Folks, I'm having a fast idle problem on a 6E arap bin. It happens after driving around a while. IAC steps at Idle are normally 50. But at times the IAC steps sits at 75 with a fast idle around 1000 rpm and a target idle around 750 I've checked all the tables and constants, removing any IAC adds. But it has not resolved the problem. Taking the car in and out of drive does not help. You have to shut the engine off and then restart it. When you do the IACs go back to 50.

Now something interesting is that I'm having a little alternator/gauge trouble and I'm beginning to think the problem happens when factory battery gauge drops down around 10 volts. But when the regulator final kicks in and the volts go back up, it does not slow the idle down.

I did a test this evening and let the car idle normally. I disconnected the alternator and sure enough, idle shot up to 1000 rpm. Connect it back up and Idle comes back down.

So, where is the "IAC step add for low voltage" table at. I can not locate it with my current XDF file. Can someone point me in the right direction and please don't tell me to replace the alternator. That's already planned for, but I would really like to locate the table or constant for this.

 

8D has just an RPM adder to the desired idle for low volts IIRC.
I dug around in the APYP hac and couldn't find an adder value equal
to 250 rpm/12.5 or 25 steps that was related to voltage.
Coincidently, one of the A/C adders is 25 steps.
Why do you want to change it when you have a mechanical problem?
Letting voltage get that low can affect several things in the bin.

 

it's not so much of wanting to change it as it is having access to it. I know there are other parameters that my XDF file is not displaying. I just want to continue expanding it's capability.

 

Here's the source code for $6E. Open it up, search through it for what you're looking for, and add it to the XDF if you find it.

http://www.moates.net/files/5)%20Sou...20Hacks/6E.zip

-M

 

That's a nice file BTW , never looked at any of the MAF stuff too much.
R_Wells1,
Anything from $C000 until the code starts are the calibration items.
$C710 is where the code starts.
The stuff before that are the memory locations for the active stuff going on while running (you can't edit those)

 

That's sweet! I wish I knew about that file earlier. For a few $6E tables in the past, I went into the BUA hac (32B) and found matching patterns to the tables that I wanted (because a LOT of the calibrations are identical between 32B and 6E). This will make it much easier. Thanks!

 

All of the known masks are available there (and have been for quite a while). Here are the rest.

File Manager - Browsing directory /5) Source Code and Hacks/

 

Please do post your findings.

 

Thanks guys for the File. I've been going through it. There are a couple of places were Battery volts are checked, but I have not seen anything that is table driven. It looks like it's hard coded to increase idle by 300 RPM, but still looking. By the way, it's been a long long time sense I've looked at code. This looks like some form of assembly language. I can make out a little of the commands. Things like jmp to a lable is self explanitory. tsta looks like test register a, dec is decrement counter, but others are harder to figure out. Is there anything available that explains the commands?

By the way, I replaced the alternator. So far so good, problem has not returned.

 

Source code for dummies....Ask questions here! - Third Generation F-Body Message Boards

This will get you started.....


I'm sure what your looking for is in there.
It's just not commented very well so you can't see it.
I suspect a flag gets set so that an adder is used somewhere else in the IAC code.

 

Where is the 8D RPM adder. I am running a CS-144 high output alternator and when the car is cold and it hasn't been run for a while it is charging the heck out of my Optima battery. The car wants to stall in this state. When the battery is fully charged it runs fine when cold and does not stall.

 

From the AUJP hac:

L8696: Is the adder for volts <11.7.
You'll have to log what's going on to see how low voltage is.

L8695:
I think this is a timer to keep the Rpm adder in after volts goes above the set pt. Not positive though. I just glanced at it. It might just add for 10 sec the go back to normal.

You may just have to add a little to your cold idle table.