Injector causing erratic idling

Rebecca_Taylor90 · Wed Nov 23, 2022 8:57 am

How are you all?

When I was at a set of traffic lights, my E90 320d N47 just started running rough at idle. I drove away, and everything seemed to be fine again. At the next set of lights, it happened again, so I turned it off and had it pulled to my mechanic, fearing the worst. They couldn't find any error codes, but they did mention a few experts who might be able to help. I looked at all of the information on Bimmertools and saw that the 4 injectors were all within +/-2.5 mg/strk except for injector 3, which was at +6. Bimmertooll says that you can only use +/-5 mg/strk. So it looks like one of my pumps broke. The mechanic wants to have them all checked out and fixed, but that will cost more than the car is actually worth.

So, my question is, do I take out the injector and take it to a nearby company with a good reputation to get it fixed? How hard is it? I'd say I'm a pretty good DIY tech. The other question is whether or not you can just change one pump. I've heard different points of view, but I'd be happy if it just got me another 10,000 miles.

Jacob_Evans2001 · Wed Nov 23, 2022 10:37 am

It should be OK if you have it refurbished and put it back in (with a new washer).
I performed two on my old e53 3.0d and it worked flawlessly thereafter.

Rebecca_Taylor90 · Wed Nov 23, 2022 11:12 am

Hi Jacob, I appreciate your input. Two appear snug, one a little looser, and the fourth is extremely loose. I am debating whether to send one, two, or all four injectors. The mechanic speculated that the high pressure fuel pump disintegrating and sending fragments to the injectors could be the cause. I suppose that would become evident during renovation. Can you tell me who refurbished yours and how you knew it was necessary? Thanks again.

Rebecca_Taylor90 · Wed Nov 23, 2022 1:09 pm

Does anybody have experience with injector cleaning that was successful, or is it a load of snake oil? It's possible that I could find out for about ten pounds...

Thomas_Green78 · Wed Nov 23, 2022 1:10 pm

To rule out HPFP failure, remove regulator from high pressure pump and inspect fuel for metal filings.

Jacob_Evans2001 · Wed Nov 23, 2022 1:21 pm

Mine was shipped by my friend, so its location is unknown, but it was in North Wales.

Rebecca_Taylor90 · Wed Nov 23, 2022 2:17 pm

Thomas_Green78 wrote: ↑Mon Jun 19, 2023 8:34 am To rule out HPFP failure, remove regulator from high pressure pump and inspect fuel for metal filings.

I'll check this out, cheers. Do you know if the chain on this engine drives the HPFP if it is HPFP? I can't figure out what that means.

Thomas_Green78 · Wed Nov 23, 2022 2:20 pm

Yes, however it may be modified without disrupting the chain if a sowcisl tool is used in the timing cover.

Hannah_Baker2000 · Wed Nov 23, 2022 3:50 pm

Rebecca_Taylor90 wrote: ↑Mon Jun 19, 2023 8:33 am Does anybody have experience with injector cleaning that was successful, or is it a load of snake oil? It's possible that I could find out for about ten pounds...

When my 320d was battling with two injectors, I tried Wynns diesel fuel system cleanser and Millers Ecomax.

Personally, I believe they were too damaged to discern the difference, so I replaced them.

In retrospect, I should have done all four since one of the originals is on its way now.

Replace your copper washers as well.

Rebecca_Taylor90 · Wed Nov 23, 2022 5:07 pm

Thomas_Green78 wrote: ↑Mon Jun 19, 2023 8:38 am Yes, however it may be modified without disrupting the chain if a sowcisl tool is used in the timing cover.

I am competent enough to attempt to remove the injectors, but I am incapable of replacing the HPFP. Hopefully, only the injectors require maintenance. However, thank you for the advice. I looked for a sowcisl instrument for ten minutes before concluding that you may have misspelt special haha'