6.4 broke down, need diagnosis help

[EriikK]

Is there any way to diagnose cam timing issues other than by taking the front cover off and inspecting?
Can you look at the cam and crank signals with an oscilloscope, is there a procedure for that?

 

[04fxdwgi]

I have the MX+ OBD reader and Torque app. Would AlphaOBD give me more detail or not? I'd be happy to invest if it does.
And yes I understand that diagnostic codes do not tell what part to replace, they are a starting point.
At this point I do not know exactly what codes it is showing, the mechanic was using his Snap On scan tool and I was kind of following along but I didn't want to get in his way too much.

Right now I just don't know enough. Is it a serious problem or is the shop not competent to diagnose it or are they not honest? I can't tell. So I'm having the whole mess towed home so I can go through it methodically in my own shop on my own schedule. Not something I can do in their parking lot.

When I get it home my steps will be something like: check codes and chase those rabbits. If in doubt change suspect sensors, I have spares of some and I wouldn't mind ending up with spare cam and crank sensors. Since the codes I saw beside the road made no sense, I wondered if it was the ECU. I re-seated those connectors, no change. But if my spare ECU is usable I might try that.

Seems to me I ought to be able to get it to idle decently whether or not it has a mechanical problem. Once I have achieved that, I can evaluate the knock and find out what it is or isn't, and check oil pressure.

Speaking of oil pressure.... Did you know that the oil pressure reading on the dash is fake? The sensor on the engine is just a switch. As long as there is any pressure to activate the switch, the computer makes up an oil pressure number to show you, based on RPM and temperature and I don't know what else. It's an idiot light pretending to be a gauge.

Absolutely this is not BS, you can check it yourself. I have this info from a very experienced technician at Chrysler HQ. And from my days as an engineer at Ford, I know they do the same thing on at least some models, I have personally verified it.

I do agree the Ford oil pressure gauge is a fake, as I did the mod on my '04 F150 to make it an actual gauge, instead of a moving idiot light..

But in the my '16 Ram, that is NOT the case. I can honestly say that the Ram pressure gauge is indeed a gauge, not a fake. Tested it over the weekend.

 

[EriikK]

How do I check the cam timing without removing the timing cover?
Would it throw a P0016 code if the cam was out of time?
I could check it by looking at cam and crank sensor signals with an oscilloscope, if somebody could advise me what it ought to look like.

 

[Wild one]

How do I check the cam timing without removing the timing cover?
Would it throw a P0016 code if the cam was out of time?
I could check it by looking at cam and crank sensor signals with an oscilloscope, if somebody could advise me what it ought to look like.

If it has a bent intake valve,starting it and letting it run,is probably gonna hurt it even more. You have to pull the heads anyways to fix the bent valve,so it's not all that much more work to pull the timing cover and check the cams locating pin.

 

[EriikK]

You have to pull the heads anyways to fix the bent valve,so it's not all that much more work to pull the timing cover and check the cams locating pin.

Yeah I get that. I'm trying to decide if I pull one head in the truck, or do I take the motor out of the truck and do it all.
I don't yet know why that valve is bent. If the timing is off it seems like I should pull the motor and go through all the valves and whatever else.

 

[Wild one]

Yeah I get that. I'm trying to decide if I pull one head in the truck, or do I take the motor out of the truck and do it all.
I don't yet know why that valve is bent. If the timing is off it seems like I should pull the motor and go through all the valves and whatever else.

I'd pull the engine,it's alot easier to figure out why it bent a valve on an engine stand.

 

[EriikK]

Once you take off the front of the truck engine access is very good.

Here is the root of the problem, a broken valve spring.

And I'm lucky, the piston was just barely kissed.

So I'll replace the valve and a set of valve springs. Would you use MOPAR 68080909AB springs or something else? Head gasket from Mopar or Felpro or something else?

 

[EriikK]

At 80k miles I'm leaning towards taking the other head off too and sending both to the machine shop, as opposed to DIY it all. But I'll leave the bottom end alone.

 

[Jeepwalker]

How does the valve seat look, the one you can see? What you could do is take the head you have off, and take it to the machine shop and get it cleaned...see what the machinist 'thinks' on the condition of the valve seats. If you have an honest machinist up there....and I've had guys tell me on heads, they were just fine, or they needed to be 'touched up just a little', then you could make a call on the other one. But you might weight the cost of new bolts vs a potentially future failed headgasket. If you had both heads cleaned and new HG's, new bolts, new lifters, then you could be pretty well assurred the top end should be good for the life of the engine (fingers crossed of course).

I would probably stick with Mopar spring/valve because it matches what's in there. As I said, I'd weigh the cost of sticking in a new set of lifters ...for sure.

 

[EriikK]

Thanks for the advice. I'll pull the lifters and take a look, at least.

 

[Jeepwalker]

That sounds like a great idea.

The shop will check the guides too ...they 'should' all be good, but you never know. If the shop comes back with a long expensive list, then I'd find a 2nd shop/guy. But overall, these days the engine should go 250k if well maintained. So if you look at it that way, they're 1/3 of the way into their life. So the chances are more likely than not they're just fine.

There's guys on the forum over 300k on their Hemi's (5.7's but....). So I wouldn't want to get too crazy on head work. Like you said, if you put it back on most likely they would be 'good'. But if you let the machinist talk you into doing one head, then you're into it for the other. And of course a machine shop probably thinks they should all look like new. ...well, they have 80k, they're not new. But that doesn't mean they're not serviceable.

 

[EriikK]

There is a good machine shop here, I've taken many things to them and been pleased. They have a big backlog now so they're not hungry for work at all. I think they'll be honest and only do what is really needed.

 

[EriikK]

I found a pitted lifter roller and a clearly bad cam lobe. The truck was only ticking a little but I want to do it all while I'm in there, this isn't a job I want to do again. The new Mopar cam and lifters are ordered. Plus a timing set and all the little bits and pieces. Heads are off to the machine shop with 1 new valve and 16 new valve springs. They said probably $420 total -- cleaning, skim flat, valve job, reassembly -- unless they find bad guides or something. Seems reasonable to me.

 

[EriikK]

I'm getting ready to put it back together. Do the new head bolts get oil or no? I no longer trust the Haynes manual.

The machine shop found bad guides on the exhaust side, and some of the intake valves were so worn in the seat area that they would have been too thin after cutting. So all new intake valves as well as 16 valve springs. The bill was $525 plus I provided the valves and springs. Yes that's real money but I think its pretty reasonable for what they did.