Advice on compression test results?

Performed compression test. Test was performed with all spark plugs removed, coils disconnected, starter relay triggered manually and wide open throttle

Manufacture spec - 178psi or more, minimum pressure of 127psi, difference between each cylinder - 14 psi or less

dry compression
Cylinder 1 - 160psi
Cylinder 2 - 150psi
Cylinder 3 - 150psi
cylinder 4 - 150psi

Compression is slightly lower then spec but all cylinders are within the 14 psi difference.

Wet compression test - added 1/2 ounce of engine oil to each cylinder. Adding oil will create an additional seal above piston rings
Cylinder 1 - 175psi
Cylinder 2 - 160psi
Cylinder 3 - 160psi
cylinder 4 - 160psi

Performed cylinder leak down test disconnected PCV hose to eliminate air leaks to intake
Cylinder 1 - 20% leak
Cylinder 2 - 30% leak
Cylinder 3 - 30% leak
cylinder 4 - 30% leak

On all 4 cylinders majority of the air leak can be heard from crank case through oil dip stick. Minor leak can be heard from exhaust on cylinders 2 and 3. Manufacturers do not specify allowed amount of leak past cylinder rings. Leak down test is simply a test to compare one cylinder to the others and look for Abnormal behavior.

Engine has high mileage and piston rings are worn. Used a bore scope to inspect cylinder walls. No scoring is noted from what the camera will show.

Engine stumble is minor and is not registered as a misfire by PCM. Could be caused by the compression imbalance between cylinder 1 and other 3 cylinders.


Recommend performing air induction service and customer drive vehicle as normal. Readdress as needed if stumbling gets worse.

Now I have replaced and
Rebuilt everything but the transfer case and rear end.just about.including driveline..so I don't wanna let go I love my truck...
Anyway the thing I think is weird is my 4× stick vibrates along with the gas pedal like in unison. But not the transmission stick.and they say is from my engine.does that make sense to anyone else?.
And what should I do they say they can't rebuild for a shortage of parts.cant be help I was told Not now.so is that strange.amd how much would a rebuild cost..thank you for your feedback

 

I don't have any advice... but we got tons of old heads 1st gen owners here!

 

How many miles?

 

Someone correct my if I'm wrong. But im fairly sure the reason your 4x4 lever shakes and your transmission lever doesn't is probably because your transmission lever is remote mounted and attached to your transmission via a cable(assuming its an automatic). Your transfer case (4x4) stick is probably mounted directly to your transfer case therefore is more likely to vibrate the same way your driveline does

 

Yes this is at least how it was on my older trucks with manual transfer cases. Auto trans is shifted by cable or nowadays by electronics. Manual transmission has linkage with attachment to the bodywork. But transfer case shifter is just a lever sticking up thru the floor. Never had a 1st gen Taco though.

If the transfer case is moving a lot, consider replacing your engine and transmission mounts. They wear out.

Those compression numbers look fantastic to me for an old truck. Yes, there is wear, but not too much. Manufacturer spec is for a new under-warranty engine. I have driven tens of thousands of miles on engines with far worse numbers before they started missing and throwing codes.

Give it a tune up and enjoy the truck. Do regular maintenance and keep the fluids fresh. That's my advice.

Welcome to TW.

Edit: to address your question regarding cost, I have no idea, and have never seen the 2.7 engine or even driven a first-gen tacoma. Also I'm not a mechanic, not even close... have only done shade-tree repairs to the small handful of vehicles I've owned to date. Finally, you didn't specify where you live in your profile, which makes a huge difference as to the cost and viability of repairs. If you live in the rust belt, for example, your truck is probably already on borrowed time.

But here's what I'd guess based on recent experience living in SoCal and deciding whether to rebuild my last truck's engine or find a new used truck to love, ultimately deciding for the latter. This is based on costs for a domestic V8, blindly and naively adjusted for what I'd expect for an import 4cyl engine, based on absolutely zero experience with these engines.

You can find shops that will rebuild your engine with shitty parts and no attention to detail for $1-2k. Hopefully the reviews and horror stories will steer you away, but some folks get lucky with this approach. More reputable shops won't even quote a rebuild, as modern engines are costly and risky to properly rebuild. They'll offer a rebuilt (e.g., Jasper) engine with a solid warranty for $4-6k installed. Another option is to roll the dice on a junkyard motor for maybe $3-5k installed. If you can do the work yourself you could do a proper junkyard swap for less than $2k.

This is all speculative though, and in my opinion unnecessary as your engine seems to be reasonably healthy based on the info you provided. Give it a thorough tune up, you should be good for quite some time. Unless you live in the rust belt of course.

 

Only have experience with 6 cylinders, but a leak down test gave me those numbers-ish on a few cylinders and it was usually leaky valves. Engines ran fine - I swapped 2 of them for an easy replacement instead of time consuming head work as I had the time and money to swap in newer motors as they were in vehicles I wanted minty. Consistent compression and leak down is good.

 

290,000

 

It's a manual.

 

Start a new thread here
https://www.tacomaworld.com/forums/1st-gen-tacomas-1995-2004.4/