Citroen XM Forum

Hi Dave,i doubt the electronic Bosch wll give any better prospects on longevity.Does anyone out there run one on veg oil ?I know the EPIC gives outstanding performance and longevity on proper fuel, but also know like many other make of pump - including some Bosch - will not tolerate the viscosity of veg oils or high alcohol levels in biofuels.
robertm

(-the beige interior of course!)

Whats he going to sit on, unless you have another estate to swop the interiors with.

I had forgotton that hatch interiors dont fit very well......

Is the bosch pump vastly different to the 2.1d bosch then?
Time for some research methinks!

Hi Dave,Like the EPIC,the business end of the Bosch is derived from the mechanical pump.However the introduction of electronics brought closer tolerance, finer control components which are affected by gumming,or degradation of the seals.I would be well interested in any ones experience of any electronic diesel pump running alternate fuels.
robertm

robertmnorton wrote:Hi Dave,Like the EPIC,the business end of the Bosch is derived from the mechanical pump.However the introduction of electronics brought closer tolerance, finer control components which are affected by gumming,or degradation of the seals.

Sorry, but I just don't understand that at all. The basic pump is virtually the same as a fully mechanical pump, but it has electric control for the metering lever, timing valve and speed governor.

All the electronics do on a VP pumped engine, is to make the pump work within defined parameters, you press the accelerator, the ECU checks the various sensors then applies more power to the metering solenoid.

One aspect to be wary of is that later pumps were built so the internal alloy casting became a bearing surface. This causes them to wear early, especially if run on Veg or Bio. I'm not sure if the type used on the 2.5 fits this category.

hI Dman,for "business end" read hydraulic head,for "finer control "read "defined parameters".The intention was neither to delve into the inner workings of the pump,nor embark on a play on words,simply to point out that "Bosch" on the label does not mean impunity from the effects of the poor lubricating qualities,viscosity and alcohol levels of alternate fuels.
robertm

Im aware, that bosch doesnt immediatly give immunity from the effects, but if it is of a similar generation to the pumps on the 1.9 and 2.1 then in my experience with a couple of mods should handle veg no problem at all.
Due to the unknown factor, i will advise my Dad to filter to 1 micron rather than the current 5 should he get the car.

The fully mechanical Bosch pumps on the the 2.1 are utterly reliable in my experience, I have got used to the notion that they will last forever, I have had two that are getting on for 300,000 miles with no problems, still have one. They are a little less efficient than the electronically controlled ones but only marginally, I would rather have the reliability.

My personal view of running with vegie oil is that the cost of overhauling the pump when the seals fail will likely exceed any savings made - unless you can do it yourself of course.

Peter

I ran a couple of my 2.5's on neat refined Bio for about 6 months until the supplier ran out of feedstock and packed up.
No noticable change in performance, no filter problems nor any starting difficulties.
I am considering trying again but this time filtered WVO.
Have a spare pump but if this became a problem would probably source and fit a straight Bosch pump from a 2.5 relay van.

John

I run my 2.5 on veg oil and normal diesel mixed. No problems at all just don't overdo the veg. I'm pretty sure from my research that the pump is significantly better than the one fitted to the 2.1. I think sure that whereas the 2.1 pump has only a single high pressure pump internally the 2.5 has more (I can't remember if it was 2 or 4), this means that it's can provide more fuel and do so under less stress.

If I get a chance I'll look it up next time I'm at HQ, the library there has a brilliant book on diesel engine technology, giving a thorough dissection on the systems used, how they work and evolved.

Steve.