Adjusting timing - relationship of CAS, timing marks, BISS?

[socalgvr4]

Ive been through the VFAQ a couple of times, including some pretty nice videos online about setting base timing. I have some questions based on things I see.

The idle is erratic, and i've already validated that the biss screw, vaccum lines, the ISC, and FIAV are properly functional.

I've set the base rpm to 750rpm at the biss, once i grounded the timing plug.
Then I hooked up a timing light to cylinder 1 wire, and checked the timing marks at the cam.. they were lined up.

HOWEVER, the timing mark on pulley against the cover is lined up to TDC and NOT 5 degrees before TDC. Which makes me think that that when the timing belt was put on the timing was incorrectly set?

The car does fire up and run and all, but has a unusual behavior of dying when dropping in RPM. I've had this sort of issue in the past on another car with bad timing as this is what is leading me down this path.

SO...

In order to set the timing, can I safely pull the necessarily pulleys off and reset the timing and loosening up the tension bearing, and re-adjust or is the timing mark on the crank pulley a red-herring?

Thanks for your assistance on this.

 

[AnotherNewb]

If you are concerned about your timing belt being off a tooth or two you can line up the marks on the cams and the mark on the timing cover to tdc and that will let you know if that is correct. Its been a while but I recall having to ground a pin on the obd1 connector and the timing jumper under the hood to set base idle.

 

[socalgvr4]

So the crank pulley DOES have to be lined up with the TDC mark

when the cam gears line up properly?

When the car is NOT on I see that this is in fact the case.

When I start the car, and ground the timing and check again, the lines line up on cam, but the mark on the crank pulley does NOT sit at 5 degree mark it sits close to TDC.

Is that right?

 

[beaner]

Yes that is fine. What you're seeing on the crank is for ignition timing only. Just clock the CAS to make it at 5 deg btdc.

 

[socalgvr4]

And when I do that, the marks on the cam side completely mis-align.

So i'm thinking something is not set properly?

 

[socalgvr4]

Okay I think I'm going to answer my own question after a little more research on my own.

*Mechanical timing

1) Line up the cam gears with the marks pointing exactly at each other and confirm with a ruler through center bolts to make sure its lined up
1A) When doing 1) above, the crank pulley mark will line up with the TDC mark.

*Ignition timing

1) Turn car on to operating temps (fan should go on then off) to reach proper operating temperature.
2) Once achieved ground the connector for timing near firewall
3) Attach timing light to cylinder 1, and check timing against the crank pulley.
4) It should read between TDC and 10 degree mark -- which the proper 5 degrees of timing.

(and if you do point the light at the cam gears the marks SHOULD Be off at this point, because we are dealing with IGNITION timing and not MECHANICAL timing)


5) If it doesnt then adjust the CAS to advance or retard timing.

Is that right?

 

[citymunky]

yup

 

To set the idle you ground the plug underhood AND a few pins on the OBD1 plug.

To set timing you ground just the plug underhood. Make sure that you have nothing plugged into the OBD1 port.

If you have a datalogger plugged into the OBD1 port then it is grounding it.

 

[Adorsey]

Under the hood you ground the ignition timming connector. *its a plug that has a cap on it and hangs out of the loom near the brake fluid resivour and firewall.

You ground #10 pin in the diagnostic port, if you don't already have a data logger installed.

Start the car too full temp.
Turn off, and ground connectors.
Turn the car on
Adjust the BISS accordingly
And let idle for a min, then shut the car off.
Unhook the grounds
And turn the car back on, let idle for 5mins and it should go to set/desired idle, if done correctly /ubbthreads/images/graemlins/wink.gif

Good luck!

 

[socalgvr4]

Thanks...After the posts and thinking about it (based on my post), I was able to successfully set my timing accurately.

Thanks to everyone who posted up.