Last chance saloon

[7 Seat Sports Car]

The ETM was from Volvo around 5 ish years ago. They programmed it too so I know it's legit. And the car has been fine up to the point of new cat. Literally no fault codes since then other than rear glass sensor and alarm siren battery.

Running rich is, I believe, permanent but codes come along once closed loop adaptations start to take over and max out. I'm not sure about higher loads but I've lost 50 to 100 miles per tank so I'd hazard a guess it's overfueling across the whole range strengthening my theory.

When it gets overwhelmed I can see maf climb to between 17 & 20 kg/hr and injector pulse goes up to 2.6/2.7ms. This is all being done with no inputs from me. It just does it, then all of a sudden it'll spit a code out and settle back down to figures in original post.


I'm happy to keep testing but I don't believe I have the experience to connect everything I'm seeing to the underlying fault hence why I'm asking all you gurus.

Thanks everyone for your time so far. Any ideas on how/what to test are appreciated.

Drew

[4x4]

Have you done a smoke test for vacuum leaks?

[7 Seat Sports Car]

Originally Posted by 4x4

Have you done a smoke test for vacuum leaks?

I haven't as I believed my prior testing of all the individual bits was sufficient. I've spent cumulatively well over a month's worth of my time into checking whatever I can and I've also pumped loads of money into parts for this so far and any more added to it robs the pot for a replacement car which is looking extremely likely. That's not an hour here or there over a month, that's a month's worth of full days under the bonnet looking for clues and trying to figure out what conditions are required and how the fault manifests itself. Trying to distil all this into a forum thread is hard.

I know it's not the most professional of approaches but I'm reasonably confident I can check stuff out without a full garage worth of bespoke test equipment. I have to justify anything I spend now.

[SteveSarre]

Hi Drew

Obviously I haven't spent as much time thinking about this as you, but to me, I think it would be worth measuring the pressure at the fuel rail.

The fuel pressure regulator is not a sensor, so you can only know that it is correct by measuring it.
Wild guess - if all the various sensors are working correctly then high fuel pressure would cause too much fuel to be injected by the injectors, and then fuel trims would be adjusted. Maybe they can only be adjusted so far, then the ECM gives up and assumes that one of the O2 sensors is bad?

Another guess - I think a major air leak (not a vacuum leak) between the turbo/intercooler/ETM would mean that less air was entering the intake manifold than the ECM would expect (based on the MAF). So then the mixture would be rich (which would then trigger compensation). Hopefully you would see this by inspection of the hoses and connections.

Hope that helps,

Steve

[SteveSarre]

https://www.pelicanparts.com/techart...sure%20testing

[7 Seat Sports Car]

Shortly after getting the car in 2010 the plastic barb going into the fuel regulator block snapped during a filter change and was effectively bypassed since then so max pump output at the rail for over a decade without issue. I fitted a regulator in order to rule pressure out. I had a new fuel pump in a box and fitted it early on in this saga. No change in symptoms. I also had a spare set of clean injectors and tested them for leakage and spray pattern into a clean jar. All good here too.

All charge air pipes from maf to manifold have off and on so many times that I'd be surprised if one was loose after every visit. I've sprayed oodles of contact cleaner over every joint, clip etc and no change in engine note at any time.

Checked timing belt and pulleys at least twice too. Everything lines up sweet.

[Baffler]

Originally Posted by 7 Seat Sports Car

And the car has been fine up to the point of new cat.

From what I can see you have basically answered your own question. That aftermarket CAT probably has a lower flow rate than the original and is smothering/restricting the engine. That'll surely throw out all your sensors.

I would be trying to source a second hand genuine CAT from a C70 2.4T or T5 up to 2005. Perhaps try Carl Sabin...I think he's on FB and or Gumtree.

Alternatively, maybe have a straight through pipe made up to see if things return to normal. I'd certainly be getting that aftermarket CAT off as a next step.

[SteveSarre]

Hi Drew,

I am intending to break a 2001 C70 2.4T auto which has a known good cat (although the car has been sitting for a while now).

It has a 5244T or a 5254T engine - not sure which - how can I tell?

The VIN is YV1NC56K92J026062

Car is in Hampshire and is SORN non runner (radiator, headlights, ETM and some other parts have been removed).

Baffler, why do you suggest a C70 as a possible source? Is it just that V70 cats are becoming hard to find?

Steve

[4x4]

Originally Posted by SteveSarre

Hi Drew,


It has a 5244T or a 5254T engine - not sure which - how can I tell?

The VIN is YV1NC56K92J026062

[Baffler]

Originally Posted by SteveSarre

Baffler, why do you suggest a C70 as a possible source? Is it just that V70 cats are becoming hard to find?

As you know, Steve, the S/V70 finished their production run around 2000 with the C70 convertible continuing for another 5 years. The chances of finding a good/tidy second hand CAT on a turbocharged S/V70 are very slim so Drew's search might be more fruitful by spending his time chasing 2.4T & T5 C70s. Plus the C70 tend to be, not all, in better overall condition underneath.