i got a 89 gtu n/a. so my timing won't advance. I have check the codes and it says 02. So i swapped out 5 different CAS, no luck. checked for vacuum leaks, tps, remanufactured ecu and even changed out the engine wiring harness. The harness got the 02 code to disappear but still the timing is retarded. then i found out that my car idles at 2000-2500 with the BAC valve plugged in. when it's unplugged it idles fine. so i swapped out 3 different BAC valves but it still does the same thing. then i ran the scanner to check codes again and the 02 code came back. What should i do??? how can i get my timing to advance, 02 code to go away, and fix the BAC thing. Any help would be appreciated.

 

How do you know it won't advance?

Timing light?

How does it drive?

James

 

yeah i used two different timing lights. connected to lead1 and the timing retarded. it drives alrite. but since my timing wont advance it doesn't seem to have the power it should have. plus the gas mileage is crappy. I know its a 7, so gas mileage and rx-7 dont go together, but it's just not performing to its full potential, especially with only 12,000 on the rebuild.

 

The ECU is obvously turning on the BAC, and richening the mixture why would you swap the BAC???

You have something on the motor that is telling the ECU that the car is not running right and the ECU is trying to compinsate.

It sounds like you have not done anything to the O2... are you sure its not grounded or bad???

 

******yeah i used two different timing lights. connected to lead1 and the timing retarded********

What does that mean? Retarded when?

The timing should advance any time you rev the engine over 1200rpm, even just sitting in the driveway.

 

well it retards the minute the engine starts revving. the BAC valve unplugged gets the car to idle right. What could be wrong that when i plug in the BAC the rpms go up to 2000-2500. this is when the engine is warm so i kno it's not the AWS. The O2 sensor was changed out 2 months ago(bosch) but I will check it again. the mechanic even said it was good, but i'll double check. my friend said that one of the pulleys may be torqued down too tight. could that be it?? thanks for your helps guys. appreciated it a lot.

 

Has the CAS been out of the car recently?

 

He said he tried 5 of them. There is almost nothing that can go wrong with the cas. It's 2 magnets with some wires. My guess would be the cas is installed a tooth off or so from where it should be. I'd make sure the tps is adjusted properly since it has been off too. Luckily you don't need the engine running to adjust it. I'd also double check to make sure that the plug wires are going to the correct places. That's easy to mess up.

 

i installed one CAS and the mechanic at Mazdas and More(kent, Wa) tried like 4 of them. i made sure that the mark on the pulley was lined up with the needle and the gear on the Cas was lined up with the dot. the tps was adjusted by the led method and one lite every time. I checked the plug wires and they are all in the rite plugs.

 

you problem is in the intake, you tampered with factory settings.

1. eliminate error code (fix the problem per FSM)
2. check for loose wires, verify electrical connections, vacuum routing.
3. check operation of idle circuit valves per FSM w/DMM
4. inspect TB per FSM
5. set the timing to 5BTDC

 

should the timing advance even if the error code is not eliminated??

 

As far as the BAC goes, I'd just accept the fact the bac has had its day. You might try to clean it with some carb cleaner. Do not force the diaphram back when you do that.

The bac goes fully open anytime you put the key to START. Maybe the bac is staying wide open and not returning to its normal duty cycle.

Pull the bac off. Just two nuts. Leave the connector on. Turn the key to ON only. The bac should be vibrating and not staying fully open.

Now pull the small wire off the starter. The one on a blade connector. You can reach under the car and feel it, then pull it off. Now have someone hold the key to START. The bac should go fully open. Now have them release the key from START and let it return to ON. The bac should close and start vibrating. Now would be a good time to spray carb cleaner into it while it vibrates. Dump and refill several times.

If you were looking at the front of the engine, looking aft, when you rev the engine with a timing light on it, the marks on the pulley should move to your left, meaning it is advancing. That is what your seeing? Right?

You might take a quick look and see if the water thermo sensor plug is connected to the back of the water pump housing.

Note that the FSM says a cold engines timing is advanced 5* BTDC when starting/cranking, then goes to 5* retarded while idling. See CONTROL SYSTEM in the Fuel section of the S5 FSM.

Then there's always the possibility one of the two wires on the BAC is touching ground. It would be the wire with a color other than Black/White. Check it out.

 

where do i download the online fsm?

 

https://www.rx7club.com/showthread.p...18#post5131218

http://69.162.44.72:8080/rx7/s5wiring/