[JStang]

I have suspected a leaky injector for a while now due to rough cold starts from time to time. I haven't been to Proactive about chasing it down because no codes were ever thrown and once the car settled into normal idle I didn't have any issues.

Over the past month or two the misfires have gotten worse to the point where the car seems to rev itself a few times on cold start. I finally got misfire codes in cylinders 3 & 6 twice and misfire in cylinders 1, 3, & 6 once. I have new injectors inbound.

Here's the kicker. The last two times that it has happened, I have gotten the reduced engine light and code 29F2 - High pressure fuel system, fuel pressure. Both times, I cleared the code, restarted the car and all is fine.

Could the bad injectors cause the 29F2 code or do you think my HPFP is on the way out too? I bought the car with 28k miles and now have 95k miles. I haven't had any HPFP issues since owning the car.

[AM330i]

Most likely your hpfp is bad. Since you have injectors coming, put them in and see if it goes away. If you still have problems you should then be able to take it to bmw and they will replace the pump under warranty. The won't replace the pump unless it has the newest injectors. I had a similar problem with my 535, rough starts ck eng light on cold starts. ck eng light and reduced power when driving hard. ended up being a combination of 2 leaky injectors and a bad pump. You can check for leaky injectors by pulling the plugs out after it sits for a little bit after driving it. If the plug is wet and smells like gas your injector is leaking.

[JStang]

Originally Posted by AM330i

Most likely your hpfp is bad. Since you have injectors coming, put them in and see if it goes away. If you still have problems you should then be able to take it to bmw and they will replace the pump under warranty. The won't replace the pump unless it has the newest injectors. I had a similar problem with my 535, rough starts ck eng light on cold starts. ck eng light and reduced power when driving hard. ended up being a combination of 2 leaky injectors and a bad pump. You can check for leaky injectors by pulling the plugs out after it sits for a little bit after driving it. If the plug is wet and smells like gas your injector is leaking.

That is the plan. I am going to install and code injectors first and see if the issue is fixed.

My HPFP doesn't act up at all even under heavy acceleration once I clear the code and restart the car.

[mondevx]

I'm having a similar issue, does your car sound like this during cold starts?

My car is sounding exactly the same and I'm suspecting a leaky injector as well. I just replaced bank 1 with index 12, but bank 2 has index 11's that were changed 30k miles ago...

Can anyone confirm?

[JStang]

That is about what mine sounds like when it doesn't miss bad. That is a normal, no code start for me.

[mondevx]

Originally Posted by JStang

That is about what mine sounds like when it doesn't miss bad. That is a normal, no code start for me.

Funny thing is, my brother has a 335i as well, and his car doesn't sound this way.. He replaced all the injectors about a year ago with index 12 I believe..

So injectors might be the culprit here.

I get some weird hesitations once in a while while accelerating, and different idles when warm and cold. 600rpm idle when still cold, and around 700/750 rpm when warmed, also intermittent.

Funny how these things only lasted 30k.. Of course if that's even the case.

[JStang]

New plugs and injectors installed over the weekend. 2 cold starts since and 2 misfires. The car is going to the dealer for a new HPFP tomorrow. Here are pictures of the plugs / injectors.

[NoSlow5oh]

Cylinder #5 shows signs of a valve cover gasket leak. If it was dry and just carbon build up, it could be from a loose plug, but it looks wet, like oil has leaked on the threads and the tip is darker and looks almost fouled from excessive oil burning.

Not saying that is any cause, but I would look into it more.

[Dann]

I'm also interested in this.
My 335i was running like crap and I had the hpfp code and misfired in cyl 1 and 2 along with misfire from low fuel.
I stuck some fuel in and cleared the codes.
Now I get cyl 1 and 3 misfire.

Mines going into a garage tomorrow morning

[techwhiz]

I don't know why you guys just don't stop at the HPFP code.
If it throws that code, it is that issue. We have enough history to know that that part is iffy at best.

I'm on my 5th HPFP.

[JStang]

Originally Posted by techwhiz

I don't know why you guys just don't stop at the HPFP code.
If it throws that code, it is that issue. We have enough history to know that that part is iffy at best.

I'm on my 5th HPFP.

LOL denial man! I had mine replaced under recall but never had a bad one.

[JStang]

I picked my car up from the dealer on Friday after a new HPFP and 3 cold starts later, zero issues. My car hasn't started up this nicely for as long as I can remember. I'm going to grab a few logs to make sure everything looks good but the car feels great.