Try looking under the plenum for a fuel leak. With out the car or history it is hard to start guessing. It really needs to have a fuel gauge on it and different hoses pinched but the first thing that comes to mind is a failing o ring on the top of the injector.
01 M5------muffler delete-poor man mod (04/11-present)
13 Mustang 3.7 V6 coupe premium (06/12-present) Wifey's DD Past
87 528e (12/96-10/12) too much rust, sold for parts
87 528e/5 4parts (01/10-03/11) sold to junk yard
92 525i/5 (11/06-06/07) sold then totaled by brother in law
92 535iA (08/99-10/06) totaled by stoopid driver
99 528iA Sport (09/06-12/07) traded for e46 xi
01 525i/5 Sport (03/07-05/11) sold
03 325xiA (12/07-10/11) traded for Stang
10 Mustang 4.uh-oh Convertible (10/11-06/12) traded for Stang
. but wait a second, 91 has nothing to do with the fuel pump or the fuel filter?
91 is fuel delivery to a specific bank so you know when it comes alone (not with 90) that it has to do with the injectors(or maybe the hose or rail that feeds them) on the left hand side of the car. No would not think that this would be fuel supply but rather fuel deliver. If some other things were wrong it could be other things, that is why you always tell all of your codes.
Hey guys, kind of a noob to the site and to M5's but not to BMW's. If this is posted in the wrong section then I apologize since this code didn't come from a Peake tool. I picked up a 01 M5 10/00 built date and have put 4K miles since I got her about two months ago (currently have 112K miles on her). My CEL came on last week and a friend of mine happens to have the BMW diagnostics software on his laptop so he ran the code(s). This is what came up:
Results: 1 errors in error memory !
174 Fuel system diagnosis 1
Error frequency : 1
Logistic counter: 79
Deviation adaption offset 1 1.00 -
Intake air temperature 54.00 degrees C
Cooling water temp. 86.00 degrees C
Lambda adaption factor 1 1.25 -
aufgetreten vor (rel. BZ) 570.00 km
Now I assume the 174 error would be p0174 which would mean bank 2 too lean. Since I acquired the car I have replaced the fuel filter and the primary 02 sensors. No hesitations at idle and WOT is great. My friend reset the code this past Saturday and I have driven almost 500 miles since until the CEL came back on last night. Again, no difference in vehicle operation. I plan on having both maf's cleaned up and check for any vacuum leaks. If anyone can chime in on anything from the above on what the other stuff means or if I misinterpreted anything, please let me know. Thanks!
Nope not the right code. 174 is a decimal code in all likely hood. Find out what it was taken with. If 174 decimal is right that is P1188. That is bank 1 . Opposite to P0174. The lambda reading says that there was way too much gas at the time of the error. Likely and injector stuck open.
The plenum was removed and no fuel smell was present. Inside the plenum looked really clean though I don't think I have enough posts to show pics. Anyway, I do get decent gas mileage and my mechanic did clean out both maf's. If the light comes back on he did mention that he would go into the injectors to inspect. He did mention that I should get a new plenum gasket as mine is probably the original. What other gaskets would be needed if/when he does go down to the injectors?
Back story: Last week I replaced the passenger side CPS and passenger side VANOS solenoid orings. (I didnt have time to do the orings on the other side) Reason for replacing was more for PM than any previous codes or SES. (Actually the SES has never been on until this weekend)
Last Thursday I drove to work fine, started the car for trip home and it stalled once when I was backing out. A minute or so later the SES came on. Pulled codes that night with my MAC scanner (OBDII) P1350, P1354, P0316, P0171, P0174. I cleared them thinking they were triggered when I stalled it, and shame on me for not letting it warm up for another minute before I started to drive. The car exhibited no driveability symptoms.
I started my journey to TimmayFest and was cruising at 75 mph (about 150 miles into the trip)when the SES came on again. Still no symptoms, gas mileage stayed the same (25mpg). Stopped for lunch 100 miles later. Went to start car and it stumbled and misfired badly, barely running. In fact it stalled once. I tried feathering the throttle to see if it would "clear out" to no avail. On the third or so attempt to start, it started and idled normally, like nothing happened. Engine would then rev out in neutral and under load. Car ran fine the rest of the day. Next started cold ok, a tad rough for a few seconds. Later in the day after shutting it down hot and restarting hot the same thing happened. Today cold start it idled rough and stalled once, but it didn't act the same as before... not total misfiring, I was able to rev it.
Got home today and borrowed a Peake tool. Here are the codes: AE AF CD CE D1 D2 D3 D5
They seem to be similar codes between the OBDII and Peake. I'm sure some will suggest I check for vacuum leaks, but I doubt it is a vacuum leak because it does not occur all the time. Another reason I doubt it is a leak is after 3 or so attempts to run the engine it starts and idles fine. No vacuum leak will fix itself that suddenly...
That being said I am open to all suggestions on where to start looking.
Pressure gauge on the fuel system and can you read your log term fuel trim with your Mac or is it just a code reader for the M5. Suspect would be fuel filter, pressure reg, but symptoms sound like the third suspect a failing fuel pump.
Thanks for the tips. Unfortunately I do not have the capability of monitoring fuel trims.
Shreader(sp) valve located near fuel filter correct? I will hook up my pressure gauge and do what I can with it.
Fuel filter is 6 months 10k miles old.
I agree to suspect regulator and/or pump. Makes sense to me. Pumps can do strange things and are common for failure... How common is the regulator to fault?
You will need to see if you can get a long hose on your gauge, you may see nothing at idle, but during a drive it will likely show you the answer. Mine will just get up through the door and I leave the door ajar.
Not by experience but reading the forum the regs seem to fail. I replace mine just in case and I think there was a difference. Shraeder is on the reg housing just in front of the filter.
If you find low pressure you may want to check the screen on the pump before you buy a new one. Mine was covered with crud and I had dirt in the tank. In Ontario this is common I have seen it in every car I have owned. Regular inspection when I buy a car. Might be what takes out pumps don't know.