Aargh! TU5JP4 engine recon

[MikeT]

The plugs as I remember were pretty clean in 2 and 3 cylinders and a bit blacker (oily) in 1 and 4.

That oil probably came past the piston rings. Do you know if the engine used much oil?

[AndersDK]

been thinking ...

actually my theori does not hold water ...

UNLESS ...

The flywheel has been removed and fitted one bolthole rearwards (anti-cw) to the engines cw rotation. That is just possible to make a retarded timing this much.

Any other possibility I can think of - is 2 different TDC sensors mixed up in the wiring or 1 TDC sensor fitted incorrectly in a wrong TDC position hole in the clutch bellhousing.

I can NOT in any way vouche for a ECU fault. Its VERY unlikely - in fact impossible - that the ECU would hold back an ignition pulse with such a delay.
It is MUCH more likely for the ECU not to function at all - thus never emitting any ignition pulses.

Thats why I keep thinking mechanical causes to this problem. Either misplaced sensor or misplaced sensor reading hole in the flywheel.

Any thoughts on the proximity of the sensor to the flywheel ?
I mean - if the sensor is either too close or too far from the flywheel during operation, you may certainly get false triggering.
Would certainly be worth checking the sensor bracket and the sensor position as well.
The sensor itself cannot cause a delay, but any other holes or bolts - in the flywheel - may trigger the TDC sensor erronously if not correctly seated.

[juraj]

would there be significant additional oxygen int he exhaust manifold? also th epressure would be inside the cylinder so nothing should be being drawn in,

ok bye

[davek-uk]

Thanks for your input guys. I've been away from a pc of late. I'll recheck the mechanical timing but I'm pretty sure it's ok. Keyways on the crank and camshafts were in good order so they are unlikely to have slipped. I'd have thought that if I'd put it back together wrong I'd have valve/piston contact problems. The flywheel was locked in the only hole and the camshafts have a bolt lock holes. After I put the cambelt on I rechecked these - and all seemed ok.

I’ll recheck this again Thursday and report back. I’ve no oscilloscope (and wouldn’t know what to do with one if I had it!).

I have had the TDC sensor out and re-seated it. I'm suspicious of this because shortly before all this went wrong, it went in for a clutch change and then back for a free driveshaft seal as they left one leaking. They agreed to do the seal labour free (thinking they would get £30+ as I had to buy the seal). As it was, the seal was just over £7 - well done Citroen!

I always do the work on my cars and I'm very suspicious if they have to have work done without me...

Mike, the engine didn’t use any oil (noticeably) between 6k changes. At 184k she worked wonderfully smooth and quiet. One of the reasons why I’d like to get the bu$$er working again.

Dave