I'm stumped....

6.0 Tech

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So im lost on this one. It is Charlie from kc turbos truck, something is broke in the motor, and it wont start. Cranks good. This apparently happened at same time, he shut it off when he heard evil noises, and tried restarting after, and its a crank no start.

Icp 1200-1500 cranking, rpm 180-200, drops as batteries start dying, ficm at 47v, l and v pwr at battery voltage. Sync was good, cmp fault was no, no ficm sync. Tried ficm off one of his other trucks, no change with ficm sync. Load tested communication wires from pcm to ficm, found 1 open. Replaced engine arness, no change. Unplugged injectors 1 at a time, none changexd. Unplugged both injector harness connectors at ficm to rule out ficm harness, no change. Shield ground is attached to intake as well. Swapped pcm from my truck that runs, they have thr same strategy, no change. Swapped ficm from my truck, no change. All pins at ficm, pcm, and inline connectors are not pushed out or broken or anything stupid like that. Swapped in new crank sensor for ****s and grins, now have cam fault, and obviously lost sync. Swapped in cam sensor that was planned anyway, still have cam fault and no sync. Swapped original crank sensor, as seemed to be what caused cam fault, even though reading rpm right, still cam fault. Swapped old am sensor back in, still cam fault. No buildup of chit on either cam or crank mounting bosses, but i will be taking emery cloth to them tommorow. Inspected crank tone wheel while cranking, didnt see any bends, doesnt mean its right, but its turning straight. Couldnt see too good thru cam hole, but thought i may have seen the cam button go by. I was just using a mirror and flashlight.

So in short new ficm, pcm, harness, cam and crank sensors, and no start. Any ideas?
 

DEEZUZ

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Did the tone wheel move on the crank and it's not in time?
 

DEEZUZ

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Didn't we come to conclusion when I fought this similar issue that the crank sensor in a way powers cam circuit?

Do you have a pico?
 

6.0 Tech

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I'm not sure on the tone wheel moving. I didnt bring stuff home to see if its tight or not. Plan was to get tje,motor running before pulling it so I don't pull my hair out after building it. And yes, the voltage from the,crank sensor powers the cam sensor. But I don't know what I got now. My dumb ads had such faith,in the harness fixing it I didn't bring my electrical **** home. Doing everything from ids readings right,now....
 

DEEZUZ

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Remember I had RPM readings but the wheel was jacked up. I know you said it spin straight, doesn't mean it didn't move
 

6.0 Tech

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Yeah, that was my first though. I brought home the stuff to do cam timing when i found the open wire. My dumb ass had forgotten my ids that night, so i figured i would rule out the harness before doing cam timing checking. Then, i for some dumb reason had so muchfaith in a harness fixing it, i didnt bring anything to further diagnose it home. :fustrate:.

It is popping like its got a broken rocker, Charlie said all rockers move good, he had checked that before calling me. Hes thinking valve seat, as it will come and go, and will occasionally have a tapping type knock with it that comes and goes.

Timing would cause it to pop as well i suppose, but it only sounds like its got one, maybe two cylinders popping though.
 

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Might be a good idea to check the dowel on the camshaft that the cam sensor reads. Had a truck earlier this year come through that the cam gear was working itself off the camshaft and causing no start because the cam was sliding back and the cam sensor couldn’t read the dowel.


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Well, no longer stumped.... Figured we had ruled out all electrical issues, tore the motor out and apart today. He broke #8 rod, cam is damaged on one of the lobes where the rod had been hitting, it appears it held the cam a bit, and the gear twisted. The gear peg is crooked, dont know if it broke off or not, as i dont have a press at home. Crank tone wheel was good though :thumbsup:.... It broke the block at the bottom of the cylinder, witb a crack starting to run up the cylinder, and it got a pretty good crack at the bed plate sealing surface. Basically its ***ked beyond all repair...

Hes got the pictures, im sure he'll post them next time hes on.
 

webb06

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Well, no longer stumped.... Figured we had ruled out all electrical issues, tore the motor out and apart today. He broke #8 rod, cam is damaged on one of the lobes where the rod had been hitting, it appears it held the cam a bit, and the gear twisted. The gear peg is crooked, dont know if it broke off or not, as i dont have a press at home. Crank tone wheel was good though :thumbsup:.... It broke the block at the bottom of the cylinder, witb a crack starting to run up the cylinder, and it got a pretty good crack at the bed plate sealing surface. Basically its ***ked beyond all repair...

Hes got the pictures, im sure he'll post them next time hes on.



Let’s see those pics!!!!


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KCTurbos

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HUGE thanks to Tony for helping me figure this out.

We figured out the problem... but it was way worse than we thought LOL. 800hp + quick spooling compounds + stock rods = BAD IDEA


Here is why we could not get cam sync, The cam pin sheered and the gear spun. With the cam so far out of timing I think that is why we were having issues...

S681mRSh.jpg



With the cam out of timing... every intake valve hit every piston which led to breaking a bunch of rocker arms. What is weird is when the truck first broke down I pull the valve covers and oil rails and none of the rockers were broken. But I think from cranking the truck over for hours and hours over the past 2 months trying diag the problem, the cam gear continued to spin and make the problem worse... thus breaking the rockers. Thinking back I could actually hear some of the rockers break while turning the truck over... I thought it was an intake valve or valve seat dropping and hitting a piston.

DmysgOPh.jpg



But this is what started the whole thing... number 8 Rod decided it couldn't handle the pressure LOL. It appear the the rod twisted and broke just below the wrist pin, then spun around and wedged itself against a cam lobe... which sheered the cam pin. What is interesting is the wrist pin and rod bearings were not affected. The big end of the rod is still attached to the crank and there was not visual damage to the bearing or the crank.

ySipD7Uh.jpg



Here is a shot of the top side of the damaged number 8 piston. It looks to be in great shape from the top LOL. It was the only cylinder without any valve marks on it.

2b4p4Vhh.jpg
 

KCTurbos

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That was a damn clean running engine too...

Yep... ran super clean. Spooled fast. AWESOME setup.

I think the w/m is what did it in. I was pushing around 760hp and 11.90 at the track and added some w/m. Only made a few hard pulls with the w/m when this happened. I won't be running that stuff anymore.
 

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Yep... ran super clean. Spooled fast. AWESOME setup.



I think the w/m is what did it in. I was pushing around 760hp and 11.90 at the track and added some w/m. Only made a few hard pulls with the w/m when this happened. I won't be running that stuff anymore.



W/M?? What’s that?


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