Xantia V6 broken exhaust (update: and rough low rpm running)

[addo]

Exactly that sort of vernacular. I've had a massive week at work (including being run into by a Mazda-driving nice Jewish girl who is also a bikini model ), so the casual lingo is probably flowing more than other times.

[CitroJim]

We could have done with you last weekend Adam.. I'm sure you could have assisted us greatly with some good Aussie vernacular which would have helped the job along enormously...

As it was we had to do with what we had. Good old British stuff...

We didn't half get through some... The RX-8 is enough to make a saint swear...

[Hell Razor5543]

Just a thought re XM exhausts, wasn't there a recent post for stainless steel exhausts for Xantias? I wonder if the same person could query his supplier if they could manufacture an XM stainless steel exhaust?

[CitroJim]

Just a thought re XM exhausts, wasn't there a recent post for stainless steel exhausts for Xantias? I wonder if the same person could query his supplier if they could manufacture an XM stainless steel exhaust?

I'm sure they can James but he'll need the car to fit it and get the pattern right... He the might sell another say, 6 or 7..

I had a close look at mine when it was up on the ramp today. It's funny old thing... Single pipe from the cat to silencer box a foot or so along then twin pipes which merge into one just before the transverse silencer and then a back box and tailpipes connected to the transverse box..

They always fail on the 2 into 1 just before the transverse box..

It is a most bizarre system as most things XM are... It's one of the joys of XM...

[Mandrake]

Thought I would post some amusing Lexia fault codes that occurred after the injector testing etc that I did last weekend. During the injector testing I actually managed to run the battery flat (!) and had to put it on a trickle charger overnight, Yes, running the fuel pump (and other accessories) repeatedly does draw a lot of current... after I was finished I ran the Lexia to see what fault codes existed and found the following:

A low battery voltage warning. Fair enough - I did run the battery down, but curious that the airbag ECU was the one that logged it. I suppose any ECU could have since they all run off the battery...

The next one was a bit odd though:

Intermittent fault fuel system - fair enough, as well as testing the injectors manually I was deliberately running it out of fuel by running the engine then removing the fuel pump fuse to bleed the fuel rail to make connecting my gauge to the fuel rail a bit safer, but hang on a second, why did the Hydractive ECU log this fault ? How on earth would the Hydractive ECU detect a fuel system fault when it is not connected to or monitoring any part of the fuel system ? For that matter as far as I know even the engine ECU doesn't monitor the fuel rail pressure. So I'm completely baffled as to how this fault was logged...

The final one is an old favourite:

Intermittent engine speed sensor fault logged by the gearbox ECU. I still don't know what's causing this, it was present when I first got the car, went away for a few months then came back again recently. I've got a feeling that some of my diagnostic procedures are triggering it, perhaps even letting the car stall due to fuel starvation during my testing. I can't imagine that the actual engine speed sensor is faulty as the engine ECU has never complained about it.

[addo]

By "fuel" for the suspension it means supply of LHM at acceptable pressure.

To show 11.2V on the battery suggests it is not in good health unless you really did run it low.

Alternator faults are "upstream" BTW and don't usually show as fault codes that relate to reliable supply of 12.7-14V. Shame it's a bugger to get to as you might otherwise look at your charging output on a scope.

[Mandrake]

Not sure I buy the fuel equals LHM pressure suggestion, the french are weird, but not that werid. I also don't think the Hydractive ECU has any data fed to it from the priority valve pressure switch. I've read the Hydractive training manual cover to cover several times and never seen any mention of it monitoring hydraulic pressure, nor any electrical connection on the pinouts that might allow such monitoring, so I'm still a bit amused and baffled by it...

I ran the battery a lot lower than 11.4v I'm afraid. The fuel pump is over 10 amps by itself and that was run probably a few dozen times with the engine off as I checked each injector multiple times as I refined my test procedure to make sure I was getting consistent results.

I also tested each injector a maximum of twice before starting the engine to clear any fuel out to prevent hydrolocking the engine, so there were quite a few engine starts with only a few seconds of running time that wouldn't have helped either.

The battery going flat seemed quite abrupt, only 15 minutes after the last time I started the engine apparently normally all I got was a click from the starter solenoid with dashboard dimming, I checked the battery voltage and it was 9.4v. So that was the end of the testing for that day. By the time I'd carried the battery up to the house it had recovered to over 11v but it took about 8-10 hours on a trickle charger to fully charge it, and it has been fine since.

I don't think theres any problems with the battery (which was new shortly before I got the car) or the charging system which I've checked before. This is the first time its ever gone down to the point where it won't start even though I sometimes leave the car as much as a week between starts.

[xantia_v6]

I think the fuel system error is the throttle potentiometer (on the pedal). Disconnect it and see if the fault becomes permanent.

[Mandrake]

I'm not sure that it is actually, there are a couple of codes specifically for the Hydractive ECU throttle position sensor on the accelerator pedal. Just a few weeks ago the Hydractive ECU logged "Intermittent fault - Incorrect accelerator pedal adjustment" for the first time, and from memory there is also a similar fault code specifically for a faulty accelerator pedal sensor, so I think the fuel system error is still a mystery, and was probably just triggered by the various tests I was running on the car.

I've noticed before for example that performing a tachometer actuator test on the engine ECU (which lifts the tacho to 1500 rpm for a few seconds while the engine is off) causes a faulty engine speed sensor fault to be logged by the gearbox! I guess it gets confused by the fact that the engine is reporting 1500rpm yet the gearbox knows its torque converter output is not turning despite being in neutral...(and thus fails a basic coherency check)

[CitroJim]

I'm wondering if it's a corrupt error code that the Lexia tries to interpret the best it can...

And during intensive testing of the like you've been doing there;s every opportunity for a few rogue ones..

I think you’re trying to over-think this Simon

If I see bizarre codes, which I do occasionally, I just clear them and if they don't come back I'm happy...

[Chris570]

I think you’re trying to over-think this Simon

What he said.

My XM had the same code when i first started it up following the gearbox rebuild. I cleared it, it hasnt come back, I put it down to the fact i was buggering with the wiring at the time, and as others have said it really will have nothing to do with fuel as engine fuel. Addo or Mike or Jim could be right but all you need to do to eliminate it is look at the wiring diagram and see that the hydractive ecu can in no way sense petrol pressure

[addo]

It's every man's right to have babies if he wants them.

[Chris570]

It's every man's right to have babies if he wants them.

Thanks Loretta, will you be keeping them in a box?

[addo]

Rats! Spotted before it caused a "What the ..." moment.

Lexia in English has some funny turns of phrase; for example "Return" doesn't mean click the return button. That's why by fuel, I believe it refers to feed pressure (probably originally described as pression d'alimentation; easy to mis-translate) within the hydraulic lines - in other words, the binary switch that triggers when latent pressure is too low.

[Mandrake]

Yes there are some amusing translation errors in the Lexia software that confuse the meaning of what they're saying, such as the "press return to continue" messages where pressing return does nothing and its F9 that you're expected to press to go back...

It always baffles me how products that are made in non English speaking countries are almost always translated to English by non-native English speakers of those countries. I mean, really ? How much does it cost to hire a native English speaker to proof read your documentation / instruction manual, whatever ? Even just proofreading by emailing it over the internet and back ? You don't have to fly them over to your country to proof read a user manual...

I can sort of excuse it for a specialty product like a Lexia which was never intended for a wide audience, but when you buy a brand new TV and there are hilarious goof ups in the spelling, wording and grammar that make it look like a demented 5 year old wrote it it amazes me that they don't see just how poorly it reflects on their product and company. Ok, rant over.

Back on topic again - while I'll take your word for it regarding the mis-translation to the word fuel (it's obviously not meant to be fuel) show me where the Hydractive ECU has any connection to the low hydraulic pressure switch, or indeed how that switch is connected to anything other than the warning light on the dashboard. (And warning buzzer for you pour souls in Aussie... )

BTW Jim et al who think I'm over thinking this fuel warning message I want to point out that I'm not in the slightest bit worried by it, its just I'm the curious sort and found it rather amusing, that's all. I'm certainly not losing any sleep over it.