300SD woes Injection Pump Timing device - PeachParts Mercedes-Benz Forum

RabidDawg · #1 07-28-2008, 01:50 PM

I recently picked up a 1980 300SD in New Mexico, had issues with the IP, got the timing close I think and planned on doing the drip timing method next weekend.
Had it running in New Mexico well enough to drive it 1000 miles back home.

When I got it here in Arkansas, VERY sluggish, so I advanced the timing on the IP all the way it would go, adjusted the valves on it and it had the power it did in New Mexico.

While I was out test driving it after adjusting the IP, I was running it up to 3500 - 3800 rpm to see how it would do, blow out anything that might be built up etc, did it twice on the third time (3rd time is the charm eh?) took off from a stop sign first gear to around 3600 and fixing to shift to 2nd when it quit, engine just stopped running and won't start.

While trying to see what might be going on, noticed one of the return hoses going from 3rd to 4th injector was cracked and leaking, so I replaced it and still wouldn't start.
Ideas?

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rrgrassi · #2 07-28-2008, 02:15 PM

Replace all filters and prime the system. Sounds like you experienced fuel starvation.

Whiskeydan · #3 07-28-2008, 02:19 PM

Is the cam turning?

vstech · #4 07-28-2008, 02:22 PM

going to need some diagnostic info before we can have any ideas...first make sure you have motor oil in the sump. Then put the supply and return fuel hoses in a clear tank and fill it with fuel and verify fuel is flowing through the pump. next verify fuel is making it to the injectors, next will be compression test.

LUVMBDiesels · #5 07-28-2008, 02:51 PM

Did you hear any "BANG" noise or did it just quit?

I would open the oil cap and try to turn the engine over to make sure the cam is moving.

I would also to the new hoses to a jar of good diesel to see if it starts.

Doing a "Diesel Purge" won't hurt either. See if it will start and run on DP.

kerry · #6 07-28-2008, 02:54 PM

Sluggishness in 617 turbos is often caused by a problem in the boost control circuit. There's a banjo bolt on the back of the intake manifold. Make sure the bolt and the associated plastic tubing are clean, open, and attached to all fittings.

Check your air filter.

bgkast · #7 07-28-2008, 03:14 PM

What kind of damage can way advanced injection timing cause?

RabidDawg · #8 07-28-2008, 08:58 PM

it just quit, no bang.

I turned the crank and the camshaft moves, I then loosened the lines to the injectors thinking maybe air got into it with the cracked return line, no fuel.

I then unhooked the return line from the IP / return lines to the filter and no fuel there either when cranking it.

I unhooked the exit line on the filter that goes to the IP and used the manual pump and it pumps fuel through, so it would appear the IP is getting fuel, just not pumping it out.

So do I see a new IP in my future?

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barry123400 · #9 07-28-2008, 09:48 PM

Your post is not crystal clear at least to me. If you remove the return line at the injection pump fuel is coming out when cranking? Or not? If not it is not your injection pump.

RabidDawg · #10 07-28-2008, 09:49 PM

Quote:

Originally Posted by barry123400

Your post is not crystal clear at least to me. If you remove the return line at the injection pump fuel is coming out when cranking? Or not?

fuel is not coming out.

barry123400 · #11 07-28-2008, 10:05 PM

My guess is the stress may have taken out the lift pump then. Disconnect the output line from the lift pump. Thats the part the finger pump primer is mounted on and see if fuel squirts out when cranking the engine. When you report what you find with this test others can suggest things.
If nothing is coming out of the lift pump take the input line to it and submerge in a container of fuel. See if pump does or does not pump it.
Another thought was maybe a fuel filters contents where agitated by the unusual increased fuel volume. Might have plugged up. So if lift pump produces flow I might consider them. The worse senario of the timing chain going is not an issue at least. That is great.

Now if the lift pump will not pump fuel with you supplying it with a container of fuel do not leap to the conclusion it is the lift pump. It probably is at that point yet another test has to be done to make sure the lift pump activation system is still there.

RabidDawg · #12 07-29-2008, 09:28 PM

during my 3 hour commute I had lots of time to think about the problem and remembered I had an extra IP that came with the car, that is supposed to be bad. So when I got home I eyeballed the old IP and it has the lift pump on it. It is full of grime from being out in the New Mexico weather, should I clean it up and give it a whirl? Are there other checks I can do on the existing lift pump? i.e. the lift pump activation system.

Thanks

Diesel911 · #13 07-30-2008, 12:53 AM

You will know for sure when you swap the lift/fuel supply pump.
The lift/fuel supply pump has a spring loaded piston and a rod that rides on the IP camshaft (while the lift pump is off get a light and mirror and take a at the cam the pin rides on).

The pin pushes on the piston against the spring and pumps the fuel out.

The spring pushes the piston back sucking in the fuel. Things that can happen-the spring can break and the push pin some times breaks also. The piston can stick also.
If the problems above happened the hand primer would still work because it is a separate pump.

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dieselnutnj · #14 07-30-2008, 01:02 AM

how many miles on the car?
Do you know any of the service history?
Hopefully your just having fuel issues, but it seems more likely given the rpm's you were running that the pump jumped time.
If as you say, you had to adjust the pump to its max allowable adjustment to keep it happy..
There's a very good chance the timing chain stretched, or the upper guide rail broke and allowed the chain to jump time on the pump drive.
I've had it happen on a 190D.

When your engine cranks, does it have an "even" sound to it, like it has compression in all 5 cylinders?
As someone else asked do you see the camshaft turning when you crank it over.

Usually when the chain lets loose at highway speeds, its all over but the crying.
Service interval if I remember is 150K on the Diesel's chain.

If your careful and check the chain and don't see any slop in it. .you can run it further.
Do you know how to do the "drip" test for pump timing?

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RabidDawg · #15 07-30-2008, 12:27 PM

It has around 135k miles.
The reason I adjusted the timing more advanced is because my father-in-law and I had a guy on the phone walking us through setting the time on the IP and we got it close enough for it to run, but we didn't do the drip method (first time diesel owner here and hadn't read up on it).

Since the altitude change from there to here is around 6000 feet we thought the timing was the problem on the car not having power when I got it home.
No power being, I could barely make it up my driveway and it wouldn't rev up with no load.
So I advanced the timing to see if would help and it did, until the fuel pump appeared to go out.

It does have an even sound to it like the cylinders have compression, doesn't spin fast like a gas engine does when the timing jumps.

what is the upper end of RPM's on these engines?
I thought it was around 4500.
Driving freeway for 12 hours or so at 3000rpm, didn't think pushing 3800 would be a problem.

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