Compression Numbers (What Next?) (1 Viewer)

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NocalFJ60

NocalFJ60

Joined
Aug 2, 2004
Threads
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San Francisco Bay Area
After having my cruiser for over 9 years I finally did a compression test and got some bad numbers. Wonder if the mileage was right when I bought it with 90K. It has 130K now.

I got a brand new guage yesterday and did a compression test this morning. I am not very happy with the numbers. It looks like my rings are kinda worn but my head gasket is leaking too. I put about 1/4 oz. oil in each cylinder for the wet test with the turkey baster from Safeway.Looks like my cylinder number 6 is good. My vacuum at the intake manifold is 19 inches.

The whole thing that started this was I am trying to pass smog. Can I pass smog with these numbers?


Any ideas or thoughts? Thanks

Dry/Wet:

1-113/125
2-93/98
3-118/133
4-130/134
5-115/125
6-143/150
 
how high?

What altitude do you live at? Those number are OK (except #2) for say Denver.
 
You are not great but not all that bad. The issue is not so much with the amount of compression but with how even the compression is acrooss the cylinders. I would adj the valved correctly then test again.
 
Cruisergreg said:
What altitude do you live at? Those number are OK (except #2) for say Denver.
Click to expand...


I am in the San Francisco Bay area, so I am probably less than 1000 ft altitude.
 
dd113 said:
You are not great but not all that bad. The issue is not so much with the amount of compression but with how even the compression is acrooss the cylinders. I would adj the valved correctly then test again.
Click to expand...

I had a valve job done about 3 years ago but will do one again soon since I have not done one myself.
 
I am not talking about a valve job but just adjusting your valves.
 
NocalFJ60 said:
I am in the San Francisco Bay area, so I am probably less than 1000 ft altitude.
Click to expand...
Well then unless you're doing your check at the top of Mt. Diablo those numbers won't be influenced by altitude. Those numbers do seem a little low for that mileage. A friend with a 170K 2F got similar values at his 6000ft home. In addtion to adjusting the valve clearance you might try the Mark Whatley diesel in the crankcase trick to see if you might have carbon build-up in the cyl bores before dong anything drastic.
 
Diesel in the oil

Fourrunner said:
Mind expounding on that Cruisergreg. I would be interested in know how to clean the engine out also.
Click to expand...
In short you drain a certain amount of oil and replace it with some diesel and let the motor idle for a time, but I don't recall the specifics. Don't want someone to fry thier motor based on my fried synapical memory.

It's been described on the LCML several times so doing a search of the achives should provide the detail you need. I believe it's also been presented in Toyota Trails, and very likely on this forum.
 
Try using ATF. Drain the oil and run the motor with ATF in it. The key to ATF is that it has a detergent in it that helps clean it out. Do not drive it just run it a while at a high idle. Drain and repeat.
 
Amsoil Engine Flush

The other option is to get some Amsoil Engine Flush. I haven't done it to my cruiser yet because they warn on older engines, removing carbon buildup can start oil leaks. So with any of these methods, that is a risk that is run, but I will probably break down and do it eventually. I did it to my wife's Solara and my Tundra, and both ran much smoother after adding fresh oil. My friends did it to their Yukon (with 90K) and Ford Ranger (with 104K) and literally had clumps of crap draining out with the old oil, especially the ford. Both ran excellent afterwards, and still are.
 
Put each cylinder at exactly " tdc @compression stroke with both valves CLOSED", and pressurize them with about 100psi .Listen to the intake and the exhaust manifolds. A hissing noise as the air escapes will tell you about the condition of your valves.Back to your original question,with MARGINAL COMPRESSION your CO %is going to be tough to pass 1.2%.......look at those HOLES ,don't assume its the RINGS. A cylinder leakage tester makes that job a lot easier and more accurate.
 
mongoman said:
Put each cylinder at exactly " tdc @compression stroke with both valves CLOSED", and pressurize them with about 100psi .Listen to the intake and the exhaust manifolds. A hissing noise as the air escapes will tell you about the condition of your valves.Back to your original question,with MARGINAL COMPRESSION your CO %is going to be tough to pass 1.2%.......look at those HOLES ,don't assume its the RINGS. A cylinder leakage tester makes that job a lot easier and more accurate.
Click to expand...

I am thinking it is the valves or head mostly since number 6 is good. I do not have the equipment to pressurize the cylinders likes that.

Can you explaing more on why it might be hard to pass CO? Looks at what holes? My plan as of now is to check out all the smog equipment with the factory smog manual and try and pass smog. Then think about pulling the head and doing somemore testing.

Thanks
 
Regarding an effort to decarbon the head.....I have had great luck with a GM head cleaner product. I was actually directed to the GM parts department by the Toyota stealership. Basically you use a vacuum line to suck the cleaner into the cylinders.....slowly or your catalytic converter will melt on your toe. I noticed an increase in power and a smoother idle. I then adjusted the clearances and power increased again.

FWIW
 
Coolant?

How is your coolant level? I had similar pattern in SoCal (89' 62-175K) with slight coolant loss especially after freeway travel. Turned out ot be a tiny crack in the head. $$$$$ later and all is good.
Good Luck
 
Kevin,first things first,when you did this compression check(1)was the engine warmed -up? (2)was the throttle left open during the entire test? (3)was there plenty of battery capacity during the cranking?......if the answer is yes ,then.....adding oil to the cyclinders was a good idea and basically the compression didn't change much(10-15psi),this means the rings are not the problem.....Which leaves the valve-seats... this is were a cylinder differential pressure checker comesinto play,it measures the(percentage) amount of leakage and it is easy to figure were its coming from.......Have a repudible mechanic do this test if you can not , and get a emissions test 4-gas while your there. Hydrocarbons(220ppm) and carbon monixide(1.2%)MAX. are the two main concerns.ALSO MOST IMPORTANT .....the air pump must be pumping into the catalitic converter.......get back to meand I'll try to be of assistance....(owner 85 landcruiser, 20years + auto/arcft mechanic)...mongoman
 
mongoman said:
Kevin,first things first,when you did this compression check(1)was the engine warmed -up? (2)was the throttle left open during the entire test? (3)was there plenty of battery capacity during the cranking?......if the answer is yes ,then.....adding oil to the cyclinders was a good idea and basically the compression didn't change much(10-15psi),this means the rings are not the problem.....Which leaves the valve-seats... this is were a cylinder differential pressure checker comesinto play,it measures the(percentage) amount of leakage and it is easy to figure were its coming from.......Have a repudible mechanic do this test if you can not , and get a emissions test 4-gas while your there. Hydrocarbons(220ppm) and carbon monixide(1.2%)MAX. are the two main concerns.ALSO MOST IMPORTANT .....the air pump must be pumping into the catalitic converter.......get back to meand I'll try to be of assistance....(owner 85 landcruiser, 20years + auto/arcft mechanic)...mongoman
Click to expand...

Thanks for the help!

The engine was warmed before the compression test and thottle was wide open. Also I had plenty of juice to finish the entire test with my optitmum battery. I will take your advice and have a mechanic do the cylinder differential pressure test. Will this tell me if I need to pull the head to replace the gasket or if it is just the valves? If it is just the valves, do you have to pull the head?

What do you mean about the air pump pumping into the CAT.

I had the following numbers 2 months ago on my smog test.

HC (PPM)
MAX: / MEAS:
15mph 196 / 267
25mph 118 / 315

CO (%)
MAX: / MEAS:
15mph 1.39 / 4.73
25mph 1.19 / 5.76
 
Last edited:
kevin,after looking at your smog results it appears that your catilytic converter is either (1) possibly dead as a doornail--OR--(2)not being supplied air from the smog pump(air-pump) to the diveter valve(mounted on the top foward fender wall).....as air is pumped into your catiliytic converter ,the air assists to light -off the CAT and to make the combustion process continue to finish burning off the leftover HCs and the COs. It is critical that this system be operational to pass an emmissions test. A stuck diverter valve is common.Bypassing the diverter valve and inject shop air down stream will get your CAT LIGHT-OFF .Also you can ck the air pump out put!!!......answer these questions BEFORE you even consider pulling the HEAD and you will save your self $$$$$$. get back to me mongoman:)
 
mongoman said:
kevin,after looking at your smog results it appears that your catilytic converter is either (1) possibly dead as a doornail--OR--(2)not being supplied air from the smog pump(air-pump) to the diveter valve(mounted on the top foward fender wall).....as air is pumped into your catiliytic converter ,the air assists to light -off the CAT and to make the combustion process continue to finish burning off the leftover HCs and the COs. It is critical that this system be operational to pass an emmissions test. A stuck diverter valve is common.Bypassing the diverter valve and inject shop air down stream will get your CAT LIGHT-OFF .Also you can ck the air pump out put!!!......answer these questions BEFORE you even consider pulling the HEAD and you will save your self $$$$$$. get back to me mongoman:)
Click to expand...

I will check that out this week. It seems like it could be something simple since I passed two years ago with flying colors and have only driven it about 500 miles since then. I will let you know what I find. Now to go read up on it in the factory smog manual.

Thanks for your help. :bounce:
 
Air injection system failures are common problem on FJ60s. Checking out the entire system is a bit of a pain but not too bad when following the Toyota smog manual. A problem I have run into is that the cheap rebuilt air pumps don't put out as much as a new Toyota pump should. If the cat is weak and the air pump is weak they might not do much to drop the CO even if the rest of the system is working. Definitely confirm the fuction of the air bypass valve and the funtion of the two check valves. The check valves can fail open allowing hot exhaust gas to cook the diaphrams in the air bypass valve. You don't want to know what a new ABV costs.

As for the compression numbers, did you ever adjust the valve clearance? That alone could bring #2 up in line with the rest of them. I use Jim C's valve adjust procedure from the IH8mud tech section. HTHs.
 
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