6.5L diesel, rough idle, smoking, metal fuse getting hot

[65dieselman]

Yes I have a 93 Chevy c3500 with the 6.5L mechanical ip , and I replaced the lift pump and fuel filter, injectors, and the smoking became less but it's still is slightly, and it had very rough idle shakes the whole truck, which I'm getting fuel in the crankcase, so I'm thinking it's time for a new ip, would this fix my rough idle and smoking problem?

Also the fuse that goes to the electric Windows occasionally gets really hot would this be a ground problem?

[Robyn]

WELCOME TO TDP


FUEL IN THE CRANKCASE ????

Disconnect the heavy red lead to the IP and then crank the engine with the starter.

Listen to the cadence of the thing turning over.

should be a nice even za za za za za za za za za za

If it goes ZA ZA ZA AND THEN A GOOFY WEAK SPOT, YOU LIKELY HAVE A BAD PISTON or a bad valve.

With it running pull the oil filler cap off. If the vapor is HUFFING really bad this will confirm an issue with a cylinder. (possibly a hole in a piston)

Go around and loosen each injector line at the injector just until the cylinder starts to miss.

If you find one that does not miss (or at least miss worse) then you have the bad hole.

A compression test will confirm the issue

Good luck

[65dieselman]

How hard is it to change out a valve or valve spring? And you don't think the ip is causing the fuel to get in the crankcase?

[trbankii]

There’s not really any way for fuel to get from the IP to the crankcase other than through the injectors and then some (major) issue from there.

[DmaxMaverick]

Fuel can leak into the crankcase via the IP, but a series of unusual failures must occur. First, the shaft housing weep-hole must be plugged, and 2 (robust, double) seals must fail. This, however, wouldn't likely cause poor running issues that you'd immediately notice, and certainly wouldn't cause the engine to knock around, until the crankcase is too full (about 12-14 qts). You'd also have significant smoke at the tailpipe, caused by excess being pushed/pulled through the CDR. That much oil dilution would certainly cause bearing damage after a short period of running.

If you are seeing a rise in oil level in a relatively short period (few hundred miles), and there is fuel in the oil (and no other foreign substance, such as coolant), coupled with rough running and increased crankcase blow-by, it almost certainly indicates a broken piston or cylinder. A large volume of fuel getting into the crankcase is indicative of both, the failure and original cause. A failed (over-fueling) injector will not only cause increased oil level, but is likely the cause of the failure, as a runaway injector will compromise a piston crown in short order. A simple condition of fuel washing past the rings will be a small volume of fuel, and won't cause all the conditions you describe, over a short period of run-time. The only catastrophic event that may cause all the conditions involves a compromised piston, likely caused by injector failure.

A broken valve or spring won't cause excessive blow-by, and won't cause a large volume of fuel in the oil, but can damage a piston crown, and can cause poor running.

In regards to your power window circuit breaker (not a fuse), it should only get hot after sustained use. A failing motor or significant mechanical resistance can cause it to heat in a shorter period, but this is usually followed by a failed (overloaded) motor, but is usually indicated by a slow, labored window movement. The circuit breaker reacts to heat, such as increased resistance in the circuit. If it's getting hot when not in use, look for an electrical issue, such as a poor/missing ground that's allowing another device to ground back through that circuit, or a switch that's not opening when released. The CB is rated pretty high, 25A IIRC, so anything that's making it hot has to be drawing near that.

[Warren96]

Did you have the engine oil tested , or is this just a theory based on a non- fireing cylinder?

[65dieselman]

Well when I check the oil stick it smells like diesel, and looks like 5w20 , ok so far I took off driver side valve cover, and I'm missing a pushrod in cylinder 4, I'm gonna take the passenger side valve cover off and check that side. Looks like I'm gonna be taking the heads off to check the pistons soon, by chance how complicated is it taking out the pistons... Never done that part ever.

[Robyn]

Hmmmmm.

Push rod totally missing ???

It may have broken and slid inside the lifter case.

This issue is WHY DID THE PUSH ROD BREAK ???

Not sure that taking pistons out is needed yet though.

An FYI

The push rods are designed to go in with a particular end UP

So when you pull the rest out, be sure to keep them in orientation.

From the factory they have a paint stripe or a colored ball on the rocker end.

If in doubt get a fresh set.
The end that goes to the rocker has a hardened ball, and if installed wrong will wear out very fast and fail.

Also, the head bolts are a one use only type.

The new ones from come with a sheet on how to torque them properly.

Felpro makes good gaskets and bolts.

Get that head off and look things over.

Clean the head, deck, piston tops.

Look the cyl wall on #4 over well.

The deck needs to be extremely clean and totally free of old gasket,rust and crud before reassembly.

Get some high res piccy's and post for us to scrutinize

Good luck

Robyn

[65dieselman]

Ok, so I only found one pushrod missing on cylinder 4 all the others look straight, so my question is where did my pushrod go... I know someone else has opened it up before me I found extra rocker arm retainers sitting in valve area ok so I got the lifter out, and I'm thinking about just ordering another lifter and Paris and button her up of course I'm replacing all rocker arm retainers just to be on the safe side but everything feels tight besides that one that's missing, what's the odds of the pushrod going into the oil pan, I know everyone will say take the head off the reason the pushrod disappear I think it's because that little plastic retainer came off and the pushrod jumped off into oblivion, can the pushrod even get to the piston or sit on the block, I think it went down by the cam I saw signs of metal scrap because of the hole where you can see the cam had a little scrap, what do y'all think do you think I should just pull the head like y'all are gonna say or take my chances and replace parts and start her up, if I can run a video scope to check out block that would ease my mind though

[Robyn]

Doubtful it can reach the pan.

The lifter case area is pretty tight with minimal openings.

Look carefully down into the lifter area and the push rod is likely laying in there.

What sort of shape is the lifter in ??? Roller and such.

More pix needed

[65dieselman]

Here is some pics, I'm sure I posted a pic of one of them, anyways the top p ist of the lifter was in the valve found it pulled it out I didn't really take a bunch as I was just doing it, the other side is good though

[65dieselman]

Well I changed the lifter and pushrod replaced the missing rocker arm retainers, and put everything back together cranked it up and it's idling fine now no smoking, the truck ain't shaking anymore, I'm going to change to oil as it has a bunch of diesel in it now, I'm hoping that once I change the fluids that I won't have any fuel getting into my oil, if fuel is getting my oil you still think it's bypassing my rings on the pistons? I know changing the oil won't stop fuel from getting in but I just figured since that one piston wasn't working that the injector was just flooding it.
Or should I just go ahead and think about changing the ip?
But anyways the truck is running like night and day difference.. Thanks for all the input.

[DmaxMaverick]

It depends on how much fuel is in the oil, and how long it ran with a dead cylinder. It's possible that the dead cylinder allowed the fuel to wash past the rings, but it would take a lot of running to amount to much fuel actually showing on the dipstick. If the amount of fuel isn't much, and it did run a lot, I'd suspect that was the problem, and you dodged a bullet. I would not suggest replacing the IP for these reasons alone. The IP actually leaking fuel into the crankcase just doesn't happen, although a very rare and unique set of circumstances can allow it. Just watch the oil level and check for fuel here on out. There will be some residual after changing a few times, but it should not increase, if the problem has been fixed.

I'd be more concerned with the missing push-rod. It went somewhere, it's still somewhere, but it may not stay there. These things have a way of coming back to bite you later. I lost an end-wrench under an engine once. It haunted me for years. 3-4 years later, it gave up. Got my $10 wrench back, at the cost of a $250 tire. Push-rods are cheap, at first.

[65dieselman]

So changed the oil and let it drain for a while, can back and checked on it after it finished draining found plenty of metal in the oil drain pan, so I decided to stick my magnet stick in the pan and found little pieces of push rod in it. Also I know I need to drop pan and clean all that out, so I decided to put oil back in the truck and cranked it up let it run, and there is no more fuel in oil, it did smoke when I first started up but it stopped shortly after hasn't smoked now, but I have noticed that when I get up to 2500 rpm or higher it started blowing light grey smoke.
I know this truck needs a rehaul since it has 392,000 miles , turbo sounds weak but hasn't locked up. Anyways no more fuel in oil, plenty of blow by looks like a train, blows smoke at high rpm if I drive it it doesn't start blowing smoke till I hit 50 mph any idea what's causing that it looks like it has a manual Watergate on it... Anyhow I'm slowly working on it.

[Robyn]

Glad you found the pieces.

This is sounding like a "rehaul" is definitely in order.

If you want to keep the costs down you can do rings, bearings and toss on a set of the Clearwater heads (China) and a fresh set of Squirts and she be good.

What did the lifter look like?? or did you pull it out ???

[65dieselman]

So now that I fixed that issue changing the lifter and what not, when I cold crank it it blows a bunch of smoke like valve seals are bad and after I take off and the temp rises the smoke disappears so that's that, it hasn't been driving in a long time even since I've own ive just been cranking it in the driveway.

So anyways it passed inspection and all , but after running and driving it this evening well I stopped and turned off the truck on the other side of town and then got back in my truck and it wouldn't crank off well I had to wait until it cooled down and the glow plugs fired it off I had to wait three hours for all this.

But once the glow plugs turned on it fired up, I'm either about to get rid of it and find me another in better shape or pull the motor and rebuild it, or just replace it all together I know I'm gonna probably need a turbo as it looks like fuel is shooting out of it turbo looks wet, anyhow what do y'all think about all this crap....

[Robyn]

Several issues here to discuss.

The leaking turbo ???

Where is the leak at ?? Front or rear of the turbo ????

It will not be fuel, but could certainly be oil.

Likely it is just all the sloppy oil residue that was blowing out the breather caused by the broken push rod.

If these engines have a fair amount of vapor coming out the oil fill tube when they are idling then there will be a wet oily slop on the front side of the turbo.


The white smoke at cold start and the hard start when slightly warm is most likely due to the injectors being worn out.

A bad set of injectors will cause very poor starts cold and when just warm enough that the glow plugs will not come on.

Have you replaced the plugs ??

Use 60G DELCO plugs.


Get a fresh set of injectors OR HAVE YOURS REBUILT BY A REPUTABLE LOCAL SHOP.

Be sure the shop does not set the pop pressure at the very top of the spec.

A more middle of the spec will be easier on the IP

A fresh set of Squirts along with new glow plugs will really help the issues.

If the engine still has a lot of blowby then nothing but a rebuild is gonna fix that.

But, a fresh set of plugs and squirts will help and you can use them after a rebuild, so it's a win win scenario.

Good luck.
Keep us in the loop.

[JohnC]

Or, lots of blow by plus hard starting could mean low compression...

Worth doing a compression check before you spend a lot more money on it.