A friend brought a 4 yr old air compressor with 850 hours on it to the shop that is driven by a 4 cyl diesel non turbo Isuzu engine. Problem is it smokes during start up. Seems he loaned it out to be used at a chemical plant for a period of time and got it back with this issue. It seems to take a long time to start and smokes pretty heavily only during start up. It runs good with no unusual noises after it is up to rpm and loaded up. Air cleaner is fine along with the glow plugs. Plans are to maybe pull injectors and send to Bosch shop. I'm thinking they probably ran some unleaded regular gasoline through it.

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Jim

Compression test, diesel purge then move to injection shop if need be.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

I say that because I WASTED money on injectors because my engine had low compression, always check compression first and foremost.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

What color is the smoke?
Is the fuel known to be good?
Definitely do a compression test; but, find out if the valves are adjustable. If they are adjust them before doing the compression test.
Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Compression issues show themselves cold and get better as it warmed up. Check compression before anything. If the fuel isn’t bad, then it’s probably compression. If they ran gas thru it and ran it for awhile it probably damaged the engine pretty seriously.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Yes, but to Sugarbear's point, a bad valve adjustment can look just like low compression. Check the fuel filter before you get into the injectors. The plugs may be fine, but there may be heavy carbon in the prechambers, if so equipped.

"probably damaged the engine pretty seriously"

Predominantly cylinder bore/piston issues?

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Jim

I would give the glow plugs a second look:



In a nutshell, slow starting, and complete failure to start. Once the vehicle does start, missing, rough idle, hesitation, and lots of white smoke until the engine warms. If you have a four cylinder, one glow plug bad will cause slight hard starting and a miss.

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96 E300d

The message here is : DON'T PANIC ! .

Take the time to properly diagnose it before you throw any $ at it .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

If they did run gas in it I'd suspect damage to the injectors first because they have tight tolerances and need the lubrication. If it ran a long time on gas the head will crack and the block eventually.

at least that happened in my 74 240d when lovely daughter #3 filled it with gasoline in Ohio and headed home to Lafayette. She made it to Richmond with a tank of half gas half diesel. Block and head ruined.

I did a swap to a 300 na including the slushbox.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The color of the smoke looks like it is white/black. I'll try to post video on youtube. All the injectors check out fine. I'm not sure about the fuel. I may drain it and fill with fresh fuel. Once up and running it runs great with no smoke.

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Jim

What is the exact model of engine and compressor?

Given this is 4 years old, it should be an electronic engine. Many times trouble codes / data can be had from the control panel.

What type of injector pump does this have? Some pumps have a cold start fuel increase system that will overfuel in order to get the engine running. If this isn't releasing the engine may smoke. Most have an injection timing advance but I'd expect a hard start if this has failed. If this is an electronic engine, all of this is done by computer.

Generally, chemical plants / refineries require an air shut off system to prevent run away of there is a flammable environment. Check to see if this is tripped.

You have checked the air filter? Generally there is an outer then a small internal safety filter. The safety filter exists in case the main filter tears.

On the compressor side, rotary screw compressors have a blow down valve to relieve pressure in the coalescer tank once the engine stops. If this isn't working, the engine is operating under a load at start up and might smoke.

Does the smoke smell like fuel or oil being burned?

Is it water cooled. If so look in the coolant recovery tank to see if Oil or crud from combustion is in it. Does the coolant smell burnt?

Can you find out if it is an Engine that sat unused for a long period of time?

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84 300D, 82 Volvo 244Gl Diesel

White smoke is associated with a coolant getting into the combustion chamber or exhaust. White smoke can also be unburned fuel and it will smell like fuel.

Dar smoke can be Oil burning or fuel poorly burned. If Oil it will smell like burned oil.

If someone put Gasoline into the fuel it often burns the tips of the Injector. when you pull out the Injector you may or may not be able to tell that if you have never seen one before.

In stead of Mercedes type Indirect Injection Injectors I have seen some Engines using pencil type Injectors with something like 3 holes in them.

If you pulled all of the injectors you could pic 2 with the worst looking ends and take them to a Fuel Injection shop to be tested. They might test one or 2 for free.

We did work for a place that someone of the higher ups decided that they could mix waste Engine Oil in with the Diesel Fuel. This is the Engine that had the pencil injectors which had 3 holes in them. Mixing waste Engine Oil in with the Diesel Fuel resulted in one or more of the 3 holes getting plugged with some white crud.

In another case a Company entirely ruined 3 Fuel Injection Pumps because someone decided they could mix the Oil that they sprayed on dirt to keep the dust down with the Diesel Fuel. When you opened up the Fuel Injection Pump it was full of cherry ice cream colored thick foam and the most expensive part of the pump was sheared in two pieces.

Not far from my House was a company that rented out large CAT Diesel Generator Sets (Engines larger then a Pickup Truck). When you got the Generator Set the Fuel Tank Was full and the Tank Cap was locked. You had to monitor how much fuel was in the Tank and call the rental company and they came out with a Fuel Truck and re-fueled it. There was no way they were going to let someone contaminate the Diesel Fuel of those expensive CAT Engines.

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84 300D, 82 Volvo 244Gl Diesel

maybe the glow plugs are not firing. The smoke you see is a mix of excess burnt and unburnt fuel (burnt because pump governor goes to full fuelling when you shut off)

It can also be a bad start timing. Some old isuzu diesels had a manual cold start lever which changed injection timing. If the pump was moved while the lever was engaged the timing goes very bad and you get a hard starting engine.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)