7AFE Engine Misfire

[Nusdogg]

Ok, on my way to work today while driving my '95 Prizm LSi, I notice a huge power loss from out of nowhere. Got to work, had some downtime, and was able to take a look what's going on under the hood of my 7AFE. I pulled each wire one by one while car is idling starting from cyl 1 til I got to cyl 4 when it didn't do anything when I pulled the plug wire off.

I tested for spark on cyl 4 and had good strong spark by using a spark plug and had it plugged into the plug wire #4 grounded to the valve cover. Then I used a test light in place of a noid light on my cyl 4 injector connector and I have power coming in. Also had a screw driver against the cyl 4 injector and heard it clicking like it should.

But, I think it may be either stuck open or clogged/restricted. What do you guys think it may be? Compression was heard when I tested for spark through cyl 4, so it's good.

[TheNightWolf]

What brand plugs?

[Nusdogg]

Originally Posted by TheNightWolf

What brand plugs?

I don't remember what brand.

But I believe I narrow it down though. Compression loss due to worn rings cause it burned tons of oil and had 80% leakage from my leakdown test. Also, compression was around 120psi and were consistant. All these tests were done at the beginning of the year, but I'm going to re-check my compression ASAP to see where they're at.

[Bitter]

recheck compression and check the plug insulator for carbon tracking and the wire for cracks in the boot or burns that let the spark jump out.

[TheNightWolf]

Originally Posted by Nusdogg

I don't remember what brand.

But I believe I narrow it down though. Compression loss due to worn rings cause it burned tons of oil and had 80% leakage from my leakdown test. Also, compression was around 120psi and were consistant. All these tests were done at the beginning of the year, but I'm going to re-check my compression ASAP to see where they're at.

What is good compression on these engines?
is it 120psi?

I have a bet with people in my class saying that my compression is fine and my engine isn't tired. lol

[Nusdogg]

Originally Posted by Bitter

recheck compression and check the plug insulator for carbon tracking and the wire for cracks in the boot or burns that let the spark jump out.

I believe the plug and wire are good, because it gave out strong spark when we tested it. And I didn't get shock or anything when I tried to feel for it by touching the cyl #4 plug wire. But I'm gonna replace the wires anyway on Friday after I do the compression test.

Originally Posted by TheNightWolf

What is good compression on these engines?
is it 120psi?

I have a bet with people in my class saying that my compression is fine and my engine isn't tired. lol

I no clue what the spec is from Toyota on these 7AFE. As long as they're consistant then they should be fine.

[Nusdogg]

Finally got to doing a compression check. Before I did my compression check, I warmed the engine up to normal operating temp, and floored the gas pedal while cranking it over. These are the results, I was shock!

Cyl #1: 40psi(This one is pretty bad; PSI dropping big time.)
Cyl #2: 135psi
Cyl #3: 120psi
Cyl #4: under 5psi

I say f*ck it, and I'mma drive it over the winter with only three cyl. It drives fine but just roughs at idle in "D". Sounds like a Subaru with exhaust with only three cyl. I disconnected the cyl #4 injector connector so it doesn't dump in fuel and f*ck up anything more. By Spring, I'll perform another 7AFE swap. Should have enough save up by then.