r-wats70 Posted January 5, 2015 Share Posted January 5, 2015 Happy New Years guys.. I have 6.4 towed in to shop...p0341 c...I crank over and have rpm , but after 3 complete engine revolutions my rpm drops to zero, cmp fault yes at that same moment, tried new crank and cam sensor.. no different, no sync as well .. ive checked integrity of wiring from sensors to pcm and all looks good...any body run in to this before.... my fuel pressure is good , and it wants to start , but loose rpm signal, used my multimeter on mvlts and it seems to give me a signal on eithr my cam or crank. any help would be appreciated Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted January 5, 2015 Share Posted January 5, 2015 Have you done the cam timing yet with a scope? Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted January 5, 2015 Share Posted January 5, 2015 Here is a copy of the diesel cam timing guide. diesel_cam_timing_2.pdf Quote Link to comment Share on other sites More sharing options...
r-wats70 Posted January 6, 2015 Author Share Posted January 6, 2015 Hey ... thanks for your reply... so i perfromed a cam timing test, first time i ve done this.... and i have signal on both , however where the guide says the falling edge 0 axis crossing is at 11, mine is at 7 teeth, does this mean my engine timing is out of spec ??..... Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted January 6, 2015 Share Posted January 6, 2015 Its out of time or the ckp trigger wheel has come loose on the crank. I would pull the ckp sensor out and try wiggling it with a screw driver see if it moves. Quote Link to comment Share on other sites More sharing options...
r-wats70 Posted January 6, 2015 Author Share Posted January 6, 2015 appreciate your input.... I know this engine has a lot of end play on the crankshaft, well over a hundred thou, however I did check for looseness previously and had a borescope in the crank sensor hole with engine turning over to see if the vanes were bent....this vehicle has had a hard life, but it doesn't explain why I lose my rpm signal after 3 second of crank on my rpm pid... while with the oscilloscope it gives me a constant signal , as well as my dvom... is the pcm shutting down on me because the timing is out?? just curious...or maybe my pcm is toast as well.... Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted January 6, 2015 Share Posted January 6, 2015 Does it have the ckp and cmp Fault pids? When you lose the rpm signal do they show fault yes? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted January 6, 2015 Share Posted January 6, 2015 Has any harness repair been done? Those are two wire PM generator type sensors and are polarity sensitive. I knew of a 6.0 where the CKP pigtail was replaced and wired backward, causing the engine to run, but run terribly, I assume that wiring the pigtail backwards caused a timing change. If you're scoping, pay attention to the "initial swing" of the signal after the -2 tooth spot, it should be positive. I've heard of (on here?) both excessive end play and flywheel problems upsetting the Sync on a 6.0. Your engine with .100" is a lot, probably enough to piss things off. Quote Link to comment Share on other sites More sharing options...
r-wats70 Posted January 6, 2015 Author Share Posted January 6, 2015 cmp fault yes , at the same time my rpm reads 0 rpm, and sync reads no, but only after 3 seconds of crank...there is never a sync yes at any time....and no I don't believe there has been any wiring repairs to this vehicle...it definitely looks original.... so if my crank sensor wheel could have moved , would it mean an engine to replace..(obviously because of the play in crankshaft thrust it should be )..im looking for an answer to customer because this is gonna be an expensive repair, I havnt been involved in a lot of these 6.4 engines for this type of issue. im trying to understand the logic in all of this....thank you Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted January 6, 2015 Share Posted January 6, 2015 I would bet .100" endplay is enough to send that crank trigger wheel into the block causing it to rub. Is this truck a ZF6? Quote Link to comment Share on other sites More sharing options...
r-wats70 Posted January 6, 2015 Author Share Posted January 6, 2015 Thank you for all of your replies.... customer is on holidays for 3 weeks, so when he comes back I can give him the .....news, recommend engine, maybe a drop in would be the best way to go , warranty and all no its not a zf6... why do you ask Matt ? Quote Link to comment Share on other sites More sharing options...
scott1984 Posted January 23, 2015 Share Posted January 23, 2015 Manual transmission play hell on thrust bearings causing excessive crankshaft endplay. Quote Link to comment Share on other sites More sharing options...
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