3.2 Carrera UK emissions fail

[sladey]

yep - and it's 3.2 carrera specific

[Nige]

I'd be looking at the Cylinder head temp sender, if the ECU is getting false readings it could be thinking its in permanent warm up mode and be running rich.

Certainly change all service items if unknown history.

The idle control valve just stabilisers the idle when off throttle and isn't adjustable as far as I am aware.

Other than that you're into air leak mode which is easy checked with spraying carb cleaner around the intake joints.

Also worth having the injectors checked/refurbished.

My 3.2 is on 155k unopened miles and has no probs on emissions check, though my MOT guy is a good un.

[Nige]

You can download full service manuals from my link here
https://www.impactbumpers.com/forum/ind ... /#comments

[RobFrost]

Thanks. Downloaded.

[RobFrost]

I'd be looking at the Cylinder head temp sender, if the ECU is getting false readings it could be thinking its in permanent warm up mode and be running rich.

Certainly change all service items if unknown history.

The idle control valve just stabilisers the idle when off throttle and isn't adjustable as far as I am aware.

Other than that you're into air leak mode which is easy checked with spraying carb cleaner around the intake joints.

Also worth having the injectors checked/refurbished.

My 3.2 is on 155k unopened miles and has no probs on emissions check, though my MOT guy is a good un.

Thanks Nigel. Correct me if I'm wrong, but the car ran smoothly for 3 hours from Jersey to Lichfield at good solid motorway speed, and had half a tank of fuel left at the end of it. Do you think that makes it unlikely it's running rich? I imagine bad running and poor fuel economy if it's running rich at all revs.

[Chris_911]

Mine consistently does 29-30 on a run including predominantly motorway.

[RobFrost]

Here's a video of the 3.2 engine hunting at idle:

https://photos.app.goo.gl/yJ1vFK3Eic1p2B6r6

This is a higher mileage car than the 2.2T and it's set up for track use, so it's entirely feasible it could be in worse condition I guess.

Also we have a few mysteries in these photos...

https://photos.app.goo.gl/ZW4iKgoipNTCUhyi8

What's the 6-pin green connector that's not attached to anything (suggestion: it has some aftermarket ECU in place of the original, and this is the original one)

What's the disconnected plug sitting on the manifold with the brown wire and possibly white/black wire? (suggestion: old cylinder head heat sensor wire) It comes from the loom which comes out of the black box in the back left corner, crosses the top of the crankcase and goes towards the back of the engine.

Can anything be deduced from the fragment of polythene tucked between the mating faces of the inlet manifold and the cylinder head? My first thought was that there could be a vacuum leak there nd it's been sucked in. I've pulled most of it out so only a tiny remnant is shown in the extreme close-up. A wider angle shot is included for context.

[Chris_911]

No idea what the green connector is - definitely not something my car has. Aftermarket kit of some sort (alarm?)

Your car has backdated heat (presumably also SSIs fitted?). The connector lying loose on top of the manifold is for the engine fan - removed in your case.

[Chris_911]

The polythene is strange to say the least. It is very easy to pull the inlet manifolds off and replace the gaskets (there are 12). There would have to be a hell of a gap for it to get 'pulled' in there. Perhaps more indicative of some poor quality work in the car's past?

[Fuchs915]

I’m with Chris on this having had hunting at idle on my 3.2. Replace the gaskets (12) and also the plastic spacers (6). As Nige says, spray some carb cleaner at each of the joints between head and manifold. Alternatively, get a smoke machine (I home brewed one) and test for leaks that way.
Good luck.


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[RobFrost]

I’m with Chris on this having had hunting at idle on my 3.2. Replace the gaskets (12) and also the plastic spacers (6). As Nige says, spray some carb cleaner at each of the joints between head and manifold. Alternatively, get a smoke machine (I home brewed one) and test for leaks that way.
Good luck.


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I sprayed some carb cleaner in there are I really was none the wiser regarding whether there was a leak or not. What am I looking for?

[Nige]

Change in engine note. Spray carb cleaner around each intake joint, if the idle speeds rises/smooths out for a few moments then you have a leak.

[RobFrost]

Searching for a vacuum leak I found a perished pipe. This is on the "vacuum limiter", right? Two pics here:

https://photos.app.goo.gl/nna7GWkhfRtXsKTT6

Those clips look crimped. Anyone know what I have to order there in the way of hose and clips, and do those clips just squeeze off? I had a look on design 911 and couldn't identify the hose on the oil diagram. Alternative, temporary solutions I suppose are Gaffa tape, heat shrink insulation.

Also, I squirted carb cleaner on it and there was no change in engine idle whatsoever. So I suspect there's a leak elsewhere.

Also, I removed and tested the ICV and it operates perfectly - however I can't hear it clicking at idle. But the exhaust on this is pretty loud to be fair. If it's not clicking is there anything I can check such as e.g. will removing its leads at idle be informative?

[PeterK]

Those clips are Mikalor (or similar brands) - they're cheap on ebay. Genuine pliers can be spendy, although cheaper alternatives are available. Alternatively, just use the other screw-to-tighten type.

[RobFrost]

Those clips are Mikalor (or similar brands) - they're cheap on ebay. Genuine pliers can be spendy, although cheaper alternatives are available. Alternatively, just use the other screw-to-tighten type.

are they removeable? Squeeze the sticky-out bit with pliers?