. Fitting the spring clip was probably the single hardest thing about the whole job, but I got there eventually.

After fitting the replacement the car was obviously 'chuffing' indicating a poor seal, so off it came again for a good clean around the seat and refit. Refitted and started without any chuffing this time.

I decided to do another leak back test to confirm all was well, and this is where it really went wrong....

The replacement injector filled the leak test bottle in about 30 seconds flat - before fuel from any of the other injectors had even reached their bottles.

Faced with this I obviously had to remove the injector and refit the original.

On the plus side my hours of work have taught me how to fit/refit injectors and what a faulty injector really behaves like - perhaps mine are ok after all.....

[5cilinder]

You should have done a vida balance test before buying a second hand (tested?) injector
If the balance test was okay with those leakback results your injectors should be okay
You should focus on airtightness of the the intake area
A leaking intake creates smoke/lumpiness
Machine 2 aluminium discs with in one a threaded plug for a compressed air connection
Plug one in the hose you take from the egr plenum and the other in the hase after the filter/airmass sensor
create pressure and listen if nothing is heared , note the pressure and leave it a few hours to see if the pressure dropps