A question for the brains trust...
I have a 2012 D4D that has just suffered from the famed cracked piston issue at 174k. Reco engine purchased from reliable supplier and installed by a local mechanic. Injectors were replaced at 134k and according to Techstream are still in spec. New engine runs really well, no abnormal noises and generally performs as it should. No chip or EGT blocking plate in new motor, inlet manifold dipped and cleaned during replcement.
My issue is it has a surging problem at low revs. First noticed it in low range 4wd holding a constant throttle on a gentle hillclimb just under 2000rpm and the revs would drop off instantly by 400rpm then pick back up again straight away, it does this fairly consistently. It doesn't seem to happen nearly as often over 2000rpm, in fact it is difficult to notice it at higher revs. When driving on the road taking off from a standing start it does it several times - all under 2000rpm. Following my wife driving, the car pulses black smoke each time it does this. When she accelerates flat out there is no smoke at all and it performs as it should.
I have replaced the Suction Control Valve, and found the MAP sensor filter was blocked so I have temporarily bypassed this and ordered a replacement. I have cleaned the MAF, replaced main fuel filter, secondary filter and tank filter, reset the ECU(battery disconnect for 5 minutes) and still no different.
I generally dont drive the car often as it is the wifes daily driver, so cannot say with certainty that this wasn't happening before the engine failure, however neither of us noticed it. Obviously every sensor, hose and connector was disconnected for the replacement so there is a chance that something has been missed, but I have had the mechanic look over it again and everything I can see looks okay. No fault codes at all.
Any advice appreciated, over to you......
I have a 2012 D4D that has just suffered from the famed cracked piston issue at 174k. Reco engine purchased from reliable supplier and installed by a local mechanic. Injectors were replaced at 134k and according to Techstream are still in spec. New engine runs really well, no abnormal noises and generally performs as it should. No chip or EGT blocking plate in new motor, inlet manifold dipped and cleaned during replcement.
My issue is it has a surging problem at low revs. First noticed it in low range 4wd holding a constant throttle on a gentle hillclimb just under 2000rpm and the revs would drop off instantly by 400rpm then pick back up again straight away, it does this fairly consistently. It doesn't seem to happen nearly as often over 2000rpm, in fact it is difficult to notice it at higher revs. When driving on the road taking off from a standing start it does it several times - all under 2000rpm. Following my wife driving, the car pulses black smoke each time it does this. When she accelerates flat out there is no smoke at all and it performs as it should.
I have replaced the Suction Control Valve, and found the MAP sensor filter was blocked so I have temporarily bypassed this and ordered a replacement. I have cleaned the MAF, replaced main fuel filter, secondary filter and tank filter, reset the ECU(battery disconnect for 5 minutes) and still no different.
I generally dont drive the car often as it is the wifes daily driver, so cannot say with certainty that this wasn't happening before the engine failure, however neither of us noticed it. Obviously every sensor, hose and connector was disconnected for the replacement so there is a chance that something has been missed, but I have had the mechanic look over it again and everything I can see looks okay. No fault codes at all.
Any advice appreciated, over to you......
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