353,000 mile M3 now a Forum car

[CamasM3e93]

[CSBM5]

Originally Posted by Honda

What can cause broken valve spring?

Originally Posted by DrFerry

Metal fatigue, over rev, or both.

There have been many occurrences of valve spring failure on the S65 including cars in early life still under warranty, so I would throw in manufacturing quality perhaps also. Engine builders like Carbahn use non-OE springs just for the failure prone reason.

[lynn]

I had a misfire on a cylinder after doing valve cover gasket and oil filter housing gasket replacement. Turns out it was because I had loosened the injector rail on the right bank slightly that caused the injector o rings to unseal. That caused a fuel leak which reduced my fuel pressure for a cylinder in the left bank to misfire. And the fuel hose connecting the two banks had a leak in the metal crimping as well.
I'd look at fuel pressure like some have suggested if it's not coil related. If that's fine then it could be valve spring as others have said.

[nick3753]

Any updates?

[smmmurf]

Originally Posted by nick3753

Any updates?

Hi Nick, Thanks for bumping this thread! We are running into cost-prohibitive repairs, mostly related to the misfire and emissions fault, which must be done by a shop with a proper lift and specialized tools. We look forward to updating as soon as there is more progress!

[smmmurf]

It's been a month since our last update, but we bring good news! The car visited MRF again for a preventative DCT service. Malek was impressed at the general condition of both the engine and transmission given their mileage; they pull strong and shift smoothly, commensurate with far lower mileage units He also confirmed that the car isn't actually misfiring and narrowed the issue down to a bad idle control valve causing a slightly rough idle - the ECM throws a hard ICV fault (visible only in ISTA) which we missed during our own diagnosis. It appears to us that the ECM throws the cyl #5 misfire fault as a side effect of the bad idle and not due to an actual misfire. Replacement parts are on order and we'll update whether this fixes the issue for good.

We also replaced all spark plugs and ignition coils, both AFR sensors, and the exhaust ring gaskets due to a lack of history and the car's high mileage. The peeling valve covers were also replaced along with fresh oil separators. This combination of new parts seemed to help the idle a lot, significantly reducing the occurrence of the cyl #5 misfire fault and allowing the car to finally pass smog

While the valve covers were off, the VANOS covers were also replaced with Slon units. The original covers were so brittle, not a single cover survived the removal process intact.

We plan to tackle a replacement of the oil filter housing gasket next. Otherwise, the car is healthy and ready for many miles to come!

[smmmurf]

Hope everyone is doing well! Just wanted to share some updates on how the car is doing.

To get the bad things out of the way first: We're still very, very occasionally getting the cyl #5 misfire fault. The last time this happened was about 3 weeks / 1000 mi ago, just after we replaced the ICV and fuel breather hose. This is so infrequent that it doesn't concern us right now. The DCT also does not like sudden hard braking when in automatic mode, particularly in the less aggressive DriveLogic modes. We can repeatably get the transmission to enter limp mode (1-3-5-7 only) by simply doing a full ABS stop from 50-0. It seems as if the transmission stalls when attempting to downshift from 2nd to 1st under such conditions; this does not happen when downshifting manually. We're happy to live with this for now as restarting the car clears the fault immediately.

The car was also overheating pretty badly, creeping up to 220-230F oil temperature just idling in 75F weather due to the extremely damaged fins on the oil cooler. The radiator also sprung a leak. We decided to address these items together with the oil leak from the OFH gasket. All in all, we replaced the radiator (new OEM), oil cooler (used OEM), thermostat, coolant temperature sensor, OFH gasket, oil pressure switch, water pump, all belts and pulleys, all coolant hoses, windshield washer pump, and auxiliary washer pump. Phew! The car now runs at 210F around town and on the highway in 95F ambient weather, and runs to a maximum of 255F after 10-minute full send up a canyon road. As far as we can tell, there are no remaining fluid leaks demanding attention.

We're now done over 1,000 mi since completing all that maintenance. The M3 is at 356,103 mi and climbing! On the exterior, the front reflectors have been color matched, rear tow hook cover replaced, PPF applied to the nearly brand new headlights, and brand new OEM Euro LCI tail lights have been fitted. A thorough wash and seal later and it's beginning to be difficult to tell that the car is nearly halfway back from a trip to the moon!

[smmmurf]

Hope everyone is enjoying the summer! M300k is enjoying the toasty weather in Northern California and is currently sitting at 357k miles.

Chasing a slight vibration at highway speed, we swapped the OEM 18" wheels and mismatched Michelin PSAS4/PSS tires out for a new set of Titan 7 T-S7 wheels and Michelin PS4S in OEM sizes. The vibration is slightly improved but still present. We'll have to continue investigating this fall in conjunction with a more comprehensive suspension refresh.

Center caps are en route. Apparently, E-series center caps are too big for Titan 7 wheels. Therefore, we'll run the standard caps that work on the G-series cars instead. Cheers!

[Honda]

Was the check engine issue solved?

[smmmurf]

Originally Posted by Honda

Was the check engine issue solved?

We currently don't have a persistent check engine light, but there is an intermittent fault that occurs about once a month which clears immediately upon restarting the car. We have not yet found the root cause for it yet. We suspect that it might be related to the transmission fault which occurs under hard deceleration, but it could be from something else entirely. The coils and plugs are new, and the compression was strong in every cylinder at our last check.

[charliev68]

Cracked Exhaust Valve Spring!!! Don’t wait till it coils over and locks open the valve. Ask me how I know?

[smmmurf]

Originally Posted by charliev68

Cracked Exhaust Valve Spring!!! Don’t wait till it coils over and locks open the valve. Ask me how I know?

We are refraining from jumping to conclusions, but it sounds like you want to share why you suspect this is the issue on our car. What makes you think we could have the same problem? Thank you.