CX 22 TRS: unstable idle

jvgavila

jvgavila

Member
Fellow Frogger
Joined
May 10, 2002
Messages
39
Location
Valencia (Spain)
Hello!

Well, not all is perfect in my 'new' CX :wink2:

Idle is unstable (goes up and down on revs) and, to keep it reasonable, I need to pull choke a bit. Even if engine is at working temperature, it is still unstable. Car seems to run fine otherwise.

Carby is a Weber 34 DMTR which seems to be fitted in several CX engines (with some changes depending on model), am I right?

I have checked distributor and seems OK. I need to check spark plugs and air filter. But wonder if somebody had had a similar problem and, of course, the solution :D (or some info to start looking)

Thanks for all your help and also for your nice comments about my acquisition. I am _very_ happy with it :roflmao:

Regards,

JOSE
 
Jose,

What you are doing by using some choke is opening up the primary throttle butterfly a bit. If you look on the carby, there should be a stop screw which this rests against when the choke is off. Get someone to operate the choke while you watch the butterfly shaft on the carby and you should be able to spot this screw. You can adjust this screw to set the idle speed.

At the bottom of the carb on one of the short sides, there should be hole which has another screw inside (may be covered by a cap). This is the mixture needle valve screw and is used to set the idle mixture. This should be adjusted to get the maximum revs for that setting of the idle speed screw. If it is screwed into far, the engine will starve and stop, if it is to far out, it will idle rich. So set your speed then adjust mixture screw for max speed, reset speed then mixture etc until you are happy with result.

If you are still having no luck, look on the top of the carb between the throats and you will see four jets. the smaller ones on the outside are the idle jets for each throat. Unscrew these and check that they are clean. You could also open up the idle mixture screw and quirt some carby cleaner down the jet holes to clear the fuel passages. Reinstall the jets and try to adjust again when engine is hot.

If still no luck, you will ahve to dismantle the carb and clean it or you may have a leak letting air into the intake manifold which is confusing the carby.

Good Luck

Ken W :cheers:
 
Ken W said:
Jose,

What you are doing by using some choke is opening up the primary throttle butterfly a bit. If you look on the carby, there should be a stop screw which this rests against when the choke is off. Get someone to operate the choke while you watch the butterfly shaft on the carby and you should be able to spot this screw. You can adjust this screw to set the idle speed.

At the bottom of the carb on one of the short sides, there should be hole which has another screw inside (may be covered by a cap). This is the mixture needle valve screw and is used to set the idle mixture. This should be adjusted to get the maximum revs for that setting of the idle speed screw. If it is screwed into far, the engine will starve and stop, if it is to far out, it will idle rich. So set your speed then adjust mixture screw for max speed, reset speed then mixture etc until you are happy with result.

If you are still having no luck, look on the top of the carb between the throats and you will see four jets. the smaller ones on the outside are the idle jets for each throat. Unscrew these and check that they are clean. You could also open up the idle mixture screw and quirt some carby cleaner down the jet holes to clear the fuel passages. Reinstall the jets and try to adjust again when engine is hot.

If still no luck, you will ahve to dismantle the carb and clean it or you may have a leak letting air into the intake manifold which is confusing the carby.

Good Luck

Ken W :cheers:
Click to expand...


Hi Ken,

Thanks a lot for your message!. I will check these things.

BTW, I am afraid of another problem: I know cambelt was changed by previous owner (he did the work by himself... and I am not sure of his competence :( ). I have read on the WEB some comments of 'unstable idle due to slight cambelt missalignment'. Could it be that?

All in all, I am glad because I enjoy learning and, trust me, I am learning in the process :D

I have found a couple of very interesting pages about the Weber 34 carby:

WEBER rebuild

and, of course:

Rebuilding the Carby

I have also the french 'Revue Technique Automobile' for the CX22TRS and also Haynes manual (which does not cover it but has some info on carbs)

I hope to have some time to work on the car in next weeks...

Regards,

JOSE
 
The 22 Renault 'Douvrin' engine has only come into Australia in a few Citroen private import vehicles however this engine should be covered in the CX series 11 manual on the web site above. Checking the correct position of the cambelt will probably involve ratating the engine to a particular position and putting some 'pins' into special holes in the crankshaft and camshaft pulleys bur this should be covered in the manual.

Another rough way to check is to view the camshaft and rotate the engine until the exhaust and inlet valves one one cylinder are both similarly and slightly depressed. Then check by putting a screwdriver through that spark plug hole and rock the engine slightly that this piston is at top dead centre.

Checking manifold vacuum can also be an indicator.

Good Luck :cheers:

Ken W
 
Hi jose, On the top of the engine, there are lots of rubber vacuum pipes, which go into a black plastic cylinder. Have you checked the condition of those pipes, and cylinder? By now, I expect they will be perished, and need replacing. See the pic, I had to replace all the pipes, and cylinder, as they had all split! john s
 

Attachments

  • CX 22 engine.jpg
    CX 22 engine.jpg
    98.1 KB · Views: 611
smiffy1071 said:
Hi jose, On the top of the engine, there are lots of rubber vacuum pipes, which go into a black plastic cylinder. Have you checked the condition of those pipes, and cylinder? By now, I expect they will be perished, and need replacing. See the pic, I had to replace all the pipes, and cylinder, as they had all split! john s
Click to expand...

Hi John,

Thanks for your reply!. Yes, I have seen all of these pipes and was one thing in the "to do" list :) . In fact, I have been studying a bit about Weber carbs in order to understand how they should work and be able to do some checkings.

Well, now 'only' problem is that I have zero free time :cry: and won't have any until about a week or so... :mad:

I will let you know what I find!

Regards and big thanks :cheers:

JOSE
 
You must log in or register to reply here.
Top