drb930

Why does my car go down the road at 35 MPH without my foot on the petal?
The car is about 1300 RPM going down the road, but when you come to a full stop the idle comes down to where it is set in the program?
NVSRAM SUJP V-4 1026B

Starting to run pretty good, finally got the 700-R4 to work properly with the help from Dana at ProBuilt.

Thanks,
Dave

pandin

It is something called the "Throttle follower", software in the chip, it keeps the IAC open until you are under a certain mph or after a certain amount of time, then it shuts the IAC.

junkcltr

iTrader: (1)

It sounds like the throttle follower gain is too high. Look at the IAC steps.

By the way, have you tried tuning with the engine running using the 1026B SAUJP_V4?
I couldn't get any ALDL loggers or the NVSRAM program tool to connect.

Grim Reaper

Could also be a faulty/misadjusted Throttle Position Sensor.

JP86SS

iTrader: (1)

I rechecked the 4B version and it connects to TP (Bypass and AP mode), ScannerPro, & Datamaster.
If the program tool would not connect then I don't think the bin is even getting loaded so the subsequent bin in memory would not be able to communicate with loggers.
Check to be sure you have the correct RT4 tools and files.
IIRC there was a newer application build posted when the board was finally released.

The slope gain value is "40" in this version.
The stock AUJP value is "150"
This was reduced in the V2 version to help people with larger TBs deal with AE issues. The higher value will make the IAC move faster when the throttle position changes.

Scamo-2.8

iTrader: (16)

I know this isn't helpful but I just can't help myself, If your car goes 35mph on idle how fast does that thing go when you step on it? lol
Sorry, I just had to.

drb930

JP86SS-

I just went down from a 58mm to a 52mm TB and set the ground idle by jumping the ALDL and waiting for the IAC to stop clicking, then disconnecting the plug and then starting the engine and setting the ground idle. Also adjusted the TPS. Car still goes too fast without any gas. Do I need to go into the program and adjust the Slope Value to ?

Thanks,
Dave

JP86SS

iTrader: (1)

Closing down the mechanical adjustment on the TB would be the only thing left to do. Watch the IAC counts as you do it. If they increase as you close the throttle blades then I'd say it is a program setting controlling the idle speed and needs to be tweaked.
Check you PCV lines to be sure they are not introducing air into the intake. Throttle shafts possibly leaking air but I think that is a long shot.
Vacuum leaks on the runners or at the cold start injector (if its plugged) could also keep the idle high.
Air must be getting in somewhere if the commanded speed is lower than your actual.
The closed throttle RPM vs. coolant table should be able to get you down to 800 or less for an idle speed. (be sure TPS% for idle condition is within the right value range or you won't be at idle where the table is active)
The Throttle follower will only tend to HOLD you at high RPM after the throttle is opened, not all the time.
HTH

drb930

I dont have any problem with the idle at stop, in or out of gear.
The PCV is all per factory specs, no vacuum leaks.
TB is adjusted to 600 rpm with IAC centered per specs.
It's only when driving the car is like coasting at 35 mph.
I know its an adjustment in the computer program, just dont know which one?

Thanks,
Dave

JP86SS

iTrader: (1)

I just noticed, according to the dates you started this post a year ago
Are the dates just screwed up or did I just lose a year?

Gotta be the TF Gain setting, go lower and see if that helps.
Just to try it, set it to 1 and see if there's a difference.
Make sure your coolant and air temp sensors are reading correctly, they could skew things and possibly cause some cold settings to take over.

ellocojorge

iTrader: (1)

drb930

Ok, i will try to mess with the TF setting.
Pretty sure the TPS is set right, i set it according to the instructions.
Car off and with an ohm meter?
You are correct and the dates are correct, we both lost a year, car still needs exhaust, wheels and tires to be a driver.
I finally got a 52mm TB down from the 58mm. 58 is just too big for this mouse motor, this motor on paper will only flow about 700 CFM.
Hopefully now i will have some time and patience to get it dialed in.

Thanks,
Dave

3 pedals

I had the same problem with my 85 vette. I am using 6E and the bin had the throttle follower set at 10, higher than any other bins I looked at. I began lowering the setting a little at a time. I now have it set at 1 and after two years of messing with it, I might be happy.

drb930

Yea, i looked at mine and the 1st block is 1, then all the others are at 12?

Thanks,
Dave

drb930

I found this thread?
Looks pretty good!

https://www.thirdgen.org/forums/diy-...llower-8d.html

Thanks,
Dave

drb930

Anyone come up with any resolve for this problem?
Car is starting to run great except for this problem!

Thanks,
Dave

drb930

Anyone?
Car runs pretty good now, but i hate this.

Thanks,
Dave

JP86SS

iTrader: (1)

Are you able to confirm the lockup is not stuck on?
Bad solenoid will do that or if the TV is adjusted too tight you will have high pressure at low throttle position. Back it off a click or two and try it. Could cause some tight engagement in drive. Just tossing more ideas.
Email me your current settings bin and I'll see if I can't reproduce this on the bench this weekend.

drb930

Yea i have checked all the things related to the lockup.
The interesting thing is yor can go down the street, and put the trans in netrual and the rpm stays up until you almost come to a complete stop, so i know its something in the programing.
I sent you my Bin before, did you get it?

Thanks,
Dave

3rdgengmachine

Hello. I had the same problem as you only I have never modified my prom yet its stock but I was having the same Idel issue only mine will do that high idel everytime I start it even warm it will go to 12 or 1300 and then come down to 600 and when I come to a stop it will stay high till my speed reaches 0 mph then go to 600. Mine started doing this just all of the sudden. I never had a problem at all with idel then one day it started doing that. Well im pretty shure it started after I knocked the egr walls out in my plenum but I dont think the issues are related. Anyway I talked to vader and got the moving idel fixed by unplugging my cruise control it was causing a vss problem. although it fixed my moving idel problem it still does the high idel everytime I start the engin and I hate it. Try looking at your cruise and see if it or something elts is causing a vss problem. I dont know if it will help you or not but it fixed mine and I though I would let ya know cause I know how idel issues will drive ya crazy lol. Good luck and let me know if this is any help.

drb930

JP-

I resent the Bin File, can you confirm that you got it?

Thanks,
Dave

drb930

My cruise control was not even there in the car until reciently, and i have a VSS for the ECU hooked up to the Trans, the Cruise Control uses the Speedo VSS, good thoughts though.
The high idle that you are taking about at start up can be changed in the Bin Program.

Thanks,
Dave

JP86SS

iTrader: (1)

I did get your bin (again) and don't see anything to speak of.
Checking the code for some "warm kickdown" type items that may be the culprit. SilvernBlack posted on another thread that he gets a similar issue but only at startup. Turning off then back on fixes it.
I don't know if this is part of the factory code or in the manual trans adders. I'll spend some time today and see if I can get any clarity on where a setting could be changed.

JP86SS

iTrader: (1)

From my other post.
Also, did this just start when the TB was changed from 58 to 52?

drb930

No, its been doing it all the time, doesn't matter which TB i use.
Also my VSS is directly from the transmission, not the speed sensor as the car has a Painless Harness in it.
If you get the car up to speed and then put it in neutral and cost the idle stays up @ about 1300 rpm until you get to about 5 mph and than it drops down to regular idle.

Thanks,
Dave