I think its supposed to be around 300 psi... and i'd say no more than 10 psi difference between cylinders. I forget what the percentage is thats allowed
Help: somethings not right
- Thread starter tobyk321
- Start date
That really sounds like exhaust leakage. Maybe you have a loose or broken glow plug. Or as said before, an up pipe or even an exaust manifold crack or bad gasket.
Or a long shot might be an injector that has compresion gasses leaking past it and into your valve cover area??? Just spitballing on this one.
I would start with the hole with the out of balance injection quantity and go from there.
Or a long shot might be an injector that has compresion gasses leaking past it and into your valve cover area??? Just spitballing on this one.
I would start with the hole with the out of balance injection quantity and go from there.
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ENGINE COMPRESSION TEST
Tools Required
J 26999 Compression Gage
J 26999-20 Compression Gage Adapter
J 43244 Relay Puller Pliers
1. Ensure that the vehicle's batteries are in good condition, and fully charged.
2. Operate the vehicle until the engine is at normal operating temperature.
3. Shut off engine.
4. Disable fuel delivery system, by removing the EDU/IGN 1 relay withJ 43244 .
5. Disconnect glow plug nut; remove all 8 glow plugs. All 8 glow plugs must be removed from
the engine during each cylinder test to obtain valid test results.
6. Prior to taking a compression reading, verify the cranking speed is greater than 140 RPM. If
the cranking speed is below 140 RPM, repair the slow cranking speed condition before
continuing with the compression test. Refer to Engine Cranks Slowly in Engine Electrical.
7. Install the J 26999-20 in the glow plug hole for the cylinder that is being checked.
Fig. 42: View Of J 26999 For A Compression Test
Courtesy of GENERAL MOTORS CORP.
8. Connect the J 26999 to the J 26999-20 .
9. Using the vehicle's starter motor, rotate or crank the engine for 6 compression strokes, puffs,
for the cylinder being tested.
10. Observe the J 26999 and note the reading as the compression test is being performed. A
normal cylinder reading will be indicated if compression builds up quickly and evenly to the
specified level. An abnormal reading will be indicated if compression is low on the first
compression stroke, starts increasing on the following compression strokes but does not reach
the specified level.
11. Record the compression reading for the cylinder just tested.
12. Disconnect the J 26999 from theJ 26999-20 and remove adapter from the glow plug hole.
13. Repeat steps 8 through 13 for all remaining cylinders. All 8 cylinders must be tested to obtain
valid test results. Record the readings.
14. The minimum compression in any one cylinder is 2069 kPa (300 psi). There should not be
more than 345 kPa (50 psi) difference between a suspect cylinder and the average compression
of all 8 cylinders.
Normal - Compression builds up quickly and evenly to the specified compression for
each cylinder.
Piston Rings Leaking - Compression is low on the first stroke. Compression builds up
with the following strokes but does not reach normal.
NOTE: Do not add oil to any cylinder during a compression test as
extensive engine damage may result.
Valves Leaking - Compression is low
Tools Required
J 26999 Compression Gage
J 26999-20 Compression Gage Adapter
J 43244 Relay Puller Pliers
1. Ensure that the vehicle's batteries are in good condition, and fully charged.
2. Operate the vehicle until the engine is at normal operating temperature.
3. Shut off engine.
4. Disable fuel delivery system, by removing the EDU/IGN 1 relay withJ 43244 .
5. Disconnect glow plug nut; remove all 8 glow plugs. All 8 glow plugs must be removed from
the engine during each cylinder test to obtain valid test results.
6. Prior to taking a compression reading, verify the cranking speed is greater than 140 RPM. If
the cranking speed is below 140 RPM, repair the slow cranking speed condition before
continuing with the compression test. Refer to Engine Cranks Slowly in Engine Electrical.
7. Install the J 26999-20 in the glow plug hole for the cylinder that is being checked.
Fig. 42: View Of J 26999 For A Compression Test
Courtesy of GENERAL MOTORS CORP.
8. Connect the J 26999 to the J 26999-20 .
9. Using the vehicle's starter motor, rotate or crank the engine for 6 compression strokes, puffs,
for the cylinder being tested.
10. Observe the J 26999 and note the reading as the compression test is being performed. A
normal cylinder reading will be indicated if compression builds up quickly and evenly to the
specified level. An abnormal reading will be indicated if compression is low on the first
compression stroke, starts increasing on the following compression strokes but does not reach
the specified level.
11. Record the compression reading for the cylinder just tested.
12. Disconnect the J 26999 from theJ 26999-20 and remove adapter from the glow plug hole.
13. Repeat steps 8 through 13 for all remaining cylinders. All 8 cylinders must be tested to obtain
valid test results. Record the readings.
14. The minimum compression in any one cylinder is 2069 kPa (300 psi). There should not be
more than 345 kPa (50 psi) difference between a suspect cylinder and the average compression
of all 8 cylinders.
Normal - Compression builds up quickly and evenly to the specified compression for
each cylinder.
Piston Rings Leaking - Compression is low on the first stroke. Compression builds up
with the following strokes but does not reach normal.
NOTE: Do not add oil to any cylinder during a compression test as
extensive engine damage may result.
Valves Leaking - Compression is low
I hope it's a simple fix.
Right after the dealer did my head gaskets, I began to hear a similar noise and took it to MassDiesel to have it looked at.
It turned out that my injectors were loose. Once tight and properly torqued, they have been fine ever since. I never checked balance rates though, so ....
Good luck!!
Right after the dealer did my head gaskets, I began to hear a similar noise and took it to MassDiesel to have it looked at.
It turned out that my injectors were loose. Once tight and properly torqued, they have been fine ever since. I never checked balance rates though, so ....
Good luck!!
what kind of compression should i see? well i will have to get my hands on a compression tester first
It there a Harbor freight in your area? They have a diesel compression tester for like 24.99
You should see 300psi. Also you may see some oil on the #4 glow plug if there is a hole/crack
well i found out that when i hold my hand over the oil fill tube and pinch off the pcv re-route it builds up enough pressure that after about 45 sec it'll blow by my hand, i also noticed that when i do this it starts to smoke white out of the exhaust. it also seems to quite the noise a little bit. the oil level is up from where it used to be, i can't smell if there is any fuel in the oi,l as i don't have a good sense of smell (i get that from my grandmother).
so its starting to sound more and more like a bad piston. guess it looks like i might have an engine build in my future. the big problem is i don't have much money to do a full out build up
so its starting to sound more and more like a bad piston. guess it looks like i might have an engine build in my future. the big problem is i don't have much money to do a full out build up
Toby do a compression test and redo the balance test
do it at ilde and in park
There is a DIY for checking compression on this site Like others have said its more important that the numbers are similar more so than the actual number
Im with Ben on the not a piston comment ,Atleast I hope not
you sure its not the regulator?
do it at ilde and in park
There is a DIY for checking compression on this site
Like others have said its more important that the numbers are similar more so than the actual numberIm with Ben on the not a piston comment ,Atleast I hope not
you sure its not the regulator?
well i'm hopefully going to a harbor frieght thats close to me today to pick up a compsesion tester. so i'll be able to do a compresion test.
Definitley does not sound like a piston to me. Sounds like a bent pushrod or one of the top caps popped off one. Could also be an injector, time will tell.
Cracked piston's don't normally let the motor behave like that, atleast mine didn't.
Good luck.
Cracked piston's don't normally let the motor behave like that, atleast mine didn't.
Good luck.
ok so i did a compression test and
#1-400psi
#2-400psi
#3-390psi
#4-400psi
#5-400psi
#6-390psi
#7-380psi
#8-390psi
this was with 6 cycles to build pressure. every cylinder made it to 280-320psi in two compression strokes and then went to 400psi in another two strokes.
but now i have a service air bag code and a couple abs codes but the abs codes seem to come and go with my truck and the abs codes never throw a check engine light
#1-400psi
#2-400psi
#3-390psi
#4-400psi
#5-400psi
#6-390psi
#7-380psi
#8-390psi
this was with 6 cycles to build pressure. every cylinder made it to 280-320psi in two compression strokes and then went to 400psi in another two strokes.
but now i have a service air bag code and a couple abs codes
but the abs codes seem to come and go with my truck and the abs codes never throw a check engine light
i wouldnt reccomend pinching off the pcv hose because this will pressurize the crank case which wont allow the oil to come out of the turbo causing the oil to find the path of least resistance which is into the exhaust housing causing white smoke.
i found this out when i put an inline filter on my PCV to cetch the oil when it was rerouted
from your compression test everything seems to be inline i would start playing with injectors and also check your exhaust manifolds for any leaks and cracks
Good Luck
i found this out when i put an inline filter on my PCV to cetch the oil when it was rerouted
from your compression test everything seems to be inline i would start playing with injectors and also check your exhaust manifolds for any leaks and cracks
Good Luck
exhaust manifolds seem to be fine, but i would like to take a better look at the pass. side up pipe at the egr split. but the strange thing is i'm not getting any DTC's that are engine related. i think the air bag code is from when my girlfriend who was helping me with compression test spun the wheel about 12 times, i think this might have pulled some wires out
i think the air bag code is from when my girlfriend who was helping me with compression test spun the wheel about 12 times, i think this might have pulled some wires out
I think you hit the nail on the head there!!
Seeing as your compression is good, I think it is safe to say your pistons are fine. I'm still leaning towards an exhaust leak.
Truck
Not what you want to hear but if she turned the wheelwith the shaft out you probably need a new clock spring assy. I hope all goes well. Jeff
Not what you want to hear but if she turned the wheel
with the shaft out you probably need a new clock spring assy. I hope all goes well. Jeffspun the wheel about 12 times, i think this might have pulled some wires out
OWWWW!!! Yeah, I'd guess new clock spring may be in order..