Uneven Compression... any advice?

[joes mama]

Hello,

I just bought a 1988 Toyota Tercel DX.

It is a one owner vehicle, has been well maintained, and has less than 100,000 miles on it.

It does not start due to low compression, and the readings (with oil) are as follows:

timing belt <- 210, 185, 90, 165 -> transmission

According to my haynes manual, the fact that the first stroke was low and each successive stroke the psi raised suggests that the culprit is the rings. The haynes manual even used the word "defintely."

I really hope that the haynes manual is wrong.

Does anybody know of something else that could be the cause of this insane compression? It just seems too unlikely to me that a engine so well maintained with such low mileage could already be in need of a ring job. It also seems strange to me, assuming the rings ARE the culprit, that all of the rings would wear so differently from one another.

If it IS the rings (god forbid), does anybody know of anything I can do (save a full on ring job) that will extend the life of the engine and get the compression back up to normal?

thanks for any answers in advance, and sorry for the long post.

- Casey

[Gasoline Fumes]

Those compression numbers suck, but they shouldn't keep it from starting.

[joes mama]

really? according to the haynes manual, 185 PSI is normal, and 154 PSI is the minimum for each cylinder. I assumed that minimum meant the minimum for the car to still run...

it also says that the maximum deviation between cylinders is 14 PSI, and I am WAY higher than that!

i checked for spark, and it's fine in that department. should i check for fuel delivery?

i assumed that with those crazy PSIs the car wouldn't start, period.

[takza]

It should start. If the spark is OK...try some starting fluid...but have an old blanket handy.

Adding some oil to the cylinders might confirm if it is the rings.

Might try cleaning the rings?

[coltarms]

Assuming that the head gasket is good, there are really only 2 places to lose compression; valves and rings. I assume that you squirted a little oil in each cylinder before you took the compression checks that gave you the numbers you posted here, but did you do a dry check first? If the numbers go up with the addition of the oil, it is indicative of failing rings. If they stay the same, it points to valves. Are your valve clearances set properly? Pull off your valce cover and do a cold checl to make sure you're in the ballpark. I believe the manual calls out for intake .007" and exhaust .011" with a cold engine, but be sure to double check. Also, Typrus' Seafoam Treatment could really help in removing a lot or kaka from the pistons, valves, and cylinders.

If this were my car I would do the following:
1. Verify Spark; rotor & cap, test batt, wires, and plugs.
2. Verify fuel delivery; carb site glass, accel jets in carb should squirt, fuel pump should hold pressure and arm should be on gear on camshaft.
3. verify air: choke, air mix screw if necessary, replace all vacuum lines including vacuum advance. Verify hose connections.
4. Get car started. Disable EGRsys for time being.....

It's not uncommon for a "well maintained" car to not me well maintained. I've known lots of people that regularly wash, wax, pay come clown for a "tune up and oil change" but never ever change diff fluids, transmission/transaxle fluids, adjust bands in auto trannys, replace tranny filters, flush coolant loops, replace vacuum lines, adjust valves.....or just warm the damn thing up in the morning!

[xirdneh]

It does not start due to low compression, and the readings (with oil) are as follows:

timing belt <- 210, 185, 90, 165 -> transmission


i agree that it should start in spite of the low readings.
these cars keep running

squirt oil in that low cylinder and try compression test again
compression should increase
if not the exhaust valve may be burnt

if two adjacent cylinders are low the headgasket may be it

[joes mama]

all of the readings were with oil added.

i took a reading of the #4 cylinder (the one that reads good 185 pressure) before adding the oil and the pressure was lower. this may indicate worn rings, but #4 is not even the cylinder with low compression.

i will take a look at the valve clearances, paying special attention to #3. is there anything I can do/see without removing the head that will clue me in as to the condition of the valves?

thanks a lot for the help guys. i really believe this is a good car...

- Casey

[xirdneh]

i will take a look at the valve clearances, paying special attention to #3. is there anything I can do/see without removing the head that will clue me in as to the condition of the valves?

but did you take a reading before adding oil
to see if psi increased or not after adding oil?

thats the only way i know of short of a "leak down test"
to tell if valve is burnt

valve clearances can be good with some burnt valves
so may or may not be able to tell anything from that

[Mickey_D]

It's not uncommon for a "well maintained" car to not me well maintained. I've known lots of people that regularly wash, wax, pay come clown for a "tune up and oil change" but never ever change diff fluids, transmission/transaxle fluids, adjust bands in auto trannys, replace tranny filters, flush coolant loops, replace vacuum lines, adjust valves.....or just warm the damn thing up in the morning!

You ain't kidding!! My father BABIED his Neon as it was the only new car he ever bought. But he never listened to me about the tranny.

112,000 miles and he never replaced the filter or fluid in it. Quickest way to destroy a Chrysler auto tranny. And now I'm stuck trying to keep it running for the wife, and she has the auto maintenance skills of a brick......

As to the OP, how long had the car sat before you got a hold of it? If it sat unattended for a while sometimes moisture can get into the cylinder and you'll get a little rust on the walls. I had this happen with an old Honda motorcycle. I wondered why a 125 could barely haul my skinny butt until one day it all just went "pop". It just so happened on a hill under full throttle!! I looked like a complete idiot as I all of a sudden did a wheelie. I don't know which was louder, the bike or my girly scream!!

[joes mama]

update...

i found out that the (manual) fuel pump was bad, so i removed it, cleaned it out and put it back in and the flow seems fine. i replaced the plugs, primed the carb with starter fluid, and tried to start the car with the pedal to the floor. it acted like it wanted to turn over but it wouldn't catch. a little combustion was going on because the tailpipe was emitting some smoke here and there.

just an idea, but could the year-old gas be the culprit?

thanks in advance.

casey

[ARCHINSTL]

just an idea, but could the year-old gas be the culprit?
thanks in advance.
casey

Possible - at least partially.
When I collected my car last year, it hadn't gone 300 miles in 3 1/2 years, so I used Typrus' favorite fluid (Seafoam), and filled the tank the rest of the way (6 gallons), and it made it back OK from TN to MO.
It might be a better idea to drain the tank, if possible, and start with fresh gas and then some Seafoam (or similar).
Tom M.

[joes mama]

i have seafoam, but i am reluctant to use it until i actually get the engine started.

the last thing i need is another variable right now, and seafoam is intended to be used at full operating temperature...

i am beginning to think it is the compression again, because i have eliminated the other variables.

why is everyone so sure that it should start with my compression numbers? according to the haynes manual it shouldn't start if any of the cylinders are under 154 psi, and i have two cylinders that fit that description...

any other ideas?

[GTSSportCoupe]

i have seafoam, but i am reluctant to use it until i actually get the engine started.

the last thing i need is another variable right now, and seafoam is intended to be used at full operating temperature...

i am beginning to think it is the compression again, because i have eliminated the other variables.

why is everyone so sure that it should start with my compression numbers? according to the haynes manual it shouldn't start if any of the cylinders are under 154 psi, and i have two cylinders that fit that description...

any other ideas?

Check that you are getting spark, and that your ignition timing is ok - sound like it might be way out. Also check that the timing belt is ok and it hasn't skipped any teeth. Your engine should run just fine, although maybe a bit rough because of the uneven compression. Once you get it running, give it the seafoam treatment, might help to remove some carbon and even out at least a few of the compression readings.

[Mickey_D]

why is everyone so sure that it should start with my compression numbers? according to the haynes manual it shouldn't start if any of the cylinders are under 154 psi, and i have two cylinders that fit that description...

The Haynes manual is a little poorly worded. It should read, "the engine MAY not run if ALL cylinders are below 154psi".

I know from experience that our engines will run with only one cylinder working at all!! I had 3 flooded spark plugs and it still started. Granted, it was chugging pretty hard and wouldn't have moved the car an inch, but the engine was running.

[Gasoline Fumes]

My Metro had borderline compression on two cylinders and zero PSI on the third cylinder with the burnt valve. Started just fine.