Diesel injector fault finding.

coab · 17th June 2016, 15:23

Maybe a bod on here can help me. The engine on my Bmw is a M47 N2 very similar to the R75 CDTi. When I start the car hot or cold if I rev the car straight away the car misses as if one injector is playing catch up. Then clears but If I leave the car to idle for 6 seconds all is fine.
Ive changed air filter, Maf, used Forte injector cleaner etc no joy. Ive got a used injector Im going to fit tomorrow and was wondering if their is a way without a leak off test (Im not bright enough to do that lol!) to see which injector is failing such as listening or looking for tell tale signs whilst car is running. My Carly Bmw scanner shows no codes. The car does sound a little noisey and I do get a sweet smell from exhaust but no smoke at all and all fluid levels never move.

Any ideas or is it a case of swapping it with them all till I find it!

Hope you dont mind me asking.

Daveluck · 17th June 2016, 16:21

From bitter personal experience unless you have something or somebody telling you which injector is faulty then its pot luck, especially as the symptoms are so short lived.

Although you can stick a screwdriver to your ear and the engine and see if one is more noisier than the others. I couldn't tell to be honest. It was all rattling.

So without meaning to teach you to suck eggs....Before you start -make sure you know how you are going to get the injectors out ( I got 3 out with a large flat screwdriver on a warm engine and one with a large slide hammer and special fittings for the Bosch injectors) and are you prepared for a stuck injector? ( do you have the right tools, what happen an f younbreak an injector )

If you scan YouTube you'll find videos that range from cars being lifted off the around via the injector because its stuck to some body lifting out the injectors with just their fore finger and thumb. Mine fell somewhere inbetween but I completely mashed one injector.

Just for a laugh I'll go a poundmon no.3 injector being squiffy.

brianw · 19th June 2016, 05:00

Here'show they remove them on Beemers!

https://www.youtube.com/watch?v=XwZOTf8vYhE

But perhaps you need not remove them to get an idea of how they are performing.
Have you seen these threads?

http://www.the75andztclub.co.uk/foru...ighlight=forte

http://www.the75andztclub.co.uk/foru...72#post2282572

If I have understood the above correctly then the compensation figures can give an indication of which injector/s are performing poorly due say to deposits/restriction.

Perhaps there is some software for the BMW that would give you the relevant live data to point you to the correct injector?
Hopefully someone else here will know.

I hope you get it sorted whicever way.

Daveluck · 19th June 2016, 07:12

Quote:

Originally Posted by brianw

Here'show they remove them on Beemers!

https://www.youtube.com/watch?v=XwZOTf8vYhE

But perhaps you need not remove them to get an idea of how they are performing.
Have you seen these threads?

http://www.the75andztclub.co.uk/foru...ighlight=forte

http://www.the75andztclub.co.uk/foru...72#post2282572

If I have understood the above correctly then the compensation figures can give an indication of which injector/s are performing poorly due say to deposits/restriction.

Perhaps there is some software for the BMW that would give you the relevant live data to point you to the correct injector?
Hopefully someone else here will know.

I hope you get it sorted whicever way.

Compensation figures are a good indicator but they only tell you so much...

My figures were well within tolerance but engine still smoked and smelled.

17th June 2016, 15:23	#1
coab This is my second home 2007 57 GOLF GTi EDITION 30 DSG Join Date: Nov 2011 Location: Newport Shropshire and Coventry. Posts: 5,137 Thanks: 2,424 Thanked 1,452 Times in 852 Posts	Diesel injector fault finding. Maybe a bod on here can help me. The engine on my Bmw is a M47 N2 very similar to the R75 CDTi. When I start the car hot or cold if I rev the car straight away the car misses as if one injector is playing catch up. Then clears but If I leave the car to idle for 6 seconds all is fine. Ive changed air filter, Maf, used Forte injector cleaner etc no joy. Ive got a used injector Im going to fit tomorrow and was wondering if their is a way without a leak off test (Im not bright enough to do that lol!) to see which injector is failing such as listening or looking for tell tale signs whilst car is running. My Carly Bmw scanner shows no codes. The car does sound a little noisey and I do get a sweet smell from exhaust but no smoke at all and all fluid levels never move. Any ideas or is it a case of swapping it with them all till I find it! Hope you dont mind me asking.

17th June 2016, 16:21	#2
Daveluck Gets stuck in 75 saloon 2.0 diesel Join Date: Feb 2016 Location: Panton, lugo, Galicia Posts: 945 Thanks: 236 Thanked 192 Times in 143 Posts	From bitter personal experience unless you have something or somebody telling you which injector is faulty then its pot luck, especially as the symptoms are so short lived. Although you can stick a screwdriver to your ear and the engine and see if one is more noisier than the others. I couldn't tell to be honest. It was all rattling. So without meaning to teach you to suck eggs....Before you start -make sure you know how you are going to get the injectors out ( I got 3 out with a large flat screwdriver on a warm engine and one with a large slide hammer and special fittings for the Bosch injectors) and are you prepared for a stuck injector? ( do you have the right tools, what happen an f younbreak an injector ) If you scan YouTube you'll find videos that range from cars being lifted off the around via the injector because its stuck to some body lifting out the injectors with just their fore finger and thumb. Mine fell somewhere inbetween but I completely mashed one injector. Just for a laugh I'll go a poundmon no.3 injector being squiffy. Last edited by Daveluck; 17th June 2016 at 16:24..

19th June 2016, 05:00	#3
brianw Gets stuck in Rover 75 CDT Connoisseur SE Rover 75 1.8 Auto Connie Join Date: Nov 2011 Location: Aldershot Posts: 921 Thanks: 126 Thanked 119 Times in 79 Posts	Here'show they remove them on Beemers! https://www.youtube.com/watch?v=XwZOTf8vYhE But perhaps you need not remove them to get an idea of how they are performing. Have you seen these threads? http://www.the75andztclub.co.uk/foru...ighlight=forte http://www.the75andztclub.co.uk/foru...72#post2282572 If I have understood the above correctly then the compensation figures can give an indication of which injector/s are performing poorly due say to deposits/restriction. Perhaps there is some software for the BMW that would give you the relevant live data to point you to the correct injector? Hopefully someone else here will know. I hope you get it sorted whicever way.