drive it

iTrader: (1)

Rbob-do you mind if we start a new thread just for the surging idle?
Seems like it's been a problem for more than a few folk here.
It just comes and goes, sometimes gone-think I've got it, then back the next day. (working on a TPI) Other than this problem I've about got it dialed in now. BTW thanks for the advice to switch to the ac delco narrow band-made a considerable difference from the bosch!
I've tried the prp gain table already, and flattened out the spark tables around the idle map/rpm areas.
There's also a section of "spark advance, idle speed control" tables.
Has anyone worked these over? Suggestions on them? I was thinking of just zeroing out all of them-any detriment to that?

Ronny

iTrader: (1)

I lock SA at idle. I ended up at 22d but yours may vary.

I also idle open loop. Consider trying that. If OL then flatten the OL A/F vs VAC values around the rpm/vac you idle at. I think I am 14.0/1 there not the stock values of 14.7. Same on VE table.

As you are aware continue to verify possible VAC leak. Some members found cracks in the lines themselves. If hoses are old replace them. cheap.

Look at datalog to see if the fueling usec is moving. I think I am stable 1.9 to 2.0 area(TBI).

RBob

iTrader: (1)

Not at all, getting a good idle can be tricky.

This can be caused by a slight vacuum leak. On TBI engines the base gasket is prone to leaking. It usually whistles once it gets bad enough.

Another area is a hill in the VE table below idle. There is a triangular area of the low speed VE table that can't be learned in. It is the low RPM low MAP KPa corner. Once learning is getting close this area usually needs to be manually flattened out.

Otherwise a slight disturbance in the idle can hit that area. With the result of a self-feeding oscillation. See our Intro to Tuning Part 2, about halfway down (the only images on that page at this moment).

http://www.dynamicefi.com/Tune_Intro2.php

I too noticed the same, you're welcome.

Go with open loop idle at first (set: Option Word 1 - Bit 2 - OpIdl). This eliminates proportional gains.

It can help to flatten the VE table around the idle area some.

No need to flatten the SA table, use the Idle State SA value (SA - Idle State SA). And make sure that this flag is set (Option Word 2 - Bit 1 - IdlSa).

Doing this holds the idle SA to that value, with the idle compensation SA adjusting it.

You can try it with the two SA compensation tables zeroed out. See how it is. Usually, the more modified the engine is the lower the SA values in those tables can be.

If the idle speed has been increased should also increase the RPM threshold for the BLM idle to decel switch over (BLM - Idle Cell RPM Threshold).

RBob.

Dominic Sorresso

Just curious, but what was the diff the AC NBO2 made? Is it worth switching from the Bosch? And what would be your criteria for deciding to do that?

RBob

iTrader: (1)

Crazy as it sounds, my criteria to swap it was to see if it made a difference. To my surprise, it was more of a difference then I expected. Overall the engine just ran better. No one thing, just ran better.

Note that this was on a '85 Camaro LG4 engine converted to TBI. Likely stock, but with new valve stem seals.

RBob.

drive it

iTrader: (1)

Rbob-thnak you! I'll work on it again this weekend and try out all the above.

For me the ac-delco made the wide band correlate much better to stioch. The bosch made it run way too rich in closed loop.

Dominic Sorresso

RBob,
Coming from you, not crazy at all. Do you think the AC is more "accurate"? What is it that made the motor feel like it was running better? What impressed you?

RBob

iTrader: (1)

It has been a while, but IIRC, the first thing I noticed was that the engine was smoother at highway speeds. It may have been that the Delco sensor was more accurate, thereby providing a more consistent fueling while in high lean cruise mode.

RBob.

Dominic Sorresso

RBob,

So would you say that you would benefit w hiway mode? Don't have that in $D0 mask,
so are there other benefits that I could still take advantage of?

drive it

iTrader: (1)

Still workin on this.......
Been going back and forth on all the above.
At times surge is bad enough that on the WUD the Launch light comes on-what table effects launch?

RBob

iTrader: (1)

Launch mode (LM) adds SA, there is a LM SA table. Can increase the delta MAP that enables LM to prevent it.

RBob.

drive it

iTrader: (1)

I'd like to try and force the rich/lean O2 sensor swings faster.
I was looking at INT-O2 window for fast rich/lean.
Or would another table have that control?
I did find a vacum leak-fixing that helped a lot,then another redo of the ve table, but still can't quite get it yet.

RBob

iTrader: (1)

Try open loop idle, there is an option flag for it. It can be easier to tune in open loop then closed loop at idle. Once things are tamed down can then re-enable closed loop idle (if desired).

As for speeding up the O2 crossover, that can be tricky. Can only go as fast as allowed by transport delay and sensor delay.

Then again, thinking about it, that is only as fast as it goes. The ECM is trying to force a crosscount at all times (when in closed loop). If anything, check that the INT isn't slowly oscillating to cause cross counts, or fast oscillating to make up for too much proportional gains.

RBob.

drive it

iTrader: (1)

Also I have the prop gain offset for idle down to 1.0 now.
What other prop gain tables can I try for improving the idle surge?

1991sleeper

iTrader: (-3)

All my pro gain tables have been dramatically reduced like 80% prolly ... idles smooth as glass ... I also have my idle sa constant I don't remember the name of the flag u gotta check for idle state sa ...

91' firebird .. 305 TBI .030 over , balanced bottom end , speed pro hyper flattops , 10.6:1 CR , all ARP rod bolts and main studs , melling HV oil pump , trick flow super 23 175cc heads, Howards HR 214/218@.050 .488/.495 lift on 114 LSA , full roller 1.6 RR = .520/.528 lift , summit dual plane intake port matched , shorty headers into 2.5" Y w full 3" flow master system and 3" cutout in front of axle , msd billet dizzy, 620cfm TBI , custom CAI , tubular adjustabke LCA pan hard , umi torque arm wonder bar , BMR trans cross member , COMP engineering SFC's, disc rear w 4.10's, drilled an slotted rotors, EBL flash , VRFPR, WBO2,

drive it

iTrader: (1)

[QUOTE=1991sleeper;5720595]All my pro gain tables have been dramatically reduced like 80% prolly ... idles smooth as glass ... I also have my idle sa constant I don't remember the name of the flag u gotta check for idle state sa ...

How bad was your idle surge before changing all the prop tables? Was it even hitting launch mode?

1991sleeper

iTrader: (-3)

Yes it was hitting launch mode ..

91' firebird .. 305 TBI .030 over , balanced bottom end , speed pro hyper flattops , 10.6:1 CR , all ARP rod bolts and main studs , melling HV oil pump , trick flow super 23 175cc heads, Howards HR 214/218@.050 .488/.495 lift on 114 LSA , full roller 1.6 RR = .520/.528 lift , summit dual plane intake port matched , shorty headers into 2.5" Y w full 3" flow master system and 3" cutout in front of axle , msd billet dizzy, 620cfm TBI , custom CAI , tubular adjustabke LCA pan hard , umi torque arm wonder bar , BMR trans cross member , COMP engineering SFC's, disc rear w 4.10's, drilled an slotted rotors, EBL flash , VRFPR, WBO2,

Ronny

iTrader: (1)

Idla SA is in constants. My unsderstanding is you place in a desured SA for idle and it is locked. In flags I recall ther may be ID SA a flag to check on.

drive it

iTrader: (1)

[QUOTE=1991sleeper;5720595]All my pro gain tables have been dramatically reduced like 80% prolly ... idles smooth as glass ... I also have my idle sa constant I don't remember the name of the flag u gotta check for idle state sa ...

__________________________________________________________


THANK YOU!!!!!!!!!!!!!!!!!!!!
I tried dropping all the prop gain tables I could find by 50%. All vacuum leaks fixed. Was still surging. Then dropped them all by 75% and voila!!!
I'd really like to know if there's a way to systematically tune these tables other than by guessing. Rbob-ideas?
I do still have a slight surge on warm start up after it's sat for a while-about 5 to 6 times and then settles down. Also at times a slight surge a couple times when put in gear(auto). Would love to even get rid of that, but I can live with it now. But night and day from before. It would even stall out when shifted into gear and warm starts-was driving me crazy! well OK just crazier than my usual.

Ronny

iTrader: (1)

Keep in mind the OEM spends 100's of hours on dyno tuning the cars. I am fortunate to have as my customer a technician that is tuning today the new Buell race bike and consumer model release. 100's of hours. Multiple dynos. East Troy Wisconsin...

1991sleeper

iTrader: (-3)

Set the idle state sa and try running open loop idle .... or try smoothing ve table at idle and cells around idle make them all the same number do the same with sa

91' firebird .. 305 TBI .030 over , balanced bottom end , speed pro hyper flattops , 10.6:1 CR , all ARP rod bolts and main studs , melling HV oil pump , trick flow super 23 175cc heads, Howards HR 214/218@.050 .488/.495 lift on 114 LSA , full roller 1.6 RR = .520/.528 lift , summit dual plane intake port matched , shorty headers into 2.5" Y w full 3" flow master system and 3" cutout in front of axle , msd billet dizzy, 620cfm TBI , custom CAI , tubular adjustabke LCA pan hard , umi torque arm wonder bar , BMR trans cross member , COMP engineering SFC's, disc rear w 4.10's, drilled an slotted rotors, EBL flash , VRFPR, WBO2,

RBob

iTrader: (1)

A lot of the ideas that are being kicked around I covered in my first port (#3 of thread). It would be helpful to reread that post.

As far a tuning in the proportional gains tables, I go by exhaust sound and the INT. But first, I rough them in by changing them by the same amount of change in injector flow rate. If a larger displacement engine is in place, say a 383, that too needs to be taken into account.

It is all about ratios. Double the injector flow and need to halve one of the two proportional gains tables. The two tables get multiplied together, hence the need to only halve one of them.

If at a steady state cruising speed the exhaust sounds like there is a bad u-joint, too much proportional gain. Look at a data log and look at the airflow at that time (gms/sec). Go into the proportional gain vs airflow table and reduce it at and around that air flow.

Flash and re-test.

As for using the INT, if the INT is rapidly increasing and decreasing there is too much gain. Would likely see this in the bad u-joint example.

A slowly increasing and decreasing INT means that there isn't enough gain. This forces the ECM to use the INT to create cross counts (O2 signal). This causes an overshoot of the AFR. Which can be heard in the exhaust an oscillation. Can also cause the engine RPM to follow the AFR change.

RBob.

drive it

iTrader: (1)

It's starting to make more sense to me....thank you once again!!!!!!!

drive it

iTrader: (1)

Another question...........
I'm trying to enter lower percentages into the tables, however it doesn't allow it.
For example in the prop duration vs O2 error the lower O2 millivolt-tried to input 10 msec however it will change it to either 0 or 25, it won't save anything in between. Isn't tunerpro supposed to save any value?

lakeffect2

RBob wrote " If the idle speed has been increased you should also increase the RPM threshold for the BLM idle to decel switch over (BLM - Idle Cell RPM Threshold)"


Thanks.... never considered that before now.

dave.

1991sleeper

iTrader: (-3)

No ... some tables r just like that ...FYI sometimes u can open the graph and manually pull the value where u want it instead of entering a number....

91' firebird .. 305 TBI .030 over , balanced bottom end , speed pro hyper flattops , 10.6:1 CR , all ARP rod bolts and main studs , melling HV oil pump , trick flow super 23 175cc heads, Howards HR 214/218@.050 .488/.495 lift on 114 LSA , full roller 1.6 RR = .520/.528 lift , summit dual plane intake port matched , shorty headers into 2.5" Y w full 3" flow master system and 3" cutout in front of axle , msd billet dizzy, 620cfm TBI , custom CAI , tubular adjustabke LCA pan hard , umi torque arm wonder bar , BMR trans cross member , COMP engineering SFC's, disc rear w 4.10's, drilled an slotted rotors, EBL flash , VRFPR, WBO2,

RBob

iTrader: (1)

It has to do with resolution, for the duration it is every 25 msec. The spark advance is every .352 degrees, then the VE table at every .39 percent, and so on.

You can look at the conversion equation to get the resolution of the varies values.

RBob.

drive it

iTrader: (1)

As for speeding up the O2 crossover, that can be tricky. Can only go as fast as allowed by transport delay and sensor delay.

Then again, thinking about it, that is only as fast as it goes. The ECM is trying to force a crosscount at all times (when in closed loop). If anything, check that the INT isn't slowly oscillating to cause cross counts, or fast oscillating to make up for too much proportional gains.

RBob.[/QUOTE]

Idle O2 error correction and O2 minor loop idle filter-would it be possible to use these?

RBob

iTrader: (1)

Can try changing them and see how it works out. The O2 idle filter is usually set low (slow filter). Try it at 50% and see what happens.

RBob.

drive it

iTrader: (1)

I had to take a break dealing with life's problems.....but back at it now.
Did I mention the super ram intake is a pia to take off and on!
I went thru everything again-vacuum lines and loose wire connections.
Changed to a birdcage intake air sensor.
I now still have a surge for about 5 cycles before it settles down when I put it in gear.
Is there any particular prop gain table to look at for this?

TORN

iTrader: (17)

Are your IAC counts still at Zero when fully warm?

drive it

iTrader: (1)

Nope, got it set so it's about 20.

RBob

iTrader: (1)

Need a current data log and the current BIN. When making the data log do the P/N to drive several times. This way there is plenty of data to lok at.

RBob.

Dominic Sorresso

RBob,

Do the PID delays come into play here and if so, what direction should we be adjusting them?

drive it

iTrader: (1)

OK, finally got it back together and logged.

Street Lethal

iTrader: (16)

Bob is 100% correct with the response he gave, not that I needed to even point that out, but it's mathematical. I know you are unfamiliar with my build, but after setting the Injector Flow Rate and SA values just to get the engine to idle, I took the lowest IAC step value I was able to attain at idle (70 steps, without touching the fast idle screw), compared it to the stock IAC step value at idle with the stock LB9 (20 steps), then made the idle adjustments that way because that is what the engine was calling for in terms of idle fueling, difference of 50 steps was increased across the board in relation to idle step values being changed. At that point, so long as your initial timing matches your spark reference, and your idle SA target is the same as in the idle cells in your SA main table, you should have no surging whatsoever in Closed Loop unless you have a vacuum leak, or a bad sensor that is skewing data...

RBob

iTrader: (1)

Looking at the log now, first thing to do is to set (check) this flag:

Option Word 7 Input Polarity - Bit 2 - 4thIn

This affects which set of TCC lockup tables are used. At this time the high gear and low gears tables are reversed in usage. Once that flag is set the ECM will use the correct tables.

When the transmission is put into drive the RPM dips down and bounces off the stall saver. Need to have the P/N idle speed higher the the drive idle speed. add 100 RPM to all entries of the P/N idle table:

IAC - Idle Speed: Park/Neut

As the RPM dips the reported AFR goes lean, probably enough to add to the surge. Increase the VE in the area of 500 - 600 RPM, 40 - 50 KPa area. Smooth into adjacent cells.

RBob.

drive it

iTrader: (1)

Thanks once again!
Closed loop at times only the slightest surge that goes away. Restart hot before closed loop can have a significant surge-was going to richen up from current 14.1 table-open loop-afr vs rpm and vac. Or is there a better option to use?

RBob

iTrader: (1)

Depends upon why the engine is surging.

RBob.

drive it

iTrader: (1)

My train of thought, (I know-not always the best lol) -After the success I had with richening the closed loop ve tables that you pointed out from my logs, I figured I would work on that basis to start with on the open loop surge. Again when it's cold open loop it's fine-it's only on warm/hot restart until it goes closed loop that it can still be a significant surge at idle.

RBob

iTrader: (1)

Is the IAT/MAT still in the plenum?

RBob.

drive it

iTrader: (1)

Yes in plenum, and did change it to a birdcage type iat

RBob

iTrader: (1)

OK, try moving it out into the airstream where it doesn't get heat soaked.

RBob.

bphage

okay so I thought I would post this here. I have been able to get a nice open loop idle but I now enabled closed loop and on with the surging idle. Given the 60lb injectors in the TPI unit... I figured it was something to do with proportional gains. I scoured the posts and read the white pages etc... I have now the best idle I have been able ot get with closed loop... but I clearly still don't know what I am doing as its not good. Note: I did push my idle back down some which didn't help but I have a mild cam and didn't think this should have a significant enough effect on the idle settings given it should work with the factory tune.

I pulled data and put it into an excel file to show my OL idle, surge with increase in throttle, then back CL idle; I do have a heated O2 on the way as the car wont go into CL until I increase the RPM to at least high 700- mid 800rpm range.. the car was still warming up some but this was a cleaner data sample. Would anyone mind helping me figure out where I need to go from here?

Can down load the file from here... I think you can only view the first sheet if you just view the link... this is all the data. If you download it you can see the other sheets.

https://www.dropbox.com/s/ua30jjnqny...prp1.xlsx?dl=0

here is a summary of the things I have done which happened sequentially with improvement in idle:
IAC - Idle Speed: Park/Neut changed. Reset to stock then made min 600 rpm
BLM - Idle Cell RPM Threshold decreased from 1100 to stock of 800
PRP - Gain vs O2 Error changed. decreased all by 1
PRP - Prop Gain Offset for Idle changed from 2.00 Gain (0x01) to 1.00 Gain
PRP - Gain Muliplier vs Airflow changed. decreased a bunch of times with improvement in idle
INJ - Small PW Correction - PORT Only changed. Zero'd out table given large injectors
PRP - Gain Muliplier vs Airflow changed. increased by 15% - INT at idle is slowly oscillating suggesting to little prp.
PRP - Duration vs O2 Error changed. decreased by 10%
Crank - Prime PW changed. decreased by 10% as cranking has been getting longer and suspect rich with new injectors

RBob

iTrader: (1)

It is going to be difficult to get a good closed loop idle with 60 #/hr injectors in batch mode. First thing is to update the ECM firmware if it isn't the latest. Version 2.4 of the EBL Flash ECM firmware has a true proportional duration.

This allows for better control of the amount of fuel added or subtracted for the proportional gains.

RBob.

bphage

Thanks RBob,

I think I have the EBL P4 Flash System; I didn't see any recent updates for that; should I have gotten the EBL Flash with Port mod? Would that have worked out better as I can buy that from you if thats the case. Anyhow, only reason I care about CL is emissions... I guess the next question is can I get it to run CL to pass emissions with 60lb injectors? Am I just over my head on this? I have tried to find a tuner in the SF bay area last summer; most I was able to get is someone willing to let me rent there dyno which is were I checked out the spark curve to be sure it was safe...(everyone does HP tuners for LS but wont touch anything else) Anyhow, if I cant get it to pass emissions then I think I may be forced to scrap the project which would really suck. So when you say difficult I guess I am looking for practical limitations. Per usual, thanks for your help as I don't know what I would have done with out your help.

RBob

iTrader: (1)

OK, the EBL P4 update that has the true proportional duration is in progress of being released. Final testing and putting together the release is being done now and into next week.

Did you get injector compensation values for those injectors? That goes a long way towards a good tune.

RBob.

bphage

Thanks! I did put in the injector compensations tables; I had posted them in the main ebl page - I changed the "0" volt setting to the 12 volt setting like you recommended.

TORN

iTrader: (17)

I tried some things here to help my surging Idle and haven't had any luck. First off a dead cold start I have a good steady idle all the way to full warm up and my IAC are down to 30. Any touch of the throttle or a restart after fully warm in open loop my IAC raises to 40 and the surge begins. Also my SA - idle state SA is at 20 but its jumping from 21 to 13 and never stops. is this close to what you guys were seeing I am running 42# injectors on a 421 with FIRST Injection system.

lakeffect2

Can you manually edit your spark and fuel tables? I'd start with this suggestion.
First make sure there are no vacuum leaks, otherwise you'll be chasing your tail for a long time on this.

Look at the spark and fuel tables around your ideal idle "point"
Now consider there is no such thing as an idle "point" We all should get that notion out of our heads. It only exists in our minds.

It's an area bounded roughly by +/- 100 rpm and +/- 10Kpa. You should have relatively little change in the area just described. it should be almost a flat spot in your tables. To me, that's how an idle sits in a stable state. Changes across those ares result in a constantly moving rpm with the constant variations in load and spark advance.


keep inmind the idle your car is happy with is not necessarily what is programmed into your BIN., I raised mine to 900 (big cam 230/236) and it sits there happy all day. (hat is until 450 hp sucks the tank dry) Others here are welcome to debate my suggestion, but honestly it works for me very well


Dave Buchholz
Rochester NY