ABF lumpy, VW mechanic stumped!

[Simeon]

I didn't do anything with the tappets, just swapped them. Why do they need compressing and how could they cause the lack of running?

I compression tested it before I swapped them out: around 13bar except for cylinder one, which was a little lower at about 10.5. Not really a problem.

[roberto]

old tappets can get so gunked up that there adjustability can get limited. when you swap from 1 engine to another you have no idea of wear rates in cam/tappets/valve seats between old and new engine so the valves might be sticking open slightly. do a comp test first and tell us how it reads. btw 3 pots at 13bar and 1 at 10.5 is not something I would be happy with(might be fine but im mega fussy)

[Simeon]

OK, so played around with it and it now starts, but it runs like a dog. Fine for about 30 secs then idles rough and revs die off if you apply any throttle.

I've scanned it and it's not throwing any codes. Stinks of fuel, but to be expected I guess as indoors and on choke. The fuel in it is pretty old, so I think I'll stick a bit of fresh in it  tomorrow.

Sadly the tapping noise has not cleared, I reckon it might be something else, but definitely top end.

[Simeon]

old tappets can get so gunked up that there adjustability can get limited. when you swap from 1 engine to another you have no idea of wear rates in cam/tappets/valve seats between old and new engine so the valves might be sticking open slightly. do a comp test first and tell us how it reads. btw 3 pots at 13bar and 1 at 10.5 is not something I would be happy with(might be fine but im mega fussy)

Fair enough, might delve under the rocker cover again tomorrow. I'm not stripping the head off if I can avoid it, six cars in my garage and only one currently works

[Sgt_Lemon]

God how big is your garage.

[Simeon]

It's big... but when you have a big garage you just fill it with crap, so there's not much room in it

Ok it's running now, a combination of messing around with connections and some of Shell's finest (the fuel in the tank was pretty old) got it going.

Plugged the code reader in and I'm getting 'no signal from o2 sensor' .. damn. Will investigate that further tomorrow.

[Sgt_Lemon]

Let me tuck a car in the corner aha, you will never know I'm there 

[Waspy]

Let me tuck a car in the corner aha, you will never know I'm there 

Me too.

[Simeon]

Presume this code (which is recurrent) is just lambda sensor (which is annoying as it's not that old), but does anyone know any testing I can do before replacing it?

[roberto]

try running car with it disconnected. you could also check all the wiring to it for breaks.