Where is the M54 fuel line schrader valve (to test lean conditions fuel pressure)?

I don't see the fuel line Schrader valve anywhere on the Realoem diagrams.

I'm sure I'm missing something obvious ... and I've asked in some of the lean-misfire threads ... but no answer yet ...

So I figured I'd ask outright in its own thread:

Q: Where is the M54 fuel system Schrader valve located?

Look at the fuel injection rail again. It's there.
Unscrew cap #2, that's it.

Pehaps these images from TIS will help. They are not hi-res but do indicate the location.





Regards
RDL

Originally Posted by JimLev

fuel injection rail

Hi Jim & RDL,

This is embarrassing...

I 'had' searched the threads for the I6 Schrader valve; but kept coming up with V8 questions instead ...
- E39 (1997 - 2003) > Good replacement fuel pump 540i E39?
- E39 (1997 - 2003) > Fuel schrader valve 540i/6
- E39 (1997 - 2003) > How do I tet fuel pressure on 540i m62 V8?
etc.

And, of course, I had looked ... and looked ... and looked - in Realoem.

I now see 'my problem'.

Under #2 "cap" appears to me to be a 'fuel injector'; for the longest time, I had not seen the fuel system Schrader valve ... simply because it was not specifically 'listed' anywhere in this Realoem diagram (and because I didn't find a picture of the M54 Schrader valve in the I6 threads):
- Getting to know your M54 engine, a photo & identification guide to every visible part in the engine bay (1)

I've never worked with fuel injectors before though.

So, until I correlated your information with RDL's TIS below, I had not realized that the non-descript un-labeled un-numbered 'bump' on the front of the rectangular "rail" which is directly above the actual fuel injector 'was' the Schrader valve! [covered by a dust cap]

Originally Posted by rdl

images from TIS will help

The TIS you kindly supplied is apparently also pointing to the same unlabeled 'nub' on the rectangular 'fuel rail' that JimLev pointed me to.

It would have been simpler if Realoem had labelled it as such; but I guess it's not a specific part you can replace on your own.


Going back to my pictures of my I6 spark plug DIY:
- Pictorial DIY for an M54 spark plug replacement on a 2002 BMW 525i E39 with 95K miles

With both your help, I now 'clearly see the fuel system Schrader valve in my own pictures!


Now I can further proceed to test the fuel system lean condition reported here:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

What I plan on doing is borrowing the Autozone Actron Fuel Pump Diagnostic Kit CP9220A to determine if my lean conditions are caused by fuel deliver.



In addition, to look for vacuum leaks, I'll be looking up how to perform an intake system DIY 'smoke test' at home.

Maybe I'll ask these consultants ...

For the record ...

Update: I'm still tracking down a random error misfire sequence:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

To that end, I've started identifying & replacing all the vacuum hoses:
- How to locate all the vacuum hoses in the E39 engine bay (1) & where to get those vacuum hoses (1) & what sizes to get for all the M54 engine vacuum hoses (1) & correcting the F-connector errors in the realoem diagrams (1).

And, now that I know where the Schrader valve is, I borrowed the Autozone Actron CP 9920A fuel system tester:
- While replacing your spark plugs (1), where can you find your E39 fuel system pressure test Schrader valve for the I6 (1) and for the V8 (1) (2) (3)

I can bet a few dollars you will not find anything.
On the other side, if you take out the injectors and have them serviced you might find a few of them might be getting clogged, or the fuel pattern is not what is supposed to be (the latter is normal, and for street driving you will not notice). They will clean them, change the filter & O-rings and re-calibrate them. Clean thoroughly the "receptacle" of the injectors - if the O-rings were bad, you will have a lean situation and fine particles will be lodged there, where the O-ring should seal. You will have unmetered air going in right there. The only way to test is with some carb cleaner: start the car (with that engine beauty cover off), make sure the engine is cold when you do this - so first thing in the morning, and with the engine idling, spray sparsly carb cleaner around the fuel rail. If the rpm climb, you have bad injector O-rings (you have to be certain you don't spray around vacuum lines, because it will alter your "test").
Also, when you are here, and the if you remove the injectors, clean thoroughly the electrical contacs - these if slightly corroded, will give "misfires" every now and then.


Now move on the other side of the engine (from driver side to pass side), and inspect carefully the boots of the coils for each sparkplug. If you see any hairline cracks - time to change them. You can still drive the car until the replacement parts arrive.
A badly torn rubber boot might even not work on that plug, or maybe randomly.

GL

Originally Posted by doru

I can bet a few dollars you will not find anything.

I don't disagree with you on the fuel system testing ... but ... at the very least, we'll get a nice simple DIY for testing the fuel pressure ... since I don't like to replace things (like the fuel pump and fuel filter) until/unless I've diagnosed them as being bad.

Bearing in mind I use the cheapest gas I can find (at the lowest octane I can get away with), my injectors may very well be clogged!
- What is the cost differential between 87 & 91 octane AKI (1)

The main thing I don't like about getting injectors serviced is I'd like to 'know' they're bad before sending them out. So I'd want to test them first. Somehow.

Plus, you don't even get 'your' fuel injectors back when you send them out.

I researched testing (thanks to Franka) and it's pretty complicated:
- Decent Techron thread

Originally Posted by bluebee

BTW, one thing that came to me loudly and clearly after reading the Witchhunter site was that cleaning a fuel injector is a lot more than just dumping a can of snake oil into the fuel tank every 3,000 miles!

The site says that "effective" cleaning can not be done while on the car, which I would tend to believe.
... stuff deleted ...
Here's what the FAQ says, verbatim, on exchanges:
Why doesn't WitchHunter Performance offer an injector exchange service?

We only clean our customers injectors, that way you know what you are getting. Some companies buy old used injectors by the truckload, use minimum wage labor to clean the injectors that work and throw the rest away. So you may be getting one with 30K miles and some with 400K on them in the same set. It is common practice for these places to grind off the original part number and give you an injector that flows "close" to your injector.



So, what I gather from this is the following assumption:

- You give them YOUR injectors
- So does another customer, and another, and another
- They clean and test YOUR injectors (and that of the other customers)
- If any of yours need to be "replaced"; they take them from the other customers' injectors

I guess what they do not do is buy injectors in bulk and use them for the matching - but apparently they do use other customers' injectors to substitute when the need for matching arises.

Do I have the basics of "matching" understood yet?

Originally Posted by doru

carb cleaner around the fuel rail. If the rpm climb, you have bad injector O-rings

Great idea! I love TEST procedures (I hate to replace anything, willy nilly!).

Originally Posted by doru

inspect carefully the boots of the coils for each sparkplug.

When I recently replaced my spark plugs, all looked good.

Plus, I have 'lean conditions"; not misfire conditions, per se.

Originally Posted by bluebee

Bearing in mind I use the cheapest gas I can find (at the lowest octane I can get away with), my injectors may very well be clogged!
- What is the cost differential between 87 & 91 octane AKI (1)

The main thing I don't like about getting injectors serviced is I'd like to 'know' they're bad before sending them out. So I'd want to test them first. Somehow.

Plus, you don't even get 'your' fuel injectors back when you send them out.

When I recently replaced my spark plugs, all looked good.

Plus, I have 'lean conditions"; not misfire conditions, per se.

A few months back, we pulled the injectors from a v8 engine (BMW) from a friend of mine's car.
The shop that cleaned them, handed out a nice report with the condition of each injector pre and post. 3 or 4 of them (I cannot recall exactly) had less than 30% flow. All had the spray pattern out. The car had about 140 k miles (225 k Km). Those were his injectors before and after. They don't inter change them. If one is toast, they tell you so, and you will have to buy a new one. At least that's how they operate here, where I live.
If you have "lean" condition, and IF it's related to injectors, you need new O-rings.

Originally Posted by bluebee

For the record ...

Update: I'm still tracking down a random error misfire sequence:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

To that end, I've started identifying & replacing all the vacuum hoses:
- How to locate all the vacuum hoses in the E39 engine bay (1) & where to get those vacuum hoses (1) & what sizes to get for all the M54 engine vacuum hoses (1) & correcting the F-connector errors in the realoem diagrams (1).

And, now that I know where the Schrader valve is, I borrowed the Autozone Actron CP 9920A fuel system tester:
- While replacing your spark plugs (1), where can you find your E39 fuel system pressure test Schrader valve for the I6 (1) and for the V8 (1) (2) (3)

Hi Bluebee
question: Did you borrow the test kit (like from a friend) or is it part of their rental service? Thanks

Originally Posted by GSA1

Did you borrow the test kit (like from a friend) or is it part of their rental service?

It's the great test-tool loaner program from Autozone.

You pay them about $160 by credit card to 'borrow' the kit; and then, if you don't return it in 90 days, you keep the test kit.

If you return the test kit within 90 days, you get a full refund of the $160.

It's a pretty good deal and they have LOTs of tools!

Originally Posted by doru

If you have "lean" condition, and IF it's related to injectors, you need new O-rings.

For reference, I'll probably follow your excellent DIY on that issue:
- E39 (1997 - 2003) > Injectors replacement and/or servicing DIY

What is fuel pressure suppose to be for an e39 2000 528i?? Im tired of searching lol>>

Originally Posted by Big Chaze

What is fuel pressure suppose to be for an e39 2000 528i??

I'm not sure but it might be in here:
- BMW_E39_E38_Fuel_Supply_System_Description.pdf

It should also be in our Bentleys.

Originally Posted by bluebee

I'm still tracking down a random error misfire sequence:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

I just re-ran into this thread trying to help out on another E39 misfire thread, when I realized I had not done the obligatory update after resolving the problem.

It took almost a year to find the cause of the lean-condition random misfire - but I finally found it by running a smoke test.
- How to make your own smoke machine (1)

a) Various vacuum hoses were worn & torn (all were replaced)
b) The CCV (lower) vent hose was leaking badly (and the dipstick guide tube was clogged solid!)
c) The corrugated "thumb" of the boot at the ICV & TCV was cracked

This thread today has a bunch of good questions for those testing fuel pressure:
> E39 (1997 - 2003) > Question on Fuel Pressure Test / Diagnostic

Originally Posted by samdayo

Having a non-start issue and wanted to ask some general questions as I've looked at a lot of threads and youtube videos but there doesn't seem one to help me answer my questions.

I'm hoping someone who has done a fuel pressure test on an E39 / M54 can confirm a possible bad pump.

Thanks in advance. I'm using the Actron fuel pressure tester cp9220a featured on Bluebee thread on finding the Schrader test valve. By the way, the adapter on my kit did not fit the rail valve well without a slight modification to the brass fitting. It would leak at the adapter because it would not thread all the way down due to the collar on the Schrader value.

Question : I've read the fuel rail is under pressure but when I first installed the tester, it was at 0 psi. Is that the case? Car has been sitting for 1 week due to non start. I'm assuming 0 is normal but I keep reading warnings about it should already be pressurized.

I can hear my fuel pump prime for 2 seconds each time I put key to 'on' position or second position.

Question : Does key to 'on' position increase the fuel pressure up to 48 psi immediately or does it take time to build up? I've watched some youtube videos but everyone likes to cut to the car running state instead of showing you what happens when key to 'on' position.

In my situation, the first time I put key to 'on' position, psi went up to 10 and I watched it climb to a little more in the next 20 seconds. It probably went up to 13-14 psi. My car is currently in a no-start situation and the most I can do is cycle the key to the 'on' position and keep priming my fuel pump. After about 3 or 4 key to 'on' position, the psi is around 40. I had to cycle the fuel pump (2 second priming each time) about 8 times to build up to 45-48 psi. Once I built up the pressure, it holds it.

Question : Is this normal or should it jump up to around 48 psi the first time the fuel pump is primed?

To remove the fuel pressure tester, I had to depressurize the rail by holding a button on the tester and dumping the fuel out. Of course, psi went back to 0.

Thanks for helping me understand the testing better. I appreciate your responses.

By the way, if anyone has a good link to test for spark on an E39 or M54 engine, please send it my way. The best I've found is to remove the coil and spark plug and then ground the spark plug and try starting the car to watch for spark. Any other ways to confirm spark?

Originally Posted by Makomagnet

Samdayo the FP should come up to ~42 psi within about 2 seconds of turning the key to pos 2.

There is a spec for how long it holds pressure (pressure drop) but in 1 week I would expect the pressure to drop to zero.

Also the FP valve is a standard shrader valve. Like a bicycle valve. You should be able to remove the gauge, then press the relief on the gauge to remove pressure.

ECU controls injectors, not fuel pressure.

Another fuel pressure test thread today:

Originally Posted by Topaz540i

spaghettidecoder is down and i cant find the bentley on my comp....

what is the proper procedure to test the fuel pump?

i assume the pressure is taken at the fuel rail from the schrader valve but does the car need to be idling, driving, under load w.o.t.?

and what is the accepted value? about 50psi in all situations?