Im just wondering if a compression test will check for bent valves because i know my timing is off and i have a cel p1390, and since my timing belt skipped a tooth or more my valves might be bent, which I hope they aint. So I was just wondering if a compression test would check for bent valves?

Im going to be going to satan to get my timing belt redone, and hopefully that will be my problem, if it doesnt fix it and it ends up being bent valves I just lost the $412 for the timing belt job, and would have to spend $1500 for fixing the bent valves. What do you think>?

1999 Mitsubishi Eclipse GS 10th Anniversary OZ Edition
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no just compression within the cylinder

Evan B
97 GS
Stamford CT
EvMan2345@aol.com

(Its actually stock sarrono red, but my digicam sucks, so it looks like a different color)

So how could I check for bent valves? I did some searching and found out that you might have to take off the head and just visually look...am I right?

1999 Mitsubishi Eclipse GS 10th Anniversary OZ Edition
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a compression check will tell you if you are losing compression, and if you suspect valves from a shitty shop's job... well, it's probably the valves... tell the dealer or whoever did it... go "hey, you did this, it made the car do this, now fix it without charging me" and then be prepared for attitude from the assholes at satan.

Well it wasnt no shitty ass shop, it was me, lol. I was changing my timing belt, and it all started from there. I got the tdc marks as close to tdc as I could. Then right after I was done I gunned it and a I got a cel P1390:timing belt skipped a tooth or more. Maybe there wasnt enough tension on the tensioner. Its a brand new tensioner, i dont know what caused it to slip.

1999 Mitsubishi Eclipse GS 10th Anniversary OZ Edition
Check Out My Site For Pix
http://mywebpages.comcast.net/EclipseRaceR/MyEclipse/VIS%20CF%20Hood/

If you are just one tooth off, that isnt enough to bend the valves. Usually if you break a timing belt, or something with the timing belt compontes breaks, and the motor looses all timing, then you can bend the valves. If your valves are bent, the you will prob build no or very, very little comrpession in the cylinder, because the bent valve will not fully close. If this is the case, the car will be running like crap, or even not at all. If you are worried, do a comp test. A valve that isnt closed all the way, will yeild little, to no compression pressure.

does your car run? if you have bent valves it won't. and if you try to start it and give it some gas, it will backfire in the intake.

Yea my car runs, it just idles rough. My friend asked me how my car ran at full throttle, I said great, and he said that I dont have any bent valves. Is there any truths behind that? Then i gave him the link with all the pcm codes and for the cel i have P1390 it said this: Check timing belt / Check crankshaft sensor and camshaft position sensor / Check PCM connector
He said it was probably just one of those sensors. If I goto satan and they do my timing belt, will that P1390 go away?
EDIT: I think my udp isnt on all the way, thats why my ps/ac belt shredded up, so what that set off the crankshaft sensor? I guess what I am trying to say is if I I bang that udp on a lil more will that tell the crankshaft sensor that its fine? Is that what the crankshaft sensor checks?

1999 Mitsubishi Eclipse GS 10th Anniversary OZ Edition
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"Yea my car runs, it just idles rough. My friend asked me how my car ran at full throttle, I said great, and he said that I dont have any bent valves. Is there any truths behind that?"

i messed up several valves (burnt them) a while ago and had those exact symptoms. the car wanted to die or studder at idle. there were no problems at any throttle point, however. thats probably not what you wanted to hear, but you should know. ;)

if i were you, i would check the ignotion sysetm first just to be sure that isnt the problem. as mentioned earlier, a skipped tooth might not bend any valves, and it could just be a coincidence that an ignition component crapped out on you. id much rather spend 20 minutes with a multimeter then a few hours ripping the head off.

Yes a compression test can tell you if valves are bent. valves that don't seal won't hold pressure, so the tester won't read a high number. But a tooth or two shouldn't bend valves.

Skipping a tooth or two will mess with the ECU, the crank and cam sensors won't agree so the ECU can be confused on what dto do with ignition timing. It may also have gone into limp mode which makes low throttle crap but WOT throttle okay. Also if only one cam skipped and the other stayed the same, you have just changed the cam profiling, increasing overlap changing timies the intake and exhaust valves open and close. Which cam make the car rough at idle, when you have increased overlap idle suffers, ask anybody with aftermarket cams. More overlap also pushes the powerband higher in the rpm range (usually).

First thing to do is get the motor back in time. Make sure you get the tensioner compressed before you re-install. Then get someone with a racket on the tensioner pulley to put tension on the belt while you torque down the tensioner.

Then do your compression test. See what she reads. She how she idles. If there is still a problem then worry about damage.

And how do you figure $1500 to replace valves? If you did the work that amount is obscene. couple hundred for the valves (if SS), and a couple hundred for machine work tops. Some new gaskets and you're good to go... as long as you didn't damage the pistons, usually just a few scratches, you should be able to do it for a third the cost. If you paid someone to do it, then they screwed up and you shouldn't have to pay anything.



15.9 @ 86.7mph

Injen CAI, 55mm TB, P&P Intake, Crower Cams, Hooker Header, ERT/Catco Cat, GS-T Muffler, AFX UDP, Crane Ign Amp, S-AFC

Thanks people, Satan quoted me the $1200-$1500 lol, crazy huh

1999 Mitsubishi Eclipse GS 10th Anniversary OZ Edition
Check Out My Site For Pix
http://mywebpages.comcast.net/EclipseRaceR/MyEclipse/VIS%20CF%20Hood/

oh satan quoted you that, satan sucks