Compression in TA22

[Sirsh]

Hi,

Does anyone know what these compression readings tell about my engine?
Cyl 1 - 145psi, Cyl 2 - 145psi, Cyl 3 - ~132psi and Cyl 4 - ~132Psi. I did it when the engine was about 50degrees as it takes too long for my car to warm up to the operating temperature of 80degrees. According to the manual I got with my compression testing unit, it means my engine has Late ignition timing or Leaking pistion rings..
Exact extract: " 2. Late ignition timing or leaking piston rings. The gauge behavior will be very much like a normal engine. Except that all readings will be down 3 or 4 divisions. Run a compression check if you havent already. If the compression is good, the ignition is late." Im not sure what a compression check is Lol. Also, the 'needle' should be steady between 17 and 21 with the engine idiling (170psi and 210psi).

I didnt know that the compression in all cars were the same?

Cheers,
Hope you can help,
Tyler.

[lukey1003]

Did you check the compression with the car idling off 3 cylinders? You should be removing all the spark plugs and checking the compression at cranking speed as far as I know.

According to the workshop manual I have the compression should be about 170psi (Minimum 127.9psi with less than 14.2 psi difference between cylinders) at 250RPM, so this would suggest you don't start the engine.
By the looks of it I would say your rings are a bit tired, but I wouldn't rule out timing either, get someone to check it with a timing light.

[Sirsh]

How do I check it running off three cylinders? I removed all the plugs when I did the test. My ta22 idles at 900rpm would this effect the reading?

[lukey1003]

Ohh if you checked it with all the plugs removed that is fine. I was just confused by this line.
"Also, the 'needle' should be steady between 17 and 21 with the engine idiling (170psi and 210psi). "

[Sirsh]

On the compression tester dial that needle, it has units of 0-30 which are equivilant to 0psi-300psi. In your opinion, just from the facts ive told you, do you think might be wrong?

Cheers,
Tyler.

[airfireman1]

You should make sure the throttle is fully open when doing a compression test. Remove the coil lead and all the plugs. Crank the engine over about half a dozen times and take a reading, it should be around 170psi. If it fails to reach that by a long way, say around 145 you then do a "wet test". That is done by squirting about a teaspoon of oil into the spark plug hole then doing a compression test again. If the compression reading is better then it shows that your rings are tired. If no improvement then incorrect valve adjustment or worn valves can be the problem. Even pressures on all cylinders are better than 1 cyl having bugger all compression as that can be head gasket,valves or piston problems.

[Sirsh]

Thanks alot Dave, I will do that testing method when Im working on my car again. Also, you may be able to help me out, I just brought a new Bosch GT40R coil pack and went to install it and my car wont idle, the only way it will run is if my foot is to the floor on the accelerator and the key is turning over the engine. The car had a Bosch GT40R coil in it before with the external resistor, I connected that back up and now thats doing the same thing :S??

Thanks,
Tyler.

[airfireman1]

The problem is that you have wired the ballast resitor wrong. There should be 2 wires going to the resistor, 1 provides 12v when the ignition is in the on position, the other provides 12v only when the key is in the start position (cranking) If the wire that only provides power when cranking is connected to the coil before the resistor the car will only run whilst cranking, this needs connecting so that it does not use the ballast resistor, you can easily check this with a multimeter. You can trace this wire as it comes from the wiring loom near the starter motor. The 12 volts wire that provides power when the ignition is on should be connected so that it passes thru the resistor first and then to the coil If you have problems pm me and I will ring you

[Sirsh]

Okay so the ballast resistor is the whole rectangular prism with one end wired to the coil and another to the relay (I think) and the one from the starter motor is directly wired to the coil, so If I change these over it should start? There is a wire from the distributor, one from the relay, one from the loom near the starter and one on the alternator I think and two wires that are connected to the resistor.



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Also, Thank you very much for the offer to help me. I'll give it a crack after work tomorrow and if i get stuck ill give ya a call

Cheers,
Tyler.

[Sirsh]

double post oops

[allencr]

Vacuum gauge? No manual for a compression gauge is going to mention 'late ignition timing' or especially ''needle' should be steady between 17 and 21 with the engine idling (170psi and 210psi)'. Chinese to English translation gibberish plus mixing 2 separate things! Toss it & search WWW for something better to read.
145 to 132 isn't great, it's poor but might stay that way & drivable for another 50,000km. They may actually be equal and it's only lower because the cyls oil is getting wiped off & starter is slowing down the more you crank.
Don't worry about the engine temp, you're only looking for a comparison between them and not an absolute & accurate number.
**
Also, the accuracy of a gauge with such a screwed up manual is hardly any question at all.

[airfireman1]

Looking at my wiring diagram you seem to have an extra RED with Black trace wire attatched to the coil.
Black with red trace should be connected to the coil + That comes from the ignition circuit and provides power to the coil only when cranking the motor over, Black should be attatched to the coil - and Black goes back to the distributor points, Black with a yellow trace goes thru the ballast resistor to the +, and you should have a small link to the coil + from the top of the ballast resistor that is the other end of it This provides 12 volts for when the engine is on or running.
The theory behind all this is that you will get 12 volts to the coil when starting the engine (maximum spark). When the engine has started you dot need 12 volts to the coil as it causes the coil to heat up, so by passing the volts to the coil thru a resistor you bet a reduced voltage to the coil and the coil remains cooler when driving.
This is very easy to verify with a volt meter. You should also be able to establis where that extra wire goes. Just to check this you can run a wire direct from the battery to the positive of the coil temporarily and your engine should stay running.
If you need to borrow a good compression tester let me know, Unfortunately I fly back up north for 2 weeks on wednesday otherwise I could have a look in perso, btw are you north or south of the river, I am up by wannneroo

[Sirsh]

Hey Dave,

Thanks for the information about the coil pack, I'll give it a crack when I get home. I'm North of the river, near midland in Jane Brook. Wouldn't mind seeing your 22 hey. I brought a TFT compression tester from SCA, what type did you have?

Cheers,
Tyler.

[Sirsh]

Dave, I used a tester light on the wires when the ignition is off, the light doesnt light up for any wires. I then used it on the wires with the acc on (ignition on but not cranking the car) and the only wire which lit up was the one coming of the distributor, shouldnt another one be lighting up too?

[airfireman1]

With the ignition off and no light thats good. You should only have power to one wire at a time as they operate off a different circuit from the ignition switch. One wire should have power when the ignition is on that one should go to the ballast resistor at the bottom, One wire should only have power when the key is in the start position(that is when cranking the engine over. The negative from the coil should go to the distributor (points). I would also suggest that you check your fuse box to make sure that the main engine fuse has not blown and that may be the reason that you have no power to the other wire.
I may be able to have a look tomorrow if all that fails. Just try a jumper wire about the same size as what is connected already, just a couple of small clips either end should do and connect it from the positive of the battery to the coil positive and try starting the engine. If it starts then you have either a blown fuse or the wiring is not correct.
My comp tester is in the shed (cant remember the brand) but not a cheap one and reads very well.