R&R inj pump. timed, but no fuel during crank - PeachParts Mercedes-Benz Forum

netboy · #1 05-18-2015, 06:53 PM

When I got this 617 engine it had been sitting for years so I checked the basics and tried to start it with no luck. It tried to start but would not. So I pulled the fuel lines off and the injection pump was only spitting out from 1,3,5 ports during crank. Assuming the IP was bad I installed a known good one from a running engine but after installation I could not get any port to spit fuel. removed IP and supplied fuel directly to fuel intake and turned IP with cordless drill with still no fuel. Whats the deal?

Diesel911 · #2 05-18-2015, 08:57 PM

Is this a Engine with a Turbo? I did not spell check the below stuff.

When the Fuel Injection Pump sits it is possible for solidified to hold the plunger upwards and it won't come down as only the Spring returns it.

If the Plunger won't come down it won't fill with Fuel and or (especially if someone has used WVO in it) the feed ports on the Fuel Injection Pump Elements could be plugged.

You need to idientify your Fuel Injection Pump. If you have an MW Fuel Injection Pump you will have 5 of what is in the pic with 13mm Nuts on each side of the Delivery Valve Holder.

If that is what you have do this one at a time. Remove the Delivery Valve Holder from one of the ones that no Fuel is coming out of.

[Don't touch the two 13mm Nuts on each side of the Element. Removing those Nuts and rotating the Element changes the amount of fuel that Element will put out. Removing the Shims under it change the timing of that particular elelment.]

Remove the Spring, the 2 parts of the Delivery Valve (note that the cnetral Valve only goes into one side of the Cylendrical Body).

In the next pic you seen the Delivery Valve holder #1
The Delivery Valve Spring #2
And the Delivery Valve Assembly #3 and #4 that are a mated pair. Also there is a groove around #4 to show you which end the Delivery Valve #3 goes into.
#5 is the Copper Crush Waher which you can leave in the Fuel Injection Pump if it does not come out stuck to #4.
Put all of that in a Zip-lock bag so it stays clean and parts don't get lost.

#6 is part of the Element and should remain attached to the Fuel Injection Pump by those previously mentioned 13mm Nuts.

With a strong Flash Light you should be able to look down the hole that you removed all of the parts from.

If the Fuel Injection Pump is still on the Engine have someone crank the Engine and see if the Plunger in the center is moving up and down. If it is not moving up and down then the Plunger is stuck in the upwards position.

Spray some Penatrating Oil or WD-40 down there and let is soak so there is some lubrication for the next step.

Now this part become kind of trickly because you are going to take a skiny Brass Punch and tap on the top of the Plunger. When I worked in a Fuel Injection Shop I used a 4 inch piece of Brass Brazing rod.

You need to take a File and round one end. That is the end that is going inside on top of the Plunger. Then you take something to use as a light weight Hammer and extremely gently tap on the top of the Punch. If it does not move rotate the Engine or the Fuel Injection Pump Camshaft a little and tap again. Pay attention to if the plunger moved or not.

The problem with doing the Tapping is that if the Fuel Injection Pump Camshaft happens to be pointing up the Pluger cannot go downwards. So you have to rotate the Fuel Injection Pump Camshaft (the Engine if the Pump is still attached to the Engine) till you reach a point on the Fuel Injection Pump Camshaft where the Plunger will be able to get tapped down.

By tapping I mean you are not swinging what you are tapping with. You are holding your Tapper about an inch above the Punch and letting it fall on its own weight onto the Punch.

If that moves the Element Plunger then spray some more lube into let that soak and rotate the Engine or the Fuel Injection Pump came shaft and see if the Punger goes up and then goes down.

If the Plunger is going up and down crank the Engine and see if fuel gets inside of the Element. If not then the Fuel Feed Hole in the Element is plugged. But, most often freeing up the Plunger solves the issue.

If the Issue is solved you can re-assemble it with the Old Crush washer till you find out if you are going to be able to free up the other Plungers.

If the above does not work you will need to get back to me on how to clear the Feed Hole in the Element because it is more complicated and there is a chance of not getting the Element back in place correctly so that job needs specific instructions.

netboy · #3 05-20-2015, 01:16 PM

Thx for the info. It is a turbo engine from a 83SD and the IP is out of the engine. I understand about the position of the cam. So if I get them freed up and working properly I should be able to connect a fuel line to it and turn the shaft with a cordless drill and all 5 ports should spit during rotation(when the lobe comes up) correct? Whats very strange is the known good IP isn't spitting out one port is there something that would cause them not to spit other than a stuck plunger or vacuum on the bellows?

OM617YOTA · #4 05-20-2015, 01:27 PM

Did you prime and bleed all the air out of the pump before cranking?

barry12345 · #5 05-20-2015, 02:28 PM

If the injection pump came off a running car that you are certain was runable. Not someone just telling you that. The injection pump is almost certainly not the problem for no fuel..

cooljjay · #6 05-20-2015, 03:15 PM

When an ip is drained of fuel, it takes a LONG time to bleed all the air out.

I had this issue when trying to get my 78 started, I went in blind with a note that said the car had ran and finally after much hair pulling out my valves were so tight the car couldn't build up compression. Once they were loosened the car finally roared to life with a huge carbon trail out of the tail pipe.

netboy · #7 05-20-2015, 09:15 PM

Yes I primed it and turned the engine thru by rotating the crank. With the IP out of the car I should be able to apply fuel to the IP, rotate it with a cordless drill and get fuel out the ports

OM617YOTA · #8 05-20-2015, 10:16 PM

By "apply fuel to the IP" do you mean fuel under pressure? Constant stream of fuel out of the overflow valve?

Diesel911 · #9 05-20-2015, 10:39 PM

Hunter has a thread about people with extra Fuel Injection Pumps that did work at one time like I have that when it comes time to use them did not.

If there was any liquid Water in the Fuel it can cause rust between the Element Plunger and the Element Barrel or rust on the ID of the Barrel. When the Plunger comes up and hits the Rusted area it can stick up there.

The same can happened with dried Diesel Fuel. Also Diesel Fuel has a certain amount of Water sort of mixed in suspension with it.

The other issue is that when the IP is pulled the Plungers are in various positions. Some of them are all the way up or close to all they way up. The mentioned dried or thick Fuel and rust can stick them in place.

The other area is the Fuel Feed Hole/Port (see pic) in the side if the Element is not very large. The same dried Fuel and Rust can plug it up as well as any Debreu that got into the Fuel Injection pump.

Then even when you are at idle speed you Fuel pressure can be only 8 psi and still be considered adequate.

Diesel911 · #10 05-20-2015, 10:49 PM

Hunter has a thread about people with extra Fuel Injection Pumps that did work at one time like I have that when it comes time to use them did not.

If there was any liquid Water in the Fuel it can cause rust between the Element Plunger and the Element Barrel or rust on the ID of the Barrel. When the Plunger comes up and hits the Rusted area it can stick up there.

The same can happened with dried Diesel Fuel. Also Diesel Fuel has a certain amount of Water sort of mixed in suspension with it.

The other issue is that when the IP is pulled the Plungers are in various positions. Some of them are all the way up or close to all they way up. The mentioned dried or thick Fuel and rust can stick them in place.

The other area is the Fuel Feed Hole/Port in the side if the Element is not very large. The same dried Fuel and Rust can plug it up as well as any Debreu that got into the Fuel Injection pump l