Bosch044 doesn't have a check valve.

[slowSfaux]

This is the 044 prime with key turned on, and engine off. Prior to installing the 044, the factory pump would prime then the pressure would sit at 45psi, then slowly (overnight) it would drop back to 0. I'm not sure if this will cause any hard start issues, but I read mixed opinions on if this pump has a check valve.

I purchased the pump through 034motorsports as part of their kit, so to the best of my knowledge it's a genuine bosch pump.

[Corradovolksb]

Most 044 pumps I have delt with do not a check valve. One needs to be added inline to keep residual pressure after the key is tuned off to prevent an extended crank.

[slowSfaux]

Like a generic in line valve? Where would that be added? During the test drive it was more difficult to start. One point even kept cranking for approximately 4 seconds and didn't start until I let off the key and cranked a second time.

[Peter1.8t]

If it's an issue for you then add one to the top of the pump. I haven't had a check valve on my 044 for 5 years now. A couple extra cranks isn't an issue to me.

[Seerlah]

This has been known for a while. Bigger issue is the premature wear on the pump. It is not designed to have fluid flow in the opposite direction, especially at the higher fuel pressures. I personally run a discontinued BMW check valve in the tank on mine. But if you Google "Bosch 044 check valve", companies addressed this issue and there are now other options on the market.

Quick ebay example: http://www.ebay.com/sch/i.html?_nkw=...44+check+valve

You can even be inclined to use a Dorman Autozone check valve. People have used those with success. But for the longevity of your pump, you should add one at your earliest convenience.

If it's an issue for you then add one to the top of the pump. I haven't had a check valve on my 044 for 5 years now. A couple extra cranks isn't an issue to me.

Going to go on a limb here and say you have a pump supplied with an adapter fitting. That is most likely a check valve, but just a crappy one.

[slowSfaux]

Good information. Does anyone know of a check valve that doesn't adapt to an AN connection? I'd rather not screw with custom hoses.

[Seerlah]

Dorman one and can be picked up at your local auto parts store.

[Peter1.8t]

Going to go on a limb here and say you have a pump supplied with an adapter fitting. That is most likely a check valve, but just a crappy one.

Nope, I'm 100% certain it doesn't because the tuner and I took it off before it was installed in the tank. It was cheap and the diameter of the valve was tiny, didn't want to impose a fuel restriction at the wrong time, as this car used to actually get driven at higher speeds, top of 5th and 6th. Hasn't been any weird wear that I'm aware off. Made some interesting sounds once on a very hot day. Other than that it just cranks a couple times longer than normal but other than that zero issues.

[Seerlah]

That is Bosch quality for you. But from what I learned and where the assumption that makes sense came from is what does less quality pumps in, even stock pumps. Starts with the same multiple crank issues, then next thing pump is trashed due to the check valve first being compromised and causing the domino effect.

I have the 034MS check valve as the adapter on mine, and it is junk. Have that check valve adapter with an OEM BMW check valve (discontinued) on mine, with the BMW unit on the line from pump to the tank lid.

[c4andmore]

The purpose of a check valve is to maintain pressure in the fuel line on hot days so the fuel does not boil and create vapor lock. All EFI systems that I have seen have a check valve either in the pump or in the system some place specifically for this purpose. Any back flow thru the pump in a system without a check valve has no impact on wear or pump operation. A check valve will make starting easier because the pump won't need to refill the fuel line while bleeding the air out of the fuel system.

Bosch fuel pumps are some of the best electric fuel pumps in the world, which is why so many auto makers use them OE and why so many enthusiasts use them for modded boosted systems. The "044" fuel pump actually originates from Bosch Motorsports. It's a very high quality fuel pump that typically last for many years even in severe operating environments. One of the key features of the "044" pump is that it can deliver not only high volume but high volume at very high pressure which is important for a boosted application where the fuel supplied to the injectors starts at 3-4 bar and increases 1:1 with boost pressure. Many electric fuel pumps have a significant drop in fuel volume as the pressure increases. The "044" pump also consumes less electrical power than most other pumps especially at higher pump pressures.

I have no association with Bosch but these are the facts based on independent testing and Bosch's published "044" pump specifications.

[slowSfaux]

Awesome information c4.

[Seerlah]

Thanks for the correction. But info I posted was told to me (about premature failure on the pump) by a very knowledgeable individual who owns his own aftermarket distribution company and set a few drag records. Not trying to open up a can of worms, but you are partially correct in regards to the pump with check valve function and so am I.

[killerkali]

jayracing check valve is the best option, works great and is nothing near being a restriction. that said, a walbro 450 is cheaper and outflows the 044, while having an internal check valve.

[dozer103]

Thanks for the Jayracing tip! Looks like it may solve my tight fuel line routing issue as well with their outlet barb...

[NOTORIOUS VR]

I've never seen an 044 not come with the check valve attached on the outlet of the pump:

[rnagy86]

I've never seen an 044 not come with the check valve attached on the outlet of the pump:

Exactly. They all come with one, people just remove it because it's "easier" to install that way. :)

[christianb5s4]

My new 044 came with the check valve from 034, the 044 that's in my tank currently has a check valve too.

[slowSfaux]

That's exactly how mine looked from 034 Christian. I'm not sure if the 044 "check valve" is faulty, or what's going on, but my pump clearly loses pressure immediately after shut off.

Has anyone else with an 044 pump put a fuel pressure gauge on their car and can attest to having a check valve from the factory?

[NOTORIOUS VR]

My new 044 came with the check valve from 034, the 044 that's in my tank currently has a check valve too.

I don't see a check valve in your picture.. just a banjo.

[christianb5s4]

It's side the banjo, you can see it in this picture at the end of the arrow. This is the same kit I am running/got another of.

https://store.034motorsport.com/bill...lications.html

[NOTORIOUS VR]

That makes sense... couldn't see the check valve from your pic...

[christianb5s4]

Yeah, it's hidden inside that banjo. SlowSfaux, just to rule issues out there aren't any potential leaks on the fuel setup correct? I believe there could be a loss of pressure despite the check valve if there's any leak where pressure could escape.

[slowSfaux]

No leaks that I am aware of. I'll pull it back out this weekend. I already ordered the jayracing check valve, so I'll see if I can power up the pump with the cap removed so I can inspect the hose in the tank for leaks.

Does anyone know where the in-tank fuel pump hose can be purchased without buying a full basket assembly? I know I seen it for sale somewhere once, but can't locate it now.

[slowSfaux]

I've been looking everywhere for the oe fuel pump hose, thinking if I have a leak anywhere, it's got to be on that hose. I'm not having any luck. Does anyone know a source for those in tank hoses, or maybe even have a used oe one sitting in their garage? I'd rather not use that gates submersible hose if I can avoid it, but it's frustrating because I know I seen the oe-style flex hose for sale at one of the vendors I was browsing recently, but now I can't find it.

[Seerlah]

I just used the rubber hose built for in tank use. You can pick it up at autozone. If not built for in tank, it will turn to mush. Then I used worm clamps with rolled edges vs fuel injection clamps. Much more usefull and I keep various sizes around my house. I use GEMI brand.

[slowSfaux]

I didn't get any videos or pictures yet, but I'm finishing up my build so I'll take some to confirm. First off, I didn't notice any leaks in the fuel system, internal to the tank, nor external. Nevertheless I swapped the fuel line with the gates submersible line and noticed no change. So I took the fitting off the 034 setup, and I noticed it did have what looked like a check valve. I replaced that with the jayracing check valve and that fixed my issue.

I'm not sure if my check valve was faulty on the 034 setup, or if that just isn't a check valve.

[Seerlah]

No...it's just a sh*t check valve. I have this same banjo check valve fitting on my pump. Back in the days most used the same BMW OEM check valve I use to solve the issue. That is why I even do run it. Ran with what was tried and proven.

[killerkali]

I didn't get any videos or pictures yet, but I'm finishing up my build so I'll take some to confirm. First off, I didn't notice any leaks in the fuel system, internal to the tank, nor external. Nevertheless I swapped the fuel line with the gates submersible line and noticed no change. So I took the fitting off the 034 setup, and I noticed it did have what looked like a check valve. I replaced that with the jayracing check valve and that fixed my issue.

I'm not sure if my check valve was faulty on the 034 setup, or if that just isn't a check valve.

Good to hear

[S4James]

I had to take my BMW valve off... damn thing started making noise at low flow (like slow cruising, etc).... sounded like a little kazoo.

[Seerlah]

Sucks to hear. Mine has been holding up, and this is the first case I heard of. Something to watch out for, now!

[christianb5s4]

Where did you install your BMW check valve Seerlah?

[Seerlah]

Between pump and pump lid.

[jbain2]

I used the Bosch check valve without any issues. Part # 16149068988. Was like 15 bucks.

[wbrunner23]

I have an extra check valve for Bosch 044 pump sitting in my garage - one came with the pump from amazon (best price) and another came with the 034 billet ring adapter kit.

PM me if anybody needs it.