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Hi,
I have R500 with same M273 engine. I also suffer from similar issues: a slight misfire at warm idle that goes away with any kind of load (moving gears from N to D is enough). No CE or other issues.
I have read all your troubleshooting steps and wonder whether you have ever checked variable intake manifold linkage?
This is very common issue on both M272 and M273. Linkage gets loose and there are even cases where internal flaps/tumblers dislodge and partially block some of cylinders. It is at least worth taking a look into.
Might be hard to believe but intake manifold was also replaced. It was actually first thing I have replaced. On that time the car was still on LPG (now removed). Air leak was also excluded by smoke-machine tests.
Might be hard to believe but intake manifold was also replaced. It was actually first thing I have replaced. On that time the car was still on LPG (now removed). Air leak was also excluded by smoke-machine tests.
MAFS also was sorted out a while ago. On that time I got new MAFS from the store but with option to return it if doesn't help. So it doesn't thus I put my MAFS back - it works fine and was replaced not that long time ago prior to start all these meddness with finding the reason of floating.
check CAT voltages on all 4 ? - they should be quite stable - on the bike one would be normal much of the time then get stupid (this bike doesn't get post CAT check sensors) . I'd like to understand how the pair on each CAT behave together - the back one isn't needed, so what impact can it have on fueling... mess it all up for fun or just throw light to scare the owner?
on idle the bike seems move around here when working.... Lambda sensor voltage 1 : 449.2 mV to 700.0mV strange my other bike is at 3361mV ?????
I have a very similar problem. So far I have changed similar things like Plato - Intake manifold ( new), throttle body ( used ), coils + plugs, all 4 O2 sensors, MAF. And the problem with unstable idle still persist. When the car is cold and I put into D or R after start, it tends to missfire or stall. Also the car sometimes feels sluggish with less power than normal, other times it goes like wild. As usual - no faults with SD. Compression is good on all cylinders.
Anything new on the topic?
As usual - no faults with SD. Compression is good on all cylinders.
in diagnostics a few years back I error on a solenoid that switched vac feed for the inlet trumpet switch-over (all done inside the manifold via the silly vac linkages that break...) the car was lazy with no top end... I found the solenoid stuck, so I bashed it around squirted lube in and gave it some excise with a car battery for a few mins - and its worked ever since - the difference in top end grunt is extraordinary
short trumpets give top end grunt - long trumpets do it down the bottom ... graph showing why we now get complex inlet manifolds
in diagnostics a few years back I error on a solenoid that switched vac feed for the inlet trumpet switch-over (all done inside the manifold via the silly vac linkages that break...) the car was lazy with no top end... I found the solenoid stuck, so I bashed it around squirted lube in and gave it some excise with a car battery for a few mins - and its worked ever since - the difference in top end grunt is extraordinary
short trumpets give top end grunt - long trumpets do it down the bottom ... graph showing why we now get complex inlet manifolds
I have a very similar problem. So far I have changed similar things like Plato - Intake manifold ( new), throttle body ( used ), coils + plugs, all 4 O2 sensors, MAF. And the problem with unstable idle still persist. When the car is cold and I put into D or R after start, it tends to missfire or stall. Also the car sometimes feels sluggish with less power than normal, other times it goes like wild. As usual - no faults with SD. Compression is good on all cylinders.
I am awaiting for new throttle body. Will post results when it arrive.
nope sits at the front, near the right bank's cam sensors and the dip stick tube - literally just took mine off and checked its operation - it had seized about 4 years back and thrown an error in engine diagnostics
also popped of vac tubes and sucked open the silly almost hidden linkages that switch over the inlet trumpets... multiple bits of hideous linkage there, with three bits inside the manifold and about 9 pivot points to lube externally - one bank seemed slightly sticky (right)
get a bit of small vac tube... take off front engine cover, pop off the small hose from each (2) black plastic diaphragm actuators (there a funny slot to get your pick on the hidden end of the pipe), suck open and closed via your vac pipe and squirt the lube everywhere that moves.... you need a bright torch and a rubber neck to bounce round to try and see anything
there's a gauze air filter on the solenoid - pull that off and clean... I would put 12 v on the two pins so you can hear it click in and out too
In addition to the shift elements for performing gear changes, there is also a multidisk clutch for reducing converter slip inside the torque converter.
The multidisk clutch is fitted with 2 or 3 double-sided coated disks depending on the engine in the vehicle and transmission model.
They are always double-sided coated disks.
• M273: Initially 2 coated disks - switchover to 3 coated disks in 02/2007-06/2007 together with introduction of additional transmission cooler
Rough idle. No misfires were detected and there are no issues with cylinder compression.
Already changed:
Coils, spark plugs, cam adjustor magnets, air pump control valves, vent valve, hoses, oil separator, air intake collector gasket (MAF top), oil centrifuge, fuel filter, fuel pump, decarbonization cleaning, and injectors.
Next up:
Air intake collector gasket (MAF bottom).
Not sure what else to check. No codes and no misfires or compression issues were detected. Air intake flaps seem to be working fine as well.
The only thing that seems off is the left and right bank ignition angle settings intermittently jump out of specified value (video) but I have no idea how to address it.
Have you checked the 02 sensors or replaced them recently? If not maybe its time for that..
Aso has the HPFP driven off the camshaft been looked at? If the oil pressure solenoid on the front of the engine is opening and closing when it shouldnt, that affects the HPFP and could explain the intermittent timing spike and rought idling.
Try un plugging that solenoid on the bottom front of the engine and see if the intermittent issue goes away and the idle smooths out. Calibenzdriver states it can take a few drive cycles for the ecu to relearn since ithe oil pressure affects lots of systems.
Plus that is a free mod. You might take the time to read the oil solenoids unplugging thread or PM Calibenzdriver too.
Rough idle. No misfires were detected and there are no issues with cylinder compression.
Already changed:
Coils, spark plugs, cam adjustor magnets, air pump control valves, vent valve, hoses, oil separator, air intake collector gasket (MAF top), oil centrifuge, fuel filter, fuel pump, decarbonization cleaning, and injectors.
Next up:
Air intake collector gasket (MAF bottom).
Not sure what else to check. No codes and no misfires or compression issues were detected. Air intake flaps seem to be working fine as well.
The only thing that seems off is the left and right bank ignition angle settings intermittently jump out of specified value (video) but I have no idea how to address it.
Have you checked the 02 sensors or replaced them recently? If not maybe its time for that..
Aso has the HPFP driven off the camshaft been looked at? If the oil pressure solenoid on the front of the engine is opening and closing when it shouldnt, that affects the HPFP and could explain the intermittent timing spike and rought idling.
Try un plugging that solenoid on the bottom front of the engine and see if the intermittent issue goes away and the idle smooths out. Calibenzdriver states it can take a few drive cycles for the ecu to relearn since ithe oil pressure affects lots of systems.
Plus that is a free mod. You might take the time to read the oil solenoids unplugging thread or PM Calibenzdriver too.
All four 02 sensors was replaced with new... I think I have already did unplugging that solenoid for tests but to make sure could you please show it's exact location on the picture?
04-20-2024, 10:16 AM
but intake manifold was also replaced. It was actually first thing I have replaced. On that time the car was still on LPG (now removed). Air leak was also excluded by smoke-machine tests.
