I just had my injectors rebuilt by a forum member, the reasons why are in this thread:
valves? injectors? missing cylinder, please advise!

I put the rebuilt injectors with new nozzles in today and...

no significant change. Still white smoke, still runs like ****. I had ruled out compression issues because the problem traveled between cylinders with the bad injector. I double checked the valves, they look good.

Anyone have any ideas? The local MB mechanic wants $85 for a compression test. Is that standard?

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1984 300CD

Hi
You can buy a diesel compression tester kit for under $30 at Harbor Freight and a remote starter switch for about $8. With the injectors removed its easy to check your compression yourself. You just need to keep the stop lever pressed in while testing to avoid spraying fuel all over. Its best to warm the engine to 85 degrees C. before testing - although you can test with a cold engine. My 1985 300td compression runs about 100psi higher when hot rather than cold.
Good Luck,
Joseph

I've noticed there is very little fuel in the pre-filter. Is this a sign that the lines are sucking air?

Also, the air intake is pulsating. Is this a missing cylinder?

In searching for leaks, I noticed that the primer pump leaks when pumped. I've read that they always leak, is this true?

You should be able to do a compression check thru the glow plugs holes in less than an hour. No, if your primer pump is leaking it should be replaced. Don't think the pulsating intake means anything.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Waiting for the compression tester to come in the mail next week. I'm just trying to rule out other problems in the mean time.

When my injectors were tested, it turned out the bad one had a cracked thrust pin and no tension in the spring. It's pop pressure was 0psi. Could I have melted a piston or something?

If you holed a piston you might be able to tell by putting your thumb over the glow plug hole and comparing cylinders 1 and 2.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

It would help if we knew what motor/car you had. Could you please put your cars details in your signature.
If its a 617 it could need a valve adjustment.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

84 300cd. Valve adjustment was done a week prior to when my problems started. Suspected a bad adjustment and double checked everything. The valves are good.

Depends on how much white smoke. Failure of the turbo bearing seal on the exhaust side might make a lot of white smoke. Aircraft that write letters in the sky inject oil into the exhaust to enable it..

The issue is generally if this was the fault the engine would still run well I tend to believe. so I would discount it for now.

If you own a digital voltmeter a quick and easy scan of the milli volts on each glow plug may indicate if it is one cylinder related now or some form of general condition. Only takes a minute to read them and record the values at the connecting glow plug harness.

Is your coolant level dropping? With the cap off the overflow container does everything seem normal? You may have a bad head gasket. Again the milli volts might indicate where.

If the white smoke starts instantly on startup just draining the coolant and starting the engine may isolate it. You can run the engine at idle for a minute or actually more without getting too hot without coolant.

Start this test with a cold engine needless to say. If it is ingesting coolant you cannot burn what is not present. If the exhaust condenses on a piece of glass it is coolant I believe is another test. Or does the white smoke smell like oil?

Your link is not working for me so I did not read your prior thread.

Hi
If you have a holed piston, you might see severe "puffing" at the oil fill hole while spinning the engine with the starter. The compression test will tell for sure.

A big air bubble in the prefilter is normal but you should see fuel both entering and leaving the filter while running- without little bubbles leaving the filter - which indicates a leak upstream. A leaking hand pump should be replaced and are not that costly.
Good Luck,
Joseph

I always wondered what was used in aircrafts writing letters in the sky. I thought it was water but it's oil? Is it fresh oil or waste oil? How many gallons per letter does it use? Does the EPA even allow that?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Probably still allowed as the volume is not high and the use infrequent. Given time and in the seeking of power the epa will eventually cite us for flatuance.

Thanks to the suggestion of tangofox007, who tested and adjusted my injectors, I pulled them all again and noticed that one injector has noticeably less soot than the other four. The cylinder corresponding to this injector is presumably not firing.

The pre-chamber looks in order, alike to the others.

I'm still waiting for my compression tester, but it seems obvious which cylinder is problematic. I'll triple check this valve and post back.

I also edited the link to the original thread in the first post.

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1984 300CD

Did you try cracking the injector nut at the injector, one at a time while the engine is running? Fuel should spray out of each and the idle note should change as each nut is cracked.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Yeah, they're all getting fuel, and I bled out any air.

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1984 300CD