Xantia 1.9 turboD Diesel Pump Change

KevMayer · Post by **KevMayer** » 07 Oct 2005, 20:33

My Xantia 1.9 turboD has an ECU to control timing advance on my pump.
There is also a throttle position sensor.

But, I've suspected for some time that all is not well and my car isn't pulling like it should.

So, I've just purchased a replacement pump off ebay.

My Xantia is a 1997 P. The pump is off a 1993 L so has the mechanical timing advance and no throttle sensor.

The "new" pump does have a device called ABLF. Does anyone know what this is ?

Can I connect the ABLF to anything on my existing system ?

Do you think my Xantia will work with the old (1993) pump ?

Thanks for any replies.

Cheers,

Kev

jeremy · Post by **jeremy** » 08 Oct 2005, 09:16

Bit confused here. Have you been consistent in your post with the use of 'new' and 'old?'

What make is everything? it makes a difference.

The 93 pump will either be roto-diesel or Bosch and will if rotoDiesel have connections for the throttle cable, fuel inlet, return pipe, a connection from the waxstat cold start device which should be on the thermostat housing (this is a bowden wire cable for a mechanical connection and an electrical connection to power the cold start advance switched by the waxstat. It will also have a pipe to feed boosted air to the extra fuel device which is a cylinder on the radiator side of the pump (as is the cold start actuator - but has an electrical connection)

If its Bosch it will have similar connections in different places and the cold start may be mechanical.

I do not know if the drive is similar. if your ECU controlled pump is an Epic - it is I think a cousin of the Roto-Diesel.

Kowalski · Post by **Kowalski** » 08 Oct 2005, 13:31

What was the fuel economy like with the old pump?

The reason I ask is that the fuel economy is fairly diagnostic as to the accuracy of the timing, i.e. if the automatic timing adjustment isn't working as it should your fuel economy will be poor.

You can sort of check whether the timing adjustment is working properly by starting the engine, and while its running unplugging the sensor that goes to the third injector (brown plug above / behind the injector pump somewhere on top / in front of the rocker cover) and seeing whether the noise the engine is making changes. On mine this change is very slight, it only changes the first time you unplug, i.e. if you plug it back in again the noise doesn't change again and you have to plug it back in, start the engine with it plugged in and unplug it to hear the change. I'm not sure whether this method is reliable as its based purely on my observation.

There are many things that can cause the XUD to not pull correctly, most of them are related to the turbo charging, i.e. stuck wastegate, leaking or blocked enrichment hose, turbo pipe being off, blocked cat/exhaust, dirty air filter and last but not least, the throttle cable can be badly adjusted so that it doesn't open the lever to the stop when the pedal is on the floor.

The XUD seems to pull OK regardless of what the timing is like (within reason) and the fuel economy goes badly off long before you get any performance loss.

KevMayer · Post by **KevMayer** » 08 Oct 2005, 18:38

Sorry for the confusion. But thanks for your replies.

My existing pump is a Bosch AS3 with Throttle pos sensor, Fuel shut off solenoid and a third connection to the ECU controlled timing advance mechanism.

The pump I've purchased off ebay (its not arrived yet by the way - only won it Thursday 6th Oct, still in the post) is a an older Bosch pump but this time off a 1993 Xantia 1.9 TD. The picture shows that its one of the early pumps without throttle pos sensor but it has a device which Haynes calls an ALBF. Haynes says the ALBF is fitted to "cancel light load advance(engine cold)". It looks like there is a diesel pipe from the pump body just below the throttle arm which runs down to a device which is bolted to a cover on the bottom of pump on the side. There is an electrical contact block to connect the ALBF to something.

It sounds like the ALBF works when the engine is cold. But, does anyone know what controls it if its on a car without an ECU ?

So, I am wondering if anyone has ever tried fitting an old BOSCH pump from a non ECU system to a turbod with an ECU BOSCH system.

What would I conect the ALBF to ?

The rest of the fuelling system is ok. I have a straight through exhaust. The cat was removed when the pipe started to leak and my local garage suggested a straight through replacement.

The boost pressure is good and no air leaks.

I've adjusted the throttle cable run before because of too much friction. So, I'm happy this is running smoothly.

I've tried pulling the plug off the timing advance connection on the pump and this causes the engine to run rough as the default without a connection is to go to full advance, almost pinking.

I'll try pulling the plug on the injector lift sensor. I suppose if their's no change in engine note then this could be faulty.

I've played around with my settings so many times that when I saw this old pump on ebay I went for it. I got it for £15 plus £10 postage. So I'm not going to lose much even if I end up throwing it away.

My economy is constant at 36 mpg no matter how I drive. This sounds on the low side of average. I get the impression though that the early Xantias without ECU jiggery pokery are generally faster and more economical. So, I thought I'd try an old pump. But, it may be trickier than I thought.

Kowalski · Post by **Kowalski** » 08 Oct 2005, 19:26

36 mpg is low, my '97 Xantia got 49mpg on the last tank, although according to my spreadsheet the average over 33,255.20 miles is 46.32 mpg, thats over a 70 mile daily commute mostly at 70mph on dual carriageway.

I've had a look under the bonnet of my '94 Xantia and there is a part of the pump as you've described with an electrical connector on it, the '97 Xantia doesn't have a similar part, it has a blanking plate and no electrical connector to match the one that the earlier Xantia has.

There is some system that turns off the glow plug afterglow if you open the throttle more than a certain amount for a certain period, I wonder whether this is used for rather than cancelling the cold idle. The cold idle is controlled by a waxstat on this older car.

I've taken a couple of photos of the bit in question, not that I think they'll be a lot of use to you, I'll post when I can.

Personally, I'd be trying to get the idle advance working properly on the pump you've got, its possible that the sensor in the injector isn't doing its job, does the check engine light come on when you unplug the injector sensor (I don't belive mine does and mine appears to work properly)?

Kowalski · Post by **Kowalski** » 08 Oct 2005, 19:26

I've got the photos of the old pump posted.

This image shows the whatsit on the front of the pump.

As you can see, it has a pipe that goes somewhere on top of the pump and an electrical connection (the orange/brown wire at the right) on the front of the pump. What you can't really see in that picture is the black plug (it was dark, and I used the camera on my phone).

Here you can see where the pipe goes to (its the little pipe in the centre of the picture), its just next to the main fuel connection.

KevMayer · Post by **KevMayer** » 08 Oct 2005, 20:09

An average of 46.32 mpg sounds really good. I bet your performance is a lot better then mine too.

I'm convinced that I have a problem with timing.

Every time i lift off the accelerator I get the "Check engine" light coming on. I'll do the test on the injector lift sensor tomorrow.

A couple of years ago I took my 1.9 td to Allard Diesel to have it tuned. Mr Allard did his best but told me that it didn't seem to pull in low revs as well as he usually gets when he does peugeot 405/306 1.9 td. So, something isn't right.

I don't think I get a lot of black smoke. During the day I rarelly see signs of smoke. At night if I accelerate hard with someone behind me I see plenty of smoke in their headlights. But gentle acceleration at night doesn't produce much if any. I think the night time check in the headlights of the car behind you is the best way to test for smoke.

Kowalski · Post by **Kowalski** » 08 Oct 2005, 20:38

KevMayer wrote:Every time i lift off the accelerator I get the "Check engine" light coming on. I'll do the test on the injector lift sensor tomorrow.

Occasionally I see my check engine light coming on, but its under a very specific set of circumstances.

If I'm going downhill at a constant speed at roughly 1200 rpm, with my foot off the accelarator, after about 10 seconds like that the check engine light comes on, but it goes off if I touch the accelarator or dip the clutch. My theory is that with the engine being on the overrun there is no injection happening (and thus no signal from the injector) but the engine mangement expects it or needs it. The fact that it doesn't show the same light if I do the same thing with more rpms makes me think that there is some cut off point where the injection pulses are expected, i.e. it expects that there is no injection at higher revs on the overrun but at low revs it expects the injection. Also, it is willing to tolerate a limited period of no injection but only that limited period and no more.

KevMayer · Post by **KevMayer** » 08 Oct 2005, 21:10

Kowalski,

Many thanks for going to the trouble of taking photos. The device in the photo is the one I am talking about. Its interesting that you have the two versions in the '94 and '97 xantias. Do you notice any difference in economy and performance between the two ?

First thing I'll do is the test on the injector lift. I agree with you that It would be good to get the existing system working correctly. I've tried asking questions about my problem here (oops...on Andyspares... RIP) but never really got a useful answer. I have seen others with similar posts about lack of economy and performance from the same model Xantia. So I have tended to accept mine as normal. Mine sounds like a Friday afternoon set up, but yours sounds like first thing Monday..lol.

If I fit the old pump, I may just ignore the device on the front and adjust the tickover so that It is just above the right setting. Just enough to give smooth starting. I may need to apply a constant 12 Volts to the device depending on which state it defaults to when the power is off.

I'll know more when I get the old pump in my hands. It will be quite exciting in a sad kind of way. I'm sure you understand what I mean.

ps. the Haynes manual shows a "throttle position switch" in its diagram of an old BOSCH pump. The switch sits ontop of the throttle arm. The photo of the one I've purchased doesn't show this switch and neither does your photo. so thats one thing less to worry about.

KevMayer · Post by **KevMayer** » 08 Oct 2005, 22:57

I've had a good look at Haynes.

An electric schematic for diesel turbos up to 1998 gives a clue.

There's a "post heating thermal switch" which when it reaches temp closes a contact to initiate an "advance corrector" relay.

The schematic shows an output from the "advance corrector" relay to the diesel pump and specifically to a unit which is probably the ALBF which I have been talking about. The "advance corrector" contact is normally closed.

So, the advance correction on the pump (ALBF) is energised until the "post heating thermal switch" reaches temperature.

Great!

except for ...where is the "post heating thermal switch" and have I got a relay on my '97 turbod ?

I suspect I have the heating switch but not the relay. But, I can soon get a suitable relay.

Or, just just leave the ALBF de energised and see what happens.

cheers,

Kev

Kowalski · Post by **Kowalski** » 09 Oct 2005, 21:38

KevMayer wrote:Its interesting that you have the two versions in the '94 and '97 xantias. Do you notice any difference in economy and performance between the two ?

Originally the fuel economy of the two was identical, but the newer car suffered from more turbo lag and a lack of torque below 2000 rpm, taking the cat off improved things torque wise, I can't tell the two apart in terms of power or torque but the newer car is now 5mpg or so better. The newer car has done less miles, has bigger wheels (which cause taller gearing) and of course has this electronic advance adjustment, I couldn't say for sure which bit made the difference in fuel economy.

KevMayer · Post by **KevMayer** » 16 Oct 2005, 20:02

I eventually got around to removing the Injector lift sensor plug whilst the engine was running. The engine note did change quite a lot, so this sensor must be working ok.