[Beast-Of-2008]

So on my quest to get the beast to full power I have replaced the MAFs, air filters, fuel filter and all 4 oxygen sensors. The only thing in that system I didn't touch were the camshaft sensors.

Before touching anything, my car had 78k miles of it and in test 4 second selection ("maf test") it showed peak numbers of 100 l/h. I changed the MAFs and it jumped up to 120s, seeing numbers even as high as 130. After replacing the air filters, fuel filter, and oxygen sensors I felt the car pull harder for the first day but didnt do any tests to confirm new l/h numbers because I was waiting for the ecu to reset. Now, however, 2 days later and my l/h numbers are back down to 100 :Thumbdown:... I have to clue what the issue can be :sad1:

If anyone is in the Atlanta area and would like to take my car with me for a spin to help diagnose the problem I would greatly appreciate it.

Also, if anyone is looking for a great shop in the area that is operated by a fellow board member I highly urge you to consider Alex's shop ( http://www.alexautoinc.com/ ) in Norcross. He helped me with the install of my terribly rusted in oxygen sensors and is a great guy to work with. It has taken me forever to find a shop I can actually trust and now that I have I feel like I must share my secret with my fellow M5 enthusiasts :cheers:

 

[M5 London]

IMO CPS sensors are important bits.

So are the Vanos Solenoid O Rings.

You could try cleaning out your oil separators too.

Do you have any engine codes ? Have you read your Fuel Trims ? What MAFS did you install ?

PS : You have replaced FAR from ALL the sensors

 

[Jan2000_M5]

Wirelessly posted (iPhone 3GS : Opera/9.80 (iPhone; Opera Mini/5.0.019802/21.549; U; en) Presto/2.5.25 Version/10.54)

Spark plugs...

 

[Beast-Of-2008]

IMO CPS sensors are important bits.

So are the Vanos Solenoid O Rings.

You could try cleaning out your oil separators too.

Do you have any engine codes ? Have you read your Fuel Trims ? What MAFS did you install ?

PS : You have replaced FAR from ALL the sensors

Any way to test the CPS sensors and the Rings easily?

I had the evaporative fuel purge valve code going on and off before putting everything in, the ses light is still on so I will pull the codes tomorrow.

I have not read the fuel trim levels, gonna go do a search on that unless someone has a quick link or explanation handy.

I installed bosche MAFS from beastpower

Spark plugs were changed less than 20k miles ago.

 

[M5 London]

Any way to test the CPS sensors and the Rings easily?

I had the evaporative fuel purge valve code going on and off before putting everything in, the ses light is still on so I will pull the codes tomorrow.

I have not read the fuel trim levels, gonna go do a search on that unless someone has a quick link or explanation handy.

I installed bosche MAFS from beastpower

Spark plugs were changed less than 20k miles ago.

The best way to check if the CPS are bad, is chuck them in the bin and see if they bounce out and into the engine bay again....

Vanos Solenoid O Rings- Just change them, no need to check them. Takes 1 Hour to do both sets and you can check Vantaam5 signature for a link to video of the procedure

ANYWAY you have engine code(s) and SES light, so being upset about not maxxing your MAF numbers at the moment should not be your focus.

Your focus should be to address what your car is trying to SHOUT out at you. You may still have low MAF numbers after you sort your SES out but its the direction you should be heading in...

Fuel trims, are much written about. They are used to iron out fuelling imperfections during part throttle at the cost of WOT fuel supply and thus power and by default L/HR numbers (A very basic overview, with little thought by me).

If in doubt, just give us the fuel trim numbers and the board will revert to you almost immediately, with the prognosis and possible solutions.

Start also checking all intake tubing post MAF and also exhaust leaks especially around o2 sensor bungs

Good Luck

 

[Vector57]

A few avenues to check out

New CPS's (all 4) and both TPS's breathed a massive amount of life back into my M5. Fuel scheduling management
is only as good as the eyes than provide input to the DME.

The same holds true for Vanos solenoid seals; hard, flattened seals will allow the control pressures to bypass.
Use factory, BMW seals since they are not "O"-rings in the truest sense; they are beveled on both outer sides,
plus a flat outer edge for extended contact with the mating bores.

The fuel pressure regulator and it's control vacuum source are definitely worth checking further. This manifold
vacuum source is supplied by a port on the lower flange area of the #7 throttle throttle body. This vacuum
hose, where it attaches to the port, is very likely "toast" due to its' high-heat environment. If leaking, you will
not be able to achieve full fuel pressure (5 bar or approx 70 psi) when at wide-open-throttle (WOT). I would
suggest replacing the regulator, along with all of the rubber vacuum hose segments. There is approximately
2 feet of hose from the #7 throttle body to the hard plastic line, adjacent to the area where the brake lines
come out of the enclosure, just under the driver side cabin air filter. Then another 4-5 inches of vacuum hose
at the regulator end. If your fuel pump is 90-100 K, replace it now. It's just false-economy to "drive it till
failure.

You might also consider pulling the spark plugs and taking some good close-up pictures. Post them here and
so we can get a good read on them. Then install a fresh set of plugs. I don't let mine past 25 K before I put
in new ones.

Good luck with your sorting out all the permutations.

Regards,
Alan