Bruunz

*Edited so it's not a horrible post

Hi,

As the title suggests, how important is it for the engine to be at operating temps when doing the compression test?

The reason why is i went to do the compression test after having the car warm and found my tester to be broken. All the plugs are removed and i only have one set of new plugs to put in. I don't want to use these new plugs if to only remove them once the car is warm. Can i do the test cold without the plugs?

I believe i have fouled a plug due to excessive crank pressure and blow-by via the PCV. Ideally i would like to save these plugs from my possible issue until i change the PCV and clean out my TB.
Although in my head i want to know if compression is good before doing all of that work.

I'm kinda stuck with a chicken or the egg scenario.

Thanks.

Car Analogy

Ok, so it seems your plugs are already out, and engine warm, only to discover your tester is broken. So by the time you get a good one, engine will no longer be warm. So either you'll need to put the plugs back in, drive till warm, then redo the whole test, or do the test cold.

Honestly it took me a bit to piece all that together from cryptic post.

Anyway, just do the test cold. What is most important is variation from one cylinder to the next, and that won't be affected by cold engine. But your numbers will all be lower than they should. So you won't be able to compare your cars numbers with other cars. Only compare your cylinders with each other.

You probably won't be satisfied with that though. So you'll probably end up wanting to do it warm. So do both. Do it now cold, do it again warm. See how much of a diff it makes. Then report back here. It would be a valuable data point that many here would greatly appreciate, myself included!

Bruunz

Wow i just read my message and agree - cryptic with horrible grammar to boot! I'm going to say i was tired and defeated when posting but it's still no excuse. Thanks for persevering with my message and working it out

Reckon these plugs are worth using even for a test? I developed a misfire over weekend which prompted me to start all of this.

3 and 4 had oil on the thread and 3 had more than 4. I'm fairly certain the issue is caused by excessive crank pressure which is making me pass oil through the intake and inevitably fouled a plug.



Cylinder 1


Cylinder 2


Cylinder 3


Cylinder 4


Cylinder 4 - 3 - 2 - 1

lesnev2000

Those plugs are worn out. I got my 2002 2 years ago and the plugs looked similar, I think mine were original with 90k on them. The difference in performance with new plugs was remarkable on mine.
If I remember your original post wording, your tester would not hold pressure. You won't get a usable reading without the tester working properly.
I would put the new plugs in, go get a new compression tester and them do the test if you think you still need it.

Bruunz

Correct - Tester would flap to no higher than 120psi and leak back to 0 as quickly as it rose. Could feel the air escaping from the tester.

Those plugs are about 6~7 years and 30,000km.

Im going to go around to a few workshops in my area and see if i can borrow one.

Bruunz

Update;

Decided to put in new plugs anyway. I will do the compression test another time. No point in holding myself up over it.
I still have a misfire. Tonight i will removing the coil packs whilst engine is running to try and identify if its a coil pack that is faulty.

Bruunz

So i found that i have a dead coil pack in cylinder #4 - i tested this by disconnecting the injector connectors to help identify which cylinder was the issue. Then swapping the coil from the suspect cylinder to another and replicating the issue.

Ordered the Denso Ignition Coil 673-2301 and will replace them all.

Meanwhile i am still on the hunt for a new compression tester.

roel03

Why don't you just order one off Amazon? Or go to harbor freight or any local parts store?

Car Analogy

The Harbor Freight one is very inaccurate at the higher pressures our engines produce. Rent a decent one for free from Autozone or similar store.

Bruunz

I'm from Australia. The faulty one i got was from amazon. I can't seem to return it as the site sends me in loops. Not sure if the cause is because its been 30 days beyond delivery.
OTC 5606 Kit https://www.otctools.com/products/co...ion-tester-kit

The same kit is $300 here from SuperCheap Auto - our version of auto zone i guess.

I'll have to wait for the weekend and go buy and have a look.