ive been reading threads on here about hg and i am reaching the 200-220,000mi mark where it seems to me that they blow out. so last night i was reading on here and got scared mine might blow on one of my trips (600miles) i do every month, so doday i did a compession test to see if anything was off and i took pictures of the plugs as i pulled them out. i havent done a since shop class in high school 14 yrs ago so i dont know so im asking you smart people if i have to repair something or if im fine. i took 6 different pictures of plus so the first pic is plug 1 through to the #6 plug. number 4 was coated in oil to the tip of the threads but nothing past there.
just did a compression test heres the facts
- Thread starter kilrspd
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- Thread starter
- #3
the compression test is as follows
1: 95 lbs
2: 125lbs
3: 97lbs
4: 100lbs
5: 120lbs
6: 115lbs
i dont know where the pressure is suposed to be so are these mormal? i have 183000 mi on mi rig and dont want to break down
1: 95 lbs
2: 125lbs
3: 97lbs
4: 100lbs
5: 120lbs
6: 115lbs
i dont know where the pressure is suposed to be so are these mormal? i have 183000 mi on mi rig and dont want to break down
Plugs look ok, they need to be replaced though. The white build up on them in most likely from fuel additives.
I would suggest borrowing another compression tester, those numbers seem quite low.
That oil covered plug is a problem (#4), you may need a new valve cover or spark plug galley gasket to fix that. If the plug galley fills with oil the spark can arc to the head and won't fire the plug as well.
As for compression test results, did you do the test with the following:
-warm engine, allows metals to expand, shows you normal operating conditions
-hold throttle wide open while cranking
-crank same length of time for each cylinder
-you are looking for results to be within 10% of each other, the results you listed are beyond that point
-if you have a cylinder that is low, you can put a cap of oil down the plug hole and retest, if the numbers come up to match the other cylinders then you know you have worn piston rings, if the numbers dont' change signifigantly then you have a head gasket or head issue that is the cause of the low compression
-don't worry so much about what the actual #'s are, just that they are close to the same. Different testers, altitude, length of time you cranked over, lots of factors can influence the results so you can't compare them directly to someone else's results with any accuracy.
As for compression test results, did you do the test with the following:
-warm engine, allows metals to expand, shows you normal operating conditions
-hold throttle wide open while cranking
-crank same length of time for each cylinder
-you are looking for results to be within 10% of each other, the results you listed are beyond that point
-if you have a cylinder that is low, you can put a cap of oil down the plug hole and retest, if the numbers come up to match the other cylinders then you know you have worn piston rings, if the numbers dont' change signifigantly then you have a head gasket or head issue that is the cause of the low compression
-don't worry so much about what the actual #'s are, just that they are close to the same. Different testers, altitude, length of time you cranked over, lots of factors can influence the results so you can't compare them directly to someone else's results with any accuracy.
Well its a possibility, I would see if you can borrow or get some one to do a leak down test on the engine that will tell you where the compression is going. The other way of testing for bad rings is to put a bit of oil in the cylinders to see if the compression comes back up. I do not know how much oil though I always use a leak down tester.
For reference my compression numbers before I did a PM HG was 175psi +/- 4psi on all cylinders.
Good luck.
- Thread starter
- #8
i would say i did none of those. it was a first thing this morning cars been sitting for a week waiting for payday. the engine was cold, i didnt touch the throttle just the key. let it turn over 3-4 times the wrote down the number the tester told me. put the plug back in and went to the next one. so basiclly i f*ed up the test and have to redo it with a warm engine holding the pettle down as i turn the key. the write down the number it shows me?
That's what I would do, this explains to some degree the low #'s, and you might see them even out once the engine is warm as well. I forgot to mention as well, pull the fuse for the fuel pump so you aren't spraying fuel while testing, so you don't wash down the cylinder walls, cause that won't help either. Post back the results of the 2nd test and we'll have better info to work with.
I was taught to crank it 6x with throttle wide open, engine warm. Note two things:
1) pressure reading of FIRST pump.
2) final reading
The first pump tells you the general health of the cylinder. The final pump tells you the overall health of the whole engine.
Typical results on a strong toyota engine will be 160-180psi. First pump should be at least half of the final number. Don't freak out at the numbers themselves as long as they're all even you're good to go
1) pressure reading of FIRST pump.
2) final reading
The first pump tells you the general health of the cylinder. The final pump tells you the overall health of the whole engine.
Typical results on a strong toyota engine will be 160-180psi. First pump should be at least half of the final number. Don't freak out at the numbers themselves as long as they're all even you're good to go
Same here. Tested 2yrs ago and just back in June.
" put the plug back in and went to the next one"
I dont know if this is correct. This may explain the low readings. I have always pulled all the plugs. And pulling the fuel pump relay is wise. Hold the throttle body open if you can. Hard to do by yourself.
I dont know if this is correct. This may explain the low readings. I have always pulled all the plugs. And pulling the fuel pump relay is wise. Hold the throttle body open if you can. Hard to do by yourself.
The other thing you will see before a head gasket problem is one of your plugs (most often number 6) will be coated with Toyota red (your antifreeze). I don't see that on any of your plugs.
Only about 20 to 25% of 80 series require a head gasket change. I was one of the unlucky ones, that is how I know the symptoms. I had all of the above.
