300D No start, only with gas held to floor, no power

[phillyilly]

Hi,


I'm having trouble with my 300D 1984 om617 in Philadelphia. I have been running it on Centrifuged WVO for about a year. Yes I won't be doing that anymore, I'm buying a bio diesel processor



Anyways-



The car ran just fine and about a month ago I went to fill up with regular Diesel. From that point forward the car kept loosing power. I would say withing a 3 day time span.



I replaced the fuel filters and it ran a little better but not much. I switched the suction and return lines. It didn't run any different. I rebuild the lift pump and installed a new primer pump (Bosch). That didn't do anything.


I installed new Monarch injector nozzles and don't have a pop tester, but it quieted the engine down, less clackety but didn't improve power. I did find 4 of 5 (old) nozzles were just about seized. And I will be pop testing new nozzles. I just received shims in mail in case they do need adjustment.


Lets see I bought a new injection pump and didn't want to mess with timing. I removed delivery valves from car and found them pretty clean. I installed delivery valves from other IP and used new crush washers. The delivery valves didn't improve issues.


I did pull one element from IP in car and used a dial caliper to mark position to 100 thousands. It was clean and fine.


The compression was checked (After a valve adjustment) -
1 - 405

2 - 395

3 - 340

4 - 390

5 - 340


Is there anything wrong with compression? Why it doesn't run right.


I saw forums online that show caked up rings and I decided to remove head and check pistons. Last night I pulled #2 piston to check. Its almost perfect. I can still see machine marks on cylinder wall and the piston had very minimal carbon buildup.


Two of the pre-chambers on head # 5 and # 3 had some caking on them. And I think #3 had one plugged up hold.


Otherwise this is where I'm at. I don't really want to tear down the engine anymore, if I don't have to.



Everything I have done, has been from hours of research and hasn't yielded a solution. The only remaining solution would be to replace IP. Maybe the elements started wearing out?


Any other thoughts?

[97 SL320]

For diesel engines in general.:

When the injector pump is in the start position and engine stopped, the fuel rack should be a full fuel. Having to push the throttle to start tells me that the rack is sticking.

Running real diesel after running glop fuel probably cut loose stagnant glop. As a side note, don't run motor lube oil / ATF as these are not designed to be burnt. If anything 2 stroke oil in the fuel could be of some benefit as a pump lube.

Define " bought a new injection pump " 100% new / rebuilt / used ? Taking apart the first two isn't a good idea when trying to fix a suspected bad pump.

Don't randomly take things apart without diagnosis. I don't know this engine specifically but the compression numbers look good enough the engine should start and run without difficulty.

Also, when chasing a suspected compression leak, always do a cylinder leak down as this tells you where the air is leaking out. While not a problem in your case, a cylinder leak down is the _ONLY_ reliable way to find a compression to coolant system leak.

[Phillytwotank]

How about linkage slop? Later style w123 “throttle” linkages are notorious for falling apart right at the firewall.

[barry12345]

You burn waste oil you start by cleaning out the fuel system when problems arise.


The head removal was a waste other than perhaps checking things. The compression numbers where good to run on. They may or may not be improved for consistency with a cylinder soak down. Where the piston rings loose in the piston you pulled?


You could have a lot of fats accumulated in the injection pump for example. What I would do is fill the injection pump with laquer thinner. Let it soak for a couple of days.


Remove the relief valve and pump the thinner out watching what is coming out. If it is bad do it again. Just hook a line to the input of the lift pump and pump the thinner in .


It is too bad the head is off. It stopped the chance of checking for too much air in the fuel. Perhaps it is best to install the head and go from there first.

You did check for growth from the vegetable oil in the vent line from the fuel tank? By leaving the fill cap loose. I had one that sat for a year It still seemed to be retaining some. It is not your problem but is just one thing you check. Plus you never leave a car on vegetable oil sitting around. It turns to a type of glue. Perhaps the centrifuge eliminates the components that enable this.

There is a small chance the elements in the injection pump are over tolerance as well. Overall it can be a considerable issue. To get to the point of establishing that is a possibility. Since you burnt Waste vegetable oil. Put a container of vegetable oil feeding into the lift pump. If it will run on this it narrows things down.

[Diesel911]

Originally Posted by barry12345

You burn waste oil you start by cleaning out the fuel system when problems arise.


The head removal was a waste other than perhaps checking things. The compression numbers where good to run on. They may or may not be improved for consistency with a cylinder soak down. Where the piston rings loose in the piston you pulled?


You could have a lot of fats accumulated in the injection pump for example. What I would do is fill the injection pump with laquer thinner. Let it soak for a couple of days.


Remove the relief valve and pump the thinner out watching what is coming out. If it is bad do it again. Just hook a line to the input of the lift pump and pump the thinner in .


It is too bad the head is off. It stopped the chance of checking for too much air in the fuel. Perhaps it is best to install the head and go from there first.

You did check for growth from the vegetable oil in the vent line from the fuel tank? By leaving the fill cap loose. I had one that sat for a year It still seemed to be retaining some. It is not your problem but is just one thing you check. Plus you never leave a car on vegetable oil sitting around. It turns to a type of glue. Perhaps the centrifuge eliminates the components that enable this.

There is a small chance the elements in the injection pump are over tolerance as well. Overall it can be a considerable issue. To get to the point of establishing that is a possibility. Since you burnt Waste vegetable oil. Put a container of vegetable oil feeding into the lift pump. If it will run on this it narrows things down.

There is in interesting point here. If the fuel pressure relief/overflow valve is gunked up it won't hold fuel supply pressure inside of the Fuel Injection Pump.
could be the same if the spring is compressed too much.

[Diesel911]

300D 1984 om617; is this a turbo diesel or a non-turboed Euro 300D? I am asking this because they have different models of Fuel Injection Pumps.

Please explain what you used the dial indicator before or after you removed the Element. Or perhaps you are using the wrong terminology and it was not an Element you removed.

My 300D 1984 with turbo has a MW type Fuel Injection Pump and if you pull out the element it mess with the Fuel adjustment on that element. Loosening the 13mm nuts (if you have not done that don't do it) and twisting the element changes the amount of fuel it puts out.

[Diesel911]

Try getting one of those 1 liter spare fuel cans or an old type gallon paint thinner can full of diesel Fuel put it under the hood between the back of the Head light and the front of the fender well (you might need to remove the Window Washer tank).

Run a separate hose from that to the plastic filter and get on the hand primer and pump until the air is out of the system and start it and go for a drive. That bypasses the fuel lines all the way back to the fuel tank fuel tank screen and any issues with your fuel tank vent. If things improve you know you have a problem from the fender well back to and including the fuel tank.

[Diesel911]

This is a picture of part of a Frantz Toilet Paper Filter that someone apparently used to filter WVO with. Notice the plastic like film.

[phillyilly]

Hi,

Thanks for all of the responses,. I will answer them back as I get time throughout the day.

Does anyone have the torque spec for head bolts? All I could find is the torque sequence.

[BWhitmore]

Have you cleaned the screen in the fuel tank? Compression readings should be within 10% of each other.

[phillyilly]

Hi,

Thanks for all of the responses,. I will answer them back as I get time throughout the day.

Does anyone have the torque spec for head bolts? All I could find is the torque sequence.


Diesel911 -. Thanks for the response. I will run some paint thinner through the pump with the primer pump. Hopefully it's just something sticking. The car took about 30 seconds to get any power with the foot to the floor.

I couldn't find any illustrations onpine showing what part of the IP could be sticking. When I removed the element, the rack seemed to be moving just fine and turning the way it should.

Although once warmed up, it took alot longer to get any power to the car.

If the rack is stuck, why wouldnt the car idle properly?

It's a turbo 300D

I used a dial caliper to measure the element spacing prior to removal.

https://ibb.co/JqTFxz4


barry12345 - piston rings weren't loose. The relief valve on IP was checked and spring adjusted. Was clean. I will run thinner through the IP and flush IP.

Didn't see any growth in tank. When you say Elements in IP could be over tolerance what do you mean? Dirt and crud is stuck between them?

Phillytwotank -. Linkage was tight. I ran car from injector pump and moved linkage by hand no change.



97 SL320 -. Thanks for the message. Rack is most likely sticking. Thank you!

The spare injection pump is used/known good pump.

Leakdown test. I'll definitely do that when I need to test engine.

Hopefully this IP can be cleaned enough. I'm not looking forward to replacing IP. Can delivery valve be removed from #1 and a dial caliper used to time pump to motor? I've seen it done that way on Cummins p pumps.

[97 SL320]

Originally Posted by phillyilly

Does anyone have the torque spec for head bolts? All I could find is the torque sequence.

I don't however it wold be a really good idea to have the hear checked for flatness and have the valves ground while it is off.

[barry12345]

There is a very small chance the injection pump elements are worn. WVO can do this. At the same time there are quite a few other possibilities.

[sloride]

Originally Posted by Diesel911

Try getting one of those 1 liter spare fuel cans or an old type gallon paint thinner can full of diesel Fuel put it under the hood between the back of the Head light and the front of the fender well (you might need to remove the Window Washer tank).

Run a separate hose from that to the plastic filter and get on the hand primer and pump until the air is out of the system and start it and go for a drive. That bypasses the fuel lines all the way back to the fuel tank fuel tank screen and any issues with your fuel tank vent. If things improve you know you have a problem from the fender well back to and including the fuel tank.

I am more along this line, saw no mention of "Viton" lines used before the switch to WVO. From my understanding it swells regular diesel lines restricting fuel flow or just turn to mush before leaking.

[phillyilly]

Yes I forgot the mention, viton lines are installed.