both actually

the mechanic idle is set with the throttle plate screws by the firewall. it should be 725-750 with the initial set coupler jumpered

the bac is there to kick up the idle under load (ie p/s pump turning, a/c on, etc) without the mechanical idle set properly the bac can't no matter how hard it tries hold a proper idle.

 

Generally what happens if the mechanical idle is set too low- the idle will fall below 750 (sometimes WAY below 750), then bounce (or surge) back up past 750 (because the BAC goes wide open to keep the engine from stalling), then the process repeats itself, over and over, forever and ever

If the engine dies when the initial set coupler is jumpered, the idle is set WAY to low. For some reason, my idle adjust screw would move this direction on its own (engine vibrations?) and I'd have to reset it again. Little dob of RTV fixed that...

 

so they said there was a lot of gas in the engine? is it possible that you're running on one rotor because the plugs are fouled on one side from flooding? similar thing happened to me.

 

ha just take it away from the mazda dealer asap........ you might as leave your car in a 9th grade autoshop class or in a chop shop.. but then again the kids might be better than most mazda dealers......

 

changing the harness is not by far a difficult job if you really wanted to make sure it wasn't just wiring buy a new harness and put it on its not like like a piston engine where theres tons of connectors and you can mix up this one with that one and blah!!!!!!!!!!! lolI changed mine peice of cake just remember the ground wires and also it will never go back in the way it came out as long as you have hooked everything up right and its not blocking motion of something mechanical then your good

 

[QUOTE=WAYNE88N/A]Generally what happens if the mechanical idle is set too low- the idle will fall below 750 (sometimes WAY below 750), then bounce (or surge) back up past 750 (because the BAC goes wide open to keep the engine from stalling), then the process repeats itself, over and over, forever and ever
QUOTE]

ummmm......that sounds familiar

 

That's where Mazda got the zoom zoom zoom advertising bit from - an out of wack Rx-7 idle..

 

One of the reasons for the dash pot on the TB is to let the throttle close softly so it will not bang shut.
If it's removed or mis-adjusted the stop screw will pein a hole in the aluminum stop.

 

So, where does one get a new engine wiring harness? Every time I work under the hood, I'm afraid it's just going to crumble to dust. I've laso had to wrap electrical tape to cover exposed corroded conductors where the insulator has already crumbled away.

Sorry for thread jacking.

 

I just have them check the microfich thing and I point out the part.



A new wiring harness would be a great thing for almost any older FC.

My S4 TII harness looked pretty good but I have stripped away wires which are atleast 2 ft from open ends and it is completely oxidized and corroded.

This is where I found most of my hesitation and fuel problems.

I would love to buy a new harness but I don't want to spend more than $200. Anythign over and I woudl rather consider an EMS like Microtech or Haltech

 

It's an odd part number, but 99541-01601 is what you need. And you need two of them. The dealer can find them on "1-H,7" of the fische. That's the oil pump and filter section.