2004 Citroen Berlingo 1.4i TU3JP Engine noise: Is this detonation knock or rod knock?

[Pilot65]

2004 Citroen Berlingo 1.4i TU3JP Engine noise: Is this detonation knock or rod knock?
Lexia says normal temps (engine/coolant and IAT), no DTCs, normal MAP values.
The noise was noted about 6 weeks ago, and seems to be getting worse every week.
Changed from 95/E10 to 98/E5 but it made no difference.

Listen to the noise here:

[Paul-R]

Link says

Video unavailable
This video has been removed by the uploader

[PaulC5]

Sounds as if there is something loose that is knocking. Have you checked the exhaust, engine mounts, crank shaft pulley, etc. Engine knocking (pinking) I would have thought is heard when accelerating whilst driving and not whilst stationary so trying to show it as you have done might not be the best way. Has the timing belt been changed when required ?

[xantia_v6]

Video is fine here. It sounds slightly more like a combustion knock to me, but it is hard to tell. If you put it in gear with the brakes on and slip the clutch to add some load, can you get it to knock continuously? the noise might be more distinctive under those conditions.

A diagnostic session, noting the timing values and knock sensor output may tell you something.

[Pilot65]

Video is fine here. It sounds slightly more like a combustion knock to me, but it is hard to tell. If you put it in gear with the brakes on and slip the clutch to add some load, can you get it to knock continuously? the noise might be more distinctive under those conditions.

A diagnostic session, noting the timing values and knock sensor output may tell you something.

Well, the noise do not increase with load or rpm. When driving uphill there is no usually no noise. That noise comes only when the throttle is opening, and at light load or no load, like when driving at steady speen on a flat road and just barely touching the gas pedal.
As seen in the video the noise is really only there while the throttle is opening, not when it is closing or held steady. The noise is locked to, and synchrounous to rpm, and from what I can tell it seems to come from the middle inside of the engine. In the video there are a few moments where we hear what I believe is real ignition knock as I play with the throttle, and this is a totally different beast, its loud and hard and and the engine feels and sounds as if hit by a sledge!
Today I:
-adjusted the valves, were a little bit out of spec but it made no difference. Checked the plugs and all looks fine.
-while the plugs were out I tried to probe for any piston slop (=worn rod bearings)... moved the crank so the piston starts moving down (any play will now be at the top cap) then using a wrench extender pushed at the piston with 5Kg or so, and measured at the end of it with a 1/100mm dial gauge.... Difficult to do and sketchy setup so the results were inconclusive, but sertainly less than 0.1mm.

One thing I noticed in Lexia live data is the ignition advance... its all over the place. At 2-3000 steady rpm and no load its pretty stable at about +25deg or so. But at idle no load its all over like +15 to -8, for no apparent reason...

[ozvtr]

One thing I noticed in Lexia live data is the ignition advance... its all over the place. At 2-3000 steady rpm and no load its pretty stable at about +25deg or so. But at idle no load its all over like +15 to -8, for no apparent reason...

It does sound like a timing or fueling issue. It sounds like it's "bogging down" on acceleration. Is the acceleration poor? Got hesitation?
In the old days I would have said it was the vacuum advance in the distributor, or the accelerator pump in the carb.
Vacuum leaks can cause the engine to bog down on acceleration, but it tends to affect idle more (poor idle or hunting).
Timing is controlled by the crank angle sensor. I would expect problems across the board if it was the crank angle sensor. Or the engine just wouldn't run.
Manifold Absolute Pressure (MAP) sensor might be a bit lazy and not reporting the change in pressure to the ECU. Could try unplugging it and see what happens?
Have you checked the fuel rail pressure? Should maintain a constant 3.0 to 3.5 bar.
Doubt it's the fuel injectors. One maybe, but not all four. More likely the fuel pump rather than the injectors.
Not much to the TU3JP engine, pretty simple little beast. That's why I like it.

[Pilot65]

One thing I noticed in Lexia live data is the ignition advance... its all over the place. At 2-3000 steady rpm and no load its pretty stable at about +25deg or so. But at idle no load its all over like +15 to -8, for no apparent reason...

It does sound like a timing or fueling issue. It sounds like it's "bogging down" on acceleration. Is the acceleration poor? Got hesitation?
In the old days I would have said it was the vacuum advance in the distributor, or the accelerator pump in the carb.
Vacuum leaks can cause the engine to bog down on acceleration, but it tends to affect idle more (poor idle or hunting).
Timing is controlled by the crank angle sensor. I would expect problems across the board if it was the crank angle sensor. Or the engine just wouldn't run.
Manifold Absolute Pressure (MAP) sensor might be a bit lazy and not reporting the change in pressure to the ECU. Could try unplugging it and see what happens?
Have you checked the fuel rail pressure? Should maintain a constant 3.0 to 3.5 bar.
Doubt it's the fuel injectors. One maybe, but not all four. More likely the fuel pump rather than the injectors.
Not much to the TU3JP engine, pretty simple little beast. That's why I like it.

Yes I agree. No, the acceleration speed and power are all normal. I once had a engine with distributor ignition, and one of its vacuum hoses came loose while at 60Kmh... worst engine noise I've ever heard, I was sure a broken conrod was slapping around on the crank. So engine detonation knock can be really bad, no damage in this case as I got the ignition off after 1-2secs.

For the TU I lean heavily toward a fuel/ignition/detonation scenario... The noise is what I'd call a ignition knock, not 'fully developed' detonation of the worst type, but just barely there and maybe too weak to be detected by the knock sensor. But why is it there now when it wasnt before... Something must have changed. CPS fail would totally upset the engine so it wouldnt even start. MAP? Maybe, it reads the right pressures but if it were way too slow in response, or has developed hysteresis,

Have tried spraying brake cleaner around injectors and manifold flange, the engine did not respond to it so no apparent air leaks.
I think we can exclude low fuel pressure as it accelerates and climbes up-hill as good as its able to with all of its 75Hp .
Will try a BSI/ECU reset and throttle body relearn. And have a look at the front for loose pulleys and camshaft timing. And examine the knock sensor, maybe remove it and knocking on it while engine is running...

[ozvtr]

For the TU I lean heavily toward a fuel/ignition/detonation scenario... The noise is what I'd call a ignition knock,

It does sound like the timing is off...but I don't know how that could be. The timing is controlled electronically by the engine ECU.
Could it be the knock sensor screwing things up? I can't see how. The engine ECU is looking for a particular...um...sound, from the knock sensor. I can't see how the knock sensor could be replicating that sound and fooling the ECU. Disconnecting the knock sensor might bring the engine light on, but it won't do any harm.
Would be nice if you could put a timing light on it. LEXIA gives timing details in live data. Don't know if OBDII gives timing.
Hmmm. Strange that the acceleration is ok. I would have bet that the engine would bog down, judging by the sound.