OT: Need some Diesel advise, Oh great collective, bathe me with your knowledge! Options

[Dr Evil]

This weekend has been very productive! All of my vehicles are at least turing fuel into noise. Now it is time to make it useful.

I put the fuel pump back in my Benz (it was out because I thought it was problematic). I adjusted the lever that actuates it and it now starts, but it runs rough.
-White smoke
-Knocks more than a diesel should
-Has no power (less then before (IMG:style_emoticons/default/wink.gif) )

I made sure to NOT crank the engine with the pump removed and to keep the pump shaft from rotating so as to keep the orientation of the shafts in both correct. I may be off a little in my adjustment, but adjusting it will be a shitty task and I would like some veriffication that it is out of adjustment from someone more knowledgable than I before I go a bleeding all over the engine again.

In summary:
- Do the symptoms scream of any particular problem?
- any advice?

Thanks all!

[Mr.C]

How long did you run it? Sounds to me like it may still have some air in the lines. I had the same symptons on my 6.2 after I changed the injection pump until it cleared out. Seen the same symptons many times in the past when I serviced old farm tractors. They all did what you described until the air purged through.

[Dr Evil]

Realy? Man that would be awsome. Should I just let it run for a while then? How long? I didnt run it long.

[brer]

bleed the fuel lines.
check that the small bleed off lines are connected and not leaking.

white not blue smoke?

[Mr.C]

Yeah, if it'll stay running let it go until it clears through. It may take a minute or sometimes longer. I took the whole pump off of mine thinking I made the mistake of missaligning it. Did it for nothing it just had an extremely bad case of air in the lines. It took a few minutes to clear up. My memory of the frustration is returning.

[Dr Evil]

bleed the fuel lines.
check that the small bleed off lines are connected and not leaking.

white not blue smoke?

Whitish.

I'll give it some time to run. It was parked on an incline and all the fuel was out of the lines. It worried me because it was shaking soo bad and sounded loud.

[Mr.C]

Yeah that definately sounds like air in the lines to me. Shaking is a sympton of air not letting the injectors hit.

[Dr Evil]

If your right I am gonna give you a beer (IMG:style_emoticons/default/biggrin.gif)

[brer]

sounds like you need to drive it really hard uphill.
that always worked for me.

[Dr Evil]

I will flog it arround the complex tomorrow and report back (IMG:style_emoticons/default/biggrin.gif)

[messix]

here's my RX for the good Dr! take with large glass of beer!

[DBCooper]

White smoke? Just for giggles once it's running take off the radiator cap and make sure there aren't any bubbles blowing up through the coolant.

[bottomend]

White smoke is usually the sign of air in the fuel lines as stated above. I'm not familiar with MB but some cars have a really hard time purging air from their systems if they have a "closed loop" fuel system. Some guys install an air bleed valve in the line for this purpose.

[bottomend]

White smoke? Just for giggles once it's running take off the radiator cap and make sure there aren't any bubbles blowing up through the coolant.

That would be very bad. It's not a common problem with MB's right? I have a ford 7.3 IDI and it's the song of death for these.

[BiG bOgGs]

If you think it is air in your lines, the simple procedure is to just crack the fuel lines where they meet the tops of the injectors. This will allow the compressible air to escape from the line between the pump and the injector. Be careful when you loosen the nut holding the line, because the fuel that is under high pressure can spray out hard enough to puncture your skin if you are right at the point of the leak. When you see clean diesel and no bubbles escaping from the nut, just tighten it back down and you should hear the engine smooth (for a diesel) and run like it should.

Jim

[BMartin914]

White smoke and rough running can also be an indication that your pump is over advanced.

Be careful with running the engine (at all, especially under load) unless you have verified for certain that your timing is correct.

[Dr Evil]

White smoke and rough running can also be an indication that your pump is over advanced.

Be careful with running the engine (at all, especially under load) unless you have verified for certain that your timing is correct.

How do I verify this? How far would make a difference; the pump is only off one tooth one way or the other and the teeth are pretty fine (many of them/small adjustment). Total allowable adjustment on the pump is about 10*

If it is off of adjustment, how do I know when it is in?

I am very certain that I have air in the lines as the pump was out of the car, empty, and the car was parked up hill causing any residual gas to pool back in the tank. I used the hand primer to get it started (took a looooong time). I can crack the fuel lines, I know they had air in them as they were left on the pump.

Messix, unfortunately that forum is hard to get info out of on a 75 115, IIRC (IMG:style_emoticons/default/dry.gif) I can try again.

[Dr Evil]

Oh ya, another tid bit of info that may lean your oppinions one way or the other.

When I had it sitting and was holding constant pedal it was kind of pulsating (not rhythmically, though) for lack of a better term. Rough, quiet, rough, etc. Also, when it is idling it is very mildly oscillating (wwAAwwAAwwAAA, ya know (IMG:style_emoticons/default/wink.gif) )

Still sounds like out of time? Air? Makes no difference, run it and see what happens?

[messix]

Oh ya, another tid bit of info that may lean your oppinions one way or the other.

When I had it sitting and was holding constant pedal it was kind of pulsating (not rhythmically, though) for lack of a better term. Rough, quiet, rough, etc. Also, when it is idling it is very mildly oscillating (wwAAwwAAwwAAA, ya know (IMG:style_emoticons/default/wink.gif) )

Still sounds like out of time? Air? Makes no difference, run it and see what happens?

air.
in high school i worked for a rental yard that rented out dozers, loaders and backhoes,. home owners would rent this equipment out and regularly run an diesel powered equipment out of fuel, then put gas in it. long story short i was pretty quick at draining the tank and purging the fuel injector pump and priming the inject lines.
don't run it any more than it takes to bleed the injectors, diesel are under a lot of stress as it is and having irregular ignition pulses can shorten the life of that little rattle can.

[BiG bOgGs]

Sorry Dr., I should have said to crack the lines open at the injectors while the engine is running. This will allow the fuel to purge the air in the lines and then when you retighten the lines it should immediately run smoother. If you crack a line and retighten it and the sound of the engine doesn't change at all you may have a problem with that injector.

My diesel engine experience comes from swapping a VW 1.6L Turbo D into my Suzuki Samurai. With the VW's the timing is set by using a dail indicator attached to an opening in the rear of the injection pump. Then the pump is moved toward the engine to advance the timing, or away to retard. Whith most for these engines being pretty old, it is usually best to adjust the pump, run the engine and see how it sounds, then re-adjust until you get it where you want. I would find out how the timing is adjusted on your engine, and then play a bit.

After you have it sounding right you can keep an eye on your temp readings to see if it is set right. If your oil temps get pretty high and your exhaust temps are low, you are probably on the advanced side of the timing. If you have high exhaust temps and lower oil temps (and probably less power) you are running too retarded.