My '90 4Runner has no power. I also have to let it warm up at least 5 minutes before I can drive it. I've got the 3.0 V6. When I put it in drive and step on the gas it barely picks up. Even if I put the pedal to the floor it just slowly chugs forward. I can put it in neutral and rev the engine with no problem. I tested the compression on 2 cylinders and go 90 psi on both. It seems low, but idk what 4Runners are supposed to get. I'm not sure if it burns oil, I haven't driven it long enough. Anyone have any ideas? thanks

 

90 psi is not near enough. my have a burnt valve? what else have you found cause that really isnt enough info.

 

should be 170 w/ a min. of 142.

 

x2 on 90 psi is too low

Which cylinders did you check?

When was the timing belt replaced?

Not that it has anything to do with the low compression, but have you checked the ignition timing?

 

idk when the timing belt was replaced, maybe never. I checked cylinder 6 and 4 on the driver's side. this is also the first time I've done this, maybe I did something wrong. I disconnected all the other plugs and checked 6, cranked the motor over and took a look, it was about 93psi. Same thing on cyl 4, same reading. I left the spark plugs in the other cylinders. just disconnected the wires. I made sure everything is back in order. It idles fine, just no power when in gear, or under load I guess u could say. it only has enough power to get up and go after its warmed up, its best when its fully warmed up. does that mean anything?

 

Sounds like the Head Gasket recall has bitten you and likely has wasted the engine too. To lose that much compression just due to leaks at the headgasket is unlikely. More likely that it's been failed for some time, that you've continued to operate it and that you have severe pitting of the cylinder walls which is causing the loss of compression. (what happened to mine)
Antifreeze in the combustion chamber can also cause severe detonation which can burn holes in pistons and crack heads.

The good news is that Toyota knows all about this. There is a recall program and if you play your cards right you'll get a new engine out of the deal.


First thing to check is the radiator fluid and the oil cap. If the underside of the oil cap is milky or the antifreeze is oily it's the Head Gasket. So check this first.

Next up are things like cracked pistons, stuck rings and other 'non-recall' failures from either abuse or neglect.


My advise would be to take it to a Toyota stealer and have them diagnose the problem.
If it's the recall and they'll do it this is a no brainer.
If it's not the recall or Toyota refuses to stand behind the recall (technically it's been ended) then discard the 3.slow and do the swap to the 3.4 (cost wise it's about the same and you'll have a way better engine.)


Fyi: severe coolant leakage can also damage the O2 sensor and the CAT, though it's unlikely Toyota will replace them under the recall you should replace them.

 

honestly I don't want to put any more money into it. its got other issues beyond a motor. do you think there is any chance this is a timing problem? or does the compression negate that? did I run my compression test correctly?

the other thing, there's no smoke from the motor ...