Car model and year: 2006 BMW E60 M5 with 172k miles
1. the M5 on a cold start would idle really weird. Would fire up, fill the cats, and then would boggle up and down 550-900 and fluctuate nonstop. If you drove the car for 2 minutes, that would stabilize.
2. When I fill up gas and try to start the car, it will start, run for 2-3 seconds, then stall. I start her up again and she fires right up and starts bogging even on a warm start. Once again, if I drive it for a few minutes, it stabilizes and all is well. I’m led to believe I have a fueling issue or perhaps electrical somewhere because even when I close my gas cap, I get in the car and it will show me that I need to tighten my gas cap. And always, after I fill up, I start having issues.
3. LASTLY but THE MAJOR ONE. intermittent misfires occasionally
And check engine light is on.
BMW specific scan is needed:
If your check engine light on. Please stop replacing parts without doing a full BMW specific scan on the car. Don’t assume ignition coils are bad. If you are a DYI person, get a good scanner and pull the codes. These cars are smart enough to diagnose themselves, well, for the most part.
What BMW E60 M5 scan tool is verified working?
Option 1. Foxwell NT530 scanner
My favorite is Foxwell NT530, costs $169 at Obd2tool.com, and look at the codes.
Please scan the car and report the errors you see. A generic OBD2 scanner will not help.
Some of the codes will be misleading: Eg: it may show you misfire in cylinders, and also show throttle actuator error. So, you have to fix the throttle actuaror.
Misfire happens due to bad throttle actuators, putting your car into limp mode.
For the record, this car will not be nice to you if you are being super nice to it by doing oil changes, giving it a nice car wash, getting it fully detailed, waxing the paint etc.
The car has huge electrical/plastic/electronic issues everywhere. It can bankrupt you in maintenance charges if you are not doing all this yourself. Lot of valves, actuators, seals, will fail and they need replacement. It can get pretty hefty if you go to a service shop.
Option 2. BMW ISTA software
If you have “gas cap” fault means the tank is not breathing in properly, either the gas cap is leaking but most likely the charcoal canister, DMTL pump or tank valves are inoperative.
There is a specific fault codes for the DMTL pump, valve, and the DMTL heating system but you have not got any of them. That being said, I am not sure how accurate the car diagnosis system regarding this system, a possibility is the system is electrically connected but doesn’t function as supposed to. The charcoal canister doesn’t have a specific code but I think it is included under “gas cap” fault troubleshooting sequence.
The DMTL system can be tested with ISTA to verify the system integrity. The “gas cap” fault should be inserted in ISTA test plan and work through the suggested steps by ISTA, or experienced tech should access the Function Structure and perform the related tests such as the DMTL system and tank vent valves, and to have a look at the fuel pressure and test the fuel pump and or if fuel filter is clogged.
Here is a list of the codes:
Multiple errors may show up, but catch the first one upstream in the flow.
If it shows TA error and O2 post cat sensor, fix the TA first.
With the V10,V8s and V12s, without expensive investment into new parts randomly, you can switch some parts to the other bank to rule them out.
If you have ISTA , run fuel pump pressure test , I had the sort of issues you are experiencing and this test showed I had fuel pressure issues , I changed fuel pump and filter and all good after . If you’ve never had pump or filter at your miles I would change them anyway.
I also changed fuel pressure sensor , fuel tank vent valves and charcoal canister as I wanted to cover everything on the fuel pressure side of things .
Option 3. Autel MaxiPro MP808K
Fuel Injectors shouldn’t be over looked here, especially on higher mileage cars.. My late 05 BMW E60 model developed a misfire on cyl no 8..on the very first run after I replaced starter motor..(which is a total pain btw) I swapped coil packs, plugs and ionic modules… still cyl no 8 misfire.
The scanner I used is an Autel MP808K.. it said “Misfire cyl no 8 with cut off as it was affecting emissions” Its running sweet now that I changed the “dodgy” injector. Incidentally I had to change the fuel rails as well, because when I disconnected the fuel line I found out that something had been chaffing away at the hose and was almost through to the inner lining of the hose..(see pic).. So I caught this in the nick of time.. To change the rail, the centre engine harness has to be disconnected at the ECU box and the whole lot lifted up and swung to the left for clearance…after that the rails come off with injectors pretty easily.. just a case of keeping everything clean after that..
Hope it helps!