3.0 V6-24 Project

The place to show off and tell us all about your XMs (or even other cars). Should it be a big project, or just some general pics, start your thread in here.
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citroenxm
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Re: 3.0 V6-24 Project

Post by citroenxm » Fri Jul 28, 2017 8:49 pm

sdelasal wrote:
On the front outrigger rust, will you be repairing that yourself? Every car i've seen has had rot in that area! In one case the steel had just disolved under the very solid underseal!
Had this in a number of areas on S2 cars. The other area that disolves is the metal in the floor around the box under the B pillar area. Again underseal keeps shape while the metal goes.
Projects:(eventually if theres any bodywork left)
93 L Xm 2.1t D auto project
93 L xm V6 12v Sei Manual

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In use.. 1995 M reg S2 2.1td auto exclusive

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MTXM
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Re: 3.0 V6-24 Project

Post by MTXM » Sat Jul 29, 2017 11:35 am

I have just rechecked the rot on my similar vintage 12v project, which like Will's car sat for a long period outside, although fortunately at least partly on gravel! All four jacking points are undamaged, but there is quite severe rust to the adjacent sills around the front nearside and rear offside and the front nearside wheel arch lower rear section is also badly holed. Regards, Matthew T.
1989 V6 Exclusive (Poland car) - Now living in a local Motor Museum!
1990 V6sei auto (grey auto)
1990 V6sei manual (gold car)
1990 V6.24 Pallas (Germany car)
1990 V6.24v (Scotland car)
Other previous XM sold and broken too many to mention!

Dieselman
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Re: 3.0 V6-24 Project

Post by Dieselman » Sat Jul 29, 2017 8:50 pm

Not done much recently, but have taped up the damaged rear quarter and tailgate with waterproof aluminiuum tape to stop rain getting in. Being a bit shiny it looked terrible so gave the tape and rear light bar a quick blast with some satin black paint. Did the rear roof plastic embelishers too. The car looks almost presentable now...

The radiator I ordered appears to have gone AWOL in Germany, so that order has been cancelled and another ordered. As a result, I've not done the thermostat yet.

Today, I read the fault codes again and am pleasently surprised that the ABS and Hydractive are now not showing any live faults. I had cleaned anf remade the speed sensor connection the other day and will do the rear wheel sensor connection in due course.


For now I seem to be going round in circles with the Lambda sensor codes.

New sensors, all connections seem fine, as metred, but the engine starts fine from cold with the lambda light extinguished and no codes. After a good while of idleing and a few rev sessions, as the engine warms up, it begins to sound increasingly lumpy and laboured. Eventually and suddenly, the engine note smooths out to perfect and the Lambda light comes on.

Having metered the sensors, I am seeing outputs of 0.1v-0.2v idling and upto ~0.75v+ when revved sharply.

After the ECU adopts open loop and the lambda light comes on, the sensor voltage is pretty stable at ~0.7v

I checked the coolant sensor and it is in range at temperature.

It appears the mixture is going lean in closed loop, so the Lambda sensor values fall, which then brings on the lamp and causes the ECU to adopt open loop.

I can't find any vacuum leaks and when in open loop, the engine appears to run well. I need to blank the evaporation valve piping to be sure there isn't a leak there.

Any ideas? Does anyone have information on exactly how the mixture regulation is performed. I intend to have a good look for air leaks under vacuum, which could be leaning the mixture, especially at idle as the engine warms. I wonder if the injector O rings might be leaking after standing 10 years.

I also made a new bolt to hold the LHM pump tightly locked, as the one i bodged in allowed the pump to slacken very slightly, which then caused the belt to smoke and shed very quickly. Belt tension on these pumps appears to be critical, due to the small diameter pulley as a result of the low drive speed and small camshaft pulley.

The other job I've done is to find why the rear tyres are losing air pretty quickly...60psi to flat in a few days. I removed the wheels and gave the tyres a wire brushing as they were still caked with cow dung. After that blew them up and applied soapy water with a paintbrush. There aren't any punctures, the valves appeared to seal Ok, but the beads were bubbling air.

Remove the valve core to completely deflate the tyre, knock the trye off the bead a little with a lump hammer, apply soapy water into the gap and try to knock the bead off more.
After re-installing the valve cores and inflating back to 60psi, both tyres appear to be holding air...at least there is no bubbling at the beead. To be continued.

The fuel guage has now adopted working properly for about 30s then flicking over to full with the low fuel warning lamp flashing rythmically. I wonder if this coincides with the Hydractive switching to firm, though that shouldn't happen at rest. I haven't been able to check for this yet ass the ride is rock hard. I'm sure all the spheres are ruptured.
92 2.1SED M.RP5740 ECZ Sable Phenicien
92 3.0 V6-24.Rp 5713 EXY Black
92 2.1SD M.RP 5685 ENT Blue Sideral
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90 2.1SD M.RP 5049 EJV Mandarin
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Dean
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Re: 3.0 V6-24 Project

Post by Dean » Sat Jul 29, 2017 11:02 pm

Sports mode will engage when stationary if the engine is revved.

I cant see the injector seals are leaking, they are a tight fit and cope with heat well.

I cannot offer any sensible suggestions as to the cause of your running issue other than that the evidence suggests you have one bank running rich and one that seems to be OK, you have new O2 sensors and i take it you have continuity from the ecu multi plug to the O2 plugs? if so i would discount them.
Are you getting any engine codes at all other than the O2 sensor?
I had an O2 sensor code coming up initially even though i was running my nearly new sensor taken from the 2.0i engine, after a good drive it never came back.
My advice, after not only chasing my own stupidity, many genuine faults but also a lot of ghosts would be that until it gets driven you could be chasing problems all over the place, some of which may not exist.

Can you borrow a Lexia? i found the fault codes pretty useless as many faults around the fueling side of things do not bring an EML light on and a fault code does not appear, i found the Fenix 3 at least to be a strange ecu and i suspect the 4 to be similar in its operation, any other old car i have had is all too quick to throw a code at the slightest cough, the PRV though can really run like a bag of spanners and the eCU seems to be completely oblivious, in short, the Fenix diagnostic function is horrificly poor.

My opinion is that the live data function of the Lexia is the most useful fault finding tool, it would be nice if more live data was available, it does not show as much as could be seen on the 2.0i engine management for instance, but you can see what the ignition timing and fuel trims are which is enough to steer you in the right direction.

D
92 Citroen XM Prestige 3.0i Auto R.P5678
14 Mitsubishi L200 Trojan
89 Talbot Express 2.0 coach built Auto-trail Chinook

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sdelasal
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Re: 3.0 V6-24 Project

Post by sdelasal » Sat Jul 29, 2017 11:35 pm

If the lambda sensor(s?) are reading lean then two possible sources to consider are (1) a cylinder is mis-firing meaning the exhaust flow gets a cylinder worth of fresh air at the misfire event and (2) A leak in the exhaust system upstream of the sensor will also cause a lean drift.
Is the fuelling system MAP/pressure sensor based or MAF/air flow meter?
Does each bank of cylnders have its own lambda sensor, or is there one sensor serving both both banks after the exhausts are all brought together? Some later systems then have an additional sensor downstream of the catalyst, the purpose of which is to diagnose poor catalyst conversion efficiency and is not used for fuel control. Steve

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Dean
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Re: 3.0 V6-24 Project

Post by Dean » Sat Jul 29, 2017 11:43 pm

One O2 sensor per bank
MAP sensor, TPS and air temp sensor

D
92 Citroen XM Prestige 3.0i Auto R.P5678
14 Mitsubishi L200 Trojan
89 Talbot Express 2.0 coach built Auto-trail Chinook

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White Exec
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Re: 3.0 V6-24 Project

Post by White Exec » Sun Jul 30, 2017 6:19 am

On the slipping belt issue, is there the possibility of twinning two pulleys (two belts) together (simple weld or bolt job?), which should more than cope, and maybe allow bearing load to be reduced ?
Chris
1996 XM 2.5TD Exclusive RP7165 Polar White
1992 BX19D Millesime RP5800 Sable
1989 BX19RD Delage Red Deceased; 1998 ZX 1.9D Avantage auto Triton Green Company car 1998..2001; 2001 Xantia 1.8i auto Wicked Red Company car 2001..2003

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Re: 3.0 V6-24 Project

Post by Dieselman » Sun Jul 30, 2017 8:24 am

White Exec wrote:On the slipping belt issue, is there the possibility of twinning two pulleys (two belts) together (simple weld or bolt job?), which should more than cope, and maybe allow bearing load to be reduced ?
A good suggestion and one that Citroen should have considered.
92 2.1SED M.RP5740 ECZ Sable Phenicien
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Re: 3.0 V6-24 Project

Post by Dieselman » Sun Jul 30, 2017 8:29 am

Back to the running issues.

I suspect it is unmetered air entering the intake, hence it gets worse as the idle speed drops as the engine warms. It shouldn't be a simple leak otherwie when open loop is selected, it would continue. I have noticed that wien revved and held at constant revs, the engine speed pulses a little at regular intervals.
I wonder if the evap cannister valves are being activated and there is too much air leakage.

I do have wiring continuity and can see the Lambda sensors output voltages. The very low readings have been throwing me, but I tink I understand what's happening now. The voltages are low due to very lean mixture.
92 2.1SED M.RP5740 ECZ Sable Phenicien
92 3.0 V6-24.Rp 5713 EXY Black
92 2.1SD M.RP 5685 ENT Blue Sideral
Prev
90 2.1SD M.RP 5049 EJV Mandarin
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Dieselman
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Re: 3.0 V6-24 Project

Post by Dieselman » Sun Jul 30, 2017 8:31 am

Dean wrote:Sports mode will engage when stationary if the engine is revved.
Not below 30km/h.
92 2.1SED M.RP5740 ECZ Sable Phenicien
92 3.0 V6-24.Rp 5713 EXY Black
92 2.1SD M.RP 5685 ENT Blue Sideral
Prev
90 2.1SD M.RP 5049 EJV Mandarin
92 2.1SD A.RP 5698 EJV Mandarin
94 2.1SD A.RP 6218 ERT Triton Green
91 2.0SI M.RP 5187 EWT White

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