A few days ago I put a new battery in my car. Now, I'd be lying if I said I had a perfect idle before, because I didn't - at least not to my standards. However, it always rose to around 2500 rpm's at start, fell quickly to about 1500, depending on the temperature, and then down under 1000 when it got warm. I say it 'wasn't perfect' because my needle didn't always 'sit' - it more or less 'hovered' between 650 and 850 (no pattern). Sometimes, if we had dry air and pretty weather (65 degrees), I'd get a solid 750 idle.

Anyway, put a new battery in a few nights ago, and SHAZAAM! I don't know what happened, but honestly, I'm afraid of warming the little **** up tomorrow for work. My idle has done something different every time I've started it up - the weather probably isn't helping 'cause we are in between seasons. But still, it shouldn't be this weird. Below are symptoms:

Sometimes holds 3k start-up rev until I hit the gas at start...

Always idles REALLY high, even after warming up - 1200-1500 rpm's. EXCEPT, when I run the **** out of it (nearly red line a few times). Then, it idles near 500 rpm's when I stop quickly after running it hard. I hit the gas to keep it from quitting... back to 1000.

Sometimes hear some 'groaning' noise coming from the engine bay - can feel it in the floorboard and sense it in the shifter - only when stationary and idling. That scares me; can't quite put my finger on that.

Anyway, I thought my only problems were getting my car not to want to overheat, but now, we've got a new contender. Any bumps would greatly be appreciated...

'90 GXL / 5 spd / rebuild 3500 miles ago / full Racing Beat Exhaust with Presilencer - bypassing air pump (belt still attached to pump for now) / K&N style intake / Koyo Radiator / new clutch fan

 

the 3k start idle is just warmup, I would suggest letting it do this and not hitting the gas to "cancell" it your idel sounds about right for a rotary.. hell I drive a 98 civic at the moment and it's idel jumps around.. one moment it may be at 600 then it will go upto 800, it could be other things causing this.. like A/C, and other pully driven things..
but dont take my word for it.. I dont have a RX-7 on the road.. yet

 

The accelerated warm up is not good. Revving to 3k on a cold engine isnt good for any car.

 

I didn't think the 3k revving warm up was good...

Anyone have any suggestions on where I should start looking from here???

Thermowax? TPS? Temp Sensor? Resetting computer?

 

To stop the warm up from happening start your car in gear and keep the clutch in for about 10 seconds.

 

I would clean up the grounds.
I have encountered hidden corrosion under the insulation at the battery clamp.
Maybe replace the cheesy ground clip on the firewall with a solid eyelet connection.

Also fix the overheating before it bites you.
-----(Banzaitoyota’s overheating checklist)
1.Are the Oil Cooler fins clear of debris and clean?
2.Does the Oil Cooler thermostat function properly?
3.Are the Radiator Fins clean of debris?
4.Is the Stock Bottom shroud still in place?
5.Are you running a Dual Belt Pulley on the Alt?
6.Did you install a NEW Water Pump when you installed the engine?
7.Is the bottom hose collapsing under load?
8.Did you have the Radiator and Oil Cooler cleaned and Flushed when installing the rebuild ( AS required by MOST REPUTABLE REBUILDERS)?
9. Have you verified water temps with a real gauge instead of the sock POS?
10. What ratio Coolant to Water are you running?
11. Are you running a new STOCK MAZDA OEM thermostat?
12. Mazda Rad Caps?
13. Stock Fan Shroud installed ( For those of you running stock Mechanical Fan)

 

1. Oil Cooler Fins are clear.
2. Oil Cooler Thermostat?
3. Brand new radiator (Koyo).
4. Stock shroud in place.
5. Am putting dual pulley on alt today.
6. Am putting on new water pump today.
7.New hoses (NAPA) top and bottom.
8. New Radiator / Don't know about oil cooler.
9. No. However, I have a tendency to trust my stock gauge because it is consistent on warm up and was through the winter too.
10. 40/60 with water wetter.
11. Putting new STOCK MAZDA OEM thermostat on today.
12. Greddy Racing rad cap.
13. Stock fan shroud with new clutch fan.

Could using a racing radiator cap and water wetter RAISE my temps? I realize that these additions RAISE the boiling point of my coolant, but would they not also increase the heat capacity of my coolant too?

 

Might be your clutch grabbing (or slipping) the flywheel. You might have a heat scorch or other mark on the flywheel that will make a little extra noise other than normal. If this is the case, you will hear it most prominant in 1st gear when you slip the clutch to get moving from stop, or when you downshift to engine brake.

 

I can hear that particular noise when idling with the clutch in or out. In fact, it seems like when I do hear it, I see a visual response from the tac - but, that could be my own little mirage.

 

By the way... Doing the 10 minute regular idle when warm, 10 minute defogger, and 10 minute AC worked like a charm. Good trustworthy idle now.

Oh, reset the computer too by taking off the neg bat terminal and pumping brake before the above...