1.6td oscillating idle and low rpm

[oblique]

Hey folks, you may remember me from such threads like '1.6TD died while driving'

So ive got a new head on it with fresh Giles injectors.

Ran fine for last 2000kms of driving now im getting a strange oscillating sound while at idle and low rpm...this changes with engine rpm and either goes away at higher rpm or I can't hear it.

Its like there's an additonal sound on top of the usual idi 'marbles'...oscillates up and down approx every second or so, maybe less.

Some issues:
1. I had an oil leak that i did not notice approx 700km ago and the sunp went down to about 2L from full on the dipstick.
2. One of the injectors (#3) isnt sealing well...i can see air bubbles coming up into the ring of diesel pooled into the 'well' between injector and socket on head.

1990 jetta 1.6td, 335,000kms

[fatmobile]

One leaky injector will cause a different noise on that cylinder.
Fix that and see if it helps.
I know it's hard to describe a noise, does it sound like it's happening on one cylinder?

Got an oil pressure guage?

[oblique]

Video:

https://youtube.com/shorts/IPegRULU940?feature=share

You can hear the idle sounding up and down. Was a lot harder to start this morning. I just checked the timing belt tension cold...could barely rotate it 30 degrees...is my IP on the way out because of this?

If this is the case, would loosening the tension help anything now? Im about 900miles from home.

[fatmobile]

 You have to loosen the tension.
 While the belt is way loose, grab the sprocket and see how much it can be moved side-to-side.

[oblique]

I loosened it this morning in a department store parking lot but didnt check for play. I've done about 500miles since and it seems ok.

By introducing slack into the belt...did I retard or advance the timing? It runs ok but produces quite a bit of smoke even on light-moderate acceleration...i dont think it was this bad before.

Thanks for getting back, driving this car is nerve wracking.

[ORCoaster]

I think you may have retarded it.  The extra length of the belt would have gone in the direction of rotation and that would have been like pulling the pump towards the radiator. Which is retarding it.  Cam and Crank would have shifted in their rotation too.  So I am not sure how all that comes together for you.

[oblique]

I am waiting for the motor to cool so I can get some slack on the TB to check for play in the shafts.

The engine got pretty warm and my temp gauge isnt working (was workign before I took the car in) and here's why:



I supplied a new oil cooler for him to install along with the head but he refused to install it because the 'bolts were too rusty' and it 'could open a can of worms'.

[oblique]

Just checked the play on the IP pulley..I can see and feel it move slightly when I apply my strength. Camshaft is rigid.

[libbydiesel]

By introducing slack into the belt...did I retard or advance the timing?

introducing slack to the belt does *not* change the timing unless you introduce so much that one of the sprockets jumps time.  The reason it does not change the timing is because while the engine is running all of the slack (or lack of) ends up in the tensioner area anyway just from the crankshaft driving all the other shafts which resist rotation.