is this possible??

[daerl]

I finished my timing belt about a week ago. yesterday, just for the hell of it, i rented a compression tester and tested the engine. i got LOW readings(120) across the engine. thing is, while I was doing the TB, I used a neighbors tester and got 150 cold. the car runs fine, starts right up, no stutter, and burns nothing (plugs are clean and light tan), no smoke. Was checking for bent valves, but I dont think I have any. I did notice it didnt seem as if the CTester was 'secure' when screwed in (the hose spins @ the lower fitting, and can wiggle a little). is it possible for the car to run fine with low compression/bent valve???? or do I have a bad tester?

Thanks!! did a search late last night, if I missed the answer sorry...

[Shag Wagon]

I had a 93 Accord once that had 125psi across and it ran really good. Or you could have a crappy tester.

[visualpoet]

Based on your description, it sounds like the second tester might not have been entirely accurate.
There's some good info here: http://www.aa1car.com/library/compression.htm

[wherm]

you should test the compressing when the engine is at operating temp. That way all the expansion that goes on inside the engine has occurred and your readings will be more accurate. Make sure your compression tester has an o-ring on the threaded end where it seats into the spark plug hole. If the o-ring is gone you'll have a leak. Let the engine crank until the needle on the guage stops bumping up. If your readings are the same all the way across then you're probably not dealing with bent valves.

[daerl]

Ok, thanks. Another quick question; I did a valve adjustment yesterday, and I think I did it wrong (too tight). Every one says "slight drag" on feeler gauge, is this when the screw just touches the gauge, or when you can just barely pull it out? And could too tight valve lash cause rough idle? Just started that today. Thanks again!

[wed3k]

too tight valve lash can cause a valve to be held open which in turn would lead to a rough idle.

what settings are you putting the clearance out?

[daerl]

I did .010 and .012, but I did it really tight to the gauge. Im gonna redo it tomorrow morning,as well as a comp. test with a new tester (the rented one did not have O rings)....

[ben_cb7]

Try a leak down test too. that will help point right to something wrong with the valves if it fails

[mtnbikaah]

I did .010 and .012, but I did it really tight to the gauge. Im gonna redo it tomorrow morning,as well as a comp. test with a new tester (the rented one did not have O rings)....

really tight on the guage is too tight, but you want a little more than a slight drag... . it's a really a "feel" thing.

i believe there is a slight range on the clearance.. i dont recall what it is, someone else would have to chime in on that, but try to go in the middle of the clearance...

hope that helps....?

[daerl]

Idle

Ok, so i redid the clearance, and its much better now. BUT there is a miss when Im idling. i pulled the plug wires one at a time,and cylinder #4 didnt cause much of a change. So i unhooked cyl #3, rehooked #4 with the wire from #3 and started the car, runs as before. i noticed that the plug wires were cracking, so I went and replaced them. still a miss at idle. if I pull #4, the engine slows, and the miss is constant. with all wires on, it is erratic. i dont get it, the car is getting about 24-28mpg, not burning anything, pulls well, doesnt smoke. Im gonna inspect the dist. cap on wed when Im off. Oh, and I did the compression with the new tester and got 145-150 across, but the engine was cold, i didn't have time to drive it and warm it. any ideas on the miss????

[brooklynkid1986]

. i pulled the plug wires one at a time,and cylinder #4 didnt cause much of a change.

if I pull #4, the engine slows, and the miss is constant. with all wires on, it is erratic.

A little confusing right there. If u unplug wires, the engine should sound terrible. If you pulled one and the was no change at all, then you have an issue.

If you have an idle issue already and you pull wires only to get a little bit of change, then it kind of sounds like you didnt quite get TDC on the valves when u were adjusting. Or possibly messed the order up (too lazy to pull book sry).

[daerl]

it idles @ 750-800 no problem, but I can sometimes feel the 'miss',and i can definitly hear it @ the tailpipe. If I pull 1,2, or 3 it does run terrible. 4,not so much. I dont understand the pulling of 3,and only haveing 1, 2, &4 and it running the same. Im pretty sure I had TDC while adjusting, I checked a few times. Cant get to it again til Wed, but it looks like i will be pulling the valve cover again..

[daerl]

compression test results, bad alternator??

Ok, I did the comp test as soon at I got home, and got this: #1-180, #2-180, #3-180, #4-168??. Tomorrow, Im gonna pull the valve cover and make sure I redid the valves on #4. My battery light has been flickering for the last few days, so I plugged in a charging system checker. I have 12.4-12.6 volts while driving. sometimes it goes to 14, but always drops. it was as low as 11.8. the haynes manual says the comp. pressure min is 135. Still have the miss, will try to figure it out tomorrow. Any Ideas?