Fouled plugs+dead cylinder

[xenogears_32]

I have an '85 tercel sr5. I have just discovered that the number 3 cylinder is not firing:-(

upon inspection I found that the plug#3 was fouled with oil.
I took the rest of them out and they were all a little oily.

Also on the last oil change I switched to 10w40 from 10w30.
I also have oil in my air cleaner. When it runs there is no smoke.
Could this be valve guide seals and or the darn head gasket that was replaced 2 years ago or the exhaust valve itself. I just really need some perspective. I'm 150 miles from home going to school.
My parents have a full garage.....I'm in an apartment. Also the other day my carb was stuttering and choking for no reason....it works flawlessly now!? And right when it corrected itself 2 miles later it was running on 3.....

Thanks,
Tyler

[Petros]

Welcome to the list!

Any number of issues could cause this, I just recently replaced an engine on another list member's car that had this issue. For some reason the wrist pin came loose and started gouging out the cylinder wall. This allowed oil to pump up into the combustion chamber and foul the plug. It too had oil in the air filter, the gouge allowed combustion pressure to pressurize the crank case.

Though this is an extremely rare failure, I had never seen this before in 35 plus years of working on cars.

Other things that can cause this is a bad PVC valve (they are inexpensive, replace yours) that allows oil into the air cleaner/carb, and perhaps more if it just ends up in #3 than the others. Also could be a broken ring in number three. I once had a piston skirt fail, damaging the oil ring and allow it to pump a lot of oil into the combustion chamber. It was still running despite making a loud clapping slapping noise.

You need to take a compression test and see if there are any mechanical issues. If you have a bad exhaust valve you will get low compression, and with a bad seal you will have oil leaking into the cylinder. IT might just be bad valve stem seals, you should be so luck, not too bad to replace without removing the head.

When you say not firing does that mean you still have spark? Did you do a power drop down test (pulling each of the spark plug wires in turn while it is running)? If you clean the fouled plug dose it run again?

Do a few more tests and see if you can tell us what is happening. You may have to replace the pvc valve, clean the plug and drive it home to do more serious work on it. OTOH you may just need a new PVC valve.

where do you live?

[takza]

You can buy a plug insert (maybe) that holds the plug back so it doesn't get covered by oil and will still fire...goes in before the plug. Doesn't fix it but allows it to run a while. Try a can or two of Pyriol oil thickener...then go with 15W40 diesel oil next time? Bosch Platinums will tend to fire in oil?

[xenogears_32]

I had spark once I cleaned the plug but I had no sand paper or wire brush so it wasnt really clean....
I'm going to get new plugs and pcv now and will try the anti foulers. When the head was milled for the head gasket the machinist (a very trusted engine/bolt action rifle builder) said they weren't leaking but with 240k miles they will wear soon enough. That was 2 yr ago.


I would think blow by goes both ways? Also I have no oil smoke in my exhaust.

Will report back after pcv and plugs....thanks again guys.

Oh I'm in usa arkansas to be specific.

[xenogears_32]

Well that didn't help. Am i right in thinking that if the valve seals are bad that on the compression stroke it would just blow by the failed valve seal up into the valvetrain which would explain all the oil being forced into the intake from the breather? it also has been sipping coolant for a little while. Now my next question is where can I find a good new and or low mileage head?

I would redo this but im thinking the coolant issue is a crack inside the head which has 240k on it and would hate to put new seals in only for it to break. Also can the valve seals be replaced without removing the head? Another thing to me is that when i drove it and say coasted down a hill in a lower # gear it tries to slow the car down just like a piston engine should. If the rings were bad wouldn't it try and run away due to lack of compression?

Thanks,
Tyler

[dlb]

it sounds like the head is definitely going to have to come off but do a compression test before you do that. check all four cylinders and if you have low compression on any of them (i can't tell you what would be low--mine are all around 170 PSI) then dribble oil down the spark plug holes and take a second set. if the compression comes up, that means your rings are worn and if that's the case, the engine will need to be pulled or replaced. if the compression stays the same, the problem is in the valves, which is a relatively easier fix since you can work on it yourself or at least take it to a shop and have them refurbish (i can't think of the word i'm looking for refurbish works) it.

why do you think the head is cracked? that would generally only happen if you REALLY overheated the engine some time. if it's cracked, it's f*cked and you need a new head. if you can't see an external coolant leak anywhere (check the rad, rad hoses, and hoses going to/from the heater) than you might need a new head gasket, which you should do when you pull the head anyway.

your coasting down a hill example wouldn't work unless the all the rings were completely obliterated. like dust. so don't rely on that. just do the compression tests and that will give you some useful info.

good luck!

[tercel4wdrules]

I have a car that's blowing smoke everytime I accelerate. I had a problem with it fouling out the spark plug for cylinder #4. I replaced it and it stopped misfiring. I kid you not, this engine is going through at least a quart of oil every 100 miles or less. I haven't done a compression test or anything, but if I had to take a guess I would say perhaps maybe something went wrong with the rings for that cylinder (a broken ring perhaps?) because it definitely wasn't running this way when I got it or it could be something entirely else which I'm not aware of. I'll look into it whenever I get around to fixing the rest of the car.

It is possible to replace the valve seals without taking off the head, such methods enabling you to do so have been discussed elsewhere on the forums. I would check the compression first like davidlucasbarnes suggested and then take it from there. I have a car that has an engine with bad piston rings and I got compression readings in the 160 psi range and of course when I poured a bit of oil, the readings rose about 20-30 psi. The Toyota factory service manual (FSM) states that max compression is 178 psi and the minimum threshold is about 128 psi. If you end up removing the head, you could take it to a machine shop and have it tested for cracks if you're concerned.

As far as I know, the oil being forced through the breather orifice (or PCV system) has to do with excessive blow-by. Excessive blow-by is caused by rings that are not sealing properly, usually due to wear.

[dlb]

As far as I know, the oil being forced through the breather orifice (or PCV system) has to do with excessive blow-by. Excessive blow-by is caused by rings that are not sealing properly, usually due to wear.

T4WDR is right. blow-by occurs because the rings are not sealing with the cylinder adequately, allowing oil to sneak past them. when the piston comes up on the compression stroke it pushes the oil out the open valves into the valve train area and up through the PCV system. if you have moderately worn rings, some people install a catchment system (a filter, essentially) in their PCV lines so that the oil doesn't get sucked into the intake.

once again, someone correct me if i'm off here.

[xenogears_32]

Ok, I did a compression check and here are the numbers #1-90psi #2-0 #3-0 #4-90......and on 2-3 I mean it wouldn't even move the needle on the gauge! To me this means that the valves are not sealing, correct? (yes I put oil down the spark plug holes) with no effect.

So the next step is to pull the head and have it pressure tested? Also when I said 240k I meant miles. As far as I know the head has never been re done.

I'm thinking there is a crack between 2-3 in the head. Wouldn't that explain the small coolant usage as well?
Also can anyone recommend a place that has rebuilt heads or a salvage tercel specialist.

Thanks

[dlb]

wow, that's grim. even 90 is way too low. yes, a crack in the head would explain coolant loss. the oil down the spark plug holes didn't improve the 1st and 4th cylinder readings at all? that's surprising for an old engine. the rings should be worn quite a bit if it has 240k miles on it.

where are you located? i may have missed it but i don't see that info.

with that many miles, you can certainly recondition (that's the word i've been looking for) the head but you might consider finding an engine with lower miles or even one of the JDM engines--search the term if you're not sure what JDM means. your current rings might last but without knowing what the compression was before this all happened, it would really suck to have put the time and money into a new head and then find out that your rings are on their last legs, or even f*cked as well. just doing the head is far easier though so it's up to you as to what you'd want to try first.

[tercel4wdrules]

If you had two cylinders without compression, I think it would barely run, if at all. Did you fully open the throttle while you were doing the compression test? The readings will be different without WOT (wide open throttle). Perhaps you should just invest in getting another engine, depending on where you live it might still be possible to get a used JDM (Japanese Domestic Market) engine - usually they are the 3A-SCV (swirl control valve), 3A-SU (twin-carb), or 3A-U. Within the past 2-3 yrs it has gotten a lot more difficult to source these engines down in the Los Angeles area. You might be able to just find a good used 4A-C or 4A-LC (front wheel drive Corolla), which will give you a bit more power.

[Petros]

It might just be the head gasket blown between cyl. 2 and 3, which would explain coolant loss. Oil will not raise the compression test if the head gasket is blown. It is pretty rare to crack a toyota head, I would think it could be rebuilt rather than replace it if it tests okay.

OTOH, the 90 psi reading on 1 and 4 is pretty low. If these came up with oil added, than you have a very worn out engine. IF oil in 1 and 4 did not raise the compression, you need to have all the valves reground, in addition to replacing the head gasket.

Either way the head has to come off before you can determine what else it needs.

Good luck.