Carrying out a compression test on a williams lump. What readings should i expect???

[Paddy_g46]

as title says im doing a test on the hybrid lump in the car im off 2 see tomorrow, what readings should i be looking for?? and should all 4 cylinders be exactly the same or can they be a bit out and not worry about it???

also is the procedure

1) warm engine up to moraml temp

2) disconnect lead from coil (the lead the feeds all the ht leads)

3) remove first spark plug and attach tester, turn engine over on key for 5-10 seconds, record reading, replace spark plug

4) remove plug 2 etc

5) test all 4 cyclinders ans compare readings


is that all the steps????

 

[Paddy_g46]

bump, im hoping some1 can help me with this 2nite as im setting off early in the morning!

 

[donsrno1]

Just make sure they are all the same roughly, should be around 13/14PSi iirc. I wouldn't worry too much about warming up the engine either. Just make sure you have the accelerator pedal flat to the floor each time you are cranking it over to take a reading.

Also, rather than remove the lead from the coil I would remove it from the dizzy cap end.

 

[donsrno1]

sorry I meant to say BAR rather than PSi

 

[Paddy_g46]

Just make sure they are all the same roughly, should be around 13/14PSi iirc. I wouldn't worry too much about warming up the engine either. Just make sure you have the accelerator pedal flat to the floor each time you are cranking it over to take a reading.

Also, rather than remove the lead from the coil I would remove it from the dizzy cap end.

if i remove form the dizzy cap though mate ill have a live king lead floating around lol, wouldnt i be better removing from the coil so there are no live parts hanging loose!

 

[donsrno1]

I've done it that way before without any problems tbh, just put it where it's not going to jump to anything. I replied over on WC explaining what someone else meant and tbh it's a better way to do it. Removing the king lead from the coil can just cause more problems as I mentioned on WC as well.

 

[Paddy_g46]

cheers dude

 

[donsrno1]

lol, don't get me wrong, your still a c*nt Just I thought I may as well reply, lol.

 

[stan*]

if you dont disconnect the feed to the coil, you risk blowing it since there is nowhere for the energy bnuilt up inside to go...hence why i said disconnect the plug ontop of it.

 

[Paddy_g46]

if you dont disconnect the feed to the coil, you risk blowing it since there is nowhere for the energy bnuilt up inside to go...hence why i said disconnect the plug ontop of it.

good point thanks mate!