[Occ224]

Hello all. 2008 BMW 335i E93 136K miles. I've been having a slight issue with my car lately. Slight jerkiness on cold starts if I put it in drive. Sometimes hesitates to start. And a couple other minor things. (I would assume its fuel pump related) Today I drove it to AutoZone to pick up a spark plug and ignition coil for a different car. like usual It had it's little issues that I named previous, on the way there but nothing bad. I didn't go WOT or anything. Turned off fine I guess. when I tried to turn it back on all the lights come on but no crank at all. (Yes my foot is on the brake haha.) I run the codes and this is what they say.

(I do have catless downpipes)

- DME active codes -
2C9C - DME: Oxygen sensor heater before cat. Conv. Activation.
2FBE - DME: Fuel pressure after engine stop.

- DME shadow (inactive) codes -
29F4 - DME: Cat. Converter conversion
29F5 - DME: Cat. Converter conversion 2.
2AAF - DME: Fuel pump, plausibility.
2FDB Fuel high pressure nach Foreigner der Einspritzung

My mhd code reader also said 12.07 volts for the battery or whatever.

I assume it is one of my fuel pumps and I do hear the LPFP working or at least I know it's trying. I also voltage tested it. When I listen to the engine bay all I hear is a single click (I assume thats the starter) which leads my brain to one last thing and that's the HPFP which costs two arms and a leg.

My buddy said "If it's not turning over and you’re having fuel issues it could be hydro locked. Stuck open injectors flooding the cylinders would explain a fuel pressure code upon shutoff." Which I've had that code
for honestly like a year. It comes and says Hi every now and again then I delete it for a couple weeks.

Do you guys think it could be hydrolocked or bad hpfp or both or none of the above? Maybe even that little o2 sensor code 2C9C?

Thank you for reading and thank you for any advice you guy have. Let me know if there is anything else you're wanting to know.

*Old issue that may be related*
About a week ago I went WOT and it started missfiring bad. Seems like only one cylinder but who knows because the SES light did not come on and no codes were thrown. Me thinking it was probably an ignition coil I went a little wreckless and tried WOT a couple more times to get it to throw a code but it didn't so I couldn't see which cylinders were misfire. Ever since after that day a week ago it hasn't missfired. Even after going going WOT a few times.

[Bimmer_Bro]

Originally Posted by Occ224

Hello all. 2008 BMW 335i E93 136K miles. I've been having a slight issue with my car lately. Slight jerkiness on cold starts if I put it in drive. Sometimes hesitates to start. And a couple other minor things. (I would assume its fuel pump related) Today I drove it to AutoZone to pick up a spark plug and ignition coil for a different car. like usual It had it's little issues that I named previous, on the way there but nothing bad. I didn't go WOT or anything. Turned off fine I guess. when I tried to turn it back on all the lights come on but no crank at all. (Yes my foot is on the brake haha.) I run the codes and this is what they say.

(I do have catless downpipes)

- DME active codes -
2C9C - DME: Oxygen sensor heater before cat. Conv. Activation.
2FBE - DME: Fuel pressure after engine stop.

- DME shadow (inactive) codes -
29F4 - DME: Cat. Converter conversion
29F5 - DME: Cat. Converter conversion 2.
2AAF - DME: Fuel pump, plausibility.
2FDB Fuel high pressure nach Foreigner der Einspritzung

My mhd code reader also said 12.07 volts for the battery or whatever.

I assume it is one of my fuel pumps and I do hear the LPFP working or at least I know it's trying. I also voltage tested it. When I listen to the engine bay all I hear is a single click (I assume thats the starter) which leads my brain to one last thing and that's the HPFP which costs two arms and a leg.

My buddy said "If it's not turning over and you’re having fuel issues it could be hydro locked. Stuck open injectors flooding the cylinders would explain a fuel pressure code upon [...]

How old is your battery? These cars do crazy things once voltage is lower than normal.
I would also check your ground wires in the engine bay. Particularly the ground wires on the starter and Alternator.

Hydro locked no. Could be fuel pump related but I would check the wires and battery first. These cars ground wires corrode and break off quite easily.

[Occ224]

Originally Posted by Bimmer_Bro

How old is your battery? These cars do crazy things once voltage is lower than normal.
I would also check your ground wires in the engine bay. Particularly the ground wires on the starter and Alternator.

Hydro locked no. Could be fuel pump related but I would check the wires and battery first. These cars ground wires corrode and break off quite easily.

Thank you for the response. I will check on those wires and battery! 🙏

[Occ224]

It could be a ground or the battery. But would that explain the longer start up/jerkiness/missfire? Or would those be separate?

[Bimmer_Bro]

Originally Posted by Occ224

It could be a ground or the battery. But would that explain the longer start up/jerkiness/missfire? Or would those be separate?

Could be separate but you don't really know at this point. If you have a bad connection it could be causing the jerkyness.
If you want to check for leaking injectors you can let the car sit overnight, then pull the plugs and see if they are wet or smell like fuel. Leaking injectors will drip onto the spark plugs.
Plugs, coil packs, injectors are the most common items for misfires.
If the car will not crank at all, it will be something other than those 3.

[Occ224]

Originally Posted by TerminatorStout

from my experience in general:
(rough numbers)

50% of no start = not enough voltage ->bad battery - bad connections - bad ground - bad alternator
20% of no start = ignition related problem -> Coils - Plugs/wires - Timing
20% of no start = fuel problem -> LPFP -
10% of no start = electrical problem - other wiring - CPS - EKP - DME - etc.


1. According to list above, start with easy & most likely. NOT ENOUGH VOLTAGE. If you can't get your battery checked / charged / replaced, then at least use a jump pack or jump start it to rule this out.

2. Your codes indicate a problem with the low pressure fuel pump. All the codes are CAT related except for (3). Two of them indicate a LPFP problem, The other High Pressure code can be caused by JB4 or MHD. If you have a tune it can demand more fuel and cause DME to produce this code.

A rough start, long start, as well as misfires under load, can also be indicative of LPFP issues as the pump fails it will bleed off fuel pressure, have a harder time building pressure when starting, and a harder time sustaining pressure at WOT.

A LPFP will NOT cause a "CLICK - no start". The engine would turn over and not catch or ignite

3. I suspect You have both problems #1 & #2. First deal with #1. Then test your fuel pressure at the rail, or buy a new LPFP if your not into diagnosis.

I highly doubt your HPFP failed, but CAN & WILL, if your LPFP is having problems and you drive it like this. <-- The reason most people have problems with HPFP. Running low on gas or OUT of gas is NO JOKE on these cars.

Thank you a lot for the reply
Quick update. I checked the battery. They said it was bad. I replaced it. It did not fix the issue. BUT after that I decided to do some more diagnosing and pulled fuel rail line #1 (the one holding the most pressure of fuel) and only about 3 little drops of gas came out. Other then that it was dry! I even had my battery plugged in so fuel could flow if the pumps were still working. My question now is which pump is it or is it a fuel pump sensor? Thank you for the help!
I also would like to add my lpfp is completely stock and never has been changed. My hpfp on the other hand has been changed for a cheaper "osirs" brand. I'd estimate about 3 years ago.

[Bimmer_Bro]

Originally Posted by Occ224

Thank you a lot for the reply
Quick update. I checked the battery. They said it was bad. I replaced it. It did not fix the issue. BUT after that I decided to do some more diagnosing and pulled fuel rail line #1 (the one holding the most pressure of fuel) and only about 3 little drops of gas came out. Other then that it was dry! I even had my battery plugged in so fuel could flow if the pumps were still working. My question now is which pump is it or is it a fuel pump sensor? Thank you for the help!
I also would like to add my lpfp is completely stock and never has been changed. My hpfp on the other hand has been changed for a cheaper "osirs" brand. I'd estimate about 3 years ago.

Not sure if the amount of fuel coming out when off proves anything. When the car is off the fuel pressure will slowly neutralize. You should hear the fuel pump prime when you open the driver door.
However, it most likely that Ali express fuel pump you have installed. It has terrible reviews online, some users only got a couple Months out of that pump before it died again. Always use bmw parts on these cars, it will save you alot of headaches. Also order from fcp euro for free lifetime replacements .

[Occ224]

Originally Posted by Bimmer_Bro

Not sure if the amount of fuel coming out when off proves anything. When the car is off the fuel pressure will slowly neutralize. You should hear the fuel pump prime when you open the driver door.
However, it most likely that Ali express fuel pump you have installed. It has terrible reviews online, some users only got a couple Months out of that pump before it died again. Always use bmw parts on these cars, it will save you alot of headaches. Also order from fcp euro for free lifetime replacements .

Previously working on the car such as changing the injectors the battery needs to be unplugged so the fuel pumps don't prime. (I've seen it happen when it's off) aswell as the lines take a little bit to drain out the fuel every time except then. I do agree with you on buying genuine BMW parts and I've learned that thru the 5 years of ownership of this car. Like I said I bought the pump over 3 years ago and then I wasn't too stern on buying genuine. I was also low on money and needed something to fix my car and I think that's actually pretty good for lasting as long as it did. (If that's the issue) thank you for your response

[Bimmer_Bro]

I agree If it got you 3 years for the price that's not bad. It's hard do say that's 100% the problem without seeing a log. But given its reputation online and your symptoms, that would probably be the best place to start.
If the car has been sitting over night, and you open the door to get in, do you hear the fuel pump prime for a few seconds ?

[Occ224]

Originally Posted by Bimmer_Bro

I agree If it got you 3 years for the price that's not bad. It's hard do say that's 100% the problem without seeing a log. But given its reputation online and your symptoms, that would probably be the best place to start.
If the car has been sitting over night, and you open the door to get in, do you hear the fuel pump prime for a few seconds ?

I'm not quite sure about hearing it prime when opening the door. But I do know the lpfp primes when I try to start the car. In the engine bay I only hear a single tick and I think that's the starter trying to work.

[Bimmer_Bro]

[QUOTE=Occ224;29664825]I'm not quite sure about hearing it prime when opening the door. But I do know the lpfp primes when I try to start the car. In the engine bay I only hear a single tick and I think that's the starter trying to work.



You checked all the ground wires right? There should be guides online on where they are located.

[Occ224]

Originally Posted by TerminatorStout

The pressure will bleed off as mentioned above, and it will bleed off a lot faster if your pump is bad. A common failure is the check valve in the pump as the valve fails it cannot supply the pressure needed as it bleeds back off through the pump.

Typical time for bleed off is 5 minutes. If you wanted you could put key in, push start button without foot on brake, and then go crack the fuel line again. Be careful.

If you replaced the battery and you are still getting a click, then it is either the connections, cables to and from or your starter may have took a crap. This is a common problem with people who are having LPFP issues or Batter issues. After so many long and / or low voltage cranks.

Edit: if you are willing you can check to see if the EKP is putting power to the pump when the ignition is on, but this will not cure the "click no start".

I'm willing to bet it's not a cable or my starter. I'm am about 95% certain its one of the two pumps/ sensors. The reason that is because I replaced my battery and tried starting my car a few times. This 100% should prime the lines filling them with fuel. After it didn't start I pulled the line with no fuel coming out. Therefore it's one of the pumps...