Xantia Revs Question

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Oscar
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Xantia Revs Question

Post by Oscar » Sat Feb 25, 2006 2:08 pm

Firstly, my apologies for posting a Xantia question, but I can't be bothered going over to the other site, as I no lnoger know what my password is and everyone over there is talking about changing windscreen wipers and what colour upholstery best suits their eyes.....

Secondly, I hope it's generic enough that the combined expertise on this site can help.

My mate John's 1.9 Turbo D Xant has developed a rev problem. We can't get the revs over 2500. When they go to 2500 when stationary, they quickly drop to 2000 and remain there.

When driving, it will inch along in 1st gear, not going over 10mph. Picks up slightly in 2nd, but still no acceleration or power. I can only get it into 3rd when going downhill.

He has changed the fuel filter but that made no difference.

John's been running a fairly advanced mix of SVO with diesel, up to 70:30 at times. He's also had some more interesting mixes of fuels.

When we had a look at the Bosch fuel pump, there is a slight amount of SVO leaking from the large nut on the front of the pump - don't know what this nut is.

The local Cit specialist thinks that the turbo pipes may be collapsed, but we're not sure.

Does anyone have any clues?
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Stewart (oily!)
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Post by Stewart (oily!) » Sat Feb 25, 2006 2:32 pm

AFAIK the turbo pipes on those are made of a hard plastic, unlikely to collapse, if the pipe linking the inlet to the fuel pump had split you would not get any extra fuel to accompany the boost, but I would have thought it still would go over 2500, I assume you are getting full throttle at the pump? then I would start pointing the accusing finger at the pump, mind you the bosch units will withstand a lot of abuse, I knew a guy who used to pout almost anything into his Xantia, thinners, kerosene chip oil, transformer oil you name it and it always seemed to survive.
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Post by DavidRutherford » Sat Feb 25, 2006 2:49 pm

Try this:

While holding the accelerator to the floor, pump the fuel primer bulb. Does the engine now rev up (and probably smoke quite a bit at the same time) ?

If so, you have the same problem as I had with my 405 a couple of weeks ago. I fixed it with a replacement injection pump (I had a spare).

I think it's a problem with the low pressure transfer part of the pump, but am not sure.
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Post by Oscar » Sat Feb 25, 2006 2:52 pm

Hi Stewart

I had a scan of the other site after all, and you suggested looking at the inline filter at the tank end for a similar problem, so as I type this John is taking the crap out of the back for us to have a look!

David, we'll try that too, thanks

O
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Post by Oscar » Sat Feb 25, 2006 4:02 pm

Well, we found the tank fuel filter under the rear seat and had a look. It's a coarse wire filter which hits the bottom of the tank and is spring-loaded so that it stays against the bottom. Clearance of about 1mm between the filter and the bottom of the tank. The filter was realtively clear although there is plenty of crud lying on the bottom of the tank. I think that this crud is probably blocking the filter when suction is put on the fuel pipe. John is not so sure.

We pumped the bulb while holding the accelerator on the floor. THis increased revs slightly, but now it's only going up to 1500 when floored, 2000 when pumping the bulb. I'm also pretty sure the bulb is shagged and could do with being replaced.

Squeezing the bulb with the pipe disconnected produced a backflow to the tank, but I couldn't tell whether the pipe is partially blocked.

All in all it looks like a fuel starvation problem, rather than anything else.

Is there another, inline, filter between the fuel tank sender and the priming bulb? And where is it? My next steps are to replace the bulb and the inline filter (if there is one) and see what difference this makes.
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Post by DavidRutherford » Sat Feb 25, 2006 4:59 pm

Oscar wrote:Is there another, inline, filter between the fuel tank sender and the priming bulb?
Not that I'm aware of.

Have you tried getting a gallon fuel can (full of clean diesel) and 2 lengths of fuel hose, making a supply and return from the injection pump to this temporary tank? that would prove conclusively either way.

Also, did this failure occur abruptly, or progressively over time?
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Post by jeremy » Sat Feb 25, 2006 6:41 pm

Curiously if you search on the other site you will find the tale of someone with a similar problem and it turned out that the catalyst was blocked by soot and the rotor of a previous turbo!

How old is this Xantia - ie has it got a catalyst, electronic pump?

Won't be additional fuel system - pipe fell of my BX and still had all revs - just no turbo, no smoke either.

Could be collapsed piping if thats possible but I think in reality that any obstruction would cause smoke of some kind. The one I referred to above smoked beautifully from what I remember.

What's the starting like? few diesels start well if there is anything wrong with the pump. I mean start properly - ie heat once till light goes out, turn key - starts first time - no feet, fires on 4.

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