Marc

I've searched the site for info on how to correctly do a compression test on a 91 3VZE but haven't found any info.

I don't want to damage any electonic components by doing it incorrectly.

I understand that I have to crank the engine while warm with the throttle body open but should I disable anything beforehand?

thanks

VolcomTacoma

Haven't done one on the 3.0, but you might want to disable the fuel pump so it's not pumping fuel into the engine without it being burned.

Fever

I just done this on mine and found my engine needs rebuilt. I have one cylinder 50 pounds lower than the rest. It is good you do this. Here is what I done.

1st with an air hose blow all dirt away from all spark plugs.
2nd remove all wires from spark plugs and remove all plugs.
3rd remove the electronic connecter wires from the coil ( this will prevent any spark from coming from the spark plug wires and shocking you. It will also save your coil. Rare cases shown that if you power a coil without the wires or and spark plugs you cna damage the coil and maybe explode the coil. The energy is built up and it needs to be discharged somewhere. I you do not know which wire to disconect, just disconect them all.
4th put your compression tester in one hole at a time. Crank engine and listen to three compression strokes. You will hear them. Four strokes won't hert. just do all cylinders the same.
5th write your readings down and compare. I do not like my compression to be any more than 10 to 15 pounds different between cylinders.

Hope this helps you and good luck.

Firefyter-Emt

Yep, that last reply pretty much sums it up. Toyotas run pretty high. A fair to good reading will be about 150psi (that would be great for a Chevy) But Toys can run will up to the 180s fresh. If you get a bad reading, add some oil down into the plug hole (a tablespoon) and re-test. If it goes up, it is normaly the rings, if it stays the same it is in the valves. If you are good with 150+ on everything and have tested for bad valves. Don't be automaticly preasured into doing the whole motor. Mine had heads done 20k ago and does not burn any oil at all. (now if I could keep the valves in adjustment, that would be another story!)

PS, IMHO. if yu do head work, replace the valves new when head work is done.. You may thank me for that later..

Marc

Thanks for the info. It was just what I wanted to know.
I've done lot's of compression checks on non EFI systems but this is my first with an EFI. Didn't want to blow anything up, I've got enough trouble without causing more.

I notice my manual suggests NOT removing the plugs when the engine is warm to avoid damaging the threads.
Is this really an issue?

Saiba Samurai

Is this the same for the 22RE?

I just picked up a tester, and I want to run the test tomorrow weather permitting.

Also, "3rd remove the electronic connecter wires from the coil," can someone draw me a picture for this? I have no idea which wires to disconnect.

bugs1961

It can be an issue. The steel plugs expand at a different rate than the aluminum head and can seize. I always pull the plugs out cold and put a fresh coat of anti-seize on the threads. Then reinstall the plugs and warm up the engine. You shouldn't have any trouble then.

Dixyboy69

You don't have these lined up right. Crank should be at "0" on timing tab and then your cam marks should fall on the dot. You are to far advanced in the crank wich is why the cams aren't lined up yet.