Rough engine- did I kill my Taco?

Hey, folks... I'm a noob (my Taco is definitely not), and I'm searching for answers to a question that's got me worried about my '99 4x4 2.7L 4cyl Taco (stock, with Bilstein rears and Alcan 5 leafs). Tried lots of thread searching on compression issues and nothing similar stuck out.

Just hit 150k with it, with no tunes or anything major besides a new starter and new rack and pinion last year. It seemed to run a little rougher last fall, and a jeephead buddy told me to run some

$25 BG 44K Fuel System Cleaner Power Enhancer 11oz.

BG 44K through it to clean the injectors. Now it runs worse, with cold starting issues below 10 degrees (I live at 8000 ft!). Pretty much have to stand on the gas every time it starts. I took it to my local shop, and they checked the compression:

cyl 1= 150 psi
cyl 2, 3, 4 = approx 50 psi each

What exactly happened here?

Another friend said the BG 44K probably knocked stuff loose and burned/warped the valves. Can anyone corroborate this?

The shop told me it's a rebuild/replace/sell choice. It's still runnin' okay as my daily driver, but how long will it last?

I posted this on TTORA, and got a lot of advice to do a leakdown test to confirm if it's the valves, and if so, replace the head. Does anyone concur?

Thanks for any help!!!

Tyler

 

if your compression is that low in those 3 cylinders, it could either be rings or valves. try checking your timing and make sure that your not off. if your timing is off the valves could still be open while the motor is trying to make compression. also take a cap full of oil and drop it down in each cylinder and resest the compression and if the compression goes up, then your rings are bad. does it knock??? ttora is a much better site to get info btw, just my 2 cents haha. hit me up if you need anymore info or have anymore questions

 

A easy way to check if the valves are bad is to start the truck and then get out of the truck while it is still running take some toilet paper and hod it at the end of your exhaust pipe if at any time the paper tries to suck into the pipe you have bad valves

if it passes that test it could be rings or head gasket

 

The toilet paper test does not necessarily indicate "bad" valves. It can also indicate timing problems or something as simple as a stuck valve. You can use any kind of paper. If your exhaust sucks it against the pipe at any point, there is a problem, but it might not be a major one.

Also, I would be cautious about putting more than a "capful" of oil into your cylinders, as any liquid poured into the cylinder will not compress like a gas and could raise pressures to an unsafe level, causing damage to rings, valves, rods, and even pistons. What the fellow is saying is correct, though, that pouring a couple squirts of oil in the cylinder will sort of seal worn rings for a few minutes (until it burns up) causing the compression readings to increase, but if you pour too much oil in, you can do a lot of damage. You can also tell if your rings are worn by simply looking out your rear-view mirror. If you are trailing blue smoke when you accelerate or decelerate, your rings are worn out. If you get a bunch of blue smoke when you start up, but it goes away after warm-up, your valve guides are worn (oil leaks into the cylinders through the valve guides while the vehicle is sitting overnight, then burns out when the engine warms up).

The over-the-counter fuel treatments for cleaning fuel injectors is one of the few things in a can that actually works. Get a good brand name, like Gunk or STP and try it again. If it is a problem with injectors, it will help.

With what you have indicated, I would suspect either a blown head gasket or a cracked head, but that doesn't normally affect three cylinders; normally just two adjacent ones. To have one cylinder so high and the other three low, but similar pressures, does not indicate normal wear. If all were at 50 lbs, and if your complaint was blue smoke while driving, I would be thinking rings. If three were at 150 and one at 50, I would be thinking broken valve or something on that one cylinder. This could even be something like a valve timing problem where in the valves are a little open during the compression stroke on three cylinders, due to a very worn timing chain.

My recommendation is that you run your pickup in to a reliable shop, such as a Toyota dealership, and have them put it on their machine to analyze what's wrong. They will tell you what the problems are and will give you an estimate for repairs. You can probably beat their estimate at other shops, but in all likelihood, the Toyota place will do a more complete repair with and do it with Toyota parts and a warranty.

You might also consider buying a used engine and having it installed if your estimate comes to over $1500. There are plenty of them out there with moderate mileage.

 

look on craigslist. i found a couple taco engines on the VT one when i was looking for one. they werent over $800 (and all 6cyl).

 

Check this out, $3k installed for a new one:
http://denver.craigslist.org/pts/1109402577.html

 

THENRIE-great analysis

 

Ditto on that, audi2000. Thanks for the info, guys. I'll be getting a leak down test done, to figure out intake valves vs. exhaust valves vs. rings (partly per advice from ttora, as well). If timing is an issue, well, then, that's a whole 'nuther bag o' worms. Hopefully the only thing I'll have to do is replace the head (rather than have to do a full-on engine swap). Although upgrading to a V6 wouldn't be all that bad, huh? I'll let you guys know how it plays out.... Thanks again.

 

Hey, guys... just thought I'd post a belated update: Took it to my local dealership (45 miles away), and they ran it through the gauntlet of tests. Verdict: bad valves. So they tore into it and found the exhaust valves were burned due to bad timing, along with burned valve seats (had to machine new seats in the head).

$2700, including a new timing chain, and she runs like a top, with 5-7 more mpg. Thanks for the advice, I feel like she'll last me another 150k at least.

 

Glad to hear it worked out for you!

 

Thats what was wrong with mine, i found a guy to give me a rebuilt motor, new belts, steering belt, and alot of other stuff for just under 3k. just about the same price,
glad it worked out for you. most the places i took it to here wanted like 4.5k to fix mine, and mine was just the #3 cylinder.