W109 4.5 not starting after winter, no fuel - PeachParts Mercedes-Benz Forum

werminghausen · #1 03-06-2020, 10:52 PM

With the warm spring weather I wanted to start my W109 4.5 and it didn't,
no matter what. I checked spark and there was spark.
I sprayed starter fluid and engine fired but not well... died.
I opened the fuel rail and no fuel. Fuel pump made the noise before start...so it is turning but no fuel pressure.
I dragged the W109 onto the lift and removed the D-Jet pump.
As this was a 4.5 implant in a 3.5 it has the early 3-arm D-Jet fuel pump.
I am currently renovating another old 3 arm that I have from my former 3.5.
See if I can get this pump running and install it.
I resealed the pump and it is tight but I am unsure about the check valve function.
Is the check valve in the early D-Jet pump supposed to be tight?
If so I'd add add another fuel check valve. I think fuel should stay in the pressurized line (30 psi).
I am happy to hear your thoughts.

Martin

Todd Miller · #2 03-06-2020, 11:04 PM

Hi Martin. May I suggest you use carburetor cleaner as your "starting fluid?" Ether is too explosive (explodes too soon in the cylinder) and can damage the connecting rods, piston tops, wrist pins, and head gasket fire rings. Carb cleaner burns (explodes) more like gasoline, so it's much safer for the engine.

Sorry, but I'm not familiar with your car enough to offer advice on the fuel pump. Normally, I crack the line at the cold start injector (if the engine has one) and then crank the engine over and watch for fuel to dribble or spray from the loose fitting at the injector. Jumping power directly to the fuel pump will sometimes get things functional again.

When you DO get it running, I'd suggest running SeaFoam in the fuel, year round. It will keep the injectors clean and the injector spray pattern nice, clean the backs of the intake valves, and keep the fuel from going bad (ethanol issues) during storage.

fonzi · #3 03-06-2020, 11:59 PM

All too common is the positive battery terminal not being connected tightly, and the smaller wire attached to the positive terminal isn’t making contact, so nothing with the d-jet system works. I don’t know if it could cause your issue, but it’s worth a quick check.

Frank Reiner · #4 03-07-2020, 12:31 AM

Quote:

Originally Posted by werminghausen

With the warm spring weather I wanted to start my W109 4.5 and it didn't,
no matter what. I checked spark and there was spark.
I sprayed starter fluid and engine fired but not well... died.
I opened the fuel rail and no fuel. Fuel pump made the noise before start...so it is turning but no fuel pressure.
I dragged the W109 onto the lift and removed the D-Jet pump.
As this was a 4.5 implant in a 3.5 it has the early 3-arm D-Jet fuel pump.
I am currently renovating another old 3 arm that I have from my former 3.5.
See if I can get this pump running and install it.
I resealed the pump and it is tight but I am unsure about the check valve function.
Is the check valve in the early D-Jet pump supposed to be tight?
If so I'd add add another fuel check valve. I think fuel should stay in the pressurized line (30 psi).
I am happy to hear your thoughts.

Martin

Quote:

Originally Posted by Todd Miller

Sorry, but I'm not familiar with your car enough to offer advice on the fuel pump.

But I'll chatter about other irrelevant things.

Quote:

Originally Posted by fonzi

All too common is the positive battery terminal not being connected tightly, and the smaller wire attached to the positive terminal isn’t making contact, so nothing with the d-jet system works. I don’t know if it could cause your issue, but it’s worth a quick check.

When all else fails, READ what the OP said!

werminghausen · #5 03-07-2020, 09:50 AM

Well thank for the comments.

When I fiddled with the fuel pump I saw that all hoses were old and hardened down there. This also made me believe I'll do a bigger renovation and replace all rubber hoses and probably open the stainer at the tank to clean it out.
Do I need parts for that stainer rebuilding- seals etc?

I will add a fuel pressure test port (see picture, pressure gauge port with a 1/4" flare connection) in the fuel rail that is under 2 bar pressure at a spot where it is easy to attach a gauge if need is.

Then the old D-jet pump... I want it to be resealed and in good condition.
As I did not know any of the history I removed it and I am rebuilding now another 3 arm D-Jet (see picture).
I will test the pump with calibration fluid soon but wanted to know about the
fuel check valve function of the pump.
The D-Jet pump I am working on does not seem to have a solid and tight check valve (picture of check and overpressure valve)
Question: is it good or bad to add another external fuel check valve downstream of the pump pressure line? I don't see a problem if the pressure in the fuel rail is kept under 2 bar...assuming the injectors are tight but wanted to ask?

Martin

Frank Reiner · #6 03-07-2020, 10:37 AM

Quote:

Originally Posted by werminghausen

Then the old D-jet pump... I want it to be resealed and in good condition.
As I did not know any of the history I removed it and I am rebuilding now another 3 arm D-Jet (see picture).
I will test the pump with calibration fluid soon but wanted to know about the
fuel check valve function of the pump.
The D-Jet pump I am working on does not seem to have a solid and tight check valve (picture of check and overpressure valve)
Question: is it good or bad to add another external fuel check valve downstream of the pump pressure line? I don't see a problem if the pressure in the fuel rail is kept under 2 bar...assuming the injectors are tight but wanted to ask? Martin

Martin:
In the event that the original, built-in check/overpressure valve cannot be made functional, an external check valve would serve the same function. The pressure regulator closes the return end of the fuel loop, and a check valve closes the feed end. Functionally either an internal, or an external check valve will close the feed end.
If the original valve set-up is not used, an external overpressure valve would be required in the third (pressure relief) line.

werminghausen · #7 03-07-2020, 11:31 AM

Thanks Frank

yes i understand what you are saying.
Now the original 'check valve' is not really a check valve (working by the pressure within the pressure line). This one is working only when spring load is stronger than the pressure in the line (30psi)... when the pump is off.

It might be that my check valve is a small plastic part insert in the overpressure plunger... and it might be damaged and does not work well for that reason.
I am trying to machine a new part here and will test if it is holding the pressure any better. See the part that I found (picture), the 'head' is out of plastic.
If the attempt fails getting the check valve going (should hold the 2 bar or 30 psi) then I'll install an external check valve downstream.

The overpressure system works fine right now I think.

By the way this pump valve is a clever design: It is a check valve (in theory),
a overpressure relief valve and it removes any air bubbles in the fuel back to the tank via return.

Martin

werminghausen · #8 03-07-2020, 09:00 PM

I machined the Check Valve insert (it is the front part of the this regulating valve) and it is reasonably tight when tested with air. I think the check valve can work this way...
The overflow valve is opening at 3.5 bar, works well.
Pump is tight and I'll start flow tests with fuel or better calibration fluid.

Thanks for your input.

Martin

Idle · #9 03-08-2020, 06:48 PM

I had this problem with a 123 240d. Much simpler to check out, of course.

I pulled the tank strainer and cleaned it. It needed it. You can but a new strainer and gasket but your's might clean up. Who knows? I did use a new gasket which was cheap.

The fuel hoses from the tank to the fuel line were cracked and brittle, so I replaced those as well. And since I had the fuel line off of one end I pulled it from the other, ran a piece of steel cable down the fuel line, and attached a cleaning brush for a .32 to one end with some fishing line. I had the cleaning brush so I though I would give it a try.

The line was not totally full of gunk but a lot of sludge and dirt looking stuff did come out. So as long as you are replacing lines and have everything apart then why not clean out the line? I realize the fuel system on the diesel is easy and simple, but there has to be a steel line moving the gas from the tank to the fuel filter canister that can be cleaned.

The sitting thing is also important. Gas loses it's higher end components over time due to the higher vapor pressure they exist at. This takes time which is why gasoline will not go bad in a month. But it might be wise to drain out the old gas and burn it off a bit at a time after putting about five gallons of fresh gas in the tank. After you clean the strainer, that is.

werminghausen · #10 03-08-2020, 10:50 PM

Thanks Idle,

my question about the strainer seal in the W109: I think it is a common o-ring for the strainer
A1114700686. O-ring has MB number 1109970145. Does anyone know the o-ring size in metric, please?

Martin

werminghausen · #11 03-10-2020, 06:57 PM

I have set up a rig for D-Jet fuel pump performance testing.
I am testing with calibration fluid.
The pump S-port will be fed by a tank (5 gallon bucket). Return port line will go straight back into the tank.
Pressure line is on a regulating valve set at 2 bar. I think the pump has to deliver 2 liters in 60 seconds (120l/h...if I recall correctly) . I'll catch the fuel delivery in a separate container and measure the output. Pump will stop after 60 seconds and I'll see if the check valve works...pressure gauge at the regulator should stay solid at 2 bar.
Tomorrow is the day, fingers crossed

werminghausen · #12 03-10-2020, 07:00 PM

Thanks Idle for your comments about cleaning the gunk out of the tank.
That is what I had in mind while being in the area anyhow, car on the lift.
I'll drain the fuel and try to clean that tank.

Martin

fonzi · #13 03-12-2020, 03:08 AM

Hi Martin, I see now that this is a thread mostly about d-jet fuel pumps. I’m returning a d-jet 350slc 4-speed right now and recently pulled out the old crusty d-jet pump, filled it with acetone, and got the pump to spin, but it’s still not pumping (when I tested after a few hours sitting in acetone). I’m now wondering if I need to remove or free up the check valve like you did. Maybe mine is stuck.

I need to create a tank to feed my pump too. I’m thinking of using a bottle with a feed and return hose.

werminghausen · #14 03-25-2020, 04:48 PM

Hi fonzi,

you need to rebuild this pump entirely and get the check valve and overflow valve to work as it should.
This pump is not made rebuilder-friendly though. You need to bend open the cold formed tabs of the cup in order to remove the bottom.
The overflow valve /regulator is different depending on if you have a 3-arm or 2 arm pump.
I have mine back and the engine started right away!
great to have the W109 back.

Best, Martin

werminghausen · #15 03-25-2020, 04:52 PM

To all

I have the renovated pump back, cleaned out that tank (think the o-ring at strainer was a 36 x 3) and everything works perfectly fine now.
Engine started nicely and now even at very cold temps the car starts right up.
I installed a pressure test port at the fuel rail and see that the check valve in the 3arm pump works great now... after engine shut down.

Martin