Running rich in open loop

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07-25-2012
JeepsAndGuns

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Running rich in open loop

This is something thats been going on ever since I have swapped to MPFI. I guess I really need to try and get it straightened out.
When the engine is cold, and in open loop, it wants to run rich. I will start the engine, AFR is around what I have set in the open loop AFR table. It will stay there just fine as long as I dont start driving. Once I pull out and start driving, it drops down to 12.5, sometimes as low as 10-11 for short bursts. As rpm's go up, the afr will raise to where it should be, untill I shift, then it will drop back down to 11-12, sometimes even 10, engine will kinda cough a bit and you can smell the fuel out the exhaust. As soon as it goes closed loop, this stops. Its like its ignoring the open loop afr table unless its at idle. Last time I did a data log, allmost all my blm's were between 125-130, so I dont think my fuel tables are off. And like I said, it has done this ever since I have swapped to MPFI. It did not do this when I still had the tbi.
Any ideas?

Here is a short vid I shot saturday morning. I started the vid just a few seconds after startup, right after my WB heated up. The clicks you hear are me shifting gears. I pull out of my parking spot in granny gear, shift into 2nd, you can see the afr drop when I shift. I then drive to the end of the driveway and then pull out on the main road. You can see it drop when I shift, and I think even hear the engine hesitate a bit when it drops to 10 for a second. Ignore the high afr twards the end, I was slowing down to come to a stop (aka, DE)

http://www.youtube.com/watch?v=jhzOa...ature=youtu.be

Also here is a shot of my open loop afr table.
07-25-2012
EagleMark

I wonder if that has something to do with IAC and manual trans? Is this an auto bin? Or look into "Deceleration Enleanment Factor vs. Temperature" and try and lean out the decel?
07-25-2012
JeepsAndGuns

The bin is BMHK.
Why would DE make it go rich once I start driving? DE, as far as I can tell works fine, you can see at the last few seconds of the video, the afr raises when I let off the gas to stop.
07-25-2012
EagleMark

Your really fine tuning a MPFI system on a TBI hacked PCM so I'm not sure it is? But worth a shot?

The scenario you are having is in Deceleration which is a higher then idle MAP kpa which causes rich conditions and emmssions, so that's where I was thinking.

It looks to be working with commanded OL AFR just lagging a bit, in that table the amount of DE is less at lower temps.
07-26-2012
JeepsAndGuns

The afr is what its supposed to be when at idle after startup, but as soon as i start driving is when it drops to 12.5, so that much cant be DE. I can see where it could be a DE setting when I come to a stop, and between shifts, but not when driving. When driving it stays around 12.5, then slowly starts coming up as rpm goes up, you can see this in the vid when I shift gears. Once I shift it goes back down and then slowly comes back up.
07-26-2012
EagleMark

That video of AFR looks to go CL when you start driving. That is going to be stoich Closed Loop. The table above is Open Loop.

Open Loop AFR tables are not actual AFR, it is a calculated adjustment to VE table based off assumtion the VE table produces 14.7 to 1 AFR when Open Loop. If VE table is not exact then neither will any adjustment based of it.

If that video was all cold start and drive it's not bad at all! The flucuations could be that VE is not accurate or choke is a little off? Cold start and warm up is time consuming as you only get one shot a day...
07-26-2012
96lt4c4

Quote:

Originally Posted by EagleMark

That video of AFR looks to go CL when you start driving. That is going to be stoich Closed Loop. The table above is Open Loop.

Open Loop AFR tables are not actual AFR, it is a calculated adjustment to VE table based off assumtion the VE table produces 14.7 to 1 AFR when Open Loop. If VE table is not exact then neither will any adjustment based of it.

If that video was all cold start and drive it's not bad at all! The flucuations could be that VE is not accurate or choke is a little off? Cold start and warm up is time consuming as you only get one shot a day...

I think this is what is going on, same thing with my Blazer. I need to do some more VE tuning.
07-27-2012
JeepsAndGuns

Yes, that was a 100% cold start (well, was in the high 70's that morning) But I started the video mere seconds after startup.
Last time I did a log my BLM's were all good, buts its been a while. If I get a chance this weekend I will do a log and see what they are like.
07-27-2012
dave w

I think the AE is a touch rich? I had a similar WBO2 behavior recently on a vehicle. I advanced the TunerPro RT data log one frame at a time to see what was happening. I could see the Inj DC would spike when AE went active. The WBO2 when very rich, less than 10 AFR rich.

I also think it could be DFCO. I've seen the WBO2 go rich when DFCO is not cutting fuel at near 0% TPS.

dave w
07-27-2012
JeepsAndGuns

AE is one setting I have not touched in this bin. I wouldnt even know where to start with AE settings. I do notice at idle, if I blip the throttle, it does go a tiny bit rich for a second, like the idle pump shot might be a bit too much. When driving and/or at speed, if I hit it, it doesnt go rich, so I think the ae up there is fine. Is there a way to reduce ae just a bit at idle?
A few weeks ago I had tried a 350 0D auto bin. Of the many things about it I didnt like. I remember when driving, if I hit the gas it would jump lean for a split second, like up to 15-17 depending on speed, rpm, and how hard I hit it. My current bin does not do this. But I did notice with that 350 bin, if I bliped the throttle at idle, it stayed at the correct afr, it didnt jump rich like my current one.
07-27-2012
dave w

Quote:

Originally Posted by JeepsAndGuns

AE is one setting I have not touched in this bin. I wouldnt even know where to start with AE settings. I do notice at idle, if I blip the throttle, it does go a tiny bit rich for a second, like the idle pump shot might be a bit too much. When driving and/or at speed, if I hit it, it doesnt go rich, so I think the ae up there is fine. Is there a way to reduce ae just a bit at idle?
A few weeks ago I had tried a 350 0D auto bin. Of the many things about it I didnt like. I remember when driving, if I hit the gas it would jump lean for a split second, like up to 15-17 depending on speed, rpm, and how hard I hit it. My current bin does not do this. But I did notice with that 350 bin, if I bliped the throttle at idle, it stayed at the correct afr, it didnt jump rich like my current one.

I think a data log would help figure out what's happening with the AFR's. I'd have the data log running and record on then hit the starter key to capture the start up in the log.

dave w
07-27-2012
EagleMark

Quote:

Originally Posted by JeepsAndGuns

A few weeks ago I had tried a 350 0D auto bin. Of the many things about it I didnt like. I remember when driving, if I hit the gas it would jump lean for a split second, like up to 15-17 depending on speed, rpm, and how hard I hit it. My current bin does not do this. But I did notice with that 350 bin, if I bliped the throttle at idle, it stayed at the correct afr, it didnt jump rich like my current one.

That sounds exactly correct for an auto bin in a manual. Think about an auto, hit gas and ...... now manual, hit gas, decel, shift, hit gas, decel, shift etc... as we always knew auto to manual bins are differant.
07-28-2012
PJG1173

i run an open loop tune and mine would do the same thing. I raised the values in the open loop afr table in the temp areas that it was running too rich in when the engine was cold. before I would have to let the truck warm up for a few min before driving. now i can jump right in and go.
07-28-2012
JeepsAndGuns

That table says temp Vs vaccume. Are those numbers MAP? I'm thinking not, because it starts at 0 instead of 20, and goes right to left. What are the values? Is it like in/hg? Then would the 0 value equil map 100 and the 80 value equil map 20?
07-28-2012
Six_Shooter

'7427, $0D?

I hate the autoformatting to change capital letters to lower case. :facepalm:
07-29-2012
JeepsAndGuns

Oh, yea, sorry about that.
7427 $0E

Had some time today and did a log to check my blms. They were all between 122-128. I'm thinking with it that close theres no point trying to adjust it any more.
07-29-2012
EagleMark

Only if you wanted it better today, tomorrow would have to be done again. Your really spot on for BLM. Lean out the Open Loop AFR and should be good.
07-29-2012
Six_Shooter

Quote:

Originally Posted by EagleMark

Only if you wanted it better today, tomorrow would have to be done again. Your really spot on for BLM. Lean out the Open Loop AFR and should be good.

I would agree with this.

I looked at my xdf for $OE, and that looks like the best table to use to lean out the open loop.

I was looking for a coolant temp comp or adjustment table, but didn't see one.
09-16-2012
JeepsAndGuns

Figured I would update this thread incase anyone finds it in the future. Just didnt want it to end open ended.
I tried leaning out the open loop table with limited success, in a few ways, it made it worse (not the running rich part, but the cold engine behavior) still was cold natured and ran not too great till warmed up a bit.

Well it turns out my problem was the bin I was using. I dont know what it was. I have since changed bins to (of all things) a 0D 5.7 auto bin.
Cold starts have greatly improved, cold idle is better, cold engine behavior/manners are better, cold engine performance is better, and cold engine a/f ratio is better. (engine has all around gotten better) So I think I am done with BMHK and I do not think I will reccomend it any more as a starting bin. I have just had so many problems with it over the year I have been running it.
However I did copy several parameters out of it into my new bin. You can read about it some here:
http://www.gearhead-efi.com/Fuel-Inj...hrottle-kicker