EML, emissions, injured Cat...

[Geoff1951]

Hello again chaps. I've a '54 plate 2.3t auto Vector, Hirsched, 105k on the clock. Practically everything's been done over the past few years - throttle body, turbo and sump drop, DI cassette, and most recently the CPS and leaking head gasket.

Everything's been fine for the last 4k, then yesterday the EML came on and stayed on. No loss of power, no change in engine behaviour, cruise control still operative, and no alarm bells other than EML. Took it to my local indy (not a SAAB specialist per se, but certainly an engine specialist, and I've known them for 15 years plus) who ran their diagnostic and say it shows "emissions outside normal parameters". (I haven't got ready access to January's MOT but IIRC the emissions were close to legal limits.) The indy said one cause could be the cat is possibly damaged and failing, possibly helped by the gradual burning off of coolant over a few weeks when the gasket was developing its fault and also the passing of unburnt fuel when it wouldn't hot-start when the CPS was similarly playing up. They found no other issues, the Lambda sensors were checked and found OK. They cleared the EML and said bring it back if/when it recurs. It uses no oil between services.

I'm happy with their judgement but would appreciate any observations. TIA.

[sgould]

There's so much that could be out, that I would think it worth getting to a Saab man and getting the actual codes.  It's £30 or so for a code against a few hundred wasted if it's not the cat.

If it is the cat, then i would consider upping the downpipe size and putting in a sport cat.

[Audax]

If you have a Tech-2 you can run a CAT test which will tell you if the CAT is failing or not. You can also observe the behaviour of the lambdas with Tech-2, how did they test the lambda sensors? If anything I'd consider a secondhand genuine Saab CAT if it turns out to be failing.

[Geoff1951]

Thanks gents.
Done 600 miles since the post, 15 mile traffic jam, much town centre crawling and lots of M-way fast travel included. No recurrence but will get it checked again before spending big money.

I've never had reason to question their judgement in the past - they know all about the vagaries of the cassette, resetting the throttle body, etc, etc, etc... and I'm sure the chap they put on my car used to work for a main dealer a few years back.



(As an aside, just seen the August "Which?" and in an admittedly small field the 9-5 beat Audi, Merc, Lexus and Jag for reliability in the older exec class. And came out top of everything for comfort.)

[Audax]

I've never had reason to question their judgement in the past - they know all about the vagaries of the cassette, resetting the throttle body, etc, etc, etc... and I'm sure the chap they put on my car used to work for a main dealer a few years back.

That makes a huge difference if they have someone on the staff who knows Saab, but part of the trouble is without Tech-2 you might end up having to guess and with a possible cat problem even with Tech-2 it can still be uncertain, if the problem comes back you could try a bottle of the cat cleaner that was referenced on here recently, it probably won't work but it's a cheap thing to try out of desperation although after 600 miles I'd suspect it isn't coming back any time soon, could have even been a dodgy batch of fuel possibly?

The main issue I've come across with garages that do all makes is that they apply experience from other makes of car to a Saab and it just doesn't work (just as applying Saab principles to other cars doesn't), it especially doesn't help when many of them say "but it's the same as a Vauxhall" and end up doing the wrong thing.

[Geoff1951]

Thanks Audax. Will check the fuel situation. The last tankful was BP, I've been using Shell for a few years now, with the odd fill of Sainsbury's (around one in 20). Just filled up with £90's worth of Shell.

Though I live near the "Home of the Astra", my chaps definitely know the difference. Not one of the dozen who work at the indy would touch a Vauxhall.

[Petemate]

Given that nothing is good for passing through a cat, be it unburnt fuel or even gasket sealant (highly recommended in all the workshop manuals I have read not to use any at all pre-cat) it would appear that the cat has suffered, but as said better to check first due to expense. Bet it is though! 

[Geoff1951]

I know what I'd like to pass through next door's cat. Bstrd keeps cr@pping on my lawn.

Back on topic. Done around 500 miles since first occurrence. Around 300 miles in, the EML came on again. Went off after about 20 miles on its own accord. Didn't know it could do that without pulling F17 or some other action. Realised the common factor in both occurrences was that I'd been on cruise at a steady 60 for around three miles. Think I'll avoid such low speeds from now on.

[Audax]

The light can go off for certain fault conditions if they clear, you should still be able to read the code so it may be worth doing if you have a code reader and then reset it again to see if it happens again?

[TomPaine]

I know what I'd like to pass through next door's cat. Bstrd keeps cr@pping on my lawn.

(Tangent: are you sure it's a cat? I nourished the same feelings towards neighbouring cats - I still do tbh, but with less reason - until I realised the cr@p on the lawn was from hedgehogs.)

[Geoff1951]

Tom - I know it's catsh!t, I've seen it in action... the only hedgehogs we see are too small to drop the stuff we find. We also get squirrels burying nuts, then doubling the damage by trying to find them. And the lawn's been so wet I haven't been able to mow it much, so the ones they don't find have time to produce saplings. I'm growing my own oak forest.  Oh, nearly forgot the fox sh1t which we also get now and again. All in a suburban garden.

Audax, thanks for that. Due for a couple of tyres soon so will get my chaps to check the computer again then.