Cylinder Compression Test For The Xu10j4rs

[SurGie 54]

Iv been to the starter specialist this afternoon and the starter works fine

It's saved me £65 anyhoo

 

After i talked to the engineer, i was told i should have not connected the small live to the rear connection (in purple arrow in the picture) as

described as the spade connection which looks like a spade shape. What i believe members meant was to connect a small live from the main

positive to the alternator connection bit in red VV. He also advised me to connect the earth from the starter (the white arrow) to the Neg on the

battery, not the gearbox which i can't see why really.

 

I know its not complicated, i just wanted to know "for sure" the sequence of where the wires should go. Fitting a new starter to a car (which i have

done a few times over the years) is slightly different to making a starter work on its own. Although, i now know that the live from the alternator

makes the cog pop out to start the engine, it then pops back when the battery is charging or engine has started, i believe.

 

I will be doing the compression test tomorrow night now.

 

Here's the picture ~ VVV

[davev 1]

i though this pic i did was clear enough to see. but i guess not.

 

http://forum.205gtidrivers.com/uploads/mon...-1257594322.jpg

[SurGie 54]

Thanks, looking back i must have missed that one. ^^

[jackherer 543]

Although, i now know that the live from the alternator

makes the cog pop out to start the engine, it then pops back when the battery is charging or engine has started, i believe.

 

No, the cog pops out when you turn the ignition key which sends power to the spade connector and it goes back when you release the ignition key when you hear the engine start, its got nothing to do with the alternator at all.

[SurGie 54]

Not sure why the cog in my motor spinning didn't pop out when i checked it then, unless its because i connected the small live wire

to the back "spade" connection in purple.

 

Oh well sorted now, no problem.

 

Im hoping to get 200 psi

[Cameron 16]

That would be why.

[taylorspug 7]

You shouldnt be connecting a live to that spade at all, in fact you shouldnt be connecting anything to it. The only connections you need to make are the ones posted in Davev's picture. And of course stick the negative lead from the battery onto the gearbox.

[SurGie 54]

Well i managed the time to do my cylinder compression today and im very pleased with the results i got

 

This is from the gearbox onwards ~

 

Cylinder # 1 was 225 psi

Cylinder # 2 was 240 psi

Cylinder # 3 was 230 psi

Cylinder # 4 was 220 psi

 

Cylinder # 1 first came out as 210 psi, which i thought was not bad. I then did the rest of them & they came out a fair bit more, so i re-tested

the first one turning the compresser round a little tighter in the spark plug hole and it came out better.

 

I understand that its ok to have a maximum of 15% difference in each of the cylinders, which i managed to get way within

this percentage.

 

I was quite surprised on the results, especially with the 240 psi one with the engine being cold N all

 

One thing was the live wire on the battery melted a bit, so taped it up and let cool before each cylinder test.

The next thing now is to start a project thread, which will start with the engine bay weld, re-spray, sub frame etc.

 

Pictures below show each cylinder test, not in order though as the picture load dont seem to let me do it in order.

Edited November 14, 2009 by SurGie

[jackherer 543]

Those figures are nice and high, should perform very well.

 

One thing was the live wire on the battery melted a bit

 

Sounds like you should be using a thicker wire!

[MrP 1]

I know people say if you have the throttle open that you would get lower readings, would this be so if you had throttle bodies on instead of the standard inlet manifold, would you get lower readings.

[welshpug 1,657]

whatever inlet you have you will need to have the throttle held open.

[MrP 1]

Oh ok didnt know that what difference does it make, would you expect lower compession results running throttle bodies.

[welshpug 1,657]

no