Who really knows the 606 injection pump? - PeachParts Mercedes-Benz Forum

Tubularfab · #1 07-31-2013, 04:50 PM

Ok, I'm about to loose it on this '97 E300. I bought it as a wrecked runner - was a friend's daily driver till the wreck, then it sat for 3 months. When I got it from him it fired right up - but as it had no radiator I only ran it a couple of minutes to pull on the trailer. It started a couple more times, then ran rough and hasn't restarted.

I've eliminated most of the usual problems as detailed in this thread: http://www.peachparts.com/shopforum/diesel-discussion/341701-1997-e300-still-no-start.html

I've now got a 32oz jug of fuel under the hood with the supply hose to the fuel heater going to it. In about 2 sets of 30 second cranks I can suck down most of the 32oz. Fuel is flowing WELL.

I have confirmed the fuel is flowing from the SOV into the injection pump. It's flowing out of the injection pump return.

I have video of the rack going to almost full throttle as I try to crank:
E300 injection pump rack movement - YouTube

If I remove the lines from the delivery valves I get some pretty good squirting after a little cranking. Initially you get foaming, then the squirting. With the lines reconnected there is not enough flow to fire the engine. In fact, disconnecting the lines at the injectors and cranking yields very, very little flow. The lines are not damaged appearing... Here is a video of the delivery rate at the pump outlet: http://www.youtube.com/watch?v=ESxLfhndP8w

I removed the return line banjo bolt / fuel pressure regulator, and can easily blow through it. After reading on here that this is supposed to hold the delivery pressure at about 1 bar, this seemed suspect. In a lathe I machined the metal away around the staked in ball, and dismantled the valve. It has an amaazingly light spring that pushes a plastic plunger against the seat. There's no way this could regulate pressure in the 1 bar range unless the hole through it is enough of a flow restriction to raise the pressure that way.

Is there any type of internal filter screen in the injection pump?
How could I have flow through the injection pump body, and nothing making it out of the pump?
Can you come up with a scenario where all the delivery valves would suddenly fail?

Please help - this is driving me mad!
Thank you!

pimpernell · #2 07-31-2013, 06:04 PM

I am no expert regarding the injection pump, but this piece of information from an expert may help you with your problem. Good luck

http://www.peachparts.com/shopforum/diesel-discussion/247039-fuel-injection-pump-starvation-good-lift-pump.html

KarTek · #3 07-31-2013, 09:03 PM

Man, I'm sorry you're having so much trouble. These pumps are really fairly simple. I can't imagine a delivery valve failing.

One thing you can do is dead end the return line to the tank. The fuel pump is just spring and cam powered and it's the spring that pushes the fuel, not the cam. So, you won't hurt anything by blocking the return.

This is provided of course, that the air is purged from the system (no bubbles out the return line before plugging).

Diesel911 · #4 07-31-2013, 09:41 PM

Quote:

Originally Posted by Tubularfab

Ok, I'm about to loose it on this '97 E300. I bought it as a wrecked runner - was a friend's daily driver till the wreck, then it sat for 3 months. When I got it from him it fired right up - but as it had no radiator I only ran it a couple of minutes to pull on the trailer. It started a couple more times, then ran rough and hasn't restarted.

I've eliminated most of the usual problems as detailed in this thread: http://www.peachparts.com/shopforum/diesel-discussion/341701-1997-e300-still-no-start.html

I've now got a 32oz jug of fuel under the hood with the supply hose to the fuel heater going to it. In about 2 sets of 30 second cranks I can suck down most of the 32oz. Fuel is flowing WELL.

I have confirmed the fuel is flowing from the SOV into the injection pump. It's flowing out of the injection pump return.

I have video of the rack going to almost full throttle as I try to crank:
E300 injection pump rack movement - YouTube

If I remove the lines from the delivery valves I get some pretty good squirting after a little cranking. Initially you get foaming, then the squirting. With the lines reconnected there is not enough flow to fire the engine. In fact, disconnecting the lines at the injectors and cranking yields very, very little flow. The lines are not damaged appearing... Here is a video of the delivery rate at the pump outlet: Fuel delivery - YouTube

I removed the return line banjo bolt / fuel pressure regulator, and can easily blow through it. After reading on here that this is supposed to hold the delivery pressure at about 1 bar, this seemed suspect. In a lathe I machined the metal away around the staked in ball, and dismantled the valve. It has an amaazingly light spring that pushes a plastic plunger against the seat. There's no way this could regulate pressure in the 1 bar range unless the hole through it is enough of a flow restriction to raise the pressure that way.

Is there any type of internal filter screen in the injection pump?
How could I have flow through the injection pump body, and nothing making it out of the pump?
Can you come up with a scenario where all the delivery valves would suddenly fail?

Please help - this is driving me mad!
Thank you!

Why didn't running the Engine with no Coolant ruin it; a couple of minutes ?
I would at the very least expect the Aluminum Cylinder head to be damaged after running the Engine for 2 or more Minutes with no Coolant

Diesel911 · #5 07-31-2013, 10:10 PM

Quote:

Originally Posted by Tubularfab

Ok, I'm about to loose it on this '97 E300. I bought it as a wrecked runner - was a friend's daily driver till the wreck, then it sat for 3 months. When I got it from him it fired right up - but as it had no radiator I only ran it a couple of minutes to pull on the trailer. It started a couple more times, then ran rough and hasn't restarted.

I've eliminated most of the usual problems as detailed in this thread: http://www.peachparts.com/shopforum/diesel-discussion/341701-1997-e300-still-no-start.html

I've now got a 32oz jug of fuel under the hood with the supply hose to the fuel heater going to it. In about 2 sets of 30 second cranks I can suck down most of the 32oz. Fuel is flowing WELL.

I have confirmed the fuel is flowing from the SOV into the injection pump. It's flowing out of the injection pump return.

I have video of the rack going to almost full throttle as I try to crank:
E300 injection pump rack movement - YouTube

If I remove the lines from the delivery valves I get some pretty good squirting after a little cranking. Initially you get foaming, then the squirting. With the lines reconnected there is not enough flow to fire the engine. In fact, disconnecting the lines at the injectors and cranking yields very, very little flow. The lines are not damaged appearing... Here is a video of the delivery rate at the pump outlet: Fuel delivery - YouTube

I removed the return line banjo bolt / fuel pressure regulator, and can easily blow through it. After reading on here that this is supposed to hold the delivery pressure at about 1 bar, this seemed suspect. In a lathe I machined the metal away around the staked in ball, and dismantled the valve. It has an amaazingly light spring that pushes a plastic plunger against the seat. There's no way this could regulate pressure in the 1 bar range unless the hole through it is enough of a flow restriction to raise the pressure that way.

Is there any type of internal filter screen in the injection pump?

How could I have flow through the injection pump body, and nothing making it out of the pump?
Can you come up with a scenario where all the delivery valves would suddenly fail?

Please help - this is driving me mad!
Thank you!

The hole is there to bleed the Air out and why there is no Hand Primer on this system.
There is no screens inside of the Fuel Injection Pump.

Disconnect the Vacuum Line from the Vacuum Shutoff and see if that makes a difference.

You might stick a Gauge in the end of the Fuel Injection Pump Fuel Return Line and see just what type of pressure you are able to get. With no Air in the Fuel Injection Pump Housing and the line plugged with a Gauge you should get the maximum pressure the Fuel Supply/Lift Pump can put out at cranking speed. You should at least be able to tell if you are getting the 1 bar.

Tubularfab · #6 07-31-2013, 10:15 PM

I wondered if someone would bring that up. Running a diesel a couple of minutes at basically no power output generates very little heat. There is a massive difference between running a completely cold engine at no power/load for a couple of minutes and blowing a radiator hose off an engine already heat soaked at operating temp maintaining highway speed. No, running without coolant is not advisable - but it's not instant death either.

whunter · #7 08-01-2013, 01:31 AM

Quote:

Originally Posted by Tubularfab

Ok, I'm about to loose it on this '97 E300. I bought it as a wrecked runner - was a friend's daily driver till the wreck, then it sat for 3 months. When I got it from him it fired right up - but as it had no radiator I only ran it a couple of minutes to pull on the trailer. It started a couple more times, then ran rough and hasn't restarted.

I've eliminated most of the usual problems as detailed in this thread: http://www.peachparts.com/shopforum/diesel-discussion/341701-1997-e300-still-no-start.html

I've now got a 32oz jug of fuel under the hood with the supply hose to the fuel heater going to it. In about 2 sets of 30 second cranks I can suck down most of the 32oz. Fuel is flowing WELL.

I have confirmed the fuel is flowing from the SOV into the injection pump. It's flowing out of the injection pump return.

I have video of the rack going to almost full throttle as I try to crank:
E300 injection pump rack movement - YouTube

If I remove the lines from the delivery valves I get some pretty good squirting after a little cranking. Initially you get foaming, then the squirting. With the lines reconnected there is not enough flow to fire the engine. In fact, disconnecting the lines at the injectors and cranking yields very, very little flow. The lines are not damaged appearing... Here is a video of the delivery rate at the pump outlet: Fuel delivery - YouTube

I removed the return line banjo bolt / fuel pressure regulator, and can easily blow through it. After reading on here that this is supposed to hold the delivery pressure at about 1 bar, this seemed suspect. In a lathe I machined the metal away around the staked in ball, and dismantled the valve. It has an amaazingly light spring that pushes a plastic plunger against the seat. There's no way this could regulate pressure in the 1 bar range unless the hole through it is enough of a flow restriction to raise the pressure that way.

Is there any type of internal filter screen in the injection pump?
How could I have flow through the injection pump body, and nothing making it out of the pump?
Can you come up with a scenario where all the delivery valves would suddenly fail?

Please help - this is driving me mad!
Thank you!

These parts look bad in your video.
http://www.peachparts.com/shopforum/mercedes-parts-reference-library/193833-om606-912-1996-97-e300-diesel-plastic-injection-pump-lines.html

"All 6 measure between 1.5 and 2.0 ohms to ground at connector to relay".
IMO; This tells me the glow plugs are dead.
FYI: Between 0.9 - 1.0 ohms it is time to replace the glow plugs.

.

Tubularfab · #8 08-01-2013, 07:55 AM

Ok, I just ran by the shop on the way to work and did a "definitely cold" resistance check on the glow plugs. All were under .2 ohms. Last time I checked them (2 weeks ago) they had been cycled fairly recently, hence the difference in the numbers..

Can I ask what in the video makes you say the lines are bad? All have new viton O-rings, and there was no fuel leaking outward. Yes, there might be a tiny vacuum leak that took the 3 months sitting idle to let some air in, but this thing was trouble free before taking the hit. Everything is wet now - I've had all the lines on and off multiple times trying to diagnose.

Now, how about the question I IM'd you about: How much pressure is the outlet banjo supposed to hold on the 606 pump? By it's design I don't see it holding any pressure; unless it's via the size of the hole restricting the flow. The spring is tiny and is easy to unseat blowing through it.

Thank you everyone!

Tubularfab · #9 08-01-2013, 08:03 AM

Here is a picture of the internals of the banjo bolt / relief valve. I added a weak pen spring at the top to show just how amazingly weak the spring in this thing is. It's hard to pick it up without it collapsing.

Zulfiqar · #10 08-01-2013, 08:57 AM

as roy said - first test the glow plugs, if you dont have them working the engine will not fire.

this relief valve is a very discussed topic, some people have installed devices in the return line to compensate for the lost pressure. The old 61x pumps had a mechanical adjustable bolt that also held pressure but those engines had hand primer pumps too. This one does not.

It relies on the lift pump on the side of the IP to fill up and bleed the rack area of the pump via the little hole on the relief valve. That little sucker (lift pump) is very powerful - it can collapse your fuel tank given the right chance.

whunter · #11 08-01-2013, 12:52 PM

Quote:

Originally Posted by Tubularfab

Ok, I just ran by the shop on the way to work and did a "definitely cold" resistance check on the glow plugs. All were under .2 ohms. Last time I checked them (2 weeks ago) they had been cycled fairly recently, hence the difference in the numbers..

Can I ask what in the video makes you say the lines are bad? All have new viton O-rings, and there was no fuel leaking outward. Yes, there might be a tiny vacuum leak that took the 3 months sitting idle to let some air in, but this thing was trouble free before taking the hit. Everything is wet now - I've had all the lines on and off multiple times trying to diagnose.

Now, how about the question I IM'd you about: How much pressure is the outlet banjo supposed to hold on the 606 pump? By it's design I don't see it holding any pressure; unless it's via the size of the hole restricting the flow. The spring is tiny and is easy to unseat blowing through it.

Thank you everyone!

They are bad...

Below 0.7 = junk.

.

Diesel911 · #12 08-01-2013, 03:06 PM

Proper use of the Ohm Meter for an accurate Reading. If you are using a cheapie Harbor Fright Ohm Meter after you set it you need to put the 2 Wire Probes together and measure the resistance in the Probe Wires.
When you have that reading you should subtract that from the reading you get from the Glow Plugs.

A high when you put the Wire Probe together on a High Quality Meter it will show no resistance.

Also concerning testing hot or cold Glow Plugs I thought they were always tested cold.

Diesel911 · #13 08-01-2013, 03:12 PM

Quote:

Originally Posted by Tubularfab

I wondered if someone would bring that up. Running a diesel a couple of minutes at basically no power output generates very little heat. There is a massive difference between running a completely cold engine at no power/load for a couple of minutes and blowing a radiator hose off an engine already heat soaked at operating temp maintaining highway speed. No, running without coolant is not advisable - but it's not instant death either.

If You have a Lawn Mower start it up and let it idle. Come back 2 minutes later and put you Hand on the Cylinder head. And, that Lawn Mower has the Fan/cooling system working.

I think if I ran the Engine for 2 minutes with no coolant I would not get away with it.
The Aluminum Head is more prone to warping even in normal circumstances then the Iron Heads are. And, more prone to have problems when abused.

Anyway best of luck.

Tubularfab · #14 08-01-2013, 05:17 PM

Try the same trick with a diesel lawnmower and I'd put my hand on it. Exhaust gas temps (indicative of combustion temps inside engine) on the gas lawnmower are gonna be in the 1700 degree F range. Exhaust gas temps for a diesel at no load - about 200 - 300 degrees F. My Ford 7.3 idi could run at high idle for 15 minutes when it's cold out and you could put your hand on the exhaust manifold.

So, everything I've found says the cold resistance of a good glowplug is under 1 ohm. Is it actually a tight range of .7 to 1 ohm? Oh, and my Fluke does measure zero across the leads.

Thank you everyone!

Diesel911 · #15 08-01-2013, 10:12 PM

Quote:

Originally Posted by Tubularfab

Try the same trick with a diesel lawnmower and I'd put my hand on it. Exhaust gas temps (indicative of combustion temps inside engine) on the gas lawnmower are gonna be in the 1700 degree F range. Exhaust gas temps for a diesel at no load - about 200 - 300 degrees F. My Ford 7.3 idi could run at high idle for 15 minutes when it's cold out and you could put your hand on the exhaust manifold.

So, everything I've found says the cold resistance of a good glowplug is under 1 ohm. Is it actually a tight range of .7 to 1 ohm? Oh, and my Fluke does measure zero across the leads.

Thank you everyone!

The one Harbor Freight Meter I checked gets 00.5 Ohms when the Meter is set on the 200 Ohm Scale and you squeeze the Probes together tight.

The Glow Plug in the Pic had a good Ohm reading but is no good because it is not getting hottest at the tip like the good ones did.