CX GTI Turbo. Thinking caps on!

[Bilkob]

I am the lucky owner of a series 2, Turbo 1 (non intercooled) GTI Turbo. The car had been stored for several years before I got it and over the last 10 or so months I've been slowly-or sometimes very quickly! bringing it back to life
Lots of jobs done and it's now going rather well.
However, it has one rather annoying problem. When hot, ie fully up to operating temp, if left idling it will start to splutter and then cut out. This takes about 5 minutes to manifest itself.
If you catch it JUST before it dies and blip the throttle, it's ok........
It is NOT any of the following
Crank sensors-replaced with Ford items
Either of the 'ECUs'
Overheating
Fuel pump
Idle control valve SEEMS fine, as in it's clean and the little disc inside moves freely
SO, I think I'm down to Fuel pressure regulator. Throttle position sensor. Knock sensor(?). Overheating wiring somewhere. Or a Ghost!
I'd WELCOME any thoughts/wisdom

[Peter.N.]

Mmm, Lovely cars I had a diesel one for some years, can't help you with yours I'm afraid. The last petrol vehicle I had used a carburetor and distributor.

Peter

[RichardW]

David Hallworth had similar trouble with his... in his blog, starting on this page: https://www.frenchcarforum.co.uk/forum/ ... start=1455

[Zelandeth]

Ignition coil breaking down as it warms up?

[Bilkob]

It COULD be.......but they are good replacement coils (Stan)
My gut feeling is either airflow meter, or fuel pressure regulator or cylinder head temp sender
Interestingly, when I swapped the ignition AEI unit for another one, it ran like s*€t and had less grunt......odd!
The car will happily cruise at legal, and perhaps other speeds for several hours, it's only when hot and idling it's an issue
It'll idle from cold start all the way up to when fans kick in with no issues at all

[white exec]

It's not idling badly only when the fans are running is it?
Thinking big (twin fans?) extra load on the alternator at idle speed, and maybe a voltage taking a dive somewhere.

On another tack - fuel vapour lock in the hot engine compartment? Pouring cold water over exposed fuel lines/pump etc can sometimes tell you something.

[Bilkob]

Thanks for replies..
No, it idles absolutely fine, hot or cold until it dies and it runs, pulls and drives really nicely, at all times, under load, etc, until left idling when warm
I think my next elimination will be fuel pressure regulator
Anyone know the part number?

[xantia_v6]

If it has a separate ignition amplifier driving the coils(s), I would suspect that. Also think about the condition of the spark plug leads.
Does the idle RPM drop before it stumbles?
You might leave it to stop and then pull a spark plug to see if the colour looks normal.

[Bilkob]

I'm pretty sure there's no amplifier, and no, no rpm drop, just a splutter and legs in the air!
I think my next obvious course of action is to get it to cut out, then pull a plug lead and check for spark

[aerodynamica]

Hi, sorry to hear of your woes! It might be worth checking the fuel pump double relay in case it is having a little fit and cutting the fuel supply as that's the only thing that I can think of that would cause a sudden stop. If the ignition coils were faulting out I think it would run on two cylinders, rough as a bag of spanners, before cutting out because one coil supplies spark plug 1 and 3 and the other does 2 and 4.
Could also be power to something major is cutting (like fuel relay) but I also recall a CX 25i (similar) story where the engine cut out mysteriously and it was caused by the steering column grazing the big bunch of keys the chap had on the ignition and tugging it when he turned left.... So I'd give the ignition key a prod or two to see it that upsets it because you never know!

[Bilkob]

My woes aren't too bad, but thanks for concern!
It's not dangling keys
I've checked big blue and the other fuel relay, but could still be them I guess, they now live out of harms way, covered in grease and WD.....
I will try a spark plug test in next few days
Also, I did check fuel pressure regulator by gently poking a small Allen key down hole on top. It was rock hard, I'm guessing that's not correct??!!

[Timmo]

I am utterly unable to help as know nothing of cx's, and little of engine electricals, But does it start back up fine after its splutter?
The only reason I ask is back when I redid my head on the bx 16v i fitted a new cap, plugs, arm etc. Ran Beautifully up until it got hot, then spluttered and died, only way it would start was to let it cool, then repeat the process, after much head scratching, retiming, checking, i put the old cap on and it ran perfectly for the next 5 years till i laid it up, i was adamant it wasn't the cap as it was New, said cap went to another mi engine and ran faultlessly, that brand and mine didn't get on!

[wurlycorner]

Argh, I feel your pain - things like this are a nightmare to diagnose on a CX
And then you get one like my T2, where you open the bonnet, see that all the vacuum lines are shot (split/hanging off) and yet the engine runs absolutely spot on

For yours, I definitely think this is a heat soak problem.
Question - does this only happen when the car is being driven, or also when warmed up at idle?
If the latter, does it make any difference if it is warmed up with the bonnet open? (does the problem not manifest itself if bonnet left open?)

[Bilkob]

OK. I've made some discoveries! It SEEMS THAT with the bonnet open, the car will idle for ever, and with it shut, it cuts out!
All the same symptoms as before, so it MUST BE heat soak/ build up.....
I did try and whip a plug out and crank it after it died, but it started straight up again, on 3!
Fuel starvation?
Still perhaps coils overheating?
After it cuts out, it's still got loads of turning power for starter so it can't be battery/voltage can it??
Am I missing something obvious??
Keep the answers coming please!

[Hell Razor5543]

I wonder if the bonnet (when it is closed) is pinching a pipe, causing some form of starvation?