i was just wondering what method you members, have done to resolve your idle issues....whether its bouncing idle ..jdm vs aspec plenums without throttle stop screws...timing problems...tps...some may not be related to idle feel free to voice your issue ...ive read many articles about idle but i would like to here your procrdure on how you fixed your problem for newbies

 

Purchased the S5 TII new, and over the years there have been some idle/driveability problems. They have been corrected by adjusting/replacing the TPS and BAC. When the TPS malfunctioned, it checked out, no spikes or drops, but a short time after adjustment it would create some problems, so I finally replaced it with a new unit maybe 8-10 years ago and has been fine since. BAC wouldn't hold the idle under a load, so that was replaced with a used unit and has been fine. I have a brand new BAC sitting in the garage if ever needed.
Actually, the only problem the car had in the last 8 years was the c clip came off the rod that controls the wastegate. Guess I've been lucky.

 

microtech and full FD intake t-body converssion,rock solid at 1400 RPMS.

 

can microtech adjust idle

 

Mine would falter and die during idle, especially when cold. It idles much better now, after:

1. Fixing the wiring to the O2 sensor
2. Verifying closed loop operation
3. Set idle speed per FSM procedure
4. Set idle mixture per FSM procedure
5. Tested and set TPS
6. Verified timing and advance
7. Verified spark present on all 4 high tension leads

 

calpatriot ...what was the reason for advancing the timing...was it to help the idle

 

yep you can adjust the idle with the MT,on my bridgey im running 18* advance and 16* gap and it idles great.

 

nice

 

I did not advance the timing. What I did was verify that the timing would advance on its own when the engine was revved. The timing is set to stock numbers, 20 ATDC for the leading coil, and 5 ATDC for the trailing coil, exactly per FSM specs.

I did not change it, only verified that it was indeed set correctly.

There is a list of things to check in the FSM ch 4a for idle problems. I was working down the list. One of them is likely your problem, either then ones i have checked or something further down in their list.

Other things to check: spark on all 4 high tension leads. I used a little $3 ignition tester that lights up a strobe light if there is spark present. If you have an idle problem, and it is ignition related, it is more likely to be the leading coil/wires/plugs than the trailing. I understand the trailing system has little effect on the idle.

 

my idle seems fine. but having the "rough 1000-1500 rpm" problem

Adjust the screw a bit, but didnt seem to help.

Is buying a new TPS sensor the "ultimate" solution ? Anybody know how long the sensor will last ? I did a search and it seems that it should last for years.

The reason I ask is because ... that freaking sensor cost a lot. I want to make sure its "worth the investment" lol

 

along time ago my tps went bad my idle was shot....and backfired like crazy so i replaced it...bingo

 

Go buy an analog VOM and hook it up to the TPS. Push the TPS plunger in and out and make sure the meter sweeps nice and even.

If there is an even sweep across the meter, then more than likely, replacing the TPS would we be a waste of money. You can pay $10 for a VOM to check and see, or you can pay $500 to check and see. Best case scenario you spent $10. Worst case, you wasted $500.

 

I wouldn't say replacing the TPS represents the ultimate solution. If you thoroughly test it and it's faulty, then yes, replace it. Get the TPS properly adjusted with the engine fully warmed. Then set the idle to 750. (with the Initial Set Connector jumpered (or shorted))Then go back and verify the TPS adjustment. Plugs and wires can also cause rough idle, as can dirty injectors and clogged cats and clogged fuel filter. The list can be extensive when troubleshooting idle problems.

 

the jdm intake does not have an idle screw ..how do you adjust it

 

after warm up, my idle sits at 750+/- 10 rpm.

so I dont think it has anything to do with the adjustment.

and yes I played with that screw a bit. it seems fine.

plus and wires and CAT (Mangaflow) are all brand new.

not sure about Fuel Filter. I think I should replace that.

the idle goes crazy only at 1000-1500 rpm. so ...

I havent test the TPS with my OHM meter yet. gonna do it on monday, if its bad ... I can get a new TPS somewhere cheaper I aint paying 500 bux MSRP price lol

 

I can adjust my idle from inside my car. I love the Rtek. Solid 750+-50 just like factory spec.

 

JDM doesn't have the adjustment on the BAC, but there is one on the intake.

 

i have a us and a jdm in front of me the aspec has an adjustment screw with a spring the jdm has nothing ,i wonder why...also how is that rtec 2.1 it has idle capabilitys

 

Maybe this might help:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-jdm-tii-motor-trying-tune-but-no-bac-adjustment-help-406531/

I have a JDM 374 BAC valve on the TII, no adjustment on the BAC, but need to remove the intercooler to make any idle adjustment.