81 280zx turbo ignition timing won't change!

[Akira]

Hey guys, I have an 81 L28et in my 75 280z. I was getting around 8mpg and running really rich. So I did a few things to the car to figure out what might be causing the issue. I added an aeromotive fpr, pallnet fuel rail with gauge, and new stock l28et injectors. I changed the spark plugs and got new wires. Changed out o2 sensor and the CHTS. Since that didn't change anything, I started going back to the basics, I got myself a timing light and saw that it was running super advanced btdc. It was going beyond the timing marker, the timing mark was pointing between 8 to 9PM. If there were markers, it would be running somewhere around 35 to 40 btdc. So, I looked at the FSM and it says timing adjustment is done by the CAS down by the crank pulley. Well, since I didn't want to personally mess with the timing, I took it to Sunrise Z and had them do the adjustments even though it looked pretty darn easy. So they began to adjust it by turning the screw on top of the CAS, you could slowly see the CAS move. They tried to adjust this fully in both directions. However, this did not change the timing mark on the pulley nor did the engine noise change. Am I missing something here? We pulled the plug on the CAS to make sure the CAS was getting a signal because the car would not start without it. Is my CAS or dizzy operating incorrectly? I would definitely like to set my ignition timing back to factory.

 

Thanks!

[randy 77zt]

Stock timing is 20btdc..if you cant get it in spec and you use up all of the adjustment on the cas bracket the your oil pump is probably not installed correctly.Put the motor on tdc of #1 cylinder compression stroke and check to see if the distributor rotor in under #1 wire terminal in the dizzy cap.If you reclock the dizzy put the cas back in the center of the brackit and recheck the timing.If can get a stock fpr. I ran stock 81zxt electronics for years.The 90 tooth crank wheel can be used to fire other aftermarket efi systems.

 

 

[Akira]

Thanks for the reply Randy, the confusing part is that adjusting the CAS in either direction had no effect on timing. Also, the timing mark at 0TDC matches with the rotor under the dizzy poiting at the #1 wire (assuming the timing mark is correct).

[Akira]

So I tried adjusting the CAS at home and well it does move! It was just really really hard to tell with the timing light in the sun, must be getting old. So I was able to get it really close to the timing marker, but not on the timing marker teeth with the CAS fully adjusted. So like Randy pointed out, I must be off a tooth. Argh, well this gives me motivation to drop the oil pump and install my 82-83 dizzy. Thanks for your help again Randy.