W210 Diesel pump timing saga (CONTINUES)

[Tinytots]

I've had the diesel pump replaced. The first 20 seconds the car sounded like it was fixed, but then unfortunately the car goes back to running like a pig.
It is now smoking beyond belief, won't idle, knocking and is slow to rev up.
The timing and pump has been checked and rechecked.
My mechanic now feels that because 1 and 2 cylinders where not firing the diesel has filled the cylinder and with the piston still moving up and down may have damaged the con rod
If this is the case we are looking at a rebuilt or an engine:fail

It is with a heavy heart that this may be the end of the road for my beloved W210, unless anyone has any other ideas

We have been starting the car with the inlet manifold off, would this make a difference

 

[johnsco]

My mechanic now feels that because 1 and 2 cylinders were not firing the diesel has filled the cylinder and with the piston still moving up and down may have damaged the con rod

If you run the engine with Nos 1 and 2 cylinders not firing, then surely any unburnt fuel should be expelled on the exhaust stroke with the exhaust valves open.
I think it's highly unlikely that you would damage the con rods.
These engines are very-robust.
Often described as bomb-proof.
The fact that you have changed the injector pump - This MUST be the area to look at.
The fact that it ran well for 20 seconds - It is unlikely that there is anything structurally wrong with the engine.

 

[Dieselman]

Air leak into the diesel pipes or the lift pump is knackered would be my initial thoughts. Another one might be the tank strainer or main filter are blocked.

Run it from a can to check.

 

[Tinytots]

I have now removed the car from this mechanic and will seek advice from another mechanic before I actually break her. Thank you for having the same suspicions as me. I just can't believe that this engine is done. I also think that there may be something like fuel lines or tank problems. I'm not giving up yet. Thanks Shane.

 

[Dieselman]

If it isn't fuel supply then look at the pump timing gear in the chain case, it could be slipping the timing.

A Bosh PE pump is a very simple and robust pump. Each injector is supplied by a separate pumping element and it would be pretty impossible for them all to go faulty at once.
The supply pressure is critical to pump filling, the lift pump needs to supply 25Psi for it to function.

Are you using the same return pipe banjo bolt each time, if so, change it for a new one as that is the pressure governor.

 

[Tinytots]

Is this the banjo at the rear left of the pump, is that right? I'll order a new banjo bolt and washers on Monday and try that.
When the engine was started and stopped the timing was rotated and to 14o ATDC and pump checked to see if it would lock, it did.
When the pump was fitted, we started the car without the inlet manifold on and we adjusted the advance and retard on the pump and it made little to no change at all.

Is there anything else I should check?

 

[Dieselman]

That is the Banjo bolt, it serves as a restrictor to keep the pump gallery pressure high and as a non return valve.

You could check the dynamic advance using a fuel pipe clamp timing device, also check the lift pump pressure.

 

[Tinytots]

Dieselman, thanks for that info on the Banjo bolt. I'll change it as soon as I get it. As for the dynamic advance, that's way out of my mechanical knowledge. However I'll pass this info to the new mechanic when I find one. Shane

 

[mejermy]

Take the dynamic test advice seriously. It's easy using a standard petrol timing light and a Gunsons type clamp which translates the pulse felt in the injector line to something the timing light can strobe onto the timing marks for you. DM is the guy to listen to on this one as I'm only at the point of investing in one of these and have never done it, but it should sweep up your issues.

 

[Dieselman]

I'm confident the static timing is correct as the pump was locked at 14 degrees ATDC.

What a dynamic test would show is if the timing goes out when the engine is running. If so, the chain driven timing device is at fault.

On balance, I think it's fuel pressure or air leakage.

 

[Tinytots]

I'll be trying this first thing tomorrow. Thanks guys.

 

[91dm]

What was the original problem and reason for replacing the pump? As Dieselman has said, does sound like a air leak.

 

[Tinytots]

I replaced the o-rings in the pump. I used a magnet to get the lift the valve out to get at the copper washer. Unfortunately the valve seat came out too and I didn't replace it properly(I think). when the car was put together again it was accelerating, but had a low rev dead spot, so I took it apart again, which made it worse. Then the mechanic I got started changing pumps and working at timing. It now runs worse than it ever did and this is when he said about the con rod damage.