I need some ideas

[pelopelirrojo]

OK. So my CX broke down last year, around August time. It's a series 1 pallas 2.4 auto.

It is still broken. Since August it has been into a garage twice (Citroen specialist), had a mobile mechanic (Citroen experienced) work on it and been looked at by 3 AA men.

The work so far is as follows:

New battery, new dizzy cap & rotor arm, new plugs & leads, new fuel filter, new air filter, tappets adjusted, oil & filter change, fuel tank drained & cleaned, fuel lines cleaned, ignition circuit checked, all hoses & pipes checked - any leaks fixed, electrical cables inspected and any suspect connections replaced & sealed.

Symptoms are: Starts OK, runs for 3 to 5 seconds, dies. If you press the throttle within this time it dies immediately. After it stops it restarts OK immediately and then dies again after 3 to 5 seconds. During cranking battery volts drop to 10.5, when running they peak at 12.5 before it cuts out again. I can keep restarting to pressurise the hydraulics and get the car to the full high position with the pump clicking off eventually with numerous restarts & runs of 3 to 5 seconds.

I need some more ideas of where to look next. If you have any please let me know.

Thanks,

Paul.

[Citroening]

Sorry to hear that you're still having trouble with CLEY Paul. Am I right in thinking that CLEY's got a plastic plenum chamber? Even a small pinprick in these can cause running issues...

A common mod is to either fit a good known replacement, or source a metal one that doesn't suffer from the problems at all.

[DickieG]

Has an exhaust analyser been plugged into the exhaust? If so what readings are you getting? I'd suspect an air leak on the inlet side either from a vacuum hose or a poor seal on the inlet manifold between the manifold/cylinder head or manifold/carb. I say this working on the principle that when starting fuel is drawn into the carb prior to it starting then once it fires up the mixture weakens excessively due to an air leak. Once it starts listen carefully for a hiss, if one is heard use a length of hose to pinpoint the source.

Does the car have a manual choke?

Has the float chamber in the carb been checked?

Failing that obviously swapping the carb would be handy to eliminate that, even if you can't easily source the correct one anything that fits would do in order to eliminate the present carb, also don't assume that because you have fitted a new part that it's working correctly,,,,

[Citroening]

Good advice Richard, however CLEY (Paul's CX) is an Injection...



I'm pretty sure it'll be the plenum chamber - we had a similarish problem with a 2500 IE a couple of months back and the plastic plenum was the culpit...

[DickieG]

OK similar principle with air leaks, do you know what make/version of injection is fitted?

[Citroening]

I have a feeling that they have the Bosch L-Jetronic system...

[pelopelirrojo]

I'm pretty sure it has a metal plenum, I remember seeing a collapsed plastic one in a photo last year and checking - if you look closely at the engine bay photo you can see a couple of metallic glints on the plenum.(Franklin, I don't believe you still have this photo!!)

The garage that had it went through the air intake system and found some air leaks which were fixed. It's possible that another could have developed or one of the original leaks come back.

I don't think it has had an exhaust gas check though. That's something I can arrange. And that should confirm the mixture & air leak? Thanks for the suggestions and replies.

At times I wish it did have a carb & normal points dizzy. So much simpler to fix! Bosch L-jetronic I think.

[DickieG]

If it's 'L' Jetronic then the airflow meter is the thing to look for and in particular the bearing that allows the flap to swing. If the engine has had a misfire/backfired it can cause the flap to pop out of the bearing and then prevent the flap moving freely.

The other thing to check will be the resistance on the airflow meter electric connector, as there can be wear between the windings and the track arm.

Both of the above issues can cause the symptoms mentioned, starts, runs briefly then stops.

[pelopelirrojo]

Thanks Dickie.

I'll check these out at the weekend.

[DickieG]

If you remove the large rubber trunking connected to the airflow meter that will give you access to the flap which should move/swing quite freely, if you see any marks of scoring on the surface where the flap swings the airflow meter needs replacing.

I'll have a look though my diagnostic books to see if I can find tests relevant for your car as to what pins you need to connect up an OHM meter to, the resistance you're reading isn't generally important it's that the resistance reading flows in one continuous flow without spikes.

[jonwend]

It does sound like an air leak but wouldn't it have to be pretty major to cause these symptoms?

I am sure there are a lot more knowledgeable people than me out there who will offer you some help and correct me if I am going down the wrong path, but I assume you know that the injectors are actually injecting? Your car has a cold start injector which squirts a bit of extra fuel into the inlet manifold for a few seconds when the engine is cold. What if this was the only bit of fuel the engine was getting?

As I say, probably a red herring from me

[jonwend]

Taking my herring for a walk around the park now (LOL) doesn't the injection relay (big blue) have a specific output to power the main injectors but not the cold start one? Have you checked the connections or substituted this relay?

I see there have been some suggestions above so if you want to substitute bits (I have a spare big blue, AFM, etc) then just let me know and I can bring them over one evening.

[pelopelirrojo]

Update: I took the concertina hose off and checked for splits, cracks etc. None.

I disconnected the cold start injector connector. No effect.

Removed & checked all the air intake pipes. dizzy vac advance pipe, breathers etc. No leaks cracks etc.

Checked airflow meter flap. Moves fine and switches on the fuel pump when operated.

It wont start at all if you press the accelerator down whilst turning it over.

So, I turned in the idle screw all the way. Starts and idles at 500rpm for 3 - 5 seconds then stops.

Unwound idle screw fully out. Car starts revs up to 2000rpm over 3 - 5 seconds then stops. Now, by opening the idle screw I have increased the air going in and it responded by revving higher not dying more quickly. This suggests that excess air is not the cause. I also got smoke out of the exhaust.

When I tried to start it with the idle fully out and the accelerator pressed it wont start it coughs and splutters a lot but wont catch.

At any time if you press the accelerator when it is running it dies immediately.

I am thinking this is more like excess fuelling not excess air.

That's as far as I got before the battery had had enough and I put it back on charge and went in.

[pelopelirrojo]

Fixed.

Faulty air flow meter. Incorrect resistance values.

At some point I will open it up and find the exact reason why.

Braggs of Briston had a spare AFM which they fitted and it fired up immediately.

Just the MOT to get through now. Unfortunately a list of corroded pipes, chassis corrossion, a ball joint & a track rod end.

[Northern_Mike]

I only read this post today, but I had exactly the same symptoms on my MX-5 last week when I broke the Air Flow Meter when diagnosing another fault..