good thread. i am having an issue at the moment that when i let off the accelerator around 3k rpms i get loud popping noises ( after burn?) at the exhaust...and after the engine is warm when i let off the accelerator and put it in neutral the car dies/floods...im guessing this is the tps NOT telling my ecu to stop dumping fuel in the engine? i'm also guessing this could be part of my 9mpg sweet mileage =P.

 

I wouldnt worry about the popping... all rotaries do it... a AFC may let it settle down a bit, just a result of the rich mixture

 

well the part that really worries me is the part when i let off and the car wants to die...cause it's died on me in the middle of a hwy with lots of traffic....

i couldnt start it back up and after several tries i figured out it was because it had severely flooded. luckily someone stopped and helped me push it off the middle of the road and onto a parking lot. I did the unflooding procedure many times and finally got it to start. The car wants to die almost everytime i let off the accelerator after it has warmed up. sometimes it dies but i am going fast enough to where i can throw it in gear and drop the clutch and start it back up.

 

Just another update on my TPS... getting a 1.1 ohm resistance in idle position. Still at 5 ohms WOT. I think the TPS is good... the tester (me) is the real problem : ) Next on my list... water thermo sender. If that doesn't fix it... BAC... will it ever end? haha

And as a side note... my car has been running best when setting the TPS with the tester lights... and not adjusting with the DMM.

Still having the bouncing idle during warmup.

Josh

 

Have you ever look at the FSM and the page called CONTROL UNIT and taken a look at what pin 2G (tps) should read with a FULLY HOT engine? Jpg attached.

 

HAILERS... I have good news and I have good news (and I didn't save a bunch of money on car insurance).

#1 Good - Yes, I have seen that sheet that you've attached, it's actually sitting on my desktop right now... I'm going to check them all sometime this week and make sure there aren't any screwy readings. I'd say 1.1 ohm is approxiamely 1 ohm wouldn't you? haha

#2 Good - I was out checking codes at the DCC port on my car today (got an itch) and to my surprise... no codes were thrown : ) that was good to see. While I was out there, I pulled the air tube to the throttle body and checked the spacing of the primary and secondary plates... those were good.

And oh glorious moment. I unplugged the BAC and I have no more bouncing idle at all. I have noticed this before when I jumper the initial set coupler. The true test will be in the morning when the engine is truly cold. That's when I usually have the most annoying bouncing idle. I'm sure it annoys the **** out of my neighbors. So, I really think it's the BAC. I left it unplugged and taped off the connector with electrical tape. The car is running rock solid now. I'll clean the BAC this week and see if it gets any better. If not, I'll get a cheap one from Kevin and cross my fingers for a better one.

So, that's it for now. But I really hope this is solved. I snapped some pictures around the engine bay today of things I was unsure about. I'll post them on this thread tonight and maybe get some feedback from you.

Take Care,
Josh

 

???????????I'd say one volt is one volt. Pin 2G. Give or take some.

A question would be: how low has your idle been dropping before the rpm's bounced?

 

I assume you mean when I start the car... during the accelerated warm up... about what RPM does the bouncing start? Somewhere between 1700-1800 is when the bouncing starts... and it continues to bounce until the car is completely warm. Initially goes up to 3k... works its way down while warming up... bouncing starts around 1800-1700.

I drove the car around all night tonight with the BAC unplugged and I never had a single bouncing idle. However, it was pretty hard to start when the engine was cold. I plugged it back in so it will start easily in the morning.

Josh

 

Ran the car all day without the BAC... started pretty well this cold morning. A little harder to start when warm... for obvious reasons. Also a little touchy now when taking off from a stop... have to rev up a bit more deliberately and slip the clutch a bit slower... don't know exactly what's going on here... oh well. I'm just happy my idle doesn't bounce anymore.

Still haven't gotten around to testing/cleaning the BAC.

Josh

 

i have the same problem like you

but when i disconnect my BAC, the engine dies!? what's the problem?

 

Your idle isn't set right. Your bac is presently carrying all the idle function and it should not. The BAC is a idle helper, not the item that makes the idle run at approx 750.

The idle should be set with the initial set coupler installed. The neuters the BAC while you set the idle. Once you have the idle at 750, you remove the initial set coupler. Now the bac is fully functional and HELPS maintain the 750 idle and HELPS keeping the engine running when loads are put on it at idle.

IF your idle was set right, you should be able to pull the plug off it and the engine keep on idling. It may change a touch but not die.

I'm talking about a normal fully warmed up engine.

 

back to this two light method...how would one go about getting these 'two lights'?

 

You have to make the tester light (under $10 parts) unless you have the mazda tester. Go get two LED lights from radio shack... both of the lights should have a positive and negative wire...like this...Radio Shack... you also need three spade connectors... like this... Radio Shack.

Once you have these parts, crimp the two positive wires together into one spade connector. Then, crimp each negative wire into its own individual spade connector. Once completed you should have a two light assembly with three connectors... one positive and two negative.

This is your tester light...

Use this tester light in the TPS adjust connector near the air filter box... it's a green, three hole connector. The positive goes in the top (single hole) hole connector and the two negatives go in the bottom (double hole) hole connectors. The TPS adjustment screw is on the TPS... it should have a small plastic cap on it to prevent movement/tampering.

Turn this screw clockwise or counter-clockwise until you get a single LED light reading. You might get two lights or no lights initially... the goal is one light illuminated. Remember to do this with engine completely warm, key on, but not running.

Once this is done... you can check the resistance at the back of the TPS connector (not the test connector you just used, the actual TPS connector that connects to the engine harness) and the sweep of the TPS... should start at 1 ohm... and sweep up to 4-6 ohm smoothly at wide open throttle... just move the throttle yourself or have someone depress the accelerator inside the car (no dead spots).

Once this is done, you can continue adjusting your idle by using a small piece of wire... 4-5 inches is good... to jumper the initial set coupler (another green connector on the driver side now... near the battery... two hole connector). Start the engine... then jumper the coupler... you should hear the BAC valve cut off some and your idle drop just a bit. This is good. Now, mechanically set your idle with the screw on top of the throttle body (under the black cap). Set it to 750 +/- 50 RPMs. Mine is set to 800 b/c my BAC is disconnected.

Good luck and happy idling

 

Whats the advantage of disconnecting your BAC valve?

 

Installing the initial set coupler makes the bac run at a set duty cycle of approx 45%.

If you did not do that, then each time you made an adjustment to the idle, the BAC would try to react to the adjustment. You'd end up chasing your tail. With the set duty cycle the bac lets in a set amout of air and does not change that amount as you make the adjustments.

Remove the initial set coupler and the bac will react to engine loads etc.

 

um...whats an initial set coupler? and in the FSM it says that when you disconnect the BAC you have to drain all the engine coolant? did you do this or did you just unplug it?

 

************************************************** ****************
Once this is done, you can continue adjusting your idle by using a small piece of wire... 4-5 inches is good... to jumper the initial set coupler (another green connector on the driver side now... near the battery... two hole connector.**************************************** **************

I think he meant he took the electrical plug off the BAC, not take it off the car. Why? That's for him to answer.

The online fsm shows where parts are on the engine.

 

i checked on the FAQs..whats the site for those FSMs?

 

First off, here's the FSM: Online FSM Bookmark it and never lose it.

Secondly, I know of no advantage to disconnecting the BAC valve other than weight reduction and removing engine bay clutter. Mine is disconnected (the electrical plug) simply because it either doesn't work or it is dirty. I haven't checked which one yet. It causes my idle to bounce and surge... you know, the stuff so many people post about around here. When I figure out if it's out of spec or just dirty... I'll either clean it or pick up another used one somewhere... or I might just keep it unplugged. It runs fine without it so far... hot starts get a little tricky sometimes. No worse than it ever did. haha.

Josh