Jetta sounds like tractor, engine very unsettled and hardly any acceleration.

[CanisLupus]

Hey guys, looks like I have a first bigger problem and hope anyone has some advice.

Use my Jetta as a daily and can't say I've had major problems with it in the last few years. Problem started today on my way to work, about 1/4 mile before I got to the car park.
Engine all of a sudden became "sluggish", not much acceleration, and my whole cabin is vibrating. Had to stop at a traffic light and I could feel myself bouncing on the seat to a nice takt...tack tack tack tack...ect. Had to go to work so parked up and left.

Had a quick look under the hood after work, checked for loose cables / vacuum hoses, couldn't see anything, so made for home. Same symptoms from cold all the way till I got home (about 10miles).

Engine sounded like she was missing, but wasn't sure as I've not experienced it before. Pulled a spark lead 1 by one and engine note changed each time.

What I then checked:

All vacuum hoses and air intake are fine.
Replaced spark plugs with another spare set - same symptoms - old plugs were NOT wet and have healthy tan.
Checked spark leads - seem fine.
Distributor, rotor arm and cap are 1 month old, checked it anyway, fine.
Replaced coil as a had a spare flying around - same symptoms.

Thought then maybe she had jumped a tooth on the belt - checked timing marks, spot on.
Earths had been cleaned a while ago but checked them all again, - all seem fine and are connected.


I got my partner to press the pedel a bit and noticed quite a bit of white smoke than usual coming from the exhaust, not sure if this was because it was getting dark and colder...but it seemed quite a bit to me.

I uploaded 2 videos to youtube, I know it is hard to tell anything by sound on video but I thought i'd give it a try, maybe someone might notice something unusual. You can notice how the engine is shaking around at idle.

http://www.youtube.com/watch?v=FVZ8X2eEh_4

http://www.youtube.com/watch?v=ryoo3IwGRMc


Don't know really what else to check right now...leaning towards trying a compression test tomorrow...I have got a kit but unsure how to use it. Just screw in, hold throttle wide open and disable spark?

Any input much appreciated guys.

[Diamond Hell]

Sounds exactly like my Golf Syncro did when the headgasket went.

Head off, skim the head if needs be, replace the valve stem seals, new head gasket, new stretch bolts, bolt it back down again - she'll probably be right as rain for another 80-100k.

[CanisLupus]

Hi Diamond. Many thanks for the input.

Would a compression test confirm this? Can do one tomorrow....or try to anyway

Saying that, I have always lost a very little coolant (maybe a tea mug full every 2 months), but didn't think much of it, maybe that would be connected.


The car as it stands right now never uses any oil, I never need to top up, doesn't lose a drop, bless! Would that mean bottom end is probably sound and I would only need to crack on with some tlc of the head?

While I have it off I will probably change everything I can. Never been "inside" an engine before but have always wanted to do some work on one when the time comes. Shame the timing is unfortunate.

Many thanks so far

[Diamond Hell]

Would a compression test confirm this? Can do one tomorrow....or try to anyway

Yes.

Timing is ALWAYS unfortunate!

[danny_p]

CO testing the coolant will also confirm, 

if it were mine that would be enough to perswade me to have it apart,   very worth regrinding the valve seats while the heads of  as it's probaly gone a  good way to the moon by now

[CanisLupus]

RIghty, sorry for late reply just got back home from work.

Right I don't know if the tester I have is rubbish but I do have varied results between cylinder 2 & 3. I didn't do a wet test unfortunately...thinking now I should have done it. tomorrow then. But overall compression on all 4 cylinders is low. According to my bently it should be between 10-13 bar, not new.

1: 75psi / 5bar

2: 63psi / 4.2bar

3: 55psi / 4bar

4: 75psi / 5bar


Just weird that the car before the above was running, as always, amazing...surely that low pressure would have been noticable? So don't know if the tester is just crap.


Few more pointers also:

no bubbles coming from expansion tank
No oil in coolant
No coolant in oil (no cream on oil cap or stick)


I did observe the following though, while engine was running and sounding like a tractor lol, sqeezing the coolant hoses temporarily stopped it, if only for a second. Further squeezing would make the engine run "Normal" - lumpy - normal - lumpy ect.


Seems to be the gasket then I guess?


Edit: Oh and also, exhaust to me does have a "sweet" odour.

[Diamond Hell]

They go between the bores, so no real coolant leakage, although some may drain into the bores overnight, resulting in the car being difficult/impossible to start the morning after.

Your pressures overall sound suspect.  Maybe test with a second tester?

[CanisLupus]

They go between the bores, so no real coolant leakage, although some may drain into the bores overnight, resulting in the car being difficult/impossible to start the morning after.

Your pressures overall sound suspect.  Maybe test with a second tester?

Heya.

Yes second tester indeed, just been to get another, decent one. Righty, looking a lot more healthy now...very happy with results, dry test:

1: 12.5 Bar / 180 psi

2: 13.2 Bar / 192 psi

3: 12.9 Bar / 188 psi

4: 12.7 BAr / 184 psi


Think those values sound excellent. Bently says "new engine" 10-13 bar. Wear limit 7.5 bar.

Very happy with results. On a note, I tried a wet test on cylinder 1, and I am not sure if I used to much oil (3/4 cap full 5litre oil bottle) but ratio jumped to 16.8 / 240 psi Oo Didn't wet test the others.


Symptoms still remain though. While waiting for the engine to warm up for the test I noticed while cold she sounded normal. AFter around 2 minutes engine started shaking again and sounded like a tractor. Sometimes though she would go normal and then go shaky again. But overall she was more in shake mode than normal...

Question is what else is there now. Fuel delivery problems? Injectors, pump? ANyone have any more ideas?

Many thanks, Nicolas

[danny_p]

those readings are more like it,   just saw the first lot and thought  well that f**ked.

2nd lot are good.

what exact engine do you have in there,  digi, kjet, carb

horrible bumpy gutless engine can be caused by air fuel ratios been uter crap as youve not mentioned it stinking of fuel it's probaly not geting enough 

[CanisLupus]

Oh sorry, I never wrote what exactly I have Oo

1987 Jetta MK2 1.8 GTi, PB engine, Digifant 2 system.

Everything is more or less stock. Just replaced many things in the last few years which needed a bit of tlc, but always bought "as is". So nothing modded, no engine overhauls, chips, bigger pumps or anything like that.

No can't smell fuel, but you have a point. Just weird it would just go from running great to this all of a sudden. Fuel air ratios had been adjusted accordingly many times. but I can have a fiddle around tomorrow.