defining good compression not.

[Speedworks]

i rebuild my engine recently and it now has somewhat 5-600kms on i.

It\'s runningpretty rough allthough my AFR logs show good and safe readings


As I\'m trying to eliminate every possible issue, I also need to consider bad compression.

Not having a compression teser I need to stick to some other parameters for now.

Such as:

- hot and cold start: near perfect and allmost better than stock
- idle is stable
- vacuum (PFC boost reading) at idle is a steady -0.4kg vacuum (underpressure)

the last one seems to be a quite good reference to check compression.

Is this a good number??

Looking at my history with piston turbo ngines, most of the would run -0.5kg so if that is a reference, it\'s OK.

anyone got some input here?

[Prof]

Having had a badly leaking injector that made the rear rotor feel like it has blown, I can say I\'ve had some experience in sounding out the compression without having access to a tester by the side of the road :2Rolleyes
 
Your vac reading on idle seems fine - I get between -0.4 and -0.6 depending on RPM.
 
You could also try pulling the EGI fuse and cranking the engine with the throttle open - you should hear some good regular beats from the exhaust - if anything seems uneven it could spell problems.
 
Likewise, you can remove the plugs and listen for the pulses there too
 
If all else fails - try changing the plugs - that\'s worked for me before now too.

[Speedworks]

Thanks,

Will do that too... but in order is the vacuum at idle a reference?

0.4kg is good acc to me

it\'s stable. I guess that , if i have a face (or more) not making good compression, vacuum would be bouncing around.

[Speedworks]

Just to add... Leaky injectors were on my mind for a long time but looking at my AFR readings (wideband LC1) those are spot on wtih my target map.

[leon]

What if you mapped the car with leaky injectors in the first place? You may be getting the target afr but it does not mean that 1 rotor is running leaner than the other, or even richer.

[Speedworks]

true true... I still have some spare injectors on the shelve. I\'ll possible switch them over weekend, as well as switching the coils as I have a spare set for those as well.

could fuel pressure be an issue? as I still need to replace the fuel filter (no idea when the prev owneer did that, if ever)

upcoming as well is a 044 Bosch fuel pump but that won\'t be much help right now