Tacoma 2.4L 2RZ 4cyl low compression

[JDang444]

Hello everyone,

I noticed my car’s running slightly underpowered and my fuel trims are high under even a light load. At idle the Long Term trim is 0, but at even slight acceleration, the Long Term trim goes to +10. I’ve checked all the vacuum hoses and the fact that LTFT is at 0 during idle tells me it shouldn’t be a vacuum leak. MAF has also been cleaned.

I did a compression test and the results were

150psi
130
90
145

With some oil squirted into the weak cylinder, it goes up to 120psi.

Now that I know it’s most likely a problem with the rings sealing, what are my options? The truck does not shake or have a misfire, although I think I can feel some kind of vibration when trying to accelerate up hills.

Will this eventually lead to a major and expensive repair? I know I could do a leakdown test and find out exactly what the problem is but it’s going to be an expensive fix no matter what right?

What should I do, sell it now? or do you think I should just drive it until it dies.

Topic

[dave]

Well, you got a couple of options:

1. pull the head. drop the oil pan. disconnect the connecting rod, pull the piston and replace the rings.

2. get a replacement engine from your friendly local salvage yard. compression test the engine before you buy it. look for a car with no front end damage and low miles.

This is a common problem with no easy fix. I have been discussing ideas with other techs and school professors on some possible ways to approach this problem. One solution that we have in mind would involve removing the push rod of the affected cylinder and re flashing the computer so your vehicle would run on 3 cylinders. This solution would obviously work better for some cars than others.

Another idea would involve keeping the top of the cylinder “wet” with a special clean burning lubricant sprayed into the cylinder just prior to the compression stroke. This would tighten the seal, similar to what you did with your wet compression test. This idea would involve the use of a specialized spray nozzle spark plug.

As far as I know, none of these ideas are on the market. All I need is an investor and I will have a solution for you on store shelves in no time. B)

[Author]

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