2.7l dies when under load. limp mode?

Hey there I've tested my truck a bunch and I think I've found the answer but need some more help.

I have an 09 2.7l tacoma. It had an exhaust leak that burnt the o2 sensor, which I then fixed. After that the truck just ran weird until it seems like it put itself in limp mode, wouldn't rev past 3k and would be bogging hard in 4lo trying to crawl up slight hills in the city.

I did a compression test which yielded:
cyl1 - 117psi
cyl2 - 120psi
cyl3 - 160psi
cyl4 - 165psi

After that I did a leakdown test, and had air from cylinder 1 leaking into cylinder 2. Enough that it couldnt hold compression.

Cylinder 3 and 4 were leaking into each other as well but not as drastically as cylinder 1 to 2.

I was thinking cracked or warped block/head but it was consistent no matter the piston position so I'm thinking it's a head gasket that went.

If anyone has anything to add it would be much appreciated!

 

Did the engine over heat at any time prior to all of this? The 4 bangers are not known to blow head gaskets very often without cause.

Why do you think a cracked or warped block or head?

Sounds like a rebuild or a used engine is in your future.

 

No white smoke, coolant was fine (no oil in it), and didn't lose coolant at all. Engine never overheated at all.

The cracked/warped block idea was just that. An idea, due to no telltale head gasket signs.

Honestly the head gasket idea is also just a guess, slightly more educated than the other guesses but still I don't have any proof until I take that head off.

And this motor got swapped back in March so I'm really not feeling like putting another in there. This is kind of just leaving a sour taste in my mouth for this 4cylinder motor.

 

I think I'd first do an exhaust backpressure check to make sure the catyletic converter isn't plugged, that could definitely cause low power.

 

Compression test lets you know something id DEF up. Redo it and see if you get the same results. If you do, regardless of WHAT it is, you are pulling the head to either fix a head gasket, valves, and to potentially inspect the pistons/rings/bores.

 

117 & 120 psi seems really low.

Did you hear air coming from the exhaust or intake during the test?

 

Did you try a wet compression test?

 

Wet compression on cyl1 & cyl2 yielded 123psi in each.

 

Nothing from the exhaust or intake that we could hear or feel. When plugging cyl2 with a spark plug it could be heard down in the motor near the crankshaft.

 

Hard to say, but that sounds kind like rings to me.

 

Not too confident on motors, but how do bad rings make cylinders leak into each other?

 

If you hear it down in the engine, the sounds like it’s leaking passed the rings into the crank case.

Most head gasket failures usually fail between coolant jackets and cylinder.

 

What makes you think it is leaking between the cylinders?

 

It’s probably blown a head gasket.

 

I can feel air leaving cyl2 when doing a leakdown test on cyl1.

 

Ohh, so then with the fill cap closed leaving through cyl2 is the least resistance for the air. Ok, I'm going to take the head apart and look at those.

 

With the low PSI you have, the head needs to come off anyways. It’s still possible it the head gasket. But once you get the head off, you’ll have a good idea.