ZX Waxstat Setting - URGENT!

[Rhothgar]

Hi Guys,

Sylvia's got an issue with her car over here in Austria.

It is, unbelievably, set to snow tomorrow and quite a bit down to 700m.. We are are 1130m.

We've just jumped into the car to go to Billa to get some provisions and the car started then stalled. Air temperature is currently 2 degrees.

It gave out a puff of white smoke as it dead. We put he bonnet up and primed it. No amount of cranking would get it to start.

In the end I loosed the screw on the electrical connector that is connected to the end of the Waxstat cable and fully opened the contacts. The car then started.

We haven't brought the BoL with us and I would like to know the correct procedure for setting up a Lucas DPC.

I searched the forum and only found a post I made two years ago.

http://www.frenchcarforum.co.uk/forum/v ... t&start=30" onclick="window.open(this.href);return false;

It was useful to read over it again as I can see I reset it two years ago.

Sylvia's car has been struggling to start in colder weather for some time now so I guess it is the Waxstat that is failing.

If anyone can PM me the relevant pages from BoL it would be much appreciated. Hers is 1996-97 1.9TD with Lucas DPC.

I know a 3mm shim is involved and testing the continuity of the micro-switch but cannot remember for the life of me how to do it.

Cheers for now.

[spider]

Should not need to use the shim I've never used one.

Lucas pump:

When the engine is cold the cable should be pulled tight so the fast idle lever has moved fully over *and* the contacts are closed in the switch.

The switch on these operates the timing advance solenoid, just pushes a cam-plate in a bit actually as far as I remember.

As the engine warms slightly and the cable relaxes, the contacts open and the timing reverts to being under mechanical control as normal.

The cold start advance is just that, I see you're in Austria though. Over here it does not seem to make much difference (I threw mine away with no ill effects)

That's essentially the procedure really.

With the fast idle cable jammed open and the switch closed idle should be about 900 to 1100 give or take. If its stalling then wind the anti-stall (the screw the 'throttle arm' rests on a bit), then adjust the idle after.

EDIT... The feed for the advance (tis just an on / off solenoid on these) usually comes from the stop solenoid wiring, probably find two wires fitted to that instead of one. Regarding testing, ensure that there is power at the switch contacts when the ignition is on. There is not really a lot else to set.

Not sure that's any help, hopefully it is as you did say "urgent"

[Rhothgar]

Cool. That was lightning. Cheers Spider. You were the main contributor last time I posted.

I think the 3mm shim thin is for the Bosch on my Xantia. Think old age is getting the better of me.

I just logged onto my Evernote account as I spent €5 on service Citroen a couple of years ago and downloaded stacks of information so I am going through that too.

When you make mention of the switch, do you mean the one on the front of the pump that the waxstat cable acts on it the one on the top of the pump?

Just checked on Citroen site and a new waxstat is only £30. Might try and get over Obertauern tomorrow if the road isn't closed and drive to Gell in Radstadt. I don't they have a waxstat in stock but you never know.

[citronut]

the contacts the wax stat cable control just feeds a negative to the servo, so dont have a live feed through them at all,

the servo has a switched live via the ignition switch

[Rhothgar]

Just had a thought. Might be totally stupid.

Would it be acceptable to unscrew the Waxstat end screw to take it all of of circuit and disconnect the spade connector so there is no feed to the advance mechanism?

Would this have the same effect as having a blanking plug in the pump as Spider as previously suggested?

The YouTube video link in the link I provided above shows the components clearly. I assume that the leaking element in that video is the timing advance we keep referring to?

[RichardW]

I doubt the wax stat is really the problem - more likely it needs a new set of glow plugs..... It should start without the advance being on, might sound like a bag of spanners and smoke a bit, but it should start right off the key.

[spider]

Yes the switch / button affair on the cold start end cable fitting.

If you did want to take the unit out the pump it just unscrews (caution it will spill quite a bit of fuel!) you must get a blanking plate from a model without one, find the nearest Lucas equipped 309D or 205D (non turbo models) or an early 306 and obtain one from there.

I'd not remove it if its not leaking though personally.

I would agree it should start and run without that anyway, even without the wax stat it should start it just will not cold idle very well (it will try to idle about 500rpm and stall on de-celleration) if the cold start cable is missing.

Sort of suspecting heater plugs (as above) or more likely air ingress.

[Rhothgar]

GP's are fine though I do agree the symptoms appear very similar.

One thing I did initially feel could be causing an issue but was unrelated because the non-start only happened once yesterday hence the urgency to rectify is that the positive cable clamp is totally split so in the end I hammered it closed an then carefully tapped it down onto he battery post.

I checked the voltage drop by measuring from positive battery post to positive feed on starter whilst cranking and it is around 0.8V. I think this is slightly excessive and could be way it was cranking over slower in colder weather.

It started reasonably well this morning. Stalled once, restarted and it was a bit lumpy.

It tried to snow this morning so temps were around 1 - 2•C

Where is the idle adjusted on a Lucas DPC? Is it the lever that comes off the STOP lever or is that fast idle adjustment?

[spider]

The tiny one next to the 'stop' arm. May need two spanners as its got a locknut on one side. Red arrow points to idle speed adjuster. I realise that pump is a bit different to yours but the adjustments are in the same place.

The larger one the 'accelerator' arm is sat against is the anti stall. Found an image from Google, its Jim's



Arrow points to idle speed adjuster. Will probably want two spanners as its a locknut. Only adjust idle speed when engine reasonably warm and more importantly fast idle cable must be slack.

The blue paint near the big bolt at the front the 'accelerator' arm is sat on is the anti-stall. Set idle then with a warm engine rev it to about 3K and lift off quickly watch tacho for "bounce" or listen to see if it drops too fast or stalls, if it does wind anti-stall a little bit (you'll need to reset idle maybe as well after this) then repeat test.

[Rhothgar]

That's really useful. Cheers.

I am reluctant to change things but have no option. It's clearly not 100% right and I like things running sweet as a nut.

I've got to be mindful to slacken off the Waxstat before I carry out the adjustments and pull cable tight as I can without affecting idle lever and retighten and I am hoping it will be something like right once Waxstat cools and contracts.

[spider]

No need. Ensure engine is warm before any adjustments. The fast idle cable should be loose by then ie not pulling the arm at all, if its still got ahold of it, temporarily release it so its not doing anything.

If you do the adjustments to the idle/stall with a cold engine you'll get slightly false readings as a cold engine without any waxstat cable pulling it will idle too slowly, this is really all the waxstat is for, to increase the idle speed when the engine is cold.

So, with a warm engine make your adjustments.

The waxstat can get lazy and move less and less , if it was still grabbing the arm, fit it so its only just loose ie about 1mm or so play left, this way it may still function. If it was free and not interfering with the warm engine, leave it as-is for now. if you wanted to adjust it, give it less freeplay but it must have a couple of mm say free when the engine is warm.

When the engine is nice and cold (stone cold better) before doing anything quickly examine where the waxstat cable is and if its fully pulling the arm or not.

[Rhothgar]

What a complete bastard!

It just shows you how an easy job can go very wrong.

Just been outside doing the settings. Fast idle now fine. Set it at 1100rpm.

Took car for a spin and reset idle. Could only get it down to approx. 900rpm then realised I had to unclip the accelerator cable to allow the arm to move back more.

Prised the clip off and lost it behind the alternator. Cannot retrieve it with a magnet! Tried a safety pin and then found a spring which I cut up and bent into rough shape of no. 74 clip on service.citroen and hopefully sorted it now.

Strange thing is with accelerator cable slack, I could not get the car to idle any slower than 900-950rpm despite winding the big nut all the way in.

Clip 79 03 066 101 is now NFP.

It is common to both ZX and XM. Has anyone got one kicking around per chance?

I hate the fact that we have a 1000 mile drive back and theoretically my Heath-Robinson clip could fail at any time.

How gutted am I?

EDIT:

Now down to 750 after re-reading post. The altitude does strange things to you out here.

[spider]

Is the clip the metal C thing holding the acc cable plastic ? , a cable tie will suffice if needed.

If you cannot get the idle speed down turn the anti stall a little bit. Does the "stop" arm stop the engine quickly ? , if not the anti stall is too "high"

[Rhothgar]

Yes. It's like a back to back R clip.

I sorted that temporarily by making a clip but will bolster it with a cable tie. I also used a big safety pin!

Sorry Spider but the altitude does funny things to you out here. I had to re-read the post about 5 times to understand it.

You said adjust the nut with the big red arrow in the photo. I was adjusting the anti-stall!

I set the fast idle from cold to about 1100rpm using the same bolt with the bid red arrow and locked it off.

I then went for a spin and couldn't get revs below about 950rpm so I adjusted the idle screw again. Now at 750-775rpm when hot. Am I right in assuming that when engine is cold again that revs on fast will have dropped by 150rpm because idle screw controls both fast and slow essentially?

[Rhothgar]

Is the clip the metal C thing holding the acc cable plastic ? , a cable tie will suffice if needed.

If you cannot get the idle speed down turn the anti stall a little bit. Does the "stop" arm stop the engine quickly ? , if not the anti stall is too "high"

I have turned anti-stall right down now. I am figuring this is going to give problems when cold now as it has been turned in a lot!

When you say quickly? How quickly?

It doesn't stop dead but it probably takes 2 seconds.