Newcomer5

In the FSM compression check instructions it says to fully open the throttle and crank the engine to check the compression. To do that do you just push down the gas pedal and turn the engine over by trying to start the car with the igniter disconnected? Thanks for any help on this.

TOYOTA 1

yes, make shure it is unplugged! and you only need to turn it over for about 5 seconds. oh and make shure the engine is warmed up!

Newcomer5

Thanks for the confirmation. I didn't want to toast myself. So I checked the compression and got 160-180 PSI in all except #4 which didn't budge the meter past 0. From doing a little reading, it sounds like a need to take it in for a leak-down test at the shop.

I'm a student with not much money. Any suggestions on anything I could do myself to get to the bottom of this/fix this without paying thousands?

Thanks

91Toyota

Pour some oil into that cylinder and see where it goes...or take off the valve cover and see whats going on...you may not be able to tell though.

Good luck!

eric-the-red

Before you take it in try the compression test again on that cylinder after squirting about an ounce of oil into it. Usually if it's bad rings the oil will seal them up a bit and the compression will go up. If it's a bad valve it won't have any effect. Though with a reading of zero it sounds like a valve isn't closing or is broken.

Newcomer5

I tried putting in a little oil and rechecking. Still read 0. Guess I'm screwed huh.

eric-the-red

Definitely sounds like a valve isn't closing on that cylinder. A leak down test will tell 100% for sure, but you're looking at minimum a rebuilt head on that side.

Team420

Whats the best way to perform a leakdown? I have never done it before, and may need to on my 93.

zlathim

The best way? Buy a leakdown tester and hook it to your compressor. Screw the adapter into the sparkplug threads while that cylinder is at TDC compression. The gauge on the tester will show % of leak. Check intake, exhaust pipe, crankcase, etc for escaping air. That will give yo a good idea where the leak is. The tester sells for about $40 at Harbor Freight, or you can spend several hundred bucks on a Snap-On model. I bought the cheap one and it worked great.

The cheapest method is to cannabalize the adapter off an old compression tester, hooked straight in-line with your air compressor. No gauges, no readings, just listen for the leak at all the suspect areas as above.