Blue smoke is traditionally oil burning, not fuel. Verify that you are not sucking gobs of engine oil in through your turbo into your intake manifold and burning a bunch of oil every morning and while you drive. a runaway diesel can only be stopped by cutting off all of the air supply, because the oil becomes all the fuel it needs to become a V8 grenade. YouTube search diesel runaway if you are not familiar.
I almost never advocate installing parts without full diagnostics first.
A couple exceptions- brake fluid leaks, fuel leaks, oil leaks that are over hot exhaust parts.
The leak is already diagnosed enough. FIX IT NOW.
The truck has fuel lines that are 30 years old. We don’t even have same type of diesel anymore, now it all has ethanol in it which the original hose is not rated for & doesn’t withstand. You need SAE30R9 or higher. Take & post pics of fuel line on the engine and lift pump as many owners (intelligently) upgrade the lift pump, fuel filtering system, and enlarge the hose diameter supplying to the engine.
If stock have 3/8” hose from the tank all the way to the FFM (fuel filter manager), 5/16” from FFM to the IP. You have 1/4” returning from the ip (injection pump), which should be replaced with clear tubing (about 6” piece) from fuel-line.com for diagnostic purposes now and in the future, it is rated for the ethanol but not friction. there’s nothing that will cause friction on this line in this location so it is fine. You have 1/8” line that goes between all the injectors on the return side. You have 5/16” line returning all the way to the tank after the injectors and the IP returns together.
The best and safest answer is to bite the bullet and replace it all now. Then this problem is eliminated for the next 20 years.
If you don’t want to do it this way look for and repair the section that is leaking fuel out on the ground, and still buy an install the 1/4” clear line coming off the injection pump. With the engine, idling you watch this clear line for any contamination in the fuel or any bubbles traveling through the line, both are indications of problems.
Ideally upgrading the LP (lift pump) at the same time is a smart move, FASS is my best recommendation currently. Buy once cry once.
Also installing a metal T at the injection pump inlet post rubber hoses for a fuel pressure sensor. Mount the gauge where you can read it while driving permanently. 8–14 psi is the ideal operating range for a DS4 ip. Low fuel pressure will shorten the life of the IP, sometimes drastically. Proper fuel pressure will improve both power supply and MPG via improved efficiency.
And now that you think I’m done spending all your millions of dollars, we will talk about the injectors. In the fleets, we learned it is best to rebuild or replace them every 100,000 miles. USE CAUTION WHERE YOU BUY PARTS, MANY KNOCK OFFS AND GARBAGE IS SOLD IN MULTIPLE PLACES. My suggestion goes one step further and having the brand new injectors sent to a reputable rebuilding company and have them all adjusted to within 25 psi pop pressure of each other.
This makes for a far more balanced running engine, which improves efficiency (Aka, both power and MPG improvements).
A fuel leak will burn the truck to the ground.
Leaking, dripping, squirting (rather than misting) injectors, not only hurt power and performance, but will actually burn your pistons like a piece of plastic on the campfire.
These engines are very economical to run long-term, providing the initial investment is made properly. Otherwise, they will eat you out of house and home.
Decide if you were going to invest in it or sell it.
There are other things of concern to look at very very soon, usually recommended before the fuel system upgrade/maintenance.
Check for any signs of leaking or seepage of oil from the two oil cooler hoses.
Immediately replace them with any signs. These houses fail instantly and take out the engine faster than you can turn the key off. Some people choose to replace with factory new hoses and factory new quick disconnect ends. Some people choose aftermarket hoses, which are slightly better and adapters to go to the factory oil cooler. My recommendation is to do what the US military mandated for all of the Hmmvs being built using the same engine: use high-pressure hydraulic hoses with JIC fittings at both ends eliminating the pennypinching components the GM used.
100,000 miles intervals also replace the harmonic balancer and the belt pulley with brand new AC Delco units. The cheaper versions tend to fail around 30,000 miles.
You can choose to invest more money in better parts that will last permanently.
The fluid dampr harmonic balancer, and Leroy diesel’s billet belt pulley.
These components are to be changed in pairs as a new one will be damaged by the old unit attached to it. One or both of these having a complete failure will crack the block and or break the crankshaft. In the fleets we learned replacing these every 100,000 miles (the improved components were not available back then) completely eliminated what was known as the weakest lower and Diesel design problem. if you like the truck and plan to replace the engine when it wears out the investment of the more expensive aftermarket parts can be justified. The fluid dampr actually performs better and will create a smoother running engine that theoretically should last a little longer.
There are other things to deal with for improved longevity like cooling system but you can control that with your foot for now.
200 F is OK all day long
210 F watch the temperature gauge more than you watch the road
220F pull over immediately and let the engine idle back down to normal temperature.
In the fleet, we learned running the trucks at 180F cost approximately 0.1 MPG, but power was improved, as was longevity of the engine and transmission.
If you are on the fence of keeping it or selling it, learn what it takes to correct the cooling system if the previous owners have not already done it and add that into your cost factor.
