LS 6.0 Runability Issue

[Doppleganger]

A buddy of mine has a 2003 2500HD. For some reason he bought a new GM crate motor a couple years ago. Has run perfectly for about 5K then started having rough idle issues. Would start and run fine one time, then start and run rough the next. CE code is the crank position sensor. Shop replaced it and no change. So they scoped it and are telling him the reluctor must have been bad - has a "chunk missing" and gave him this pic as 'proof' :

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Do any of you guys see anything? I found it odd the truck even starts (and runs fine half the time) with a bad CPS let alone a chunk missing from the reluctor? I wouldn't be surprised if it isn't a missed or loose ground. This shop (same ones that installed the new motor to begin with) told him the labor would be 20+hrs to remove-replace (@ $180hr) - not including a new crank (they told him a whole crank would be better than pulling-pressing a new wheel on it....and yet suggested a new billet reluctor that would have to be.....pressed on - wtf?). Motor is 2-1/2 yrs old, with a 2 yr warranty so GM wont do anything. I told him at the time to just have his original rebuilt - he thought buying a new one would be better.

 

[Latetotheparty]

I dunno, I think regardless of what you might infer from the photo, I'd want to get that CPS signal on a scope to see what it looks like. It would seem a bit odd that the reluctor magically let go a chunk like that. In any event, if the reluctor is bad the waveform from the sensor will show it clearly.

 

[TotalyHucked]

The fact that it's not consistent makes me think grounds as well. Typically if it's a CPS issue, whether it's the reluctor wheel or not, it won't run at all or will run like crap all the time.

 

[Cjcullom]

I had a rough idle and loss of power in an 02 6.0. I even took it to GMC and they could not find it either and guessed a head gasket. At the cost of labor these days its cheaper to find a motor used for $800 and put in a new driver. Bonus: You now have a good 6.0 that you can freshen up for next time if needed.
2 of my 6.0s have over 250k and my 5.3 has 302k......The LS platform is the shiznit and I choose to drive old beaters rather than spend 60+K in a new truck.
But feel free to chase the ghost if you wish.
R

 

[Doppleganger]

I had a rough idle and loss of power in an 02 6.0. I even took it to GMC and they could not find it either and guessed a head gasket. At the cost of labor these days its cheaper to find a motor used for $800 and put in a new driver. Bonus: You now have a good 6.0 that you can freshen up for next time if needed.
2 of my 6.0s have over 250k and my 5.3 has 302k......The LS platform is the shiznit and I choose to drive old beaters rather than spend 60+K in a new truck.
But feel free to chase the ghost if you wish.
R

I'm not chasing anything and would never have interest in a 'crate' motor anyways. I think this shop he's talking to is half the problem - they were btchy with him 2 yrs ago because he refused their offer of $100 for the old 6.0 (which was running fine at the time so again I wondered why swap it out anyways). Their latest email to him was that the exciter ring is no good so he needs a new motor (?!).

 

[TotalyHucked]

Yeah I'd be finding a new shop

 

[Bextreme04]

A buddy of mine has a 2003 2500HD. For some reason he bought a new GM crate motor a couple years ago. Has run perfectly for about 5K then started having rough idle issues. Would start and run fine one time, then start and run rough the next. CE code is the crank position sensor. Shop replaced it and no change. So they scoped it and are telling him the reluctor must have been bad - has a "chunk missing" and gave him this pic as 'proof' :

You must be registered for see images attach

Do any of you guys see anything? I found it odd the truck even starts (and runs fine half the time) with a bad CPS let alone a chunk missing from the reluctor? I wouldn't be surprised if it isn't a missed or loose ground. This shop (same ones that installed the new motor to begin with) told him the labor would be 20+hrs to remove-replace (@ $180hr) - not including a new crank (they told him a whole crank would be better than pulling-pressing a new wheel on it....and yet suggested a new billet reluctor that would have to be.....pressed on - wtf?). Motor is 2-1/2 yrs old, with a 2 yr warranty so GM wont do anything. I told him at the time to just have his original rebuilt - he thought buying a new one would be better.

One of the known issues with a 24x reluctor on the Gen III motors is for the press-on reluctor wheel to separate or come loose. As you can see from the pic, the 24x reluctor is two thin plates pressed onto the crank. It looks like maybe the inner one has come loose and wobbled enough to contact the sensor. Most builders will tack weld the reluctor to the crank to prevent this from happening.

The two wheels should have the raised and lowered sections completely offset. Seeing that both raised portions overlap like that means that it has 100% slipped. If you look at a picture of a stock one, you can see all the holes on the side where the two wheels are pinned together, a billet one looks the same on the two offset raised/lowered edges, but is a single solid core with no holes on the sides.

Here's a good side pic of a billet one so you can see how clearly they should be offset, not overlapping at all.

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Heres a factory 24x reluctor where you can see the small holes where the two disks are tacked together. Again, you can see the clear offset of the two disks.

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To change out the reluctor, you just need to heat it up and the old one will fall off. Then stick the new one in the oven at 450 degrees for 20-30 minutes and then drop it on. You will need a special tool to align it properly(and it isn't cheap)

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It's made by Goodson (PN: RRJ-350)

 

[TotalyHucked]

Ohhhh, good catch. I wasn't paying close enough attention to the two pieces of the reluctor wheel, I was focused on the chip and the fact it's intermittently running bad. The one that's loose may be so loose it's rattling around, allowing the engine to run good sometimes and poorly others

 

[Doppleganger]

One of the known issues with a 24x reluctor on the Gen III motors is for the press-on reluctor wheel to separate or come loose. As you can see from the pic, the 24x reluctor is two thin plates pressed onto the crank. It looks like maybe the inner one has come loose and wobbled enough to contact the sensor. Most builders will tack weld the reluctor to the crank to prevent this from happening.

The two wheels should have the raised and lowered sections completely offset. Seeing that both raised portions overlap like that means that it has 100% slipped. If you look at a picture of a stock one, you can see all the holes on the side where the two wheels are pinned together, a billet one looks the same on the two offset raised/lowered edges, but is a single solid core with no holes on the sides.

Here's a good side pic of a billet one so you can see how clearly they should be offset, not overlapping at all.

You must be registered for see images attach

Heres a factory 24x reluctor where you can see the small holes where the two disks are tacked together. Again, you can see the clear offset of the two disks.

You must be registered for see images attach

To change out the reluctor, you just need to heat it up and the old one will fall off. Then stick the new one in the oven at 450 degrees for 20-30 minutes and then drop it on. You will need a special tool to align it properly(and it isn't cheap)

You must be registered for see images attach

It's made by Goodson (PN: RRJ-350)

I think you nailed it.

 

[Camar068]

a billet one looks the same on the two offset raised/lowered edges, but is a single solid core with no holes on the sides.

good to know solid ones are available

 

[Doppleganger]

An update on this 6.0 issue. Got the motor to a reputable builder - guy does 40+ LS rebuilds a year. He noticed things right out of the gate, all pointing back at the shop that installed it.

Reluctor wheel was fine - other than obvious marks where someone used a screwdriver and pried-tweaked them apart on one side - but main issue looks to be the pressure plate apparently (NV4500) wasn't installed or adjusted correctly - I thought these were self adjusting? - there were gouges on the back of the pressure plate - kept a constant pressure on the crank not allowing it to float. One crank bearing was like new on one side, but dug deep into the other side. Crank is not fixable. Only 1,000 miles of light use.

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There was also 2 holes drilled into the nose of the crank - builder couldn't have balanced it if he wanted to. He also suspects this motor once had a SC on it....so much for the 'new' crate motor my friend thought he was buying. The rods were all labeled with white paint marker - something else he thinks points to this was not a new crate motor.

So the motor needs torn down and totally gone through. Will need a new crank, bearings - pan had metal in it so oil pump and lifters as well. The heads were also the wrong ones - they were a square port for a later motor (?) - originals were cathedral ports. In order to make the original intake fit (cathedral vs square) this 'shop' put 2 spacers underneath the intake. Weight and bolt down of the intake was all that held them in place.

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Builder said there was heavy potential for a heluva vacuum leak sooner than later. Builder has a fresh set of the correct heads (he builds about 40 LS's a year) as well as a crank kit. Awesome guy helping my friend out with cost of parts + labor setups. One plus is that the bores are beautiful so no machining is needed. Another oddity - it had a bracket and sensor on both the front and back for 2 different reluctor wheels. The stock harness was also hacked up to accommodate a different CPS. All this is being repaired as well.

I understand corner cutting in shops but this mess was no accident. The shop that did it (in Columbus, OH) not only screwed up and obviously was fudging the whole install, but then they offered him $100 for his original LS - he refused. Wound up selling it to a friend of mine (the builder who is now fixing it). When the builder opened it up, he found a healthy amount of brake shavings inside it. No accident there either. I'm pretty sure I know the shop name that did it - will post it once I can confirm it. He said this shop is who ordered the motor - I told him to call the place they supposedly ordered it from (Speedway Motors) and see 1- did they even order it from them and 2-what exactly was ordered?

How it ever ran is beyond everyone.

 

[TotalyHucked]

Holy cow!! That's a new level of screwing someone over

 

[Doppleganger]

One other thing...when he pulled the motor he found the bell housing bolts were finger tight. He said literally the weight of the ratchet broke them loose.

Originally the clown shop couldn't get it to start for almost 3 weeks after installing it.....said they found some grounds that were loose. When the builder pulled it, he said there were 7 grounds added (to everything) and at least 4 bolts missing and from where he thinks grounds originally attached. Whats more, all the hacking to the harness was twisted wires and black tape. One union was twisted together with 2 strands of copper.

You'd have to TRY to make stuff like this an issue. wtf?

 

[Camar068]

One other thing...when he pulled the motor he found the bell housing bolts were finger tight. He said literally the weight of the ratchet broke them loose.

Originally the clown shop couldn't get it to start for almost 3 weeks after installing it.....said they found some grounds that were loose. When the builder pulled it, he said there were 7 grounds added (to everything) and at least 4 bolts missing and from where he thinks grounds originally attached. Whats more, all the hacking to the harness was twisted wires and black tape. One union was twisted together with 2 strands of copper.

You'd have to TRY to make stuff like this an issue. wtf?

share with the locals so they lose business. I mean that's in the "hollers" hillbilly rednecking.

 

[hoagster]

Yeah I'd be finding a new shop

Me to! But I'd be investigating it my self. These motors are to easy to work on.