Low Compression?

Low compression on one cylinder normally points to exhaust valve leaking which requires a valve job not a whole engine

This guide can help us

https://www.2carpros.com/articles/the-reasons-for-low-compression

Please run down this guide and report back.

girl friend backed into a hill and plugged the exhaust with dirt car started and ran for awhile then died now it sounds like the engine is free spinning i checked the timing belt it wasnt broke or out of time
ive done a compression test and all cylinders have only 30 to 60 pounds of pressure if my gauge is working right i just purches the compression gauge so it should be right could the plugged exhaust blown the head gasket or messed up anything else ? thanks for any help you can give

Hi there,

The first thing to do is make sure that the exhaust is still not blocked up if it is you will have all sorts of problems, check this first.

Mark (Mhpautos)

I brought the car in about a week ago due to some misfires in cylinders 1, 3, and 4. The mechanic, who is very trusted, did a compression test and said that the 3rd cylinder basically had no compression, only 50 lbs. The 1st and 4th had 200 lbs., while the 2nd had 150. He said that the 3rd cylinder was likely causing the other two to misfire due to non combusted materials pushing back up into the intake.

The mechanic said it was probably a valve problem, and though I've asked him several times he insists it is probably not a head gasket. I agree that I don't see any other symptoms of a head gasket problem. The engine was too old for any valve repairs to do much good without causing other problems, he said. He told me to try, as a last ditch effort, various engine cleaning products.

I tried a number of those, and the engine began to run much more smoothly. Whereas before it would hiccup during acceleration, the acceleration was now near perfect, and there was a lot more power than there had been. The car also ran smoother while driving it.

However, the idle performance of the car got worse. I lost about 200 RPMs off of what was already a low idle. As of today, it now stalls anytime it is not being given gas, but seems to run fine when it is getting gas. Even before I saw the mechanic, the misfires seemed not to occur when giving the engine gas.

So I am trying to figure out #1) why it would have misfired only on idle if the compression on that cylinder was really that bad, in other words, if something caused the compression to be better when getting gas, and #2) what could have happened that would cause the engine to operate more smoothly after being cleaned but at the same time to lose idle RPMs and now to stall altogether.

Thanks!

HI there,

What you need to do is a wet & dry comp test, tis will prove the sealing quality of the valves, your mechanic should know this and i am amazed that he did not do this very simple test.

mark (mhpautos)

My car is not starting and the mancanic said it is not getting enough compression. Now we do not know what to do next.

When he says it is not giving enough compression what is he basing that on? Did he do a compression test on all cylinders and if so what were the results. To not start that compression must be pretty low and I don't see that many miles on the car yet.

Engine Mechanical problem
1997 Honda Civic 4 cyl Front Wheel Drive Automatic

My civic is burning oil especially at start up. I checked compression and it is 180 psi on all cylinders. All cylinders go to 90 on first stroke then 120 psi on next then up to 180. Spark plugs have black soot on them. Engine runs smooth and quiet.

Any ideas for me.

Could be worn valve guides or seals. Does it burn oil while running or just on start up? The comp will be good if there is oil in thecylinders, that is what is called a "wet" comp test. Try having a cylinder leak down test done, if the air escapes past the rings you know it will need to be bored and new pistons/rings, if the cylinders hold air, it is most likely the valve seals/guides. Also check the PCV valve for proper operation

my daughter overheated my car and so we blew a head gasket we replaced that and checked the head over it was not warped and we could not find anything else wrong. now we checked the compression after it was all put together and it is low is this caused by the timing or are the piston rings burnt out or do you think we missed something on the head. also i should say when they put it back together it kept sheering the pin on the cam shaft pulley so my brother made one out of steel and it quit doing it.

What compression numbers are you seeing in all four cylinders? how are you compression testing it? It should be testing with all four plugs out and with the throttle plate at wide open, this ensures that the engine is not fighting anything and there are no restrictions.

Are you sure the cam timing is set properly? Set the crank at TDC and the cam gear should be lined up with its marks.

I have a 1995 Honda Civic Lx 1.5 5 speed.. i recently changed the head in it... it ran like a beauty for a five days or so then just died suddenly... the cam chipped itself and it jumped time i set the time and replaced the cam... still no compression help me please...

Not sure what "chipped itself" means. But, what is the likelihood that there is something not set right and there is a valve that is open at the wrong time thus giving no compression?

the cam shaft where the timming belt sprocket goes chipped on the end where the sprocket is bolted to cam where it is slotted at.

Thanks for the info. You need to double check the settings of the crank and cam as it appears that a valve is slightly open or you have a leak and it should be easy to hear or see.

when sitting the timming what two pistons remain up and what two remain down

#1 is always supposed to be up.

92 honda civic vx. 102k miles. 1.5L vtec

I just ran the compression test. For the dry test the results were: cylinder1: 195psi (6 cranks) 2: 200psi (7 cranks) 3: 200psi (8 cranks) 4: 200psi (8 cranks)
wet test results: cylinder 1: 220psi (7 cranks) 2: 230psi (8 cranks) 3: 230psi (8 cranks) 4: 230psi (7 cranks).

I was told that it should be reading 125-135psi on the dry test. Why do you think it is consistently reading so much higher?

Could you explain to me how to set my cam and cam shaft to set my timming.If no 1 is always up is it the only one up and the others down? I'm sorry this is my first time on a honda if you could just walk me thru it I would be forever grateful.

[quote:d5a171cd2e="dukeslowride"]92 honda civic vx. 102k miles. 1.5L vtec

I just ran the compression test. For the dry test the results were: cylinder1: 195psi (6 cranks) 2: 200psi (7 cranks) 3: 200psi (8 cranks) 4: 200psi (8 cranks)
wet test results: cylinder 1: 220psi (7 cranks) 2: 230psi (8 cranks) 3: 230psi (8 cranks) 4: 230psi (7 cranks).

I was told that it should be reading 125-135psi on the dry test. Why do you think it is consistently reading so much higher?[/quote:d5a171cd2e]

Carbon build-up in the combustion chamber will raise the compression pressure or a head resurfacing job.

Try engine decarbonizing-might work

The no.1 and no.4 should be up- Put the engine's no.1 piston on compression stroke, find the timing indicator it should be real close to the scale-take a socket help it to the 0 mark.Take a rod and feel for the piston whether its all the up on the no.1 and also the rotor in the cap should be pointing to the no.1 sparkplug wire tower.

Now look at the cam and crank sprockets alignment per the book if not you have to do it all over. The ValveTrain and Ignition Timing must be met in order for the engine to fire.

Good Luck!

[quote:41c1d4845f="rasmataz"][quote:41c1d4845f="dukeslowride"]92 honda civic vx. 102k miles. 1.5L vtec

I just ran the compression test. For the dry test the results were: cylinder1: 195psi (6 cranks) 2: 200psi (7 cranks) 3: 200psi (8 cranks) 4: 200psi (8 cranks)
wet test results: cylinder 1: 220psi (7 cranks) 2: 230psi (8 cranks) 3: 230psi (8 cranks) 4: 230psi (7 cranks).

I was told that it should be reading 125-135psi on the dry test. Why do you think it is consistently reading so much higher?[/quote:41c1d4845f]

Carbon build-up in the combustion chamber will raise the compression pressure or a head resurfacing job.

Try engine decarbonizing-might work[/quote:41c1d4845f]

How do I do engine decarbonizing? And if I need to buy anything what do you recommend buying?
Thanks

can i use a manual for 1996-2000 to adjust motors timing correctly... i can not find a manual where i live for 1995 honda civic lx 1.5

[quote:efac132c08="dukeslowride"][quote:efac132c08="rasmataz"][quote:efac132c08="dukeslowride"]92 honda civic vx. 102k miles. 1.5L vtec

I just ran the compression test. For the dry test the results were: cylinder1: 195psi (6 cranks) 2: 200psi (7 cranks) 3: 200psi (8 cranks) 4: 200psi (8 cranks)
wet test results: cylinder 1: 220psi (7 cranks) 2: 230psi (8 cranks) 3: 230psi (8 cranks) 4: 230psi (7 cranks).

I was told that it should be reading 125-135psi on the dry test. Why do you think it is consistently reading so much higher?[/quote:efac132c08]

Carbon build-up in the combustion chamber will raise the compression pressure or a head resurfacing job.

Try engine decarbonizing-might work[/quote:efac132c08]

How do I do engine decarbonizing? And if I need to buy anything what do you recommend buying?
Thanks[/quote:efac132c08]

In today's high tech-everyday is new stuffs-check Autozone or Napa and select the best and follow instruction. Or just bring it in and have them do it -they got the machine.

On the hood there is a timing specification. Use that as the setting point and I am going to assume that you know about general timing. On the Honda, can you find the pig tail clip that is used to jumper the computer? It should be up under the dash in the corner above the passenger feet. This clip should be jumpered with a wire to connect both sides. This disables the computer and you can adjust the timing from there. Once you have it set take the jumper back off.

92, honda, civic VX Hatchback. 102k miles 1.5L Vtec.
I would like to do a compression check on my civic, but I can't find anywhere in my service manual at what psi it should read at. All I find is my compression Ratio (9.3), so I am not sure how to find out what psi it should read at?
Also, am I suppose to disable the fuel pump since it has fuel injection?
Thanks

okay here is what i have come to understand about the timing. i have to set the tdc mark with the pointer on the timing belt cover. then i am to turn the crankshaft counter clockwise 360 degrees back to tdc. but do line it up with the timing belt cover mark again or the pointer on the block.. that is where i am now confused...

[quote:872650e59c="dukeslowride"]92, honda, civic VX Hatchback. 102k miles 1.5L Vtec.
I would like to do a compression check on my civic, but I can't find anywhere in my service manual at what psi it should read at. All I find is my compression Ratio (9.3), so I am not sure how to find out what psi it should read at?
Also, am I suppose to disable the fuel pump since it has fuel injection?
Thanks[/quote:872650e59c]

Between 125-135 psi give it 20% +/- from highest reading

Am I suppose to disable the fuel pump since it has fuel injection?
Thanks


Between 125-135 psi give it 20% +/- from highest reading[/quote]

[quote:c8cec20ae1="dukeslowride"]Am I suppose to disable the fuel pump since it has fuel injection?
Thanks


Between 125-135 psi give it 20% +/- from highest reading[/quote:c8cec20ae1][/quote]

Fuel pump fuse or fuel pump relay-

[quote:35022848ca="rasmataz"][quote:35022848ca="dukeslowride"]Am I suppose to disable the fuel pump since it has fuel injection?
Thanks


Between 125-135 psi give it 20% +/- from highest reading[/quote:35022848ca][/quote:35022848ca]

Fuel pump fuse or fuel pump relay-[/quote]

Where can I locate the fuel pump fuse or relay?
I referred to my service manual and it says nothing about it.

To kill the fuel system-find and remove the PGM-FI Main relay behind the left side of dash near the fuse and relay block.

Good Luck HTH

I had my engine overhauled last year and according to mechanic it was left "new". That mechanic has disappeared from scene (I hope from Earth) and I now find that two of my four cilinders are under compressed, or almost non-functioning. My good little car is thus chugging along pretty faithfully (though when AC is connected it'll stall at idling or even very low speeds) on only two cilinders. My new mechanic (I trust him, yet...) says it's a valves problem and he'd have to again open up motor, a rather expensive job for an old car. Is there any way of fixing the under compressed cilinders or valves or whatever without too much expense? Anyway. I'll probably sell the car, but I'd rather give it away in a decent condition, as in every other way it's still a beauty, than just take it to the vulture park???

Is there anything else I need to do? like disable the ignition or anything else for testing compression?

IF there is low compression the head will need to be removed. $$$

HAving said that, if the car is in nice shape otherwise, it may well be worth it. IF not to you then someone else. The Hondas can go far, beyond 1600000. IF the car is in the northeast and has been exposed to the harsh winters then it may be another story.

HAve him give you an estimate and also a worst case scenario to help you decide.

Is there anything else I need to do? like disable the ignition or anything else for testing compression?[/quote:04a1ec94c2] Go ahead and remove the PGM-FI main relay.then do your dry and wet check, makes sure you remove all the sparks plugs and mark the wires and also block the throttle plate wide open-

Is there anything else I need to do? like disable the ignition or anything else for testing compression?[/quote:9d5769205e] Go ahead and remove the PGM-FI main relay.then do your dry and wet check, makes sure you remove all the sparks plugs and mark the wires and also block the throttle plate wide open-[/quote:9d5769205e] Can I just hold down the gas pedal all the way when cranking the engine instead of blocking open the throttle? Also when doing the wet test, do you recommend using any special oil like marvel mystery?

Is there anything else I need to do? like disable the ignition or anything else for testing compression?[/quote:13458a0fb4] Go ahead and remove the PGM-FI main relay.then do your dry and wet check, makes sure you remove all the sparks plugs and mark the wires and also block the throttle plate wide open-[/quote:13458a0fb4] Can I just hold down the gas pedal all the way when cranking the engine instead of blocking open the throttle? Also when doing the wet test, do you recommend using any special oil like marvel mystery?[/quote:13458a0fb4] You cannot be in two places in one time get a helper while you look at the gauge-10W30 will do it. You need to puff it atleast 5 times

Is there anything else I need to do? like disable the ignition or anything else for testing compression?[/quote:46117a2cde] Go ahead and remove the PGM-FI main relay.then do your dry and wet check, makes sure you remove all the sparks plugs and mark the wires and also block the throttle plate wide open-[/quote:46117a2cde] Can I just hold down the gas pedal all the way when cranking the engine instead of blocking open the throttle? Also when doing the wet test, do you recommend using any special oil like marvel mystery?[/quote:46117a2cde] You cannot be in two places in one time get a helper while you look at the gauge-10W30 will do it. You need to puff it atleast 5 times[/quote:46117a2cde] So is that a yes, it will be sufficient to have a helper press down the gas pedal while cranking and me looking at the gauge? How much oil am I supposed to put into each cylinder? Thank you for your responses, I really appreciate it.

I have recently experienced an idling problem. Every time I slow down and the vehicle does into a choked idle, mostly ending in a stall. As long as I give it gas, it runs, if choppy at best. I recently replace the spark plugs and did a compression test. The #3 cylinder had a very low compression, compared to the others. What should I do?