Bartel22

I have a 496 HO on my dyno right now that is giving me a run for my money. A little back ground, the motor lost oil preasure at around 4800 and wipped out the crank. Had the long block built localy, and i dressed the rest. Go for first start up on the dyno and it is only hitting on 4 cylinders. 2 left and 2 right. This is a volvo setup with a mefi4 ecm. Both my merc and diacom software tell me a crank senor sync fault. Take a known good sensor out of a running motor and the same problem occures. Started checking connections on all sensors, found nothing. Out of sheer desperation i turned the crank sensor 80 degrees to the block and it picks up all cylinders and runs great. Put the sensor back the way it should be and drops to 4 cylinders. I have even gone as far as pulling the pan and the rear main caps and comparing the reluctor rings on both cranks ( wiped out one vs new one). both sets of rings identical. I am very lost.

Philm

if it runs great when turned 80 degrees to the block, why not just leave it there??

Bartel22

i was thinking about bending a bracket to hold it there. But when all is said and done its still not right.

GO4BROKE

iTrader: (1)

I think volvo drops 4 cylinders to make a shift. You are probably missing the limit switches on the shift assembly.

Raylar

Bartel22:
I suspicion the reluctor rings on the crankshaft are damaged. It only takes a little nick or hit to wipe them out and cause your problem. we stock the replacement reluctor rings for the crankshaft. they are $226 per set of two. This usually happens from crankshaft improper handling during takedown, shop rework or reassembly on block. No other problem would cause what you are seeing.

Best Regards,
Ray @ Raylar

kiowa

hello,

i have exactly the same problem with a mastercraft x40 with a 6.0l indmar motor.
i have checked the reluctor rings and dont see any damage.

Can someone please help me.

Raylar

What year is the 6.0L engine model? Their is an early version reluctor that is called a 24X reluctor with large and small teeth on the reluctor and a late version whcih is called a 58X reluctor with all the same size reluctor teeth. If you use the wrong crankshaft sensor on the different reluctors the engine will not operate. As for just a 4 cylinder only operation, if the sharp leading edges and corners of the reluctor are not knicked or damaged or teeth badly damaged then you either may have an engine in a trouble code-reduced power mode from something else wrong on the engine or you could also have a cylinder batch firing A or B mode out in the ECM if it is the Mefi 4b type, Hope you have scanned the engine with a code reader to verify its not a code problem other than just a crank sensor code?

Best Regards,
Ray @ Raylar

kiowa

its round about a 2006 model.

the motor was rebuilt and the crank was undercut by engineering due to engine not running with oil.
i use diacom to check the faults:

this is what i get
(81) crank sync fault

it is the mefi 4 system and has only one crank sensor just behind the starter motor.
I also have replaced the sensor with a new sensor with the same part number but problem stil persist.
also im told that it has a new mefi ecu.

when i connect the diacom there are no faults present, however as soon as i crank the motor it logs the fault.

Raylar

As a newer Volvo 6.0L engine it should have the 58X type reluctor and that fault code indicates you may have a newer MEFI-5 type ECM . Did the shop use a replacement crankshaft? If they did and they used a 24X reluctor equipped crankshaft it will not work.
I would also recommend you talk to the tech department at Indmar and let them diagnose that code fault issue and verify the crankshaft reluctor type.

Best Regards,
Ray @ Raylar