Gringo Grande

iTrader: (97)

So...before I begin I would like to first thank Arghx for his very informative posts as well as Chuck for his excellent tuning notes. I've been able to get this far based on information provided by these gentlemen.

Car:
NS Setup
MP
DP
High Flow Cat

Previous owner apparently liked to "tinker". The first week I had the car I removed probably 1-2 pounds of horrible wiring. The engine itself was a rebuilt by a reputable builder on the forum and of the 2500 miles on the engine, I've put 2300 on it.

The car had a high idle which progressively became worse. Basically when in neutral or stopped with the clutch in, the idle would sit at about 3500-4000rpm.

Attempt 1:
I purchased a PFC + Commander and followed the basic initialization instructions. Car idle did not improve.

Attempt 2:
I engaged in searching and reading on the forum (imagine that...I actually searched!) and learned about adjusting the TPS and a little more about the AAS. My TPS was HORRIBLY out of spec so I readjusted it, the AAS, my throttle cable, and reinitialized the PFC. I also learned that on a NS mod that the fast idle cam had to be fixed away from the Hot Wax Rod with a wire or other method. This had not been done on my car so I did so.

Sweet! I now had a surging idle between 800-1500. I saw this as an improvement! I figured I could fine tune the idle from here...two days later, after a 100 mile trip...the idle went back up to 3500 and stuck there in neutral/stopped. Crap.

Attempt 3:
Purchased Chuck's awesome notes and read some more. Adjusted everything per Chucks TB notes and reinitialized the PFC and the learning process again. I was stoked! Idle was around 1000! Hallelujah! No more looking like a jackass when I was stopped!

I then drove around town for a couple of miles and pulled up to a light and BANG! Idle back up to 3500-4000. Not surging...just stuck there. WTF?

Items I have left as far as I can tell that may help solve the issue:
-Datalogit will be here this week.
- AWS was disconnected (plug disconnected) but not blocked off. I do not know if this would cause any issues.
-I have not pulled the ISC to test it yet. I will attempt to do so in the next day or so.
-I cleaned off the Dashpot and it seems to be working correctly.
-I still have some concerns that the Throttle Adjusting Screw may be part of the issue and may be configured incorrectly. I do not believe the stock screw is in place as the screw does not pass through a nut to lock it into place. I believe there should be a nut there? Please confirm?
-Clutch switch. Everyone talks about the clutch switch and maybe I'm just in re-re mode but for the life of me, I do not understand where this part is and what you pull apart to inspect the spring. Kind of embarrassed about that as it should be the easiest thing for me to check...anyone have a good picture?

Well...that's all for now. I'm open to thoughts and ideas! Thank you!

hotmail6

Sounds a bit like a random air leak. You still have the original rats nest right...

asianguy02

iTrader: (4)

Yeah, the throttle adjustment screw should have a lock nut present, but i doubt that is your problem.... how far down is the throttle set screw twisted in? Obviously not too far on account of your previous time at 1k rpm idle, but thats always something to check. Also check the rats nest and crossover pipe for air leaks, unless you have a efini y-pipe then just check the vacuum lines. The fast idle cam should be positioned about halfway between full open and full closed, I dont know how you wired it, but at full open I *think* it will open the secondary butterflies in the TB a bit.

Thats what comes to mind off the top of my head, and dont forget to check the TB-Elbow joint for a gasket since that can cause an air leak too. Ill get a pic up of the clutch switch later if someone doesn't get one up first.

Gringo Grande

iTrader: (97)

First of all..thank you for the suggestions. I have a NS (Non Sequential) mod to the turbos so I have no rats nest to deal with (thank goodness!).

I picked up a nut for the TAS (Throttle Adjusting Screw) this morning before heading over to Import Faceoff. After installing the nut and readjusting the TAS my idle is now at a steady 2000RPM. MUCH better than the 4000 it was at before.

I now strongly believe that the TAS was backing out/in due to engine movement/vibration causing the issue. I'm going to fine run through setting the TAS, AAS, and Throttle Cable again and re-run my idle learning in the PFC tomorrow and I have a strong feeling that my idle issues will be resolved.

Thanks again to Arghx and Chuck for the threads and notes and thank you for all who took the time to respond in the thread.

arghx

iTrader: (3)

Since you are getting a datalogit, set up your wideband to work with the box. log "advance" and "aux" under the monitor window and have no other boxes checked. This will provide you with the data you need for further troubleshooting. Then you need to chart

-- Advance rpm,
-- Advance tps voltage which is the VTA1 full range signal
-- Advance ???(2) which is ISC valve duty cycle where 0 = 0% duty and 1000 = 100% duty
-- Advance IgnL which is leading timing
-- Advance Speed which is vehicle speed in kph
-- Aux AN1 wideband AFR. depending how you wire it up and configure it, it may be Aux AN1 - AN2 wideband

Careful analysis of these trend lines can point you in the right direction:

-- A "sticky" TPS voltage line indicates a possible dashpot problem or some other throttlebody issue because the throttle plates are open too much

-- If ISC valve duty cycle is pegged high (90-100% duty) or low (near 0 duty) then the air adjusting screw may need adjustment or maybe even your throttle adjusting screw

-- If rpm is dropping very low on deceleration, then shooting up and surging your F/C speeds may be too low, your dashpot may need adjustment, or your air adjusting screw may need adjustment

-- If rpm is sticking high on decel, the TPS voltage is steady at its normal resting value, vehicle speed is near 0, and leading ignition timing is elevated then your F/C speeds may be too high. The PFC is advancing timing too much on decel.

-- If rpm is surging/oscillating heavily and AFR is leaner than say 13:1 or 13.5:1 you may be leaning out due to IAT heatsoak or just the fuel map (Base/INJ tabs) tuning

-- If rpm is surging/oscillating heavily and AFR is jumping around then you may need to adjust your injector pulsewidth (base x INJ value in the base map tab) map so that the PFC will smoothly interpolate between cells