Hey guys. i Apologize ahead of time for bringin another thread like this around. believe me i'm searching and tryin tricks i've found so far and its been getting progressivly worse.

Problem is - 1989 Mazda Rx7 GTUs Idle Hunts from 1500 rpm to 1800 rpm. in a pretty smooth climb/fall. constant.

Vehicle Background: Rebuilt 13b N/A Motor Large Street Port, Rtek 2.0 ecu
its been doing this before rebuild, but ALL sensors/manifold were transfered from old keg to new keg so this doesn't surprise me.

What i've tried:
Adjusting TPS - LED method, this doesn't help idle, but solves the Hesitation and popping past 5k rpm
Adjusting TPS - Ohm Method, This causes all hell to break loose, Pops, Hesitates, and No Idle Fix
Replaced TPS - No Change
Unplugging TPS - RPMS Smooth out, and raise to 2200 - 2400 rpm
Unplugging BAC - No Change Noticed
Moniter Rtek - Watched both Narrow and Wide TPS paths and ECU see's no dips or loss of signal.
Adjusted Top Screw - can never remember its name, but its Right on top of Throttle Body. Adjusted both all in and all out, Idle Changes Slightly, but Still Hunts. Currently its Screed completly In.
Looked for BAC Adjustment - Could find a hole, but no Adjusting screw, can those be threaded all the way out???

Ask Any questions i've tried to cover it all but i'm sure i've missed somthing.
Thank you for looking this over and i apreciate any help. this is driving me insane i just wanna hear my Ported idle once lol

:edit: Just Relized i have a CLEAN, Spare BAC Valve. and i plan to try switching that. Still want other ideas, and i wil update on that.

 

n/a's dont have an adjustment on the bac valve. You said you unplugged the tps and rpms smoothed out. I would assume its a mix of vacuum leaks and misadjusted tps....

Also did you disable the bac before adjusting the screw on top of the throttle body? Adjust tps while fully warmed?

 

1: Yes, Unplugged TPS and Rpms Raised to 2200 - 2400 Rpm but smoothed out

2: No, didn't unplug BAC while adjusting the TB screw

3: Yes, Drove around for 10 - 15 mins before and after each adjustment.

Does the BAC need to be unplugged while adjusting the TB Screw??

ALSO just remembered, i have a CEL light on ONLY at closed throttle. any opening of the throttle CEL light goes off. Code is for the TPS FULL RANGE - Rtek 2.0 Palm View

 

if you dont disable the bac before adjusting the screw on the throttle body your going to run in circles forever. The fact that you made your idle go up or down with the throttle body screw without the bac disabled means more than likely the bac isnt working or barely working.

If your getting a code i would replace before moving onto other things.

 

Now on that note, (just read this) the Nipples where one of the BAC lines run on the TB is heavily corroded.

I'm going to replace BAC with my Spare and Report back asap. Thanks for this info

 

UPDATES: BAC Replaced, No Change, Re Adjusted TPS (LED method), CEL Light Still on at Closed Off at Open, Coolant IS flowing to TB from BAC

 

step 1) take off your BAC valve and throttle body and blow out the coolant passages through each with compressed air
2) reinstall the BAC and throttle body
3) top off coolant level
4) back screw off of secondary throttle stop butterflies(this screw is on the front middle of the TB near the TPS) and screw it back down until it lightly touches the cam stop
5) warm up the car and turn it off but leave the key in the on position
6) hook up your voltmeter negative lead to the battery negative
7) hook your positive voltmeter lead to the green wire off the TPS connector by backprobing it
8) adjust the TPS screw so that your voltmeter reads 1 volt with the throttle closed
9) do a slow sweep of the throttle while watching your voltmeter, it should slowly ramp up to ~4.5 volts at 30% throttle without any spikes or drops in voltage, if it does find one that doesn't do this
10) unhook your voltmeter
11) start the car and attempt to set the idle by screwing down the screw in the top center of the throttle body
12) hook up a timing light and see if the engine will idle below 1k RPMs then you can set the timing properly

if the idle is still high and bouncy then you have a faulty thermowax.

 

Thank you Very Much i'll get right on that.

Anyway to Bypass that Thermowax set-up without removing the AWS Set-up?

 

if none of that fix it then your linkage for the throttle is somehow sticking, which is very uncommon.

np

 

PROBLEM FOUND!!!!

Thank You Karack for the Secondary Throttle Stop Adjustment. Pulled that back and Baam! Smooth Idle at 900 rpm, Readjusted Top TB Screw and Puuuurs Like a Kitten. Thank you VERY VERY VERY MUCH EVERYONE!!!!

 

Hey man sorry to threadjack but I have a question for you.

Did the bouncy idle go away after the car warmed up? Mine is doing the same thing but it seems to go away after the car has been running for about 5-10 min.

My idle was worse than the 1500-1800 bump you mentioned, we cleaned the IACV and it seem to drop down to what you had.

So yeah..I guess my question is if it did it regardless of how long the car was running or if it eventually stopped once it was warmed up?

 

do the same steps i mentioned, that procedure is one i came up with to clean the AWS system(the thermowax and BAC passages can get clogged up which cause the thermowax to stick partly open) and reset any monkeying that other people may have done to the throttle body as well as tune up and reset the TPS, timing can also affect idle quality and RPM figures. sometimes people use the secondary idle screw to set the idle which is incorrect and will cause idle issues.

you're welcome.

 

It has always had this issue since i bought the car 1 year ago. but i didn't wanna figure it out til my Blown motor was fixed.

And this would happen cold, Warm, Hot, anytime it was spinnin over it was hunting lol.

Karack - I Still plan to, lol Thank you

 

hmmm..maybe my problem is different then. I'll try the steps you mentioned when I get a chance Karack to see if that may be my problem..

My only concern really is that it stops after the car has warmed up a bit.