300Tdi FIP lever

[RRC200Tdi]

This is probably an easy question, but the internet has failed to find an answer for me. What is the assembly on the FIP circled below?

 

I have found two different posts where someone has asked about this lever and spring assembly and no one ever replied. I have noticed that this assembly is not present on 200Tdi FIPs but is present on 300Tdi FIPs that have EGR, so one assumes it is related to the EGR system. When I removed the throttle spindle cover I saw that this lever (circled) was somehow interacting with the internal fueling lever. When throttle is applied the circled lever is activated and presumably affects the internal fueling lever and governor system. The springs on the circled lever suggests that the internal movement of the governor and fueling lever can overcome the interaction of the green lever. That's about as much as I can deduce, but what does it do? Should I remove it from my FIP since it is non-EGR? One thing about this mechanism is that it makes it a bear to reinstall the fuel spindle cover and governor spring cage, and its removal would make reassembly considerably easier. 

[western]

Looks like a hand throttle connection, the accelerator pedal cable is below. 

Where does the other end of the cable go? 

[Will@LRW]

It is only on EGR 300Tdis. It may be the "Load Dependent Compensation" as detailed in the PDF manual at the bottom of this thread: 

 

I may be wrong, as there are lots of modules for the VE pump in that manual, but it states "These adjustments lead to “softer” engine operation, and cleaner exhaust gas at part- and full-load".

Agree it's a damn annoying lever to be there when you want to take the top cover off!

 

[Snagger]

My 95 300Tdi has EGR but not that.  It’s fitted to the throttle quadrant, by the look of it, but I can’t see a cable out the back end, so it might be a simpler version of what Will was linking to, just raising the idle speed when cold conditions make it contract.  I can’t see any way for it to affect injection timing directly, but the timing would need to advance a little with raised rpm under normal circumstances and a governor system in the pump would do that at all times, not linked to this device.

[RRC200Tdi]

Thanks guys for the information on this confusing module. Below is a picture from Atlantic British for a new 300Tdi injector pump fitted with EGR.

 

 

Hopefully this photo is more helpful. There is nothing else connected to this lever. The rod is attached to the throttle lever. When throttle cable is pulled it rotates the throttle lever which then pulls on this lever. At idle there is no tension on the lever, therefore I can't see a way idle would be affected, whether warm or cold. Load compensation is a possibility (though it is different than the one in the manual), which might make this a helpful mechanism to keep in place, even for a 200Tdi, as it is entirely mechanical and thus should be functional. The worrying thing is that there are at least four adjustments (two grub screws, the center shaft, and the slot with the torx screw). That many adjustments suggest it may be very bad if it is improperly set 🤔

[Snagger]

Ah, that’s a useful photo.  I had believed from the first photo the stamped steel component was a bracket, but this side shot shows it’s and operating arm.  I suspect the springs or the rod inside them are made of a temperature sensitive metal that will lengthen or shorten the rod and operate that arm to adjust the timing.  It could just be a simple timing advance/retardation lever with spring damping to allow for timing optimisation at various throttle settings, with the rpm governor inside also having inputs, so that the timing advances for open throttle (as more fuel is being injected, which takes longer) and retards it for overrun, the springs giving a softer change that gives smoother variation in engine performance.  Just a guess, though.

[vulcan bomber]

I've always thought that's a damper for the throttle to reduce the amount of kangarooing the vehicle does.

[HoSS]

Is it not something like the ALDA on merc engines? Enriching depending on load (although theres no pressure input in this case...)

[Will@LRW]

Here's a pump on a 2004 300Tdi with no EGR.

Here's my 97 pump with the lever. The red circles show about where the lever engages. As suggested above, the only thing I can think it would do is affect the rate of change of fuelling based on the force applied by the accelerator pedal.

[RRC200Tdi]

Very fascinating. Thank you, Will, for giving us a look at the internals. I wonder if vulcan bomber is right... I may be wrong but it looks like that internal lever in question might catch/stop the whole fueling lever assembly, either at idle or maybe when the throttle lever is rotated with the pedal. I really need to take mine apart and try to understand the relationship with the parts, but as my Tdi is running well at the moment I am not willing to 🙂 

I still can't help wonder why it appears to be specifically associated the EGR FIPs, when all of these possible functions would benefit all 200 and 300Tdi engines.

-j

[pat_pending]

All this is very interesting.

There are lots of variations of the VE pump and the lever in question is where the cold start advance is found on some other pumps.

This is normally operated by a separate temperature controlled mechanism, and holds the timing a few degrees advanced up to around 2000rpm whilst cold.

This looks like it may well do that, but is not temperature sensitive, although additional low rpm advance may well help throttle response at all temp's anyway.

One problem with diesel advance is that it raises NOX emissions, the purpose of the EGR is to reduce NOX, so if this lever is only found in conjunction with EGR, there is a possibility that these engines can take advantage of the low rpm timing advance because the EGR is bringing the NOX levels back down.

 

 

 

[vulcan bomber]

This mechanism has nothing to do with timing advance. The injection is advanced by the plunger assembly lower down which rotates the cam plate inside the pump.

[pat_pending]

21 hours ago, vulcan bomber said:

This mechanism has nothing to do with timing advance. The injection is advanced by the plunger assembly lower down which rotates the cam plate inside the pump.

 

I'm certain the linkage shown is part of a cold start function, the usual method of achieving that is to advance the timing.

I'm aware of how the overall advance works, although I've not stripped a VE pump I'm not sure what else the lever could be doing to aid cold starting.

There are several cold start devices that can be fitted to that series of pumps in different locations, they all advance the timing.

As an aside, that lever with different linkage is also used as a mechanical fuel cut off on some VE pumps.

I've had quick google and I couldn't find a Bosch manual specific to 300tdi.

I think I've got a couple of old pumps somewhere, I'll have to dig them out and see what linkage they have.

 

 

[RRC200Tdi]

I finally had an opportunity to test this lever I and I am highly confident that @vulcan bomber was correct in suggesting that it is for minimizing kangarooing and it is absolutely brilliant! Now that it is set correctly I don't have to work the throttle when going over speed humps while ascending a hill.  When adjusted incorrectly it definitely will change fueling dramatically, but that it not its intended purpose.