druggist

iTrader: (4)

I'm running stock except the power fc. Snipped the proper wires and capped them off. When I start the car on a cold engine, the rpms start at 2000, slowly go down as the water temperature go up. Does the power FC not bypass the AWS? Is that the AWS that is causing this? On my stock ECU, I used to be able to just rev the throttle at startup and it would go below 1000, but thats the the case with power FC. Asides from that the car runs fine, idles well once around 65c.

cib24

Not sure. Mine acted the same way as yours on the stock ECU. Would start at 2,000 RPM but if I blipped the throttle it would drop to about 1200 RPM and stay there until warmed up. on the PFC it starts at 2000 RPM and stays there for about 30 seconds and then drops to about 1500 RPM for another minute or so and then drops down to about 1000 or lower.

I think the AWS is like 3000 RPM but I have a Japanese import so it's not installed like it is on US cars.

94VRotary

iTrader: (6)

Did you reset the ecu?
Did you set the TPS at right location?
Did you perform the initial ecu learn procedure?

AWS shouldn't be working if you snipped the correct wiring.

Banzai-Racing

iTrader: (11)

The throttle body thermal wax (coolant lines to/from TB) holds the throttle open and slowly closes as the water temp increases. This is not electronically controlled it is mechanically activated.

Next to the TPS

t-von

iTrader: (8)

The AWS isn't a bad thing. It has MANY advantages. When my fd was bone stock, I always let it do it's thing. Some people think it causes premature wear? Well my original engine blew at 108,000 miles from over boosting. When I opened the engine, all the bearings were in perfect contidion. My engine actually ran smoother when I let the AWS do its thing because not only does it warm up the cat sooner, it also warms up the combustion chamber faster. This keeps the plugs from fouling from all of the fuel being dumped in during cold start. It also keeps carbon buildup down. On my NA 20b I actually programed in a fast idle with my BAC valve. I'm a believer in fast warm up.

Banzai-Racing

iTrader: (11)

The PFC does not control the AWS, which only revs the car to 3000 rpm for 20 seconds.

druggist

iTrader: (4)

So you're saying it's normal and let it do it's thing

jza80

iTrader: (32)

My car does exactly the same thing when I have a Power FC installed. Takes awhile to get down to normal idle speed too, presumably as the engine coolant gets up to full temperature.

t-von

iTrader: (8)

Based on my experience, as long as your getting instant oil pressure, the engine will be fine. As Banzai pointed out, the PFC runs the engine different so I wouldn't stress over it.

DaleClark

iTrader: (55)

The 3000 RPM startup, as stated, is caused by the AWS system. AWS was a US-only thing to hurry up and get the pre-cat hot to meet emissions standards. Japanese cars don't have AWS, there isn't even a spot for it on the intake manifold. That's part of the reason why the PFC doesn't control it, the PFC is designed for Japanese cars.

The 1500-2000 RPM slowly descending idle is due to the thermowax on the throttle body. The RPM at which the cold idle starts can be adjusted with the adjustment screw.

AWS, in my opinion, is a good idea for one reason only. Mazda HAD to put it on the car to be able to sell it in the US. That's about it. It can be REALLY hard on the turbos if the car has sat for a few months. Turbo bearings are dry, suddenly the car is revved to 3000 RPM and the turbos are brought up to speed before full lubrication hits them. Bryan at BNR has said he's seen a lot more bad turbos from cars up north where they sit all winter then are suddenly started in the springtime. But, for everyday driving, it's not bad, it's just annoying and unnecessary.

The thermowax/fast idle cam isn't a bad idea, especially in colder climates. I've removed mine, but it just doesn't get really cold around here. That fast idle can get the heater working sooner, the car up to temp and where it's fuel efficient sooner, etc. If you DO remove it, take your time and properly remove all the parts. I've seen a few that are just half removed and the cam is still there where it can stick and catch on the throttle blades, causing the throttle to stick open. That's a REAL bad thing - a sticking throttle can lead to accidents. Properly removing it requires the removal of the TPS and you will have to re-adjust it afterwards.

Dale

t-von

iTrader: (8)

^ My turbos were in great shape with not so much cracking on the manifold flange and very minimal shaft play. I think turbo wear has more to do with how one uses the car. Boost alot and you will wear them down faster. Not letting the engine bay cool down properly before shutdown will also damage the turbos. I didn't abuse my fd when stock. I can't speak for the guys at BNR but there's really no way they can say AWS plays a roll in accelerating wear on the turbo bearings without proof. There's far to many other things that accelerate wear. I used the AWS probably more than most and had zero side effects. I fully respect the theory behind the cold start long term dry condition but, my turbos didn't experience any ill effects as stated above.

kensin

iTrader: (22)

What would make the aws all of sudden stop working ?
mine was idling at 3k rpm on cold start since i got it. Just lask week it stop idling at 3k and would idle at 2k instead blipping the throttle would bring the rpm down to 1100 or so but sounds rough while going from 2k to 1k while declining

mdp

I am amazed at this somewhat ancient thread that no one mentioned the easy way to bypass the AWS in the morning. First, for folks who don't want the AWS to engage in the morning, just put the transmission in first gear, push the clutch petal down all the way, and start the car, presto no AWS, only the thermowax and fast idle cam will be working. Now kensin, use that procedure to determine if the AWS or fast idle is the problem. If it is he thermowax cam, check the linkage and replace the thermowax pellet. If it is the AWS, disconnect the AWS plug and measure the voltage as you cold start the engine normally. If you get a voltage then the computer is sending power to the AWS solenoid. If that is the case check the solenoid using the shop manual page below.


Good luck

DaveW

I do that every time I start the car. I have done that since I realized just after I got the car in 1992 that it reduced the start RPM.

kensin

iTrader: (22)

nice !! Ill get to checking. Thanks for the pic refference

mdp

Also, while the solenoid is out apply 12 volts to it to make sure it isn't stuck or sticking.