98 K2500 6.5TD Knock, Black & White Smoke, Squeal

[98K2500Sub6.5TD]

I'm new to the board and posting for the owner of the truck. I've owned 8-10 Ford 7.3 TurboDiesels and PowerStrokes over the years and done a lot of work on them as well as several VW 1.6NA and TDI diesels. I'm pretty familiar with how diesels work but am a novice on GM diesels.

The patient is a 1998 K2500 Suburban 4x4, 4L80E auto, 6.5TD, 8600GVW with 154,000 miles. Truck was purchased at 118,000 miles and had it's 2nd Jasper reman engine installed shortly before it was purchased in early 2009. The truck does have a modified computer from a Canadian company I can't recall. It is noticeably faster than a stock 6.5TD and I'd estimate it's putting out about 210hp and 420ft-lbs at the crank. It has a pyrometer and you can easily hit 1100 degrees fahrenheit if you do a 0-80mph run or when pulling a trailer. It has not been overtemped since 118,000 miles. We don't run it over 1100 degrees and prefer to stop at 1050. Since about 122k it has been run on Rotella T 5W-40 Synthetic and Wix oil/fuel filters. Truck is burning about 1-1.5qt of oil on a 7-8000 mile oil change interval.

A few weeks ago the truck suddenly started running rough on the highway. Went up a hill with no issues, coasted down a hill with no issues, throttled up for the next hill and it started running very rough and tapping/knocking and squealing. Truck was limped about 3 miles to next town. The knocking and squealing are intermittent. When started cold the truck blows a lot of white smoke that doesn't have much much of a typical diesel exhaust smell to it and doesn't really have much fuel smell either. It will continue to idle white. If you pop the throttle you will get black smoke and then back to white. If you drive the truck it smokes excessively. Foot to the floor on some 0-50mph runs the exhaust would alternate between black and white as you accelerate. It was a steady stream of heavy smoke, not a normal amount. More like you were attending a tractor pull. When warm, it sometimes surrounds itself with a cloud of smoke and sometimes not when at idle. Truck seems to have normal or near normal power. There was not a recent fuel stop before the problem started so I don't suspect bad fuel.

Serpentine belt was removed to eliminate any pulley noise. No change. Fuel filter was changed. Filter element was dirty (was almost at change interval), but bowl and fuel in the bowl were clean. Fuel had the normal color, smell and feel of good diesel. We drained fuel with the valve open and saw no water. Air cleaner was checked and looked normal. Truck starts up without an extended cranking time.

Check Engine light is not on and the bulb is good. I have a generic Actron OBD II scanner and pull no codes. Does this vehicle require a more capable scanner?

I do plan to take an oil sample and send it to Blackstone Labs. The oil shows no visual signs of water and smells normal. It feels like the oil out of any other IDI diesel I've been around that is nearing the change interval.

I know of some things I can check. This is our busy work season so we haven't got to them yet.

Crack injector lines while running and look for rpm drop. Left side is easily accessed. How do you best get to the right?

Put T fitting in fuel return line and check return pressure. I understand 12psi would be normal here. Can someone recommend a decent fuel pressure gauge? Can you access the line with the intake on?

Pull valve covers and check for rocker, pushrod or spring damage. Best way to access RH valve cover?

Block turbo veins with a screwdriver to see if squeal goes away.

Do a compression test. I'm assuming the procedure is pull all 8 glow plugs and insert compression tester there. How do you disable the fuel system for the test? Anything else I need to know? I see that minimum compression is 275psi with no more than 20% variation. That seems like a really low number to me from what I'm used to. What is an average reading? I'm at 600' elevation.

Those are the easy things. Going further than that would probably not be possible until October unless it goes to a shop.

I did see a post about flexplate bolts being loose. I guess it's possible but that does not explain other symptoms. How do you check the bolts? Just through the inspection cover on the trans? Does anyone have a proper torque setting? Can this engine be turned over by hand by the crank bolt?

I'm pretty confused here as we seem to have conflicting symptoms. If there is power loss, it's not significant so that suggests I have good compression. White smoke is lean, black smoke is rich and I've got both. It really seems like a fuel problem to me but that does not explain the tapping/knocking or squeal. There could be multiple failures, but my experience is that 2 failures almost never happen at the same time.

I have spoken with Bill Heath and based on the Jasper reman and squeal he suspects a cheap rod bearing may be going bad and allowing a piston valve collision. I'd like to try and eliminate all other possibilities before removing heads and/or pulling the engine for exploratory surgery.

I should add that I do not have a factory shop manual for this vehicle.

I have posted a video at https://vimeo.com/43645103
Please ignore my finger that got in the way. I believe you can see and hear everything you need to around it.

Thanks to anyone who can help.

[greatwhite]

I'm kinda leaning towards and injector gone bad.

Kinda sounds like one hammering.

But that's just a guess.

[westcoasttowing]

i have the same problem did you ever figure it out?