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

[Ben82]

So in the faults it logs whether the TC is in lockup or not... but is not something you can actively monitor in Lexia? how bizarre is that! (not very with the way PSA are )

SEDRE DIagrams... these are for Electronic Injection: " onclick="window.open(this.href);return false; (remember to download the album to be able to see them ) However I can't seem to see the crank sensor , and not sure what else it'll be under? if you have any ideas, I'll be happy to check.

[Mandrake]

So in the faults it logs whether the TC is in lockup or not... but is not something you can actively monitor in Lexia? how bizarre is that! (not very with the way PSA are )

You can actively monitor the torque converter lockup on mine Ben, its in one of the parameters measurement screens - the one that shows the engine rpm, (torque converter input) "gearbox input" rpm (torque converter output) and "gearbox output" rpm. (differential / road speed)

On that page it says "lock up" - open, piloted or firm. Open means unlocked, piloted means controlled/limited slip mode (about 50 rpm regulated slip) and firm means full lockup.

It's important to note though that the open/piloted/firm status is not actually the desired mode that the ECU is trying to achieve, its simply based on the amount of measured slip. Less than 50 rpm of slip it says firm, 50 rpm to maybe 100 rpm it says piloted, more than 100 rpm it says open, all regardless of what the ECU is actually trying to achieve.

To see what the ECU's "intention" is you need to look at the EDS3 (from memory) electrovalve under pressures to see how much current is flowing. minimum current means the ECU wants it open, maximum current means the ECU wants it locked up, some intermediate value means its trying to regulate the controlled slip mode.

SEDRE DIagrams... these are for Electronic Injection: " onclick="window.open(this.href);return false; (remember to download the album to be able to see them ) However I can't seem to see the crank sensor , and not sure what else it'll be under? if you have any ideas, I'll be happy to check.

They may not call it crank speed sensor. It might be called engine speed sensor ? It's down behind the back of the engine between the engine and gearbox somewhere, possibly accessible from underneath with the car on ramps, but I'm not sure what the wiring route is from the sensor to the ECU or where the connector is.

Edit: the engine speed sensor is item 1313 on your diagram.

[Mandrake]

Today I fixed my mistake in the fuse box wiring for the starter relay modification, I had accidentally tapped into the feed going to the engine ECU to supply the additional relay, thus the starter helper relay was running off the ECU fuse F2. Its been working fine for 9 months but when I discovered my mistake I was unhappy to leave it like this.

Also I had a 3 way spade junction of hell connected in series with the feed to the ECU as a tap so I was worried there could be an intermittent connection there.

Mike (superloopy) pointed out to me there is a perfect place to get a power feed for the relay, I'm rather embarrassed I didn't discover it myself during the initial modification. When you lift the fuse tray out there is a hatch at the front, and opening it reveals a bus bar with a terminal coming directly from the battery terminal and a spare terminal just waiting to be used! The red wire on the right is the one that I've added to supply the starter helper relay, so anyone else doing the starter mod, get your power from here, elegant and tidy:



I then had to sort out the wire to the white plug that connects to the ECU - there was only a short stub of about 25mm that then went to the spade connector I added, the idea was to remove the spade connectors and use an insulated crimped butt joint to join them back together, however the amount of wire left was very short and I was unsuccessful at getting a good crimp within the cramped working environment.

I know I'll probably get told off for doing this, but I resorted to a soldered joint. I cut the sleeve off a butt connector and used the tube as something to solder onto with a fillet joint between wire and tube at each end:



I then slipped the original butt connector insulating sleeve back over it and for good measure heat shrinked over that too:



Not ideal but I think it should be very reliable, certainly more reliable than the spade connectors that were there before.

Did any of this make any difference to the running problems ? Apparently not as it was misbehaving again afterwards, but I'm glad I sorted out the wiring and got things put back to where they should be!

The next thing I checked was I put my scope on the crank sensor signal at the ECU connector and in the few minutes that I was testing it, it seemed fine. The amplitude is far higher than I was expecting, about 8 volts peak to peak at idle in fact! I didn't think to take a photo of the waveform, but it looks like a slightly kinked triangle wave with the tips rounded off. Every dozen or so pulses there is one missing to key the location of the flywheel.

So, couldn't find anything wrong there...and there's no camshaft sensor on this engine as its a waste spark system.

I then checked the knock sensor. Hitting the top of the inlet manifold at the mounting bolts, or cam box in front of the plastic top cover with a tyre lever produces a damped oscillation of about 50mV peak to peak. With the engine idling there is a small amount of what looks like white noise on the order of 20mV or so, which does increase a bit with engine rpm, but even at 2000-3000 rpm (under no load, mind) the noise is less than 50mV. If I hit the inlet manifold while the engine is running at 2000 rpm you can hear the rpm drop away a bit as the ECU retards the timing.

So, I couldn't find anything wrong there either, although I wasn't testing it under load. It would be interesting to monitor it during driving.

Next thing I did was to check the voltage waveform on the injectors - this too looked perfectly normal on all three, exactly as the example waveforms in Scanner Danners videos look, so can't see anything wrong there either, although again, not tested under load.

I was going to check the coil primaries but didn't because I can't back probe the connector and didn't want to go stabbing the wires.

After doing all this I went for a drive and the car was misbehaving... What I did notice with the Lexia is that once again under wide throttle, especially below 2500rpm it was more often than not staying on a lean reading... which means its either genuinely lean due to fuel starvation, or a misfire is causing a false lean reading...

If it is running lean from fuel starvation the lean mixture would cause the engine to ping under load and lead to the knock sensor retarding the timing - so it does make sense given previous symptoms and troubleshooting.

So, how do I tell if I have an ignition related misfire (remember my new coil pack crapped out and I'm back on the original 15 year old one) or whether I have a fuel starvation problem. (The fuel pump was showing only 60% of the rated delivery when tested, and was intermittently quite noisy for a while, although that noise has stopped)

Perhaps I do need to get that pump out and check the pickup mesh...

[lexi]

I would pop that collet out with a home made tool and stroke any possible red herring out. It is one of the possibles for modern and classic cars alike.........choked tank ..........or choked banjo.

There is 18mm birch ply here to cut a circle........or I could cut a disc in steel with plasma cutter. then weld 3 prongs on and 1/2" socket on top. You would need to make a cardboard template, with holes where the prongs are going. Has anyone tried tapping that collet round with a soft hammer and wooden dowel?

[xantos]

1) Runs a lot better immediately after resetting the ECU, but then deteriorates with driving, sometimes minutes, sometimes hours of driving time.

2) Runs a lot better if its left to idle for a while before driving, especially if the ECU has just been reset. Runs much worse if driven away quickly after a cold start, and continues to run poorly for the rest of the trip.

3) Performance only ever gets worse the more you drive it in a given driving session, never better. If it starts off bad it stays bad. If it starts off good it typically gets worse. The only variation is how quickly it gets worse.

Given that the ECU reset restores normal performance immediately, suggests to me that the adaptive behaviour of the ECU is learning from "bad" data.

Didn't read the whole story but something caught my eye.

I remember on my previous car (Hyundai Accent; year 1995) that it had similar symptoms. It was running ok for a few miles or a few hundred miles then it started to misfire. I just had to switched of ignition and then back again and it was fine for a few miles or a few hundred miles... There was something wrong with the injectors and had them replaced and afterwards it was fine.

[lexi]

Just looking at all these fancy sprays. They should have one for diesels that you spray on called





SHUT UP YA BASS!!

[Stempy]

[Mandrake]

I think either me or this car must be jinxed...

While tinkering with the cruise control today I put the Lexia on and saw my old friend the "intermittent oxygen sensor open circuit" fault appear again, for possibly the 3rd or 4th time since I replaced the oxygen sensor only a few months ago..

So I watched the parameters measurement and started it up to let it idle. On a good oxygen sensor it should be warmed up and swinging between 0.1 and 0.9 volts in about 60 to 90 seconds at most.

I left it nearly 5 minutes and the best it could do was 400 to 500mV. Faulty! I fiddled with the wiring near the connector, disconnected and reconnected it, very little change. There was a small response but not much.

I then held the RPM at 2000 for a minute or two - even if the heater circuit is faulty the higher engine speed should warm up the oxygen sensor through the exhaust gases, but there was no improvement which suggests its the signal wire that is open circuit not the heater.

I checked the voltage on the oxygen sensor connector - 13.8 volts on the heater wires and the 0.45 volt bias voltage on the signal wires, so the harness connection is fine.

I reset the ECU and took it for a quick drive with the oxygen sensor unplugged to see what would happen - the intermittent hesitation was greatly reduced but there was still quite a lack of power so I think this intermittent oxygen sensor is just another problem on top of the main problem, whatever it is!

When I got back I plugged the oxygen sensor in again and tested it - what do you know, its working again, swinging between 0.2 and 0.8 volts... so whatever the problem is (broken wire ?) it's intermittent. Great, another intermittent fault is just what I need!

I'm getting rather sick of new parts failing on me, I've now had a completely DOA map sensor that I had to send back, a new OEM brand coil pack that lasted 9 months then failed, and now an oxygen sensor that's become intermittent to the point of near failure in only 6 months! It's not a £20 generic O2 sensor either, its a £65 genuine OEM Bosch one, so I am NOT happy. Now to see if the seller will replace it...(I got absolutely no response from the seller of the now faulty coil pack so I won't be holding my breath)

Edit: according to my ebay history I only bought the oxygen sensor in March, so its only 4 months old.

Fingers crossed it decides to work on MOT day on the 22nd, otherwise it might fail the lambda test...

[Chris570]

If it makes you feel any less cursed my XM killed a Bosch lambda sensor in less than 1000 miles.

where did you get yours from?

[Mandrake]

From these guys:

http://stores.ebay.com/motorpartsworld" onclick="window.open(this.href);return false;

Now that I check my ebay messages I see some correspondence from them at the time I bought it that suggests they're not fly by night, I've just emailed them to see if they will replace it under warranty.

The Sagem coil pack that failed after 9 months I got from this crowd:

http://stores.ebay.com/nationalclearancecentre" onclick="window.open(this.href);return false;

No response after more than two weeks to my ebay email about that failing, I doubt I'll hear from them.

Pity you can't change your ebay rating of a seller after the fact...

[Northern_Mike]

and it looks like the Berlingo has knackered a Lemforder drop link, a pattern (though not cheap) strut mount and OEM strut bearing in less than a year..

[Mandrake]

I seriously doubt the quality of some replacement parts Mike, despite both being OEM brand one failed in 9 months and one in 4 months, while the original coil pack and oxygen sensor lasted 14 years! The original oxygen sensor was still working too, it was just quite sluggish because it was choked up with carbon...

[Mandrake]

Well they've replied to my email about the oxygen sensor asking me to send it back and they'll send a replacement when they receive it.

Which isn't much use to me as it would put the car off the road for a week or two, allowing for finding weekends to remove and then refit it... I can't exactly go driving around with a hole in the exhaust, especially with an MOT coming up next Monday.

Is it too much for me to expect them to send the new one first so I'm not off the road ? After all its their faulty part, not mine...

[Ben82]

You should say as much to them too Simon They'll probably will do it... if you look at it from their point of view, you could be trying to get a 2nd O2 from them for free. (I know you're not, but they don't know that).

[addo]

I have a low mileage front sensor out of an Alfa 147 2.0 TS 2001; it was apparently used in the "swap and pray" school of fault finding.

If the sensor nose is the same I can sell it for postage. You will need to splice the lead as it's short.