BX Starting Problem

kiwi · Post by **kiwi** » Sun Jul 06, 2008 10:56 pm

19TZS with Solex carbie (yea I know crap carbie) ever since it went in to have this damn head replaced not only the leak (see other thread) but starting the Baby from cold eg first thing in the morning has become a mission.

Stuck auto choke? or is there a connection with the two electronic solenoids on the side of the carbie? I noticed one they replaced the spade connection to it?

Next question would the BX 16 carbie interchange or parts be stripped from?

Of course it being winter here these problems dont half show up!

DLM · Post by **DLM** » Sun Jul 06, 2008 11:13 pm

This could possibly be in the area of the infamous wax-stat, which is triggered by coolant temp, and is also at the highest point of the engine coolant system. If they've refilled coolant & bled the car properly then it'll be full of coolant: if not it'll probably be floating in an air lock. Whether this will have the effect you describe I don't know.

By refiilling and bleeding properly, I mean filling using a temporary header tank stuck into the radiator filler. Such a thing could be a bottomless 2-litre plastic drinks bottle, inverted and with an o-ring on the screwthread to provide a seal.

I'm currently 100 miles from my Haynes carb manual, though I suspect there's one on the web somewhere. I seem to recall that the 16 and 19 carbs are variants of the same Solex family (34?), but potentially with different jet sizes and maybe a couple of other differences. A usual this depends on the date of the cars. Sorry, this is very non-specific.

mnde · Post by **mnde** » Mon Jul 07, 2008 11:14 am

Here's what you're after:

http://www.rwbsmith.plus.com/citroen2/

Cheers,

Mark.

mnde · Post by **mnde** » Mon Jul 07, 2008 11:55 am

I'm pretty sure the waxstat has no part to play in starting from cold. The first thing that should happen is that the choke butterfly is instantaneously pulled open by a preset amount by a vacuum acting on a diaphragm in the pulldown chamber, which in turn actuates linkages to open the choke. What happens next depends on whether yours is the single or 2-stage pulldown type - does the carb have a black reservoir on the side?

The waxstat will only start to operate (assuming no airlocks), progressively opening the choke, once the coolant has exceeded a certain temperature.

Is the car easier to start from cold if you hold the accelerator pedal down fully, then operate the starter? When cold (only), you can observe that if you operate full throttle manually (ie twisting the drum on the side of the carb), linkages will open the choke slightly. If the vacuum pulldown is ineffective and the choke flap remains shut, the car will be very difficult to start as the mixture will be over-rich.

Alternatively, of course (apologies if you've already thought of this), the very cold weather will highlight starting problems caused by ageing HT leads, distributor cap/rotor arm etc. Also worth checking all the ignition parts have been put back together properly by the mechanics following the head replacement... e.g. do you have a good spark on all cylinders?

Cheers,

Mark.

DLM · Post by **DLM** » Mon Jul 07, 2008 3:28 pm

It's been a long time since I owned a petrol BX, though I did drive a couple over 8 years or so. Please excuse me if I'm spouting irrelevancies.

What you have reminded me of is the insert in the manual for carb-fed 16/19s, which advises a specific cold-starting procedure: something along the lines of " depress accelerator gently, then hold and attempt to start, releasing as engine starts". If I recall correctly, there's a different approach from hot. Does something need to be cocked in the carb for a cold start?

Admittedly, this is the "new car" advice, where all is working as it should.

AndersDK · Post by **AndersDK** » Mon Jul 07, 2008 6:00 pm

Lift up the inlet air duct to have a peep down the carb.
Is the choke (uppermost) butterfly flap strangling as it should from cold ?

Quie often its a simple problem with the spring loaded rod connection to the choke strangler flap or the flap turning dry in the barrel. Sensitive bits here.

And no - your 1.6L carby wont match. Even the solonoid valves are usually different, but take a look before the mission is deemed impossible.

Solonoid valves are easy to check :
have ignition on - then play with the spade connector on each valve. Easy to recognise the faint click from the plunger operating - and enjoy the electric chok when disconnecting (the door bell coil syndrome

)

kiwi · Post by **kiwi** » Wed Jul 09, 2008 4:10 am

Dang thanks for that Anders.

Weird as it seems the colder the Car (longer between starts the harder it is to start). Frustrating actually worrying for one of those cold mountain starts over the winter.

cacaolat · Post by **cacaolat** » Sat Oct 04, 2008 1:05 pm

The same thing has just happened to me about 1 hour ago. I had this problem 3 times before. Last time in early January. It did not do anything to fix it because the car was alright after that, it seemed a distant memory, but now I am there again.
I have tried the spark tester, but could not really see a spark. Maybe it was too bright or because I flooded the engine. There is some smell of petrol.

I will have a look trough all the good advice given at the time. like new ignition leads etc. huh

I was happy with my old Bx as it is comfy and nice to drive, but now after LHM leaks and starting problems again.??...My wife already refuses to drive it.

cacaolat · Post by **cacaolat** » Sat Oct 04, 2008 3:28 pm

Ok the above happened but half an hour later, I checked the sparks with the help of someone. All fine. After that the car started again. I observed some spray coming from the exhaust, this could be proof that the engine has been flooded ?!
Now I will read those instructions of how to start a petrol bx in cold weather, that may have been the problem, even on the other occasions...
sorry that I am writing on someone elses thred instead of creating a new one

ellevie · Post by **ellevie** » Sat Oct 04, 2008 7:55 pm

These intermittent problems can be very frustrating.

The spark tester should give a clearly visible flash even in daylight, so if you didn't see a flash then there is a very good chance that the problem is a weak or missing spark due to a problem in the ignition circuit. The engine being flooded would not prevent the flash.

The next step is to identify the type of ignition you have. If you logon to http://service.citroen.com you should be able to identify they type of coil you have by looking at the illustrated parts diagrams. Search for ignition coil under ---free services---spare parts---bx---searches. The search will return a number of documents called "ignition harness-spark plug-coil". You should be able to identify your coil from these.

If you have the long round coil it should be fairly easy and cheap to fix the problem without buying anything. If it is one of the others you may have to buy a coil or possibly an ignition module. GSF are doing coils fairly cheaply for £20 to £30. Vehicle Electronics Online are doing modules fairly cheaply at about £12. Mark (mnde) had an ignition problem some time ago which turned out the be the shorter fat coil. If it is the long round coil like my 19TRS then it is probably just poor connectivity on the low voltage part of the ignition circuit -- if so, I will try and guide you.

Good luck !

cacaolat · Post by **cacaolat** » Sat Oct 04, 2008 8:13 pm

the problem is that the first time I used the spark tester I was alone and had to turn the ignition and look for the spark at the same time....I thought I did not see it but then I am not sure. Half an hour later I got my wife to turn the ignition key so I could look closely and there was definitely a spark.

ellevie · Post by **ellevie** » Sat Oct 04, 2008 9:06 pm

That's a shame. I used my spark tester only last week when I brought one of my 19TRSs out of retirement and put it through the MOT (I've been driving a diesel for the last 18 months. I place the tester on the plug nearest the o/s wing and put my arm in through the window to turn the key and I can just get my head around the bonnet to observe the test. I suppose it's best to wait until the problem comes back again. Make sure you know exactly what the tester looks line normally for future reference.

BTW did you figure out what type of coil you have ?

tom · Post by **tom** » Sat Oct 04, 2008 9:32 pm

I really wouldn't be using a spark tester around a flooded engine if I could smell fuel.

ellevie · Post by **ellevie** » Sat Oct 04, 2008 10:00 pm

This is a sealed neon tester. No naked spark is produced.

cacaolat · Post by **cacaolat** » Sat Oct 04, 2008 10:24 pm

yes the tester is sealed just as the standard spark plug caps would be....