hornbm

Well I got the thing to idle... sorta. I found out that if I have someone hold the flap in the AFM open just a little the thing will idle.

I went back and tested intake manifold pressure, it was around 10 PSI. How much is normal for FC's anyway? The 10 seems a bit low.

This leads me to believe that the engine is not drawing in enough air at idle. I went back and double checked the vacuum lines, and there doesnt seem to be a problem there. Is there anyway I can set the engine to draw in more air?

The other interesting part was about the TPS. It was way out of adjustment, so I set it back to what the FSM says it should be. No difference.... so I ran the car with the TPS unplugged, and it ran exactly the same. I know the TPS has got to be working, you can here the clicks when you push down on the throttle with the car in on, but not running. Again the thing ohmed out ok once I adjusted it.

Does anybody have any ideas what might be wrong here?

NZConvertible

Sounds like a problem with either the safety switch in the AFM or the circuit opening relay. The switch closes when there's airflow through the AFM which turns on the fuel pump via the circuit opening relay. Check both as per the FSM's instructions. You mean manifold vacuum when idling? 10psi is not possible, I think you mean 10inHg. It should be 14-16inHg, but that's with a good idle. Increase idle speed, either with the BAC screw or the throttle-stop screw. There's no point in setting the TPS until the idle is sorted, because adjusting the idle throws out the TPS setting. That's just the emission control solenoids (relief and switching) you can hear clicking, so yes, the TPS is working.

Sort out the AFM or circuit opening relay first, that sounds like your main problem.

hornbm

saftey switch in the afm? Never new it existed. I was just figuring that it was not drawing in enough air to hold the AFM open a little bit.

How do I go about testing the afm, or the saftey switch issue?

HAILERS

Install the fuel check connector near the right hand strut tower. Yellow in color. Two socket.Jumper the two sockets with a piece of wire. Turn the key to ON. Listen for the fuel pump. If you hear the pump...then start the car and see and watch it idle.

For information on the fuel check connector....see http://www.iluvmyrx7.com and download the factory service manual. The Fuel section will do. Read it for further information.

NZConvertible

If the AFM flap completely closes, a switch in the AFM opens the circuit opening relay which cuts power to the fuel pump. This stops fuel being pumped out of broken fuel lines in the event of an accident.

The yellow check connector Hailers refered to bypasses the switch in the AFM so that the pump can be run without the engine running. This is only for testing the pump or pressurising the fuel system. You shouldn't drive with the switch bypassed for obvious safety reasons, but it will get your car running until you can replace or repair the AFM. Like I said, it's in the FSM.

hornbm

ok, before I even read this, I tried that this morning. I got the thing to idle... sorta. I got out of the car to adjust the CAS and the second I touched it, it died. I tried all day but I could not get the thing to idle again.

After doing this, I removed the jumper wire, and then started trhe car. It was fine, then the next time it started it was fine as well. (still no idle) However the third time the thing allmost started and then died immediately. I checked the fuel lines, and it felt like the pressure was no longer in the system.

So I reconnected the test connector and sure enough the thing started. I disconnected the wire, and the first and second time it started fine, but the third time it died again. I was just amazed, so I repeated exactly what I have judt done 2 more times, and they both wouldnt start past the third time.

I figured that the aditional fuel pressure had thrown the ECU into trieng to compinsate for it, much the same way an OBDII automotive computer system works. I left the battery unplugged for about an ho0ur so the battery backup in the ECU would die. I connected every thing back up, primed the fuel system, and everything worked fine. The third start worked perfectly, although the thing would still not idle.

Now as I noticed this, I was checking the timing opnly top find out that the trailing plugs were not firing. I adjusted the timing, and then they fired. It dint make a bit of difference how the engine ran though.

After all this and checking the afm, I'm stumped. The thing even when its beign reved a little feels like its gasping for air. Its feels very lurchy, and you can hear the motor raise and lower rpm as the compuetr tries to fix whatever it can. The thing is just not drawing in enough air. Which means a vacuum leak right? I went back and checked all my vacuum lines today to, and they are perfect. Tried using brake cleaner around the hose copnnections to see if it would change anything, and nothing.

The only thing that is in doubt is the timing, I've tried two different spots on the pulley to stab the CAS at, one being where the an apex seal crosses teh leading plug hole of rotor 2, the other being halfway inbetween the two spark plug holes. Still wont improve.

Where should I be looking next?

NZConvertible

Our ECU's are nearly as clever as that. They're 17 years old remember... No, a vacuum leak draws in more air. But is not the volume or air that's the problem, it's the fact that it's unmetered, so the ECU isn't providing enough fuel.

Remember the only thing stopping air entering the engine is the throttle. If the engine's turning over and there's enough air bypassing the throttle, then it is drawing air in, no matter what other problems you may have. Your problem is either not enough bypass air (throttle settings), not enough fuel, incorrect ignition timing or all of the above.

I'm not sure about your CAS stab-in attempts. There's only one right way, so make sure you do it the way Mazda says.

hornbm

I just talked to a rotary shop and they said dont even think about anything else untill you know the timing is perfect. They reccomended I get a racing beat pulley, instead of trying to mark TDC myslef.

NZConvertible

Doesn't your pulley have timing marks? Is it stock?

hornbm

no, when I bought my motor, I didnt get any pullys, so I carried over the FB ones, anyway the fb ones weren't keyed like the FC and the way it lines up to the hub is mirrored the way it is on the FC, so its hard to guess where to stab the CAS at.

looks like I have to get a racing beat pulley now