My Citroen XM 3.0 PR-Vestige

[Dean]

It sounds odd is what it sounds, like cavitating oil

[misha]

...i also have a strange noise from somewhere that does not change with engine speed which you should be able to hear in the video,...i just started it for 10 seconds as i had no water in it at all...

It is a strange noise indeed.Could be hudraulic pump noise because of air presence in the hydraulic system, but it sounds too loud to be that.
I would avoid to run the engine on dry cooling system(without coolant)because you can damage a water pump pulley seal(weep hole seal)....if it's not damaged allready.It's lubricating itself with coolant and can easily be damaged when the pump is running on dry.

Lay a hand on hydraulic pump body to feel is that sound comming from it.With that noise it should be felt instantly.

[MTXM]

First off well done for sorting the timing Dean and I had a feeling you might need to pull the chain cover! The noise is indeed odd and I wonder if it is water pump related through running dry as suggested by Misha. I would also wait until you have some water in the engine and it may go away! From the Lexia I noticed there is very little movement on the mixture and oxygen sensor readings and none at all on the throttle strangely! With regards, Matthew T.

[Dean]

The engine is full of coolant, I wouldn't run it dry, the return is capped and the flow is an upright bit of pipe as a header. In this stat I can only run it for 1-2 minutes before coolant temp gets to an indicated 50c and I shut it down.
It is not the hydraulics from what I could tell.
In the video it was idle only as it would not rev at all but when it was stone cold it was running fine and reving no problem at all. After a minute it would stall as soon as throttle was applied

[misha]

Bad tps or it's connection?

[Dean]

Misha the throttle position sensor is giving just over 3 volts output at idle as confirmed with a lexia which also states throttle position is 'MID'. There a steady 5 volts being supplied, if i remove the TPS i can get it to output 1v but not fitted. At WOT it outputs 4.5v which seems about right so its like the throttle is sticking open, but isnt. I shall investigate this.

The speed sensor (crank sensor) fault is still present and the car was reving happily when cold but after a minute would not rev at all with idle speed fluctuating and the engine cutting out if the throttle was touched at all, stumbling when touching the throttle could well be a TPS issue although i think its time to stop ignoring the crank sensor fault as the TPS would not cause rough running and an unwillingness to rev.

Crank sensor checks out too with 5v supply and ground at the sensor plug, all three pins have continuity back to the ecu plug, the Tach works and the lexia see's engine speed fine yet the Lexia insists this is a permanent fault and no other codes come up if i unplug the crank sensor.

Im just going to stop now as i dont have a spare TPS here and i want to be able to run the car with a complete coolant circuit to have time to investigate or even let it reach full operating temperature.

Here is a video of the first start when it was running fine up until the 2 minute mark when it started to get lumpy, also i did not touch the throttle from the 2 minute mark, the fast idle and hunting was all its own doing this was just after starting to cycle through the gear box to get the oil moving about. starting again shortly after it would stall as soon as the throttle was touched not recorded as i was in a rush to get changed to go out. Please note the blowtorch is not for the final solution lol.
https://youtu.be/nytqMLnv2UI" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

D

[White Exec]

Hi D

Could the TPS might be getting its 5v at one end, but not properly grounded at the other? I'm assuming it works like a simple pot, so swings output from almost supply voltage to almost ground. Just guessing here.

The latest video shows the noise being pretty well independent of engine speed, and coming and going. There's an interesting moment when you turn the engine off (or it cuts out) right at the end, where the noise can be heard alone. It sounds different, very mechanical (rather than a fluid), rather like a noisy belt idler or thrashing belt system.

Listened to it several times more: final noise, after power cuts, is like (overtight?) belt "scrunch" - or a dry seal (unlikely).

[misha]

When my tps failed the problem was between its rest position and the middle.It was working normally from middle to max position.
When i would hit the throttle fast,it would stall for a second and then rev.If i would pressing the pedal slowly it would stall and die.Idle was perfect with it connected or disconnected when it failed.
Could be the same problem with yours,but it's unlikely that both are bad.
Check the one from yours 2.0i,it should be Bosch unit and if it's... it have a same Bosch number.

[Dean]

The TPS itself checked out fine, but while it was off the throttle body i hooked the lexia up and played with it while looking at the live data screen and quickly realised that full throttle was idle and idle was displaying Mid throttle which is all i think the lexia will display.

A further play with the multimeter showed that the TPS reads two ways depending on how its wired up, either higher resistance with throttle applied or lower (well it would wouldnt it) so some snipped wires (swap pin 1 and 2 positions) and hey presto, the lexia at least seems happy.

https://youtu.be/cYyNbIp_Ruc" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Im not starting it yet as i am still going to wait for the hose to turn up but its a promising start and certainly could not of been helping matters when the ecu was being told the car was literally at WOT when the throttle plate was closed.

D

[misha]

What happened with pins positions?Why you had to swap places of pins 1&2?
Tps have 3 pins on both....tps side & connector's side.You have donor's car engine wiring.Connector can't be plugged wrongly.What am i missing here?