[SR20DET] Are my rings fucked?

[Nikzilla]

So my mechanical timing was off previously by 2 links on the camshaft sprockets and it was preventing my from setting my timing properly.

Previous thread:
http://zilvia.net/f/engine-tech/549482-sr20det-my-mechanical-timing-off.html

Now I'm really certain I have it dead on, there is 9 links between my camshaft marks, and the exhaust cam is dead on 12 o'clock relative to the engine block at TDC. Although I still can't get the timing in the right range, but I can get it at 15-16 BTDC with the CAS maxed out, however I can't get it to idle for shit.

It's stumbling and dying on me at idle, but if I just hold the throttle open it will run with a bit of a vibration, or if I advance the timing past -15 it runs smoothly. IACV was never adjusted, I was told that if it's stock, don't touch it.

I thought maybe my valves were bent since my cams were off, so I did a compression test.

Dry:
1. 150 psi (3 pumps for about 140psi, 6 pumps for 150)
2. 150 psi (3 pumps for about 140psi, 6 pumps for 150)
3. 135 psi (3 pumps for about 120psi, 6 pumps for 135)
4. 142 psi (3 pumps for about 130psi, 6 pumps for 142)

Wet (3 squirts of oil from a squirter):
1. 155 psi (3 pumps for about 140psi, 6 pumps for 155)
2. 170 psi (3 pumps for about 150psi, 6 pumps for 170) <<<<<<
3. 160 psi (3 pumps for about 145psi, 6 pumps for 160) <<<<<<
4. 160 psi (3 pumps for about 145psi, 6 pumps for 160)


In case you're wondering, the reason why my rocker cover was off is because I had lifter tick after mis-shifting 3rd to 2nd at high rpm. It was running fine beforehand.

Could my piston rings be fucked?

[pablito_s13]

normal compression

[Nikzilla]

normal compression

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If you give me your address I will send you flowers

[pete240]

have you checked for boost/vac leaks?

[Nikzilla]

have you checked for boost/vac leaks?

I had a couple but it's all air tight now.

[di-devol]

How are you taking timing with the gun? Are you using the loop at the back of the motor?

Take a pic of your cas, so we can see the orientation of it.

[Def]

Do you have cams? If so you should open up the IACV screw slightly (maybe 1/2-1 full turns). Cams mean the engine needs more airflow at idle.

Have you checked a consult feed to see what your timing is vs. what the gun is reading? It should be pretty steady at 15 deg BTDC on almost any ROM tuned ECU, as most don't change the idle timing.

It'll jump a bit here and there to stabilize, which is the exhaust tone change you hear with an SR idling.

[Luvs2slide]

You need to ensure your mechanical timing is set dead on. Your cam angle sensor should be roughly in the center of the adjustment. I made this picture after fighting with the timing on my car after doing it like 20 times for the first time, now its super easy. Good Luck.

http://i76.photobucket.com/albums/j1/luvs2slide/Timing_zps167ce6a5.png (http://s76.photobucket.com/user/luvs2slide/media/Timing_zps167ce6a5.png.html)

[Nikzilla]

You guys have been extremely helpful! It turns out it was the IACV, even though my engine is stock. I just screwed it out a turn and it idled steady, and then I drew it back into 825 RPM.

Thanks guys!

[Def]

Take the IACV out and clean it out with throttle body cleaner. They like to get gunk in them if you have any sort of blowby, especially on S13 SRs since the baffling in the valve cover sucks.