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had some poor mileage problem

DS4 IP seem to works but...
when check out with Tech 1:
no DTC
TDCO learned -1.5 (fine) ...relearn at same value
DES/ACT timing 4.9 (very low timing value vs TDC )
fuel mm 12 (too high at idle).

about 230.000 km on it.

think is an IP problem but ask to some Guru if is time to change IP or there is something to check before buy a new one.
Is the engine up to operating temps when you get those values?
 

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A stretched/worn timing chain can cause issues
 

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it was long time never check with Tech 1A the timing....
and a Fass lift pump set to 14 psi was installed, ... more then needed to IP? ...too much pressure can take effect on timing?
when installed Fass LP seen what pressure is raccomented, and 14 psi was in spec, or not so bad for a DS4 IP...seen others forumist setting more pressure, but i don't know if their IP timing changed.
for what i know DS4 is not influenced by inlet pressure...or not?
My airdog runs at 11psi. The DS4 only needs 5psi constant to be happy.

I would reduce your pressure down to 11-12psi.

Anything above and beyond that will get returned to the tank via the return so you basically end up just polishing your fuel constantly
 
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What scanner or software are you using to see that info?
I need to test it too
I have Fuel pressure, Boost and EGT gauges in my truck to monitor things
 

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I don't know what else to check

ECM takes the value from the CPS to determine the Crankshaft position, and then set Base Timing and DESIRED TIMING.


something else that escapes me????
ECM also takes values from the Optical Sensor and utilizes both CPS and OS for timing
 
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