OK...I've tried just about everything and I keep having this intermittent problem of no starting due to no fuel is getting past the injectors (sometimes) on start up...fuel system, grounds, battery is all fine and she runs great once she fires up...
Soooo....yesterday I was out in the parking lot ....no start...I took the air filter out and she fired right up...so this seems to indicate that for some reason not enough air is flowing through the AFM and yes I do have a new Filter. Any Ideas ? perhaps the door is not opening enough sometimes maybe ? any help appreciated

 

By "no start" - is it cranking & not starting, or not cranking, or what?

Also, the RX-7s don't have airflow meters - they use manifold pressure & RPMs to determine airflow.

-=Russ=-

 

3rd gens detect airflow by manifold pressure. 2nd gens determine it by a mass airflow sensor. If it is an S4 make sure that the MAF is level this has caused problems for people before.

- Steiner

 

Really? I didn't think any of the RX-7s had mass airflow sensors.

-=Russ=-

 

This falls under the "if you don't know it to be true, don't answer" category.

 

I had a similar problem with my AFM.

I had an engine rebuilt, and it would not start. Once it did start - it ran hella lean, and made the manifold glow. After a while, it wouldn't start. After a small fortune strapped to a mazda diagnostic machine - it turned out that the harness that clipped into the MAF had a short that was messing up the signal to the ECU. Once that had been rectified - the car ran flawlessly.

On the same note - I had a buddy whose Fc's MAF was so fouled up that the flapper door wouldn't swing easily. It would hang up, and sometimes not even open. A quick bath in degreaser helped that right along.

Take the MAF off the car, and make sure that it is clean and swings freely. Also inspect the clip and harness - especially where the wires make that great 90 degree turn right before the clip.

 

Well ok...whatever that thing is just behind the airbox with the wires going into it ...it turns over just fine and usually starts...everthing is tip top on this one...but occaisionally I get a no start meaning it is turning over really good, just no fuel getting past the injector,,,then five, ten or thirty or so minutes later she fires up....and it seemed that when I took out the air filter she fired right up...now that will have to happen each time because I have installed:
1. New fuel pump (I've saved all old parts for spare)
2. new cables and battery
3. fuel pump kill switch in case it was leaky injectors
causing mild flooding...
4. replaced and cleaned all grounds including cleaning
main fuse box under the hood...
5. new fuel lines and fuel filter...
6. a couple of relays that affect the injector system
(replaced by Mazda dealer) in troubleshooting pro-
blem two or so years ago (kept old parts for spare)
7. several more that I have forgot for now...oh yeah
cleaned all connection junctions that I could reach
....and I still occaisonally get this intermittent no fire up...was just wondering what that unit that I called an
AFM or MA whatever would do to or not do to cause this...thanks again for any help guys and gals....

 

Apologies. Everything I'd found online when researching the RX-7s indicated that they all used manifold pressure, which was why they wouldn't take well to heavy bolt on mods.

-=Russ=-