93 touring, 40k on motor, mods are apexi intakes, dp, blitz bov, catback

First, when I start it cold it runs fairly rough, nothing horrible but might need the plugs/wires changed or something? Smooths out when it warms up (no not thick white smoke like a coolant seal, just the smell of gas and a few hiccups), but when it's fully warm (gauge just a little below half) and i'm rolling, it'll keep the RPM at 1500-1600rpm, when I come to a stop and release my foot off the gas/clutch it'll be 900/1000/1100/1200 RPM stable (changes to one of those every time I stop). Thought possibly it's from the aftermarket BOV... in my experience they like to leak some vacuum @ idle. car has the silicone hoses and all of that, runs fine and smooth under acceleration

Now the heat from the HVAC, on floor and position 4 heat cranked to hot, recirc off... it never really gets all that hot, warm sure, maybe I have a lower temp thermostat in the car? The water temp gauge always sits a little under half which I know isn't dead nuts accurate but hmm

 

First off, the aftermarket BOV shouldn't affect idle unless you have it plumbed REALLY weird. The FD is MAP based, so it only cares about vacuum leaks after the throttle body - the car will run just fine with the entire intake before the throttle body removed.

A high warm idle is usually one of two things - either your throttle body is stuck open slightly, or you have a vacuum leak after the throttle body. Hopefully you don't have a bad lower intake manifold gasket - this is common on the '93s, Mazda used a paper gasket that fails over time from the heat, the new one is metal. Anyhow, the gasket doesn't seal properly, you get a vacuum leak, and idle comes up. Royal pain to fix, too.

On your heat - could be air in the heater core. In general, the FD's heater isn't anywhere as good as it should be. One person had luck cleaning the heater core - might want to do a search on that.

Dale

 

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/unclogged-heater-core-yay-499700/

Link to my post about opening up a plugged heater core. And now my heat is just nuclear hot!

 

The engine was replaced 40k ago and the heater core about 30k ago, hopefully it's neither problem, i'm talking about crappy heat in 5f ambient temps too

 

it must have been because i unplugged the battery/reset ecu to disect & clean the interior, today i started it cold and it wasn't running all missing like, still has the high idle though will clean tbody once interior/exterior are how i want em

 

Im having the same problem.

I was playing with the dashpot.

At first my idle would drop suddently only to about 1k if i clutch in and i didnt like that so the idiot i am, i turned the dashpot all the way in.

Fixed that problem but then my car was bucking?? Only thing i touched was the dashpot so i "tried" to turn it out the way it was before. I think i got it right except now im having that high warm idle.

DO i have to reset the ECU? Even if i only adjusted the dashpot?

 

yes the dashpot can cause high idle. easy test would be to unscrew the dashpot until it makes no contact with the lever and see if your idle drops.

 

Wow thanks for the advice, ill try that tomorrow after work.

Quick question, do i have to reset the ECU after this whole process?