bad idle and stuff!!!!

[mitsubluetalon]

hey guys, just finished putting my engine back together, new head. but now it idles really funny.

below 1000rpm the engine is really shaky and almost sounds like its missing, and it takes a long time for it to start, feels like i'm trying to start a carborated engine or something.

but at rpm's above 1000 like cruising or spooling, it runs great. actually the best fuel efficiency i've seen in some time now. i'm really sure my timing is perfect, and i'm thinking that the only thing it could be is the cam position sensor, i put that back on after i was done putting my timing cover and everything else back on so i'm not sure if its fully reset back to starting position

number 1 piston was at top dead center and my cam lobes were both up and notches both lined up but i'm not sure if the rest of my engine is exactly on time as well with the cam angle sensor.

so i was wondering, just to rule out the cam angle sensor, would i be able to take the cam sensor off and rotate it 180-360 degrees over manually and put it back on? would that mess anything up if it is not the problem? thanks

Jason.

 

[steve]

You can reset the CAS easily.
Turn the crank until the timing mark on the harmonic damper lines up with the T on the plastic front cover, take the CAS off and make sure the coupler timing mark lines up with mark on the CAS and reinstall it.

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Pressure test your intake to make sure you don't have any leaks, including the injector insulators where the injectors fit into the head. A vacuum leak can make the car idle poorly and run lean up to the point that you build boost when it will start going rich and get richer as boost goes up.

Run a compression test to make sure the cylinders are good and no valve problems.

Check the ignition timing to make sure it's 5 degrees BTDC. Check the ISC coils and set the base idle speed.

Let us know what your idle vacuum is.

Steve

 

[DSM90AWD]

below 1000rpm the engine is really shaky and almost sounds like its missing, and it takes a long time for it to start, feels like i'm trying to start a carborated engine or something

The CAS being 180 out does not make much (if any) difference at idle. Mine was out when I recently did my cams and ran the same either way (was out at first). More likely your ignition timing or cam timing is off.

To check cam timing, with the #1 at TDC / Cams aligned the crankshaft pulley timing mark at TDC on the ignition scale on the lower timing cover (assuming your crank pulley is not separated).

 

[szewczyd]

I have a very similar problem with my 90 TSi FWD, I believe that it is timing related. Smooth above 1.5k otherwise runs rough and will sometimes stall out.

 

[ddavisaf]

The CAS being 180 out does not make much (if any) difference at idle. Mine was out when I recently did my cams and ran the same either way (was out at first). More likely your ignition timing or cam timing is off.

To check cam timing, with the #1 at TDC / Cams aligned the crankshaft pulley timing mark at TDC on the ignition scale on the lower timing cover (assuming your crank pulley is not separated).

Make sure you check that.

 

[mitsubluetalon]

THANK YOU EVERYBODY!!

thats some awesome information guys, thank you i will check everything and i will get back to you.

Jason.