My 04 accent 1.6L DOHC still having problems that don't make sense. Have my car timed by a friend after head gasket was fixed and both intake valves in cylinder 3 where changed. The timing was off (retard 3 teeth on intake cam and advanced 1 tooth on crank). Car was running rich at idle the cam sensor malfunction code. But besides lack of power run with no shake at idle. Had it timed properly and now runs rough at idle and fine at speed. Only p302, p303 and p2188 every now and then.



I bought a vacuum gauge to hopefully help point me in the right direction. The following links are videos of me testing my car.



First video is hooked up through the brake booster

The second is through the PCV valve hose.

Both reading are roughly the same. I know the gauge is calibrated to sea level and I am just around 560 feet above sea level.



http://www.youtube.com/watch?feature...&v=L1jnZ7oaTeU



http://www.youtube.com/watch?feature...&v=PhjH1eEZ3KQ



From what I have been reading I think I got burnt valves or chaber leak and a clogged exhuast. I believe my CAT is failing (as it rattled at times). I start off both at idle, then quick throttle and last slow throttle open to around 2000 rpms or so. Wasn't in car just pulled throttle control. Then idle and a few more quick throttles.



ANY THOUGHTS?



If burnt valves which is better to check: compression or leak down test?

Could timing being off as much as I mentioned earlier mask a problem so well? Burnt vavles are burnt valves. I know nothing happened when it was retimed as I was there.

 

A compression check is a nice thing mostly because you get a very quick, very easy look at what goes on with no special tools besides the gauge. A leakdown test will tell you exactly what/where you have a problem.



No youtube@work.com sorry can't comment on the videos.



In unrelated news, I think (speaking only for myself, not for the site) you might be able to get better advice if you would just stick with one thread instead of making all these different ones for the same mystery problem.

 

Sorry about different posts. However I have found in the past that most people stop reading posts from older enteries even though it moves it up to the top of the list. Hopefully you could let me know your opinion later about the video Stocker.

 

I just finished a compression test on all four cylinders. The following are my finding:

Cylinder 1 dry 201 wet 211

Cylinder 2 dry 201 wet 211

Cylinder 3 dry 201 wet 211 the first time I did the test on this cylinder after. 2 minutes the reading dropped to 160 (dry) I did the test a second time in case the gauge was not tight enough and the reading was 201 and stay at 201.

Cylinder 4 dry 205 wet 211

The test was done with the throttle held open and a turn of 5 cranks. In cylinders 2 3 and 4 there was a pop sound on the second stroke for both the dry and wet tests.



Could that be stuck valves? Don't remember hearing in the the 1st cylinder. Guess it is pointing that way with the vacuum test too.



Any way of freeing stuck valves other then to remove the head? Guess a leak down test wouldn't tell me much more other then if it is intake or exhaust?



Thanks for any help

 

The compression test comes back the second time looking perfect. That's a really nice set of numbers. The vacuum gauge looks normal for valves, but the vacuum level may be off a little? Have a look at the examples at the bottom of this page. Specifically scenario #10 if you're near sea level.



Are you SUPER-DEE-UPER SURE the timing is right?



Skip the first 10 minutes

http://www.youtube.com/watch?v=WgrfT0LFMhc

 

Those numbers seem high for 5 pumps, does anyone agree? Anyways that pop sound might have been from the air hose fitting o-ring not fully seated. I hear that a lot but usually only happens once.

 

your compression numbers are good. I don't think you have ANY valve/piston issues. Your issues are fuel or timing.



If it runs rough @ idle and fine @ higher RPM, it could be a bad fuel injector.

Have you pulled them examined them? Checked their spray pattern?

 

At the pressure he's got at idle, PLUS the way it ran changed when the timing was "fixed" I still have my penny ante on timing.

 

I just rechecked the timing. The cam sprocket pinhole is right at 12 (put a pin through it and into the notch), the crank sprocket engrave triangle in the tooth pointed at 1 (as the keyway faced 3). Even put a dowel down cylinder 1 and watch it fall and rise and stop as the cam sprocket pinhole hit 12. Gave it a little turn and the dowel instantly started to drop. So i would say it is on. Very much so from the guy that did it before me.



So I guess all I got left is to:

Check again the vacuum hoses, intake for leak

Change the TPS

Change fuel injectors (don't know how to check the spraying of the ones in there)

Seafoam crankcase



Anything else?



Already check:

Plugs Replaced

Wires Replaced

Coils Replace with no change, old one put back on

Cleaned the ISA

Cleaned PCV

Seafoamed the intake, gas tank (had no smoke out the tailpipe)





I noticed on Hyundai service website the the cylinder pressure should be 218psi, witht the limit of 208psi. It holds pressure, so thats a good thing. Think there is any reason to do a leakdown test? If the valves were sticking, would it show or would the psi push the valve into place? We know it seals or I would have no compression.



Lastly, would or could timing being off by so much masked any problem? I mean stick, bent, worn valves so show in any case. But as for bad injectors, TPS, intake leak, could it?

 

Easiest way to check for a vacuum leak is, get a stick of incense(light it), and wave around anywhere there could be a vacuum leak (when the engine is COLD but running, before any fans kick on). If you see the smoke disappear somewhere, or see it curve towards a hose/joint, you know it's sucking in air...and there's your leak.



You can test the injectors by removing the injectors/fuel rail/wiring harness (but reconnect them) and have them spray into a bucket or 4 cups. You'll notice right away if any of the injectors aren't spraying the same as the other 3.

You can also send your injectors out to RC-Engineering in Torrance California, to have them tested, but it's $25 per injector..so not cheap. (other places closer to you might also do the same service, but pricing is going to be same/similar).



also, do you have a ODB-II reader? Investing in one would help you diagnose the problem. You might have something as simple as a bad sensor returning goofy data @ low RPM. It would save you from doing needless repairs/replacement trying to track down this problem.