joge

For the past couple years, if I would push my 2010 535IX (172,000 miles) hard, I would get a check engine light. No run ability issues, just the light. The local garage would tell me that it is very difficult to diagnose and delete the code, telling me that if it comes back on and has running issues that I should address it at that time as it would be easier to diagnose. A few weeks ago it came on after a stop for fuel. It has been on ever sense. It has also run extremely rough at times (setting the check engine light until shut down and re started). The gas mileage is suffering also. I took it to a shop that specializes in European cars. They did a smoke test. No leaks They say it may be the PVC valve which is built into the valve cover (a $1,200 repair) or the fuel injectors (a $3,600 repair) I am not convinced it is either of these. I have also noticed that when getting out of the car when garaging it at night, that the fuel pump continues to run for about 15 seconds. (In the past, this has been an indicator of a weak battery) The battery has been replaced consistently every 2 years under warranty :O) Any information from others that have had a similar issue would be much appreciated.

audiophool

How hard is 'hard'? Any mods on the car? https://www.engine-codes.com/p0174_bmw.html

A new VC is a $412 part at FCP Euro, and the gasket is $42 for the OE part (I re-used bolts last time I had mine off). Coils are $406 for a set of OE BMW, and you can get Bosch for $22 each. I could replace all of it in a lazy afternoon. Sounds like your specialty shop is really charging huge margins, especially if you did the coils at the same time as the VC since they have to come out to do the VC. I'd find another shop if they want you to spend $5k on a 'what if'. Is it possible they said fuel injectors and not coils? Injectors are not cheap, FCP has them for $1278. Those quotes sound a lot like 'go away and don't bother me' numbers.

When coils are weak or in combination with worn spark plugs, you will get misfire which will set codes and can cause rough running, so will bad injectors, O2 sensors etc. Did the shop pull diagnostic codes? Do you have a scan tool? I use a Foxwell 510 and it can show all the BMW codes, plus pull live data for fuel pressure and a myriad other data points, plus program injector values and such. If the check engine light is on, there are codes to read.

As for the fuel pump running, are you sure it's that and not the water pump? The water pump is designed to keep running for a while after shutting down to circulate coolant whilst the turbos cool, and it will run longer if you've been driving hard before shutting down.

joge

Thanks for the feedback. Correct, it was the injectors they were quoting. By driving hard, I mean accelerating fast on a on ramp. That's about it. No modifications to the car.

audiophool

Mine will randomly misfire and set limp mode, then would work fine for months after re-starting the engine. I've taken to carrying the Foxwell in the car and will scan it next time. I'd recommend one if you don't have a scanner that does BMW codes.