I have tired searching for a solution to my question but haven't found anything specific enough, so I apologize in advance if the answer is already available.
About every other time I do a wot run in second or third gear it'll throw an SES light. And every time it is some combination of misfire codes always involving multiple cylinders. Other symptoms include slightly rough idol and lots of hesitation and bucking before the engine is up to temp (without the ses light).
I am confused where to start as I seem to only be registering symptoms, no sources.
In talking with a few other guys the symptoms seem like they may stem from a faulty crank position sensor. Is that a good place to start?
Thanks in advance to anyone who can offer any help!
id replace the mass airflow sensors if they haven't been replaced in the past 50k miles.
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Mike
91 M5 Alpine White II, Silver Gray 3/90 production
17x8/17x9 M system with PS2, 20mm touring roll bar; Ground Control Coilovers; EAT Chip, CD43; bmw/nardi blackline steering wheel, 3.8 Cam Gears
08 535i / 6 speed
Space Gray; Gray; Sport/Premium/Nav
00 M5 Ti Silver; Imola/black sportiv --Sold
Engine:
Supersprint Headers, Dinan CAI kit and MAFS, Throttle Bodies, Cams, Ported heads, Exhaust, Custom dinan software, Evosport Pullies, Dinan clutch and lightened flywheel; Ignition solutions plasma coils
Suspension:
Dinan Stage 3 with front and rear Strut Tower Braces, Beastpower Sway bar brackets, Dinan Wheels with 275/285 PilotSport, X5 Thrust arm bushings, Stoptech 355mm 4 piston front, 355mm 2 piston rear brake kit, Dinan 3.45 diff
Interior/Misc:
Eurodash, updated steering wheel, Bluetooth retrofit, Sirius Retrofit, hardwired V1, Widescreen Mk4 nav, M audio retrofit, Ice Link, BSW Stage 1 speaker upgrade, bmw towbar
I haven't had a chance to test the MAFs yet, but I'll try and do that soon and report back.
What should happen when I disconnect the mafs at idle?
EDIT:
I just ran out at lunch and ran the MAF test and got a max reading of about 90 at 7000 rpms wot in second gear. Adjusted and its still below 100. So I guess new MAFs are a must, hopefully that will help with some of the other issues as well.
Last edited by Evilburn; 23rd September 2008 at 20:55.
Reason: added info
I don't think the car will run at all with a bad crank position sensor - my mercedes was dead in the water with a bad one. However, the M5 will run with a bad cam position sensor.
Steve
00 M5
Last edited by TurboCarrera; 23rd September 2008 at 21:13.
I did the tests with Adam at lunch. We had it in the right mode, besides, 90 in any mode would be bad I think.
He did notice a slight short lived improvement when he cleaned the mafs a couple weeks ago.
The reason we deduced the bad crankPS is because of this SEL only coming on at high RPM during a Full throttle run. The car would go into limp mode then a shut down start up of the engine would make the EL and limp mode go away.
The MAF's definitely do not appeat to be operating correctly though.
Also, I'm pretty sure the dealer history said that multiple CamPS's have been replaced in the last 15K.
Bob
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2001 Jet Black M5
2006 Jeep Grand Cherokee Limited 5.7 HEMI
2001 Dodge neon - Slomatic winter beater
Last edited by REKIII; 23rd September 2008 at 23:28.
My 2001 M5 49,000 miles just developed the exact same symptoms within the last week. I had the dreaded oil filler cap failure blow about two and a half quarts of oil all over the passenger side of the engine bay a few weeks ago. I cleaned every thing up pretty well but have not checked the air filters yet for oil contamination of the maf. I'm hoping that is all it is and not oil soaked coils or something worse. I will be watching this thread closely....
The reason we deduced the bad crankPS is because of this SEL only coming on at high RPM during a Full throttle run. The car would go into limp mode then a shut down start up of the engine would make the EL and limp mode go away.
This is classic bad MAF! The DME is protecting the engine since it sees that fuel is way off.
(When you disconnect the mafs at idle the DME (obviously) ignores the MAF and runs on a mapped air/fuel... which will, if the MAFs are real bad, result in a SMOOTHER idle.)
Bad cranksensor and the car will not run - more common after a clutch replacement and someone misaligns it.
Linear Mode
