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How do you all get 6.2s to 300K miles

just a thought. you can find other squarebody trucks with the tach option. pull that tach and swap it for your fuel gauge. then swap the low coolant light for the fuel gauge. you might need to calibrate them but then you'd have factory gauges in there and retain the unmolested factory look on your dash! the tach uses your alternator to get signal. we can help you wire it in if you decide to go that route.
 
When posting pics, tap that “ attach files “ box.
Choose photo library then tap which photo You want to load into a post.
I upload one pic at a time, seems it gets complicated if loading more than one at a time.
After the photo gets to 100% loaded then there will be a sign on it, insert or some such, tap or click that button then choose full size.
After that one pic is entered into the post box then I tap the return button on my phone key board to drop a line, then, go back to the attach files button and go through the same process for each pic that I want to display in a post.
If You do not tap the insert then full image the pic will load as a thumbnail and them things sort of suck in a matter of their own. 😹
 
that should plug right in to the existing harness. not sure what the bottom left gauge is for, I assume factory boost?

if the tach doesn't work, then we'd have to see which pin in the harness goes to that gauge, see if there is a wire in the plug, trace it back to the engine compartment or add that wire and feed it to the engine.

@Will L. or others that know, if he has the older delco 10SI alternator that only has the two spade terminals, how would he get a tach signal? our rigs have a 4 wire connector on the alternator. something is telling me the signal comes from the cam sensor on the oil pump drive.
 
that should plug right in to the existing harness. not sure what the bottom left gauge is for, I assume factory boost?

if the tach doesn't work, then we'd have to see which pin in the harness goes to that gauge, see if there is a wire in the plug, trace it back to the engine compartment or add that wire and feed it to the engine.

@Will L. or others that know, if he has the older delco 10SI alternator that only has the two spade terminals, how would he get a tach signal? our rigs have a 4 wire connector on the alternator. something is telling me the signal comes from the cam sensor on the oil pump drive.
Yup- factory was oil pump drive. The term was ESS Engine Speed Sensor. It uses a two wire sensor. In hmmwvs that have a turbo and db2- they use the same crankshaft cps trigger unit that has 4 prongs (drawing a complete blank on the proper name). But the cps that is used in ds4 is a 3 wire, and the one for db2 uses a 2 wire. It sends the rpm signal to the tcm and the tach.

IMG_3123.png
 
Has it always had this issue since you bought it or is this new?

The black smoke is unburned fuel. It can happen from air intrusion, but 95% of time is lack of oxygen to burn all the fuel. That oxygen is supplied by air flow- so a restriction in air filter, or lack of boost.

The ATS turbo was a dealership option on Ford, not GM. The dealership option in early days for GM was the Banks Sidewinder.

Take several pics of the turbo, try to find the name plate on the turbo. When you post the pics please DO NOT choose thumbnail.
Here are photos and videos of the turbo setup,

 
You have a major problem with fuel supply.
That clear hose should stay full of fuel all the time. A tiny bubble remaining in it is normal but not draining empty.
You cranked that engine a really long time until you got fuel up to it. Then as it started the aeration was major but being empty would account for that.

There is a strong chance you are starving for fuel which is a loss of power in itself. Then this causes aeration at higher rpm which causes aeration again.
the injectors not getting full flow as they should will cause them to spit fuel rather than atomize it whichbis where that power loss is at and having droplets- that fuel doesn’t get burned driving the piston down. Instead it gets minute amounts of liquid fuel into the exhaust where it does burn and that is smoke.


On the turbo- it sure would spool up fast and helps more than being naturally aspirated - but is leaving a lot on the table for power, mpg, and engine life.

Yes too much boost is bad. To big of a turbo can cause problems but that one is quiet a bit too small. Back in the 80’s & early 90s GM did even think a turbo was mandatory.
A lot has been learned since then.

If a guy wants a lot of low rpm boost say for city towing or off road- a 14cm hx35 is a good size. For mixed towing and offroad an hx40 with 16cm housing is better. If you towed a trailer on the freeway all the time bumping that hx40 up to a 18cm could be good.
You don’t need to change it now. But turbos taking on more of the work extends engine life. So once the current issues are dealt with, start researching and learn what your application should use. Because unless you never exceed 55mph driving and never tow above 45mph- there are definitely better options out there. For now just ensure you are not leaking air pressure at the hose connection from the turbo, and give the impeller blades the jiggle test.

Back to fuel- do you have a mechanical lift pump or electric? If electric which one?
You need a metal T in the fuel line after the rubber. Some guys put the T close to the ip, some use a metal pipe & extend from the ip to behind the intake manifold opening area and put it there. Get an electric fuel pressure gauge in the dash somewhere and that sensor obviously goes in the new T fitting.
You want never under 3psi.
5psi is your target and never over 8psi.
Whenever you go over 5psi, it is forcing a timing advance.

Next is timing. Do you have a timing gun & adapter?

Then I question the injectors condition.
At 100,000 miles you should rebuild your injectors, at minimum test them.

Doing the water down the intake trick to clean out carbon will help it burn better, and sometimes cleans carbon off the injector tips and makes a nice difference in both power & mpg. Things like injectors, turbo are efficiency gains. Not just power vs mpg but helps both.

Please fill out your signature line with the engine details including lift pump, those turbo specs, that aftermarket fuel filter set up, and any other modifications made. It will really help in diagnosis as time goes on.
 
I hear often about 6.2 Detroits going to 30K miles and more, but can they really do that? My 1990 K5 Blazer with a swapped in 1985 6.2 Detroit Diesel w/h the ATS Turbo Kit which is at 85K miles (the vehicle itself has 279K miles) ... Already have quite a few in it with the following:

- Fluidampr swap from harmonic balancer
- 4 row Aluminum Radiator
- 4L60E Transmission (plus a Hayden external cooler)
- Spin on filter + water separator
- Radio + sound system
- Transmission temp guage
- That and other miscellaneous stuff such as new seals, bushings, window motors, hoses, mechanical stuff, new grill, etc.


The engine and transmission are fine (except for the engine leaking oil part), but this is all just normal wear and tear for a 40 year old vehicle, I just use it for regular plain old driving, no towing or anything.

I live on my installation, where damn near all my daily trips are within a 2-4 mile radius, so as of now, I change my oil every 3K miles. I use the Rotella T4 varient as (as stated prior) I leak quite a bit. Though if any other options are better, please do tell.

But for those who own similar applications, what do you all do to keep these vehicles going?

(Photos of said vehicle, including paperwork from previous owner:

https://photos.app.goo.gl/ksTMNAVU6ra73RpK9 )

Fixed it for you. Little too happy on the 0's. Generally if GM's 6.2 (and punched out 6.2 called a 6.5) Disposable Diesel doesn't find a way to kill itself with, eating glow plugs, cracking the main webs clean out, cracking a cylinder, breaking a crankshaft, spitting the block corner off with attached starter, dropping a valve, getting hot and loosing ring tension for instant blowby hell... You will likely have the heads off around 200K for cracking into coolant passages or blown head gasket.

The timing chain stretch requires an IP timing adjustment every 6 months.

Heavy Duty use requires oil changes at 2500 miles! Short trips are HD use. When we were hauling heavy in the grades around here 3000 miles was too long as shown in UOA. Nothing like changing the oil 2X a week. Others like @jrsavoie hauling flat lands and not throttle floored all the time, due to less fuel burned, are easier on engines and the oil.

Your short trips require frequent use of a battery charger to "top off" the batteries or they will walk down their charge (RC) due to sulfation. Glow plugs and it's control system as well as the heavy starter will be on your repair list often. Your odds of high miles out of the engine are NOT GOOD with short trips. All it takes is one snapped glow plug to stick in a valve and smack a piston... then you see all the main web cracks and have to get another engine. Like a 454 and throw the fuel down it: A 454 is cheaper TCO than fuel + parts and oil for a 6.2. Of course you would want a warmed up 454 as a properly tuned and turbo'd 6.2 can outrun a stock 454. A 350 and a NA 6.2 for say 1988 are the 350 doing a slow walk away from the NA 6.2 on a long grade. Back then the 350's dumping fuel to save the cat, with high sulfur gas of the era, smelled just as bad as a 6.2.

Where exactly is the engine oil leaking from? If it's the oil cooler lines this was covered already. Crankshaft seals could be age or worn main and other bearings.
 
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