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Car had the classic deadbolt, head gasket issue. They were replaced with the newer parts along with all the new followers, cams, etc. Heads were rebuilt and pressure tested. Car went back together and developed had a weird miss.
Dealership takes a look, determine that there are multiple scenarios where injectors are being shut off. Discover engine harness has oil in it. Replace engine harness and all sensors. Car still has miss. Decide to replace ECM with new unit. Idle and cold start miss go away. However miss at low load stays the same. If the car is accelerating there is no miss and car has full power. Miss has been isolated to cylinder 7. Leak down is <5% and compression test is inline with all other cylinder.
With a pressure meter hooked up and checking cylinder 2 normal versus cylinder 7 we see an interesting anomaly with the pressure graph. Red is cylinder 7.
honestly couldn't tell you what to think...if your heads fully came off and were cleaned during this process along with brand new gaskets all around...you should have no issues.
What RPM do you have the miss? Iv got the same on cyl7 at about 1500RPM
I just did the headbolts too. Im wondering if something has been missed putting everything back together?
Pull the fuel rail off and check to see if any injector is leaking, that's my next step.
Do any of you guys have any weird sounding noises from the cam adjuster (intake)?
Im just wondering maybe someone skipped a step or something when putting the car back together after the headbolt install
This is exactly what my 507 sounds like on a cold start when it has been sitting for at least 5 days! The "ticking" continues until the oil temperature reaches 143 degrees.
This is exactly what my 507 sounds like on a cold start when it has been sitting for at least 5 days! The "ticking" continues until the oil temperature reaches 143 degrees.
Yeah I think mine is fine... listen to the one above me... that sounds really sketchy.
Would these be controlled by the Eurocharged tune?
no...the tune won't be specific to each bank. its pretty rare even with full standalones to allow for individual cylinder correction.
the M156 engine was CAD designed so I'd doubt the head flow characteristics to allow for a deviation of 11%. deviation is unavoidable with OEM built engines, but not of a spread of 11%. I'd look to maybe the possibility of air flow restriction of some sort? it wouldn't be a fuel flow issue as fueling will be based off metered air and oxygen sensor reading.
does your trims always have a 11% spread, or was it just this instance? my LTFT's with larger injectors and e85 tend to have a spread of about 3-7% at times, but never static.
08-15-2019, 12:40 PM
