Vacuum Pump Failure, picking up the pieces? - Page 2 - PeachParts Mercedes-Benz Forum

eightiessadies · #16 06-18-2014, 10:02 PM

Finally got a new vacuum pump installed.
Got 20 hg of vac.
But car runs like poop.
Very low power, white smoke, burning smell.
Missing at idle.

Is my injection timing messed up?
Chain skip a tooth but not break?

Could it be serious engine damage.?
Should I get a compression test?

I drove for 20 minutes and it didn't get worse
Or better so I'm not sure it could be bad
Or clogged fuel

eightiessadies · #17 09-15-2014, 08:40 PM

My car has been at an indie shop for 2 1/2 months now!
Vacuum pump exploded and I replaced it and cleaned up the shrapnel. See previous posts for details.
Afterwards, It ran very poorly with lots of white smoke ( good vacuum tho)so I took it to an indie mechanic to have the timing inspected.
He says the chain jumped a tooth, as I surmised it may have from reading posts here, and that he wants to line up all the timing
And see if it will run to determine that no rods or valves were bent and and establish that the head won't need to be pulled before we get into replacing anything. Seems to think compression is ok but seemed to be having trouble with his readings?
Apparently if he lines up the timing marks on the crankshaft pulley and the cam tower Then the injector timing is off. I guess the car ran successfully once and then acted as if the IP timing slipped. And he and his crew have had many unsuccessful attempts.
Forgive me if that makes no sense...... Just relaying info that I have only minimal understanding of.
So he's no longer trusts the marks, or his interpretation of them and is trying to get official mercedes guidelines for setting the timing with the marks at the crank, cam, and injection pump on this specific car which is a California 1983 240d with a 1980 engine.
There is the smallest chance that the crank pulley was swapped from the old 83 engine when the '80 engine was put in. But I'm working on ruling this out now. So assuming that's not the case.......if anyone can help my questions would be......

Is there relevant and completely unambiguous literature available

s the timing procedure/ alignment really any different
Between 1980 and 1983?

Am I, or my mechanic missing the point, or a point. Do I need to take it somewhere else. I don't know enough about this issue to really know if my mechanic does. He comes across as intelligent, and knowledgeable but this is a long time to wait for results, starting to shake my confidence.

Any perspective on this situation, thing we may have missed, not thought of.

Thanks!

Carpenterman · #18 09-16-2014, 01:18 AM

Two-and-a-half months is ridiculous.

Here's what I would do:

1) check cam timing. As simple as aligning the marks on the cam tower/gear and reading the setting on the crank balancer. Should be zero degrees or a few degrees after if chain is worn. Good enough for now. You should have more or less okay cam timing if the engine turns over--I think the pistons would be hitting the valves if it was 1 tooth off on this engine.

2) check the injection timing. You will need a drip tube that is attached to the #1 cylinder fitting on the injector pump after removing the element inside. You set the crank balancer to the specified degrees (24 degrees BTDC on the five cylinder diesels--not sure what yours is), wire the throttle open, remove the vacuum from the shutoff valve, pump the hand pump on the side of the injector pump like crazy, and see if you get 1 drip per second.

If not, mark the injector pump location to the block, loosen the nuts holding it to the block (you'll have to remove the other three lines from the pump to do this) and rotate the pump with a bar or such against the block until you get the one drip per second. If you can't obtain this by rotating the pump, return the pump to original markings and tighten.

Now you will have to remove the vacuum pump, loosen the retaining bolt on the side of the head, mark the chain to the gear, hold the chain away from the gear (there is a tool but you can use a band of sheet metal) and advance the pump one tooth.Try the drip test again. If no dice, go back and advance another tooth. The pump is probably retarded. Once you are back in the ballpark, finally re-time the pump using the drip tube method.

3) do a valve adjustment

Actually I am doubtful that the pump timing gear would skip a tooth because the chain is held close to the gear by that retaining bolt on the side of the head. It's more likely it skipped at the crank sprocket which should show up on your initial cam timing inspection. That would be indicated by an extreme after top dead center reading at the crank. On the five cylinders, I think one tooth is 18 degrees. Someone needs to chime in on the four cylinder values, both for the skipped degrees and the pump timing setting.

At that point, I would remove the chain tensioner and cam sprocket, slack the chain way down on the passenger side of the crank sprocket, and turn the crank with a socket on its nut. You will have to go counter-clockwise if your cam timing reading was off toward after top dead center.

The mechanic needs to get access to the factory service manual or you must take it to someone who knows what they are doing. The only real data to know is the injection pump timing value at the crank and the number of degrees off for each chain tooth. Someone will post those values here for you soon, I'm sure.

Good luck and keep us posted.

Stretch · #19 09-16-2014, 01:29 AM

It sounds like the mechanic needs to read the FSM

It is very simple.

Cam timing is checked via the "2mm lift" method

PeachPartsWiki: Measuring Timing Chain Stretch

If you try to align the cam mark with the crank markings on a used OM617 chain then you are a ****ing donkey

After this has been checked

Do this

PeachPartsWiki: How to Set IP Timing via the Drip Tube Method

Carpenterman · #20 09-16-2014, 12:29 PM

Dear Stretch,

Of course the 2mm lift method is more accurate. I was just trying to get the OP into the ballpark. Using the cam marks should be adequate to determine whether the chain has jumped.

This engine has more immediate problems than a stretched chain.

Signed,
****ing monkey

Stretch · #21 09-16-2014, 12:52 PM

Quote:

Originally Posted by Carpenterman

Dear Stretch,

Of course the 2mm lift method is more accurate. I was just trying to get the OP into the ballpark. Using the cam marks should be adequate to determine whether the chain has jumped.

This engine has more immediate problems than a stretched chain.

Signed,
****ing monkey

At risk of making it seem worse - I hadn't actually read your post. I wasn't referring to you.

I was, however, a right grumpy git this morning. I didn't mean to upset - I apologise if I have offended.

Carpenterman · #22 09-16-2014, 02:42 PM

No sweat. We're all just trying to help.

eightiessadies · #23 09-16-2014, 04:42 PM

Thank you both, and it sounds like you're recommending essentially the same thing.
It sounds like if the mechanic has the valve cover off that he should easily be able to verify the relationship between the crank and the cam sprockets or what have you. And then follow the drip test procedure. Am I correct that this procedure applies to my particular engine. The mechanic said he couldn't do a drip test on this injector pump?
He also mentioned some device on the side of the injector pump that works to hold it in place while it's timed, that he says is not there.
So I'm thinking either that he does not know how to time the injector pump. Or, he had mentioned getting it to start but that the injector pump timing might be slipping. Is that possible?
Any thoughts?

eightiessadies · #24 09-16-2014, 04:47 PM

Is it possible there is some type of damage to the timing device or intermediate shaft that would not be visible and cause the injection pump to not be driven properly?

One more detail, he said that after one Timing attempt, the car started right up and ran with no smoke for about three minutes after which it began smoking and idling roughly.

Stretch · #25 09-16-2014, 05:06 PM

This mechanic seems to be full of excuses and not solutions

Some MW IPs from about 1983 have a little cover on the governor that allows what is commonly called the A-B timing light. This is an easier way of setting begin of delivery. However a drip test can be done with or with out this ability. A drip test is the standard test.

Perhaps it is time to find a different mechanic.