Do you notice a "flare" when cranking? In other words, can you actually hear the engine rpms increase when the PCM reports the rpm increase?

 

No the rpm seemed constant audibly. When I graphed my RPM on AE while cranking it has spikes. From around 160 to 200 and even an odd one at 230. This is why I ordered a new sensor to rule that out. Sensor is working and giving pulses and I know they are rare to fail but it does have those spikes every so often. Wasn’t sure if that was normal but thought I’d try it to rule it out. I’m not confident that will be it.

 

I would suspect the sensor as well.

 

Sensor should show up tmr and I will hope to get it in over the weekend and will report my findings. Do you know how to check tone wheel timing manually?

 

So I installed a new crank sensor and still don’t have cmp/ckp sync. Possible spun tone wheel? Any more suggestions?

 

You need to scope the wave forms at the PCM to see what the patterns look like. It’s still possible to have a wiring issue. If you don’t have clean, correct patterns at the PCM then I would back probe the sensors and check there. If you do, then you have a wiring issue.

do you have any rust “lifting” the sensors out of their bores ever so slightly? There is little tolerance for the air gap.

i haven’t seen a tone ring fail yet on one of these unless something physically broke or bent it.

edit: have you checked crankshaft end play?

 

You need to scope the wave forms at the PCM to see what the patterns look like. It’s still possible to have a wiring issue. If you don’t have clean, correct patterns at the PCM then I would back probe the sensors and check there. If you do, then you have a wiring issue.

do you have any rust “lifting” the sensors out of their bores ever so slightly? There is little tolerance for the air gap.

i haven’t seen a tone ring fail yet on one of these unless something physically broke or bent it.

If I have load tested, ohm tested, checked short to ground and voltage, checked hertz readings on both sensors at the PCM you think I could still have a wiring issue? I know a scope would prove it but I would need someone to do it that knows what they’re looking for don’t I? I don’t have a scope and have talked to a few mechanics with scopes but they have never done a 6.0.

 

You’ll need to have a reference to proper waveform pattern. If you’d load tested all the wiring then it’s probably unlikely it’s wiring but RF interference is still theoretically possible.

usually you can find good known patterns on iATN but you’ll need to pay a subscription.

check your end play and make sure you have no rust on either the CMP or CKP sensor mounting surface and see if it goes into sync.

And just to clarify you do know the 2614 is for the CMP sensor correct?

your failure of smoke and stalling at road speed is a little peculiar.

 

I have checked for rust jacking and cleaned the mounting surfaces on both sensors very well. I tried moving the harmonic balancer in and out to check end play and it was tight but maybe that isn’t a great way to do it? The tone wheel looks centred in the hole with borescope. I would assume if it wasn’t then I wouldn’t be getting rpm and Hertz readings from it. This thing is a brain teaser for sure.

 

If you find nothing wrong with the CMP signal at the PCM I’d suspect you have a PCM problem with interpreting and/or relaying the signal to the FICM.

 

Yes I realize the 2614 is for the cmp, but I had did everything to prove that circuit so I moved onto the ckp circuit and sensor. The 2614 only shows after a lot of long cranks so could just be from that I have heard.
I have changed out the PCM and FICM from a running truck with no change.
I agree smoke out the pipe seems weird when it quit and when I got it home I did have cmp/ckp sync and ficm sync and it would smoke fuel out the pipe when trying to start so I thought it was a base engine problem. Did compression test on it borescoped and it and it seemed fine so I tried starting it again and then didn’t have sync and I have been trying to diagnose that ever since. The only thing I can think of is the tone wheel spun a bit but still had sync so it was injecting fuel but at the wrong time hence the smoke and no start. Then when I was doing all of my compression checks it spun more and lost sync altogether.

 

To clarify, you have no sync AND no FICM sync?

if that’s the case, a scope is your only answer to see the patterns and how they overlap (as the PCM sees) without disassembling or overlaying the CMP and CKP harnesses

 

That is correct. I have no cmp/ckp sync and no ficm sync.
Talked to a friend with a 4 channel scope. Is it easy to see the overlay to check the timing of the wheels? He says he has samples of proper waveforms but not one of them overlayed to prove the tone ring hasn’t spun.

 

First check to make sure you have good clean patterns on both sensors.
then You’ll need to find a known good pattern of them combined.

 

Did another test. According to the document you posted mathewd11 I come up with a manual way to check the cam crank timing. I put my borescope in the cmp hole and centred the cam pin as best I could in the hole. Then I put my camera in the ckp hole and counted the teeth on the tone wheel as I slowly cranked the engine over clockwise as viewed from the front of the engine. According to the document you sent I should count 11 teeth and then be at the spot on the tone wheel where there is two missing teeth. I counted 31 teeth so this proves my theory that the tone wheel has likely spun on the crank. Theoretically it could be the cam gear but the engine does good on a compression check and will run on ether so I’m going to assume the cam is timed properly. Guess it’s time to pull the engine out. At least I finally figured out what’s wrong.

 

You are turning the engine over in correct rotation just to verify?

 

I turned the engine over clockwise as viewed from the front of the engine which should be the correct way to count 11 teeth. Even if I turned it the wrong way there is 58 teeth on the tone wheel so 58 minus 11 is 47 and I counted 31. I think that should prove that the wheel has spun. What do you think?

 

Yes the tone ring has probably spun. Your compression test results rule out the cam gear spinning on the cam.

does it move easily if you try to move it with a screwdriver?

 

Hi guys. Been a while but I was finally able to get time to pull the engine and tear it apart. I was correct. The pin on the tone wheel broke and it spins freely on the crank. I found the other half of the pin in the pan. No other damage. Man such a small part can really cause a lot of work. Now to decide wether to rebuild or part the truck out.

 

Thanks for posting the conclusion.

 

Yes of course. When I read threads I don’t like it when they are just left blank with no conclusion.
Now I’m dealing with another issue. When I did my head gaskets a few years back I had some heads built from new castings with all new seats and valves etc. now that they are removed again I see a couple of cracks from the glow plug holes to the exhaust valve seats. I have read a lot about cracked 6.0 heads but haven’t really found a definitive answer. I was thinking of overhauling the engine but now if I had to buy new heads that adds a lot of unforeseen cost. Is it common practice to replace the heads with these cracks or don’t worry about them?