Jump to content
duncan-uk

Testing diesel injectors

Recommended Posts

So I'm wondering if my 530d is not feeling a little flat. 

 

Nothing i I can put my finger on but just not quite the pep I expect. 

 

I plan to remove and clran the inlet manifold and check check the map sensor. Also I will check the fuel filter pressure sensor. 

 

But might injectors need cleaning? 

 

Mpg is fine and goes ok but I do get a load of black smoke first time it gets a heavy boot but clear after (as if crud has built up and is the cleared)

 

or maybe the turbo isnt isn't as fresh as it was?

 

thoughts?

Share this post


Link to post
Share on other sites

as its an *30d is its a single variable vane turbo?

 

modern injectors tend not to need cleaning but they do wear and get noisy.

Share this post


Link to post
Share on other sites

Well, I'd be interested to hear your findings as you dig into it. I've been wrestling with a 'cheap' 530D I bought almost a year ago and have spent no small amount of money going through various sensors and the like to try and improve it. In the case of my car, it's hard to put a finger on it - some days it feels OK, some days it feels a bit gutless. Some days it seems to run nice and clean, some days it seems to lay grey clouds of crap when I put my foot down. And it sounds like an old transit most of the time.

 

I've done the MAF sensor (genuine Bosch), MAP sensor (FAE), replaced all the vacuum lines, under-passenger seat fuel pump (Pierburg) and all of these have incrementally helped for sure (MAP sensor especially) but I'm now starting to turn my attention to the injectors but the cold and wet weather has seen me not quite have the enthusiasm for going out and having lengthy diagnostic and dismantling sessions as yet. But really need to get a leak off test done and also read the injector adjustment values with INPA as I suspect something is amiss with the injection system.

 

Certainly be interested to compare notes as you go along.

 

One thing worth trying as a simple test is to disconnect the MAF sensor. You can quickly verify whether it's actually working .. if the performance feels the same and flat, then the MAF is not working. If you notice the car feeling a lot more lethargic then the MAF is working. I just did this on mine the other day was I wondered whether the (new) MAF was actually working and the drop in performance with it unplugged was pretty significant.

Edited by chicaneuk

Share this post


Link to post
Share on other sites

^ thanks it's not a maf issue I know that and it's not as if there is anything actually wrong I'm aware of so it's more just a mid-life refresh I'm thinking about. 

 

Its a heavy car with modest power so not a rocket ship but just a feeling I'm getting it's not quite up to par. 

Share this post


Link to post
Share on other sites

An interesting measure of performance I think is the 'bum dyno' and looking for power delivery at specific RPM. If you look at the performance information for the 530D, from somewhere like here:

 

https://www.carfolio.com/specifications/models/car/?car=280698

 

It says peak torque is 302lb/ft from 1750RPM-3000RPM - mine felt flat at 1750RPM and replacement of the MAP sensor made it feel considerably more punchy at lower revs and it was useful to know where peak torque should be delivered.

Share this post


Link to post
Share on other sites

Long ago when I got my 530d it was not very happy.   I discovered 2 problems.   Firstly the variable vanes on the turbo were stuck and it had actually burnt the turbine.   Secondly it had been fitted with a replacement MAF and I discovered in TIS (I think!) that you actually needed to reprogram the DDE to use that part number MAF.   After fixing these two it was much happier.

Share this post


Link to post
Share on other sites
10 hours ago, black-cat said:

Long ago when I got my 530d it was not very happy.   I discovered 2 problems.   Firstly the variable vanes on the turbo were stuck and it had actually burnt the turbine.   Secondly it had been fitted with a replacement MAF and I discovered in TIS (I think!) that you actually needed to reprogram the DDE to use that part number MAF.   After fixing these two it was much happier.

 

Sorry to push in on this thread but, out of curiosity, in that situation, did you find a difference in performance if you disconnected the incorrectly programmed MAF? I replaced the MAF on mine a while back and I get a noticeable performance drop with it unplugged BUT I did never re-code it in DIS so no idea if the MAF is correctly configured for my car.

Share this post


Link to post
Share on other sites
2 minutes ago, chicaneuk said:

 

Sorry to push in on this thread but, out of curiosity, in that situation, did you find a difference in performance if you disconnected the incorrectly programmed MAF? I replaced the MAF on mine a while back and I get a noticeable performance drop with it unplugged BUT I did never re-code it in DIS so no idea if the MAF is correctly configured for my car.

 

New type MAF came in 2001. So yours should have it from the factory with correct DDE software.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×