compression test

[mark53]

hi all ,newby here.

just recently brought my gti,im having trouble with a stumbling of the engine,hesitation when pulling away ,not perfect idle ,engine revs up/down slightly tho accelerator pedal is steady,

so far have cleaned throttle body then run adaption
replaces plug & leads
checked coil pack in total darkness & a water spray no problems seen
done compression test cyl1 180,cyl2 175,cyl3 200,cyl4 200 psi forgot to hold throttle open when doing test will rerun test tommorow

only thing vw diagnostics come up with is ecu incorrect coding? not sure what this means any ideas ?


you help will be great as cant wait to experience this lovely little car

many thnxs mark

[alexperkins]

How did you clean the throttle body?

[mark53]

i removed it from the car and used carb cleaner & cotton buds

[alexperkins]

You may find benefit from cleaning it whilst on the car which is the preferred method with many of these cleaning products.

Start the engine, with the air filter removed. Have an assistant rev the engine, and whilst they do, spray in carb cleaner directly into the TB. If the engine starts to choke, tell them to rev it more.

You may have a dodgy alternator also - I had similar symptoms and it turned out to be the alternator at fault.

[mark53]

ok today replaced gasket under throttle ,slight improvement ,local garage said add lead to petrol will today ,apparently helps with valvae seating as he said cyl1 175 & cyl 2 180 could be cause of problems any thoughts?

[alexperkins]

I wouldnt add lead additive...these cars were never designed to be ran on leaded petrol

Have you attempted to clean the throttle body again with it fitted to the car and running?

You may have a head gasket problem - have you got any gunk under the oil cap or oil in the coolant at all?

[mark53]

no they appear clear of gunk ,kk no lead replacement then

[mark53]

what do you think of compression cy1 175, cyl2 180 ,cyl3 200 , cyl 4 200 ?

[alexperkins]

I dont think its too far under. If it was 145 or so, I would be concerned.

I'll have to see what the tolerance is for compression on these engines. What engine has yours got -ARC or AVY?

[mark53]

the engine code is AVY

[mark53]

sorted

[6n2stan]

For future reference Mark, what was it?

[6n2stan]

My bad, I've seen the other thread