Polo engine advise

[AudiA8Quattro]

I need some opinions on my brother's 1993 Polo 1.0L engine code AAU. It is a single point injection engine.
It struggles to start and won't idle.
Below about 1500rpm the fuel comes back up the injector housing, i even managed to get a flame, if you blip the throttle at low rpm it sounds like a misfire with the fuel shooting back up.
Compression test results were, cyl 1 - 11 bar, cyl 2 - 13.5 bar, cyl 3 - 13 bar, cyl 4 - 12.9 bar.
Using a colortune spark plug, the fuel/air mixture looks perfect in cyl 1 at about 2000 rpm.
The crankcase ventilation hose is still chucking out loads of sh!t with the engine warmed up.
I first thought the problem was cyl 1 rings, but now i think the inlet valve in cyl 1 is the problem.
I should of added oil in cyl 1 to see if the results improve, but unfortunately i didn't have any 
Any opinions?

[Ess_Three]

It looks like it's time to lift the head and have a look 

[AudiA8Quattro]

Looks that way mate.
I only repaired it and rebuilt the head 25k miles ago.
The history of engine isn't great, it had a piston replaced in no.2, and the head gasket had failed again when bought it off ebay.
Although that was in 2005, i don't trust the engine.
I'm thinking of just getting a 2nd hand unit to put in it.

[Ess_Three]

Looks that way mate.
I only repaired it and rebuilt the head 25k miles ago.
The history of engine isn't great, it had a piston replaced in no.2, and the head gasket had failed again when bought it off ebay.
Although that was in 2005, i don't trust the engine.
I'm thinking of just getting a 2nd hand unit to put in it.

I'd be tempted to do the same, I think. 

[danny_p]

cheat

you need to make an adaptor bodge ( but will be a highly usefull bit of kit once made )  that basicly allow you to screw an airline into the sparkplug hole

i found if i took the one way valve out of one of the extension hoses for my sealy compression tester i choudl screw the other end of one of the extension pipes onto an airline fitting.


ether put the cyls tdc on compression and hold the enigne there firm ( it will try and turn ) or just take the cam out.  give it 100 psi  and you'll soom here where the problem is     normaly show up as low as 30 psi if it's bad

[AudiA8Quattro]

Thanks for the replies guys.
Danny, i don't have an air compressor, it's about the only thing i don't have 
I think it has to be a problem with the inlet valve on cyl 1, why else would a flame leap back out the injector unit?
What i don't understand is, if the valve is sticking or the seat is bad, how come the engine runs fine above 1500 rpm??

[justalex81]

Thanks for the replies guys.
Danny, i don't have an air compressor, it's about the only thing i don't have 
I think it has to be a problem with the inlet valve on cyl 1, why else would a flame leap back out the injector unit?
What i don't understand is, if the valve is sticking or the seat is bad, how come the engine runs fine above 1500 rpm??

just pull the head and rebuild it. pi55 easy on a 1.0 surely?

[AudiA8Quattro]

Thanks for the replies guys.
Danny, i don't have an air compressor, it's about the only thing i don't have 
I think it has to be a problem with the inlet valve on cyl 1, why else would a flame leap back out the injector unit?
What i don't understand is, if the valve is sticking or the seat is bad, how come the engine runs fine above 1500 rpm??

just pull the head and rebuild it. pi55 easy on a 1.0 surely?

Not quite that simple. First of all the car is at my brother's, i need it here.
Secondly, i can't be 100% sure the head is the problem, as i outlined in my previous post, the engine has suffered from bottom end problems and headgasket failure.
Also, i only rebuilt the head 25k miles ago, ok i could just do it again, but a bit of worry really.
I think a 2nd hand engine could well be a better bet, they only go for about 100 quid.

[droofer]

i think you should buy another engine, but try and listen to it running 1st, if the engine has a history of problems, whats the next one going to be? they are usually quite hardy, but if the bottom end has been cocked about with and you dont know whos done it, i would put a good known runner in 

[danny_p]

if another motor is only 100 quid  its not worth the hasstel working out whats broken