Compression Testing?

[jpetrovic]

My car has been acting really funny, very rough idle like one of the cyl wasn't firing so i checked fuel. that was fine. next was spark, i changed plugs, wires and checked the cap and rotor everything is fine. Then i started to pull the spark plug wires one by one while it was running to see if that would do anything, and when i pulled out the second wire (starting from the left side going right) it didnt effect the all ready crappy idle. but when i pulled the other plug wires the engine almost died so one cyl isnt firing or the compression bad?
since the spark was there. and plugs and wires ect were fine i figured compression.


so i got a compression test to test the second cyl, when i crank the car it goes up to 150psi. (i figured that is pretty standard lookin at some of the other posts here) then after the crank. The psi drops down to 0 very rapid. it takes 1 min or less for it to drop to 0.


Is the compression suppose to drop that rapid? and if not is it time for a new motor?

[jpetrovic]

i did some more searching around and my coolent is the color of coffee. :( think this could be the head gasket? but there isnt ANY smoke from the tail pipe.




edit: also i just noticed i posted this in EFI Tech. im such a n00b. sorry :-/

[A18A]

i dunno what's wrong, but your car looks sexy in your sig :thumbup:

[Civic Accord Honda]

sounds like old coolant/water if ur oil looks like oil and not like a milky way bar, did u replace the cap and rotor? u can allways rent a compression tester and check and if its fine id grab some junkyard fuel injectors

[2oodoor]

don't cry head gasket just yet, change the coolant after you do a flush...
you need a few more symptoms to say HG ok..
valve adjustment is another part of a tune up on one of these with some miles on it..and of course when you do that you ensure the valve timing is spot on then procedure after that is recheck ignition timing and dist. condition.
Bleed the air of of coolant too btw..

[jpetrovic]

don't cry head gasket just yet, change the coolant after you do a flush...
you need a few more symptoms to say HG ok..
valve adjustment is another part of a tune up on one of these with some miles on it..and of course when you do that you ensure the valve timing is spot on then procedure after that is recheck ignition timing and dist. condition.
Bleed the air of of coolant too btw..

i've flushed it once with the stuff you buy at autozone and the coolent was a bit discolored but i didnt think to much of it, i thought it was maybe old coolent... that was 7 months ago/32kmiles ago. now it its just Pure coffee colored no hit of the neon green. i guess i'll have to take the car to somone for valve adj b.c idk anything on how to do that.


sounds like old coolant/water if ur oil looks like oil and not like a milky way bar, did u replace the cap and rotor? u can allways rent a compression tester and check and if its fine id grab some junkyard fuel injectors

Cap and rotor are little over a yr new. i did do a compression test the results are up there^^^^^^ Injectors could be the cause. i've had them cleaned out last year and i keep up on the seafoam treatment every other oil change. but they are old.... i just did an oil change and i guess it was normal? it came out Black but when you put light to it it was somewhat of a brown color. idk if thats normal or not..


i dunno what's wrong, but your car looks sexy in your sig :thumbup:

thanks

[nswst8]

Is the suspect cylinder spark plug firing. Pull the plug, attach the spark plug wire and ground the spark plug threads (I just use a scrap wire wrapped around the threads and hooked to a good ground).

Have someone turn the engine over to see if the spark plug fires.

(detatch the coil wire, so the engine does not start)

[Oldblueaccord]

Plug wont fire without the coil attached. ;) if the plug is oily it will have a hard time firing off.


jpe I think you may have 2 things going on somewhat related. The oil in the rad is a sign of the headgasket leaking or even a crack in the head somewhere.

The compression reading on that cylinder seem ok/ bad maybe because there's to much oil in the cylinder sealing everything off. You can take your valve cover off and check the rocker arms on that cylinder and look at the cam lobes to see if there worn down. The valve cover comes off rather easy. If you have a feeler gauge its easy to set the lash on your valves once the cover is off. There alot of youtubes on how to do it on Hondas, nothing to special about it. It just take a wrench there no shims to mess with.

wp

[jpetrovic]

yeah i was looking at some leak down tests and a very helpful video on how to diagnose these kind of problems,

But on all the videos i see on compression testing there Cyl holds a Psi. but my cyl it dose not hold psi, it just drops to Zero in less then a min. and that could be a head gasket, piston rings, the valves or a cracked head
soo lookin at this video its really helped me understand what the problem could be if i see a certain type of symptom during a leak down test.

http://www.youtube.com/watch?v=ofSiTGeLXvc

anyone want to add to the info this guy said? i think its pretty cut and dry

[kentwat]

How many miles are on the motor? Was the plug in that cylinder oily? Also, has this miss just started all of the sudden or has it come on slowly. Are you getting popping out the exhaust?

[jpetrovic]

How many miles are on the motor? Was the plug in that cylinder oily? Also, has this miss just started all of the sudden or has it come on slowly. Are you getting popping out the exhaust?

just hit 170K miles the motor has been idling a bit rough since it was at 110k miles. the car does not back fire during idle. or while its receiving gas, only when the engine "Bogs" down while driving it really starts to back fire, but the back fire isnt loud, just alot of semi loud popping back fires.

when when i say it idles a bit rough i mean that the RPMs are fine, just the engine vibrates soo much it shakes the steering wheel and dash violently, allmost like you start off your Manual car and didnt give it enough gas and the whole interior shakes, thats VERY extreme but its like that but not That bad, but you do see and feel it all shaking, oh and the plug was not oily

[Oldblueaccord]

Did you check the spark at the plug?

When you reinstall it put another plug in it JIC that ones just bad,part failure happens.


wp

[integratuner77]

I believe you just have a bad compression tester.. your cylinder will not hold pressure because when you crank the motor it is going through a full cycle. The cams are still installed and it is releasing the pressure through the valves as it should.

The compression tester should have a one way valve with a release. As you crank it it allows the pressure to build up but not escape so you can reach a peak value. Then you should hit a button on the compression tester to release the pressure.

The more I think about this the more I'm sure its just your tester. That spike you are seeing is the compression stroke. Then its releasing as soon as the exhaust valves open and the piston moves up again. Try a different tester.

[Civic Accord Honda]

ah missed where u posted results of test, yeah your tester is bad lol, maybe the coil or dizzy is going bad?

[jpetrovic]

damn autozone rentals :( maybe it was bad, the spark plug does spark i tested that, Oh and on rough idle it came on slowly, it was starting to get bad, i never could figure it out. then while on the highway it just pretty much gave out when i was passing a few cars at 110mph. just Instant power loss of course. I've take good care of the motor with maintenance but i havent been to terribly nice to it, i beat it like a red headed step child.. alot... its hard not too!! its funnn :D i really dont think its a spark related issue. im thinking maybe some head work.

[Ayeobe]

Man freakin misreading shit.

Good luck finding a good compression tester. If your cars manual, i understand driving it a little hard ... but i dont beat on it too much. How good was the spark?

[jpetrovic]

Man freakin misreading shit.

Good luck finding a good compression tester. If your cars manual, i understand driving it a little hard ... but i dont beat on it too much. How good was the spark?

The spark is good, yeah the car is a manual :flash: im gonna have to get some new test tools from another store, thats gonna be a few days though b.c i dont have a day off for a lil bit of time and its raining out, along with the holiday this weekend. i guess i'll let ya guys know when i get some time to diagnose the problem

[Civic Accord Honda]

id replace the fuel injector before doing any head work lol

[3gmodifier]

hey man, I have been working out of my garage as a Honda/Acura specialist for 4 years now and with what i have read, it could deff. be a few diff, things. but when i hear that it bogs down when get on or going uphill, i think fuel filter, faulty cap and rotor, possibly a spark plug(but u said it was good so never mind), maybe a worn out/clogged, or stuck injector, but have u had the timing checked? get that checked and if its fine, get a comp. tester that will hold a peak psi and see what happens. if it still leaks, and u still have shity looking coolant, then start with the head gasket. and while its off, get the blocked decked. if your doing it yourself, at least get the head resurfaced. And also, while the head is off and at the machine shop, have them do a leak down test, and check the valves, retainers, springs, and tolerances. make sure you torque the head back down following the 2 step procedure and test the comp. before you start. hope this helps. late!