Ok this is a follow on from this thread:

Link

I've been trying to solve why the DPF is constantly regenerating.

It's got so bad it does it every 10 miles or so.

Add that to the crazy sucking noise it creates when coming off the throttle when it's regenerating. It sounds like a dump valve going off.

This seems to be linked to the fact the throttle is closed.

I'm continuing the battle with this and last weekend I decided to try some DPF foam cleaner in the DPF.
Tried 2 cans, did naff all. Same issue.

After that I was checking under the bonnet and could hear what sounded like air escaping from the Oil filler cap.

This had me confused because it made no difference if I removed the cap, same sound, but if I put my hand over it the sound stopped.

Confused I instinctively decided to take the engine cover off. I immediately realised the noise was coming from number 1 injector...WTF I thought.

I put my hand on the part in the picture (injector carrier?) and pushed down and could feel either the injector pulsing or the piston pumping.
As I pushed down I could see the carrier moving up and down.
I then realised the bolt was loose, so tightened it up.
The noise immediately stopped.

Now further to this for the last couple of weeks I've had running issues.
Bad idle, stuttering on acceleration and what felt like a bad driveshaft causing vibration when crusing under 2.5k.
After tightening the injector these symptoms seem to have all but cleared.
​However what I don't understand is why when it was idling rough did it instantly smooth out when disconnecting either the MAF or EGR?

Anyway my question is what should the injector bolt be tightened too? I don't want to cause issues by over tightening it.

Secondly what are people's opinions on whether this was contributing to the DPF issues?
Obviously it would have been pulling in extra air messing the fuelling up in that cylinder.

I'm going to buy a new aftermarket DPF anyway as it's done 189k miles, but want to make sure it's not going to suffer the same fate.

 

Ok further to my post above. (I know I'm talking to myself here it seems)

Anyway the issue with the bad running turned out to a bad injector on no. 4 cylinder.
Eventually it just gave up and died altogether.
After a few hours of absolute hell removing the damn injector I put a refurbished injector in and all is well again. No more shuddering.

Just in case anyone is interested. To get the injector out I had to remove the solenoid (dead anyway) and weld a tube to the top of the injector and then used a make shift slide hammer to remove it.
After about a million whacks it came out.
Absolutely crusted and carboned in.
Also don't do what I did trying to twist the injector and break of both cam lugs for the injector fuel lines, they are very brittle!
Had to epoxy them back on.




Can anybody explain why the injector had no part number on it whatsoever?