[catalin199522]

Hello everyone, sorry if someone else posted something similar,

I have a problem with my n20 x3 f25 2.0i, 220.000 KM



If i start the car in the morning, everything looks fine, if I drive for 30 min or more, then stop the car, and let it in the parking spot for 30 min-1 hour (the engine is still a little warm) when I restart the car, sometimes it does exactly like the video shows.

I already changed:
Timing chain, Vanos adjusters, Injectors, Sparks, Coils, Vacuum pump. The engine does not eat any oil... I added around 8000 KM ago some Injector cleaner, could this affect the HPFP or LPFP, or maybe I clogged the fuel filter?

Any help would help.

I have no errors on the Ista+, I checked there by going manually to test the misfire, and got some random misfire on cylinder 1 (after I accelerate to 3000 RPM and let the gas pedal instantly, but the ECU doesnt consider them frequent enough to show an error)

[Billfitz]

Fuel, air, ignition. That's what an engine needs to operate. That RPM fluctuation probably wouldn't be caused by air or ignition, so fuel is the likely issue. It looks like after resting a bit the fuel supply takes a while to stabilize, so I'd be looking at the fuel pumps.

[catalin199522]

Should i test my lpfp maybe fuel filter first? Considering that the car works normally at any speed i think hpfp is unlikely to be the cause.

Should i also Remove the reason that a vacuum leak could be there?

[Billfitz]

Unless you have diesel there is no fuel filter other than the one in the LPFP in the tank. A vacuum leak shouldn't go away. Since it's not terribly expensive I'd replace the LPFP.

[catalin199522]

Originally Posted by Billfitz

Unless you have diesel there is no fuel filter other than the one in the LPFP in the tank. A vacuum leak shouldn't go away. Since it's not terribly expensive I'd replace the LPFP.

Would the LPFP act like this only on the restart of the car? not on cold engine?

[Billfitz]

I don't know. But at 220,000 km I wouldn't be surprised if both the pump and filter are in need of replacement.

[catalin199522]

Do you know if there is a method to test LPFP and HPFP? just before changing them

[Billfitz]

I've never done it, but if anyone has they'll have posted a video on youtube.

[tw12321]

I recently had this issue as well. Changed spark plugs and coils and it made a big difference to almost completely fixed, however it is still very slight occasionally. Also looking for answers.

I replaced o2 sensors. Done valve cover twice, smoke test, coils and sparks so far trying to fix. Started for me once I replaced my milvs for modified ones.

[catalin199522]

Originally Posted by tw12321

I recently had this issue as well. Changed spark plugs and coils and it made a big difference to almost completely fixed, however it is still very slight occasionally. Also looking for answers.

I replaced o2 sensors. Done valve cover twice, smoke test, coils and sparks so far trying to fix. Started for me once I replaced my milvs for modified ones.

I have done all of that, Still no difference, i am thinking that by using some injector cleaner i somehow reduce the life of the LPFP or clog the fuel filter. If you dont have any errors like me, i think you should just wait for something to break before knowing what was the problem otherwise you will just throw parts at it without knowing the right one

[tw12321]

Originally Posted by catalin199522

I have done all of that, Still no difference, i am thinking that by using some injector cleaner i somehow reduce the life of the LPFP or clog the fuel filter. If you dont have any errors like me, i think you should just wait for something to break before knowing what was the problem otherwise you will just throw parts at it without knowing the right one

I’ve got errors but I’m thinking mine is tune related at this point as I had a lot to fix since some major upgrades without revisions.

Hopefully will sort it this coming week.

[catalin199522]

Originally Posted by tw12321

I’ve got errors but I’m thinking mine is tune related at this point as I had a lot to fix since some major upgrades without revisions.

Hopefully will sort it this coming week.

I got no errors, this thing happens randomly, someday i have it someday it doesnt, and it makes me nuts because there is no error so i can resolve it

[tw12321]

Originally Posted by catalin199522

I got no errors, this thing happens randomly, someday i have it someday it doesnt, and it makes me nuts because there is no error so i can resolve it

Is the car stock? No tune? Does weather vastly vary on those days? I’m under the assumption mine is just tune start up trims right now but will know more by end of week