I suspect you have the valve timing incorrect, it is difficult to set up, you need locking tools and front crankshaft pulley modifications and if you don't use the correct pulley holding tool whilst tightening the bolt, the timing will move. These CAY(x) engines are a disaster and blow pistons because people use 95RON fuel when they should use 98RON but the revised pistons help them cope.

 

And just to comment on the engine. It's a BMY, but what you say quite holds as well. These engines are a disaster, just 1.4 litres with lots of power from turbocharger etc, if we only knew when we bought the car! This is the second time the engine is replaced, first time was in a garage at ~100000 km.

 

Thanks Crasher for the feedback, much appreciated. We did buy and use an appropriate camshaft holding tool, and had a high precision tool for verifying the top position of piston1, while tightening the timing pulleys and chain. That said, it was our first experience, so we might had done a mistake we are unaware of. We checked back at the end with everything mounted and we could insert the handing tool fine at the high point. If you or anybody reading have ideas of further checks we could do, that would help us for sure. We also just ordered an OBD-II with enhanced diagnostic capabilities and allowing ECU flashing, hoping to get further enlightenment (it's a thinkdiag), and planning some trial and error intervention with that.

 

The BMY isn't quite as bad as the later CAVD but still an awful unit; I dread working on them but my mechanic is a sadist and loves them, his Golf 5 has the 170PS BLG where the wick is turned even further up on exactly the same parts.

 

The timing is easy to check, fit a dial gauge plug adapter and calibrate it so it hits 0 at TDC, fit the crank pin and turn until it hits where the dial gauge must be bang on zero

 

Thanks Crasher. I can follow until the gauge plug calibration of the TDC at zero. Not understanding the second step, what is the crank pin you mention (do you mean we have to reopen the timing carter?)

 

There is a hole in the back of the block where you take out a bung and screw in a stop bar which hits the crank web and SHOULD leave the number one piston at TDC at which point the cam plate must engage without any fiddling.

 

Got it, thanks. Will let you know how it goes!

 

We have opened the timing carter and redone the timing to our best, using the crank pin and the cam blocking tool. After remounting, the P0321 code is still there (cleared, and reappeared, car still in limp mode). A couple of related doubts:

• at the TDC the two camshafts are close to a 'jump', instable position (care is needed to properly insert the cam tool). This seems reasonable, as close to the TDC valves are being affected. However when removing the tool the two shafts have tendency to move in opposite directions, if the pulleys are not tighted.
• the main crank pulley has been tightened using a wrench nut holder of good quality/strength and two people doing the work. To do better would require to fit diamond rings which we could not find for our car.

Should we be worried by any of these ?

 

The diamond ring and spacer conversion are part number 03C 198 159 A and costs £58.62 but if you have to take it apart again (as I did at least five times on the last CAVD, which WILL be the last I do) you can buy the washer on their own. Don’t forget the O ring that goes inside the bush and that every single bolt on this system is one time only. I assume you have discovered the inlet cam VVT hub bolt is left hand thread? I absolutely hate working on these after that horrid exI had at the beginning of lockdown, I never could find out what was wrong.

 

Thanks Crasher. We checked the timing today and the cam tool fits perfectly. At most a 0.01mm shift from TDC, but I guess it's within tolerance.
By looking with thinkdiag I noticed that the OBD reports engine speed ~850rpm while the G28 data stream is at 960-1000rpm. I have no idea if this is normal or pointing to a problem with the G28 sensor as the P0321 code suggests. I might try to put yet another new sensor, although it's really a tough one to reach.

 

I am now wondering if the problem could come from the reluctor ring on the crankshaft seal. I am sure we mounted it at the TDC but right now can't recall if we checked it was the one with the camshaft at the right position. If we were 360deg off, would it be a problem, and is there a way to check it now ?

 

You fitted a new crank oil seal without the special jig?

 

Having the same problem , limp mode and long crank 5-7 sec . Engine totally renovated after overheating, 13 bar compression and engine on TDC . Changed rear main seal with special tool and cables to sensor are ok . Any insights on solution?

 

Please also start your own new post in the appropriate forum and include a full car code scan and the VIN plus a story.