M278 long crank position of intake camshaft fault

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ncampos976
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M278 long crank position of intake camshaft fault

Post by ncampos976 » Wed Sep 04, 2019 11:03 pm

hello all, i have a mercedes W221 with a M278 that has an extended crank with a stored fault for the intake cam adjuster bank 1, the cam adjuster has been replaced, the only way to check base timing are looking through these dumb windows and looking at the pick up wheels for the cam shafts, its not a definite answer to tell if timing is on, but the chain has not jumped time, and my belief is that the cam pick up wheel has spun slightly on the intake cam shaft on bank 1, i will be attaching all the wave forms that i have pulled from the vehicle, it uses a hall sensor for all the intake cams and for the crank shaft. im having trouble uploading the files, can i only do images?
Attachments
278 known good cam timing.psdata
(11.43 MiB) Downloaded 10 times
278 intake cam timing bad.psdata
(11.54 MiB) Downloaded 10 times

ncampos976
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Joined: Wed May 23, 2018 3:35 pm

Re: M278 long crank position of intake camshaft fault

Post by ncampos976 » Thu Sep 05, 2019 7:10 pm

attached a picture of the compared graphs
Attachments
sd.jpg

vasek
OneWave
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Re: M278 long crank position of intake camshaft fault

Post by vasek » Thu Sep 05, 2019 7:13 pm

Hello.
If the camshaft disc has a backlash on the shaft, then this would be seen on the waveform or in the scanner values.
In the waveform shown - there is no backlash.
Perhaps this can be seen on the oscillogram of the starter scroll.
M278 VS M278.PNG
The parameters of the camshaft base position should be visible on the scanner in the current data .
M157 CAMSHAFTS DATA.PNG
(11.67 KiB) Not downloaded yet
.
The problem with this engine always starts with the oil pressure.
When starting the engine for a few seconds, there is no oil pressure required for the operation of the hydraulic tensioner and VANOS.
Few people were able to restore the operation of this engine by replacing only one VANOS intake.
.
First of all you need to read the TIPS documents for this engine.
Check engine number for installed or not oil check valves in the head block's.
What type of chains are installed.

ncampos976
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Re: M278 long crank position of intake camshaft fault

Post by ncampos976 » Thu Sep 05, 2019 8:31 pm

all of that has already been done, this is a repeat customer, has had new tensioners and check valves installed

ncampos976
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Posts: 4
Joined: Wed May 23, 2018 3:35 pm

Re: M278 long crank position of intake camshaft fault

Post by ncampos976 » Tue Sep 10, 2019 6:55 pm

replaced the right side intake cam shaft and it corrected the problem, the tone wheel spun on the cam shaft

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