Need help getting engine to run right after lc-1 install

[hsrs10]

PLEASE HELP!
I am trying to get a decent tune on my megasquirt II. I had a narrow band o2 and could get wide open throttle to run fairly decent, but I could not get it to idle correctly. I recently installed a LC-1 wideband. I calibrated the sensor from 0-5v, changed the config file and updated settings in megatune. I can now get the vehicle to idle great, but it coughs and backfires in the exhaust on accell. When I accelerate it goes full lean, I have tried to richen it up in the ve table, no help. I pulled a plug - plug is black indicating it is running rich. I read through the manual and found a section where it says it will show it is running lean if it is running extremely rich. So i tried leaning it out - made condition worse. I am new to tuning, so I may be doing something wrong. From what I understand, I set up a AFR table and try to set ve table so ego correction stays at 0. any help would be greatly appreciated,

What I have - 388 sbc, brodix 200cc runner heads, holley stealth ram intake, 58mm t/b, 24lb injectors, stock hei remote coil, 280/290 duration 488/510 lift cam.

I have included my msq file - I have not taken a datalog yet - can't drive far enough to do any good.

thanks again,
Jason

[ae1969]

I would shut off ego control or raise the RPM to at least 1200 rpm for now. Until your idle is nice and stable.

I would set the VE values 600 and 1100 rpm cells to be identical. All the ones around idle for now. This keeps the car from hunting.

I would set the ignition at those lower cells near idle to be identical at 600 and 1100 rpm. Also keeps the car from hunting.

Your accel enrichment is way to high in my opinion.

Your threshold is 20 which is fine for now but I would change the accel enrichment to the following.....

154 15
80 10
40 8
10 5

You are blipping the throttle an having massive amounts of fuel being added. Once you start getting throttle response dialed in then you can start lowering the TPS threshold

[ae1969]

Also........

When you turn the Ego back on ......I would set your idle AFR cells to 14.7 ......... most cars will be happy with that. Some cars like running a little richer at idle but that comes with trial an error.

You dont adjust the AFR table to make ego correction go to 0. You set your AFR table where you want it.......and ego correction FORCES it to go to the value you want.

Once you have it all dialed in you may find that 5% control may be enough.

IN my case I dont even bother with ego control below 1200 rpm now... I have my idle cells dialed in exactly where I want.

[ae1969]

Also........ When you turn the Ego back on ......I would set your idle AFR cells to 14.7 ......... most cars will be happy with that. Some cars like running a little richer at idle but that comes with trial an error. I dont even bother with ego control below 1200 rpm now...
944 2.5 L Turbo EDIS 4 MS2 My Success Story
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Posted by email.

[hsrs10]

Thank you very much for taking the time to help with my problem!

The reason I set up th accell enrichment so high is that when I blip the
throttle, it showed that it was going to lean. Do you think that it was actually going so rich that it was thinking it was lean?

Also, how do I know where to set the ve values? Do I just look at the afr gauge and try to get it to read close to 14.7:1 by adjusting ve values? I guess this has been one of my greatest struggles in learing how to tune is what to look at when I am making adjustments.

I will try all your suggestions when I get home tonight and will repost how it went.

Thanks again for your help.

[hsrs10]

Thank you very much for taking the time to help with my problem! The reason I set up th accell enrichment so high is that when I blip the throttle, it showed that it was going to lean. Do you think that it was actually going so rich that it was thinking it was lean? Also, how do I know where to set the ve values? Do I just look at the afr gauge and try to get it to read close to 14.7:1 by adjusting ve values? I guess this has been one of my greatest struggles in learing how to tune is what to look at when I am making adjustments. I will try all your suggestions when I get home tonight and will repost how it went. Thanks again for your help.
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135525#135525 -------------------- m2f --------------------


Posted by email.

[hsrs10]

I changed my settings as recommended. I set ego controller authority to 0, set mt acceleration enrichments as stated, evened out lower part of ve table and ignition adv. table. I started vehicle and set ve table values at idle to make afr gauge read close to 14.7:1. Vehicle idles fine, does not smell rich. I still have a problem when giving a slight blip of the gas - afr goes full lean for a second and then goes back to 14.7:1. I tried reving engine to about 2500 rpm and holding it steady, adjusted ve table to make afr gauge read about 13:1, engine still is backfiring some through the exhaust and smells rich tried leaning it out more, no difference. I don't get what I doing wrong. With the narrow band sensor - it never went lean when blipping gas and never backfired through exhaust.

I am still a little confused about tuning. What is the purpose of the ve table? why couldn't you set the afr table and set ego authority to 100% and then megasquirt would try to give the engine the correct afr. I know this couldn't be done - just trying to understand everything. I think I have the megasquirt manual memorized as many time as I have read it, I guess it will all make sense to me once I get everything dialed in.

hopefully this thing does not get the best of me - I am starting to think a carb would have been a lot easier.

Thanks for the advice,
Jason

[hsrs10]

I changed my settings as recommended. I set ego controller authority to 0, set mt acceleration enrichments as stated, evened out lower part of ve table and ignition adv. table. I started vehicle and set ve table values at idle to make afr gauge read close to 14.7:1. Vehicle idles fine, does not smell rich. I still have a problem when giving a slight blip of the gas - afr goes full lean for a second and then goes back to 14.7:1. I tried reving engine to about 2500 rpm and holding it steady, adjusted ve table to make afr gauge read about 13:1, engine still is backfiring some through the exhaust and smells rich tried leaning it out more, no difference. I don't get what I doing wrong. With the narrow band sensor - it never went lean when blipping gas and never backfired through exhaust. I am still a little confused about tuning. What is the purpose of the ve table? why couldn't you set the afr table and set ego authority to 100% and then megasquirt would try to give the engine the correct afr. I know this couldn't be done - just trying to understand everything. I think I have the megasquirt manual memorized as many time as I have read it, I guess it will all make sense to me once I get everything dialed in. hopefully this thing does not get the best of me - I am starting to think a carb would have been a lot easier. Thanks for the advice, Jason
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135587#135587 -------------------- m2f --------------------
Attachments:08-09-06.msq

Posted by email.

[ae1969]

Can you post your current MSq and a log file (5 minutes revving at idle......sustain it at a specific idle etc.............)

The idea is to get VE dialed in as close as possible. (PHils megalogviewer) is great for doing this. Then setting ego to control from that point on.

Ego control creates huge jumps if you try to get it to correct too much too fast.

You will get lopping idles, erratic part throttles and all kinds of whacky behavior if you try to let ego correct your bad tuning.

[ae1969]

I would shut off ego control or raise the RPM to at least 1200 rpm for now. Until your idle is nice and stable. I would set the VE values 600 and 1100 rpm cells to be identical. All the ones around idle for now. This keeps the car from hunting. I would set the ignition at those lower cells near idle to be identical at 600 and 1100 rpm. Also keeps the car from hunting. Your accel enrichment is way to high in my opinion. Your threshold is 20 which is fine for now but I would change the accel enrichment to the following..... 154 15 80 10 40 8 10 5 You are blipping the throttle an having massive amounts of fuel being added. Once you start getting throttle response dialed in then you can start lowering the TPS threshold
944 2.5 L Turbo EDIS 4 MS2 My Success Story
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=135482#135482 -------------------- m2f --------------------


Posted by email.