Since lean idle seems to be a common problem with '165 users I thought I'd share what helped me out a little. Still didn't correct idle in drive or low throttle, but helped in park. I went through every table and constant I thought might be remotely connected to idle afr, but the only thing that seemed to effect closed loop idle is upping the min MAF airflow. I still need to fix low throttle and drive, but I think I can get the results I want by tweaking the median/high/low O2 parameters.

 

I tried raising the min maf airflow above where it idles in drive and it helped out drive, but in park it's rich enough to give me a headache. Back to the O2 parameters.

 

Which MAF are you using? I couldn't find any min MAF flow in the ARAP hac (except maybe for MAF diagnostic). There's a min Base PW, though (something like 1.58 ms)

Are you using closed loop with a commanded AFR of 14.7?
Are you using open loop? If so, what is the commanded AFR?

If it (actual WB reading) doesn't match the commanded AFR, there's 3 possible fixes. 1) MAF tables & Scalars 2) VBatt Offset PW 3) PW Offset for Small PWs.

At idle, it's best to use MAF Table, because idle flow rates are basically the smallest possible, and that area of the MAF table won't hurt much other places.

If your fighting the commanded AFR, there's an Open Loop A/F % Change vs LV8 table that may be fighting you, starting at $03DC. There's also an Open Loop A/F % Change vs Coolant table at $041A (conversion = X/2.56 - 13.67), and at $0419 there's an offset that must be 221 (DD).

My guess is that your XDF is wrong, as I just found the conversion mistake above, and the wrong way will show that open loop has 13.67% enrichment in open loop when warm, and you probably set that to 0. This would have made the commanded AFR very very lean. With it fixed to what I said above, you can set the offset to 0, and it will now command 14.7 with no offset, when warm. When 90-133 F stock ARAP should (if XDF is correct) show about -3.9% (a little lean).

 

It's 32B with the digital v6 maf, the min maf out constant is at LC6F0. It's lean in closed and open loop and the effects don't seem to go away until ~2000 rpm.

It just occured to me that I might be fighting the effects of the aldl being hooked up. If so how do I disable it? There's a noticeable change when the laptop connects.

 

That is definitely not what you want to change for this problem. Your problem is either the MAF calibration table, or commanded A/F problem.

My first guess is:
LC425 MUST be 221 (DD)
The conversion equation for the Open Loop A/F %Change vs Coolant which starts at LC426 MUST be X/2.56-13.67. When it's set to this, use 0 for most places, to command 14.7 in open loop.

Second guess is you're not properly using the BPW vs LV8 table, this is how the 32B MAF calculates the fuel required. If you're using the automatic calculation and not this table, then, maybe your injectors don't flow what you think they do, or 32B doesn't do it correctly. Maybe you don't have the correct MAF table for that sensor. Maybe you have a decent vacuum/duct leak that lets un-metered air in.

LC023 is adding about 8 degrees of spark advance when you connect to the ALDL. X/2.844, (can set to 0, and most people do that first thing). This will make the RPMs jump when you connect. I don't think there's any other thing happening with ALDL connected, such as AFR change.

 

After it connects remove the 10K resistor from A & B.

RBob.

 

That's simple, I have a moate's aldl cable so I can just flip the switch.

I'm not entirely sure what my injector size is, I'm using ford F1ZE's (15lb/hr)which are rated at a lower psi than delco's. My guess is 17lb/hr since the target afr and actual afr are pretty close with that size (above 2000rpm). I already set the aldl spark to 0. Does that equation apply to the other open loop % change tables?

 

No, just for the Open Loop vs Coolant. Both the offset at 425 must be DD, and the conversion for the table at 426 must be X/2.56-13.67 for it to work correctly.

Also, I'm not sure why your problem goes away above 2000 RPM. If your MAF tables are correct for that sensor, maybe just an air leak that becomes neglegable when the flow is above a certain range. Otherwise, maybe the MAF has a problem, or something else is crazy.

 

I am thinking that it might be a linearity problem with the Ford injectors vs. the GM ones. The injectors might not respond the same way the GM injectors did. Even GM injectors don't all respond the same. That is why they have different injector offset tables. You might try increasing the injector offset for the range you operating in. It will richen it across the board, but have the most effect on the idle a/f ratio. Speed Density TBI guys running increased fuel pressure or larger injectors see this as a bath-tub "U"shaped VE table.

1 usec is 1/1000th of 1 second. So 1,000 usec = 1 millisecond of pulse width. The offset is ADDED to the BPW along the way in the calculations. At a normal 13.8 volt output of the charging system you are going to see a roughly .75 msec BPW increase from the offset. To make the fueling richer, add to the offset table. To make it leaner, remove from the offset table. What the table does is accounts for the actual opening time of the injector. Too little offset and the engine will run lean, especially noticeable near idle and at lower rpms when engine load is light. Too much offset and the engine will run rich, noticeable under the same situations.

If you can't get it cleaned up with the injector offset table, I would go for the Injector BPW vs LV8 vs RPM table and increase the BPW in the affected RPM/LV8 ranges.

 

The maf tables and maf are stock. The injector offset being off makes sense, I didn't even think to change it. Working all the ghosts out of this ecm swap has been a bigger challenge than I expected.

 

The BPW vs RPM vs LV8 table is probably different between the V6 and V8 engines as well.

 

Another piece of the puzzle, the int and blm's never do any enriching. Always stays at or below 128. Ideas?

 

Can you email your cal and XDF? I'll pm my email address. I'd like to help with my eyes directly on the data, rather than stabbing in the dark.

 

You have mail.

 

The only thing that sticks out as strange are the large PWs you have in the BPW table. Makes me wonder if the load scaling factor is making it seem like much less load is there, causing it to use only the lower load portion of the table. The V8 stuff uses 80, and you have 116 there (I don't have a stock V6 bin to compare though).

Or, it's stuck in some single fire mode and needs this table to be double the normal size.

Is your canister purge vacuum hose hooked up and giving you extra fuel when the throttle is open a few %??

When you say 2000 RPM is normal, do you mean 2000 RPM while driving or while in neutral and no load?

I didn't see anything that would limit the BLM or INT to a max of 128. Not sure if AIR injection parameters could somehow prevent it from going rich if it is calculating a request for AIR by mistake.

How lean is it at idle? What do you mean that it's "lean in closed loop"? And INT & BLM won't go above 128? Seems like open loop. Is the O2 sensor going cold?

I gotta get back to work

 

Ignore the BPW table, I haven't tuned with it yet. I copied those values out of the '302 bin. 116 is the correct v6 load scaler.

It progressively richens from 17:1 at idle to stoich at about 2000 rpm while driving or in park. It's in closed loop, but the int/blm never goes above 128, only below. I've seen it dip to 118 occasionally, but never above 128. It's almoast like it's ignoring lean conditions and only correcting when rich. I have an LC-1 so the sensor never goes cold, and I'm sure it's accurate. I'll play with the AIR seetings a little.

 

I think we've been through this already, but need to ask: has the MEMCAL been set up to fire the injectors at the proper rate? The ECM should be firing the injectors once per revolution, which is every 3rd DRP. An 8-cylinder MEMCAL will fire the injectors every 4th DRP.

RBob.

 

I programmed the cylinder select (code 41) parameter as a v6. What do you mean by the memcal?

 

You need a 6 cylinder memcal.

 

It's out of a 3.1L cutlass '727 ecm.

 

Still no luck. I've enabled and disabled the AIR and didn't have an effect either way.

 

I think the important problem is related to the 128 clamp issue. If it's lean and open loop, it's still also a calibration issue (MAF or PW table), or some hardware problem.

I didn't see any other things that would clamp your INT and BLM to 128, though, so who knows, could be something hidden still.

 

Is it possible it's in field service mode?

 

Alright, after messing with various tables trying to find what I might have fudged on I finally found what screwed things up. The lower O2 mvolt table was off. Just goes to show any time you mess with the O2 tables make sure all points are equally spaced from the median voltage. Still didn't fix the lean idle, but the int/blm's aren't locked below 128 anymore.

 

Yeah, those are confusing. I haven't figured out how they work yet.