finding stop solanoid & or wiring Mk2 xantia 1.9TD

falling-out-with-my-car · 04 Aug 2010, 10:30

my Dads pump leaked on filtered WVO he put in a tank of diesel and the leak stopped for good he is now back on the veg, mind you his xantia is a mk1 vsx and their pumps do seem to be of better build quality overall able to handle the demanding stresses of pumping thick veg oil.

Xaccers · Unread post by **Xaccers** » 04 Aug 2010, 20:14

After 10+ years the seals have weakened, which the veg exposes and highlights. Look at the number of other rubber components in the fuel line which fail by the same time letting in air (primer bulb, fuel lines etc).
If you return to derv before the thicker veg increases the cracks then you can often get away with it, but what's the point? Our cars are fitted with excellent robust pumps which can easily run on veg without modification, so it's worth doing a proper service and replace the seals.
Easier to do with an older fully mechanical pump as there's no armour and from experience without the extra electronics of later pumps they perform better, so the easiest option is to source an older pump, replace the seals then do a swap.

Unread post by **KennyW** » 04 Aug 2010, 21:53

Hi Nigel,

It appears you have resolved your problem after reading the messages. I've sent you a pm anyway

Kenny

falling-out-with-my-car · 05 Aug 2010, 19:36

Xac wrote: Easier to do with an older fully mechanical pump as there's no armour and from experience without the extra electronics of later pumps they perform better, so the easiest option is to source an older pump, replace the seals then do a swap.

doesnt the pump have to be matched to the ecu then?

Martin at Pleiades has an xantia 1.9td estate that will only do 20 mph he is thinking about changing the pump but worries about the throttle chip wired to the ecu.

so Xac are you suggesting an older pump could be used without this throttle sensing chip? and if so there would be no connection to the ecu thats ok is it?

regards Nigel.

Xaccers · Unread post by **Xaccers** » 05 Aug 2010, 21:30

falling-out-with-my-car wrote:
Xac wrote: Easier to do with an older fully mechanical pump as there's no armour and from experience without the extra electronics of later pumps they perform better, so the easiest option is to source an older pump, replace the seals then do a swap.
doesnt the pump have to be matched to the ecu then?

Martin at Pleiades has an xantia 1.9td estate that will only do 20 mph he is thinking about changing the pump but worries about the throttle chip wired to the ecu.

so Xac are you suggesting an older pump could be used without this throttle sensing chip? and if so there would be no connection to the ecu thats ok is it?

regards Nigel.

Throttle sensing chip?
Jim's the pump guru, but I don't recall anything about a throttle sensing chip.
Later semi-electric pumps can adjust the timing slightly, controlled by the ECU using the needle lift sensor and crank sensor inputs.
Keypad immobilisers can be disabled by unplugging the keypad when the engine is running. Not sure about MK2 immobilisers, they have a fob sensor in the steering column, would be interesting to know if it can be disconnected like the keypad, or if the immobiliser is a bit more intelligent.
AFAIK the throttle and workings of the pump are purely mechanical.
The Lucas EPIC(fail) pump is electronic with a fly by wire throttle that takes all the fun out of a 12v 2.1TD

I'm sure some people have said their very early TDs don't even have an ECU.

Unread post by **CitroJim** » 05 Aug 2010, 21:43

No, there's not a throttle sensing chip but what Martin may mean is the load pot on top of the throttle lever. This is just a normal potentiometer used to give the ECU an indication of load. Basically it measures how far the throttle is open and when compared with the engine speed it can make a stab at how heavily the engines is loaded (i.e. wide open throttle and low RPM means a heavy load) and can adjust the timing to suit.

No worries about swapping one from another as long as the original alignment of the pot is maintained.

Unread post by **KennyW** » 05 Aug 2010, 21:49

Hi All,

Reading postings with interest.

I've just tried to put my old pump back the old gal and it would not start.

Put the 2nd pump I got and she is back running again.

Jim mentioned the pot on top of the pump, i believe that's where my problems lie with my orig pump as i know for definite it has changed.

Jim and the others correct me if I'm wrong but I think it needs to go to the specialists to correct it.

Kenny

Unread post by **CitroJim** » 05 Aug 2010, 21:54

Kenny, this is the third post tonight I've made about load pots

I doubt very much it'll cause a non-start though and most likely it would cause rough running.

Have a look at my reply to Shaunfc1 to save me repeating myself! I'm going to do a test plan for Shaun to test his pot tomorrow and this should be good for you too...

Unread post by **KennyW** » 05 Aug 2010, 22:00

Thanks Jim,

I will hopefully get a lexia check done to see what comes up

Kenny

falling-out-with-my-car · 06 Aug 2010, 12:36

so in rough terms the potentiaometer on the top of the pump is a throttle sensing chip which determines load? how does the ECU change the timing if it is fixed by a toothed belt. surely it can only change the mixture???

sometimes it is not always possible to know the correct term for these computer items.

Unread post by **KennyW** » 06 Aug 2010, 13:13

Hi Nigel,

I think the ECU determines the amount through checking all the sensors and the needle lift sensor on injector No 3.

I'm sure Jim will correct me if I amwrong.

Kenny

Unread post by **CitroJim** » 06 Aug 2010, 13:32

falling-out-with-my-car wrote: how does the ECU change the timing if it is fixed by a toothed belt. surely it can only change the mixture???

The pump has an axial cam ring that is moved relative to the body by the electrically-hydraulically operated timing piston (device). The relative position of the cam ring determines timing. This is, incidentially, just a development of how the mechanical pump achieves automatic advace with speed; the mechanical pump just usies building hydraulic pressure with speed to operate the timing device and thence the axial cam ring.

I'm not going into how the ECU sets the timing as I think it is beyond the scope of this thread. Just be content that the ECU determines the optimum timing for a given set of circumstances and the pump obeys it's command (mostly).

I will explain if anyone is interested but it's fairly heavy electronics and feedback loops.

falling-out-with-my-car wrote:sometimes it is not always possible to know the correct term for these computer items.

It's not a chip and it's not a computer device. It's a simple enough pot (a diminutive of potentiometer) - a very standard and ubiqutous electronic component, most commonly encounterd in the form of a volume control.

If I hear it called a chip one more time I swear I shall not be held responsible for my consequent actions.

falling-out-with-my-car · 06 Aug 2010, 22:34

jim,

Thank you for explainning that
if you'd have said volume control in the first place......

anyway this thread is way off topic from my orriginal question to find a posative supply capeable of supplying an electronic fuel pump in the engine bay Now that has been found with the use of a battery supplied remote control circuit which is relay and fuse protected its all sorted thank you to everyone who took part.