Have a customer that complaint is motor loses power at WOT
No codes registered
High side fuel pressure 90 psi, Air pressure 80.
Low side fuel pressure 22 psi.
Testing vacuum with a compound gauge at diaphragm pump inlet under 2 in hg.
Now this is where it gets weird, after a few seconds of running the compound gauge oscillates wildly
into pressure and vacuum, on shutting down the engine the gauge slowly climbs to 5+ psi.
I assumed it was caused by bad check valves in the diaphragm pump, after replacing the pump I get the same result.
To me this doesn't seem normal, but I don't work on Mercs enough to really know.
No codes registered
High side fuel pressure 90 psi, Air pressure 80.
Low side fuel pressure 22 psi.
Testing vacuum with a compound gauge at diaphragm pump inlet under 2 in hg.
Now this is where it gets weird, after a few seconds of running the compound gauge oscillates wildly
into pressure and vacuum, on shutting down the engine the gauge slowly climbs to 5+ psi.
I assumed it was caused by bad check valves in the diaphragm pump, after replacing the pump I get the same result.
To me this doesn't seem normal, but I don't work on Mercs enough to really know.