$EE unstable idle in closed loop

[Big don]

I am having trouble getting a stable idle in two different lt1s. As soon as they go into closed loop or on hot restart there is a great deal of surge sometimes to the point of stalling. I have done all of the usual checks for air leaks and have done data logging. what I am looking for is what is mentioned in EEhack as O2 reference voltage and intergrator delay. I have looked in both Tunercat and Tuner pro for these tables but i cannot seem to find them.
I have been a member for several years but this only my second time to post so I hope I get this right.
Thanks.

[lionelhutz]

You probably need a better xdf definition file for Tunerpro, such as this one or the one at Steveo's site. AFAIK, Tunercat still does not have these tables.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?6260-94-95-EE-xdf-(EEXTRA)

http://fbodytech.com/eex-tunerpro-definition/

[Terminal_Crazy]

Hi
FYI
I've found that if the VE tables (or other parts of the tune) are "wrongly calibrated" the idle in Open Loop has to make a big jump into the Closed Loop settings.
As Closed Loop settles down to where it wants to target, the idle will settle down accordingly.

I also think you have to go out and drive the vehicle to get the O2's hot which helps the BLM's settle down if your logging/tuning.
BLM's and VE's can change daily and on a whim with the LT1.
Tuning in the garage DOES NOT give the same results like you'd expect.

A Hot restart (80C+) always seems to start off much leaner than previously and can take a couple of minutes to drop back down to where it was.
There are tables for IAT sensor but they never seemed to do a lot when I've played around with them.
Interested in any feedback you have with this, please expand the knowledge.

Mitch

[steveo]

closed loop idle can be bitchy

the o2 delay settings will help especially if using headers

if using different injectors, correct injector settings will help

sometimes more advance helps

sometimes 100 more RPM helps

sometimes individual cylinder trims for closed throttle helps

sometimes increasing IAC involvement by closing the throttle plates more helps

possibly end of injection timing will help (this is fairly new research)

if emissions aren't a concern, open loop is a perfectly fine solution too (in real life engines are rarely at their best at stoich anyway, and if you need more fuel to get it behaving, closed loop is not really an option)

[Big don]

thanks for all the help. that adx really put a lot more parameters to deal with. First I had to get a new bin because tunerpro would not edit my tunercat bin I have in my S10 with the lt1. So I had to copy all my settings to the new bin and reflash using EEhack. Everything worked except the speedo scalers and they read right but it will not show over 12 mph.
I believe I can fix that. My first time using tunerpro.
This car is on its fourth v8. One tuned port and its third lt1. It really gets driven a lot of miles. Anyway,the cam in this this particular motor has always had small idle surge on a warm (not hot) restart but it was just really a nuisance until my optispark went bad then the surge got much worse. Not all optisparks are created equal. So I thought it was timing but I may have been going the wrong way or too many changes on top of each otherfor me to remember. I am a lot older than I used to be.

The surge I had before was worse in cold weather so it may be an air or water temp sensor. Anyway thanks for the help and sense I have a new bin I am starting back on floor one.

[steveo]

AFAIK, Tunercat still does not have these tables.

it does have a lot of the o2/integrator parameters last i checked (a fairly recent addition, maybe a few years ago now?)


First I had to get a new bin because tunerpro would not edit my tunercat bin I have in my S10 with the lt1.

you almost certainly had $EEB instead of $EE. there's no good XDF for tunerpro for EEB, most people just start over like you did.


Anyway,the cam in this this particular motor has always had small idle surge on a warm (not hot) restart but it was just really a nuisance until my optispark went bad then the surge got much worse. Not all optisparks are created equal.

if your new opti made it run differently it might be faulty. a lot of problems are more apparent at idle. it might not be 'idle surge', it might be a miss.

[Big don]

Thanks for coming back to me. First that was something I was interested in and will investigate
My tunercat bin wasis $EE not EEb and tunerpro would read the bin just would not edit it. I tried the tunerpro bin on tunercat and it would not read it either. I had just installed a tc update and I thought that might have something to do with it.
The optispark is probably faulty. A couple of years ago I decided to put the optispark inside a conventional small cap hei. When I went to figure it out I went to a friend who had been wrecking out a lot of lt1s and had a bunch of old optisparks around so I took them home and put them on a lt1I had put on tdc and the timing was different on every one of them. Some was as much as eight degrees different. This can make a big difference on how one acts and lt1s are not the easiest engine to check the timing on.
Anyway I built a few of these distributors and am currently working on putting one of them on this engine and using the lt1 electronics on a early small block but I just have not had a chance to yet.
In spite of the possible timing issues I am just wanting to get the ldle / restart problems patched so I can better use the car until I can get ready to get rid of the optispark.

Thanks for the quick response and I have enjoyed and used the great amount of info you and all the other members have contributed
Over the last few years without me having to ask many questions. And I say thanks again.

[steveo]

Some was as much as eight degrees different. This can make a big difference on how one acts and lt1s are not the easiest engine to check the timing on.

if you want to achieve proper base timing with your distributor-opti-thing, i can help with that.

just like you would do on a normal distributor car, you can lock your timing advance electronically to a value using eehack's 'raw' button at the bottom.

... i didnt make a real control for full timing advance override since that'd be kind of dangerous if you use it accidentally, but the command is there

pretty sure this locks it to 10 degrees but you'd have to test it. you can have the datalog screen open at the same time to confirm it's done.


0400000000000000000000010A

(change the last two digits to the hex of the timing advance you want, for example 05 for 5 degrees or F for 15 degrees. i guess if your engine will stay running with 00, that'd save you using a degree wheel.)

then mark your crank to whatever value you picked and use a timing light. if you don't lock your timing advance in place i bet it'll be damn near impossible to get that thing timed properly.

[lionelhutz]

That's odd that TC and TP can't share a bin. The versions I have will swap the bin back and forth just fine. I haven't updated TC for probably a few years now because I hardly use it anymore so maybe TC did change the software somehow recently to cause that.

[Big don]

Thanks for the help on that timing lock that will save some time. The way I did it on the bench motor(see photo) wa





s to zero the idle over speed/underspeed and level base timing to a stable figure and then read the timing marks I had put on the balancer with a timing light and then reflash the ecm. It worked but took a little while.

I tried to get the tunerpro program to fix the speedometer scaler problem but it did not work out so I went back to the tunercat program and redid alot of timing stuff and the speedo works, the trans shifts again and the surge is a lot better than it was. I was going through wrong way on spark. I took a lot out and that helped a lot.
It still needs to be fixed.
Now the tunerpro not doing the speedo right I can't use it for editing the bin for the surge and drive the car too. Hmm.

I hate to ask this but could I possibly be doing anything wrong?

The engine in the photo is from a stock 96 ybody. I have changed it to a 95 and it has a unstable idle also but I am almost positive it's because the headers and it looks like that stuff in tunerpro could fix it as long as I don't drive the car.

Steve's I would like to compliment you on EE hack. I could not even begin to guess how many hours you have in developing that and I am planning to put it to good use as soon as I get smart enough to figure it out.
As you said lt1 guys are a odd lot.

I don't know why tunerpro would not edit my cars tc bin. It seems I used it to do some 6E stuff a few years ago but something always seems to keep me from successfully using tunerpro. I am not very well versed on using PC's and have a lot of problems. I can lose a file in a heartbeat.

[Big don]

It looks like I lost a photo.

Let me try again14111
Let's see if this works
One of three is a start14113
One more14111
I havv got to find a better way.

[steveo]

that's a great rig. right up my alley

as far as tuner pro goes, move the file to the desktop or something and try again. must be a permissions issue. if it persists I'm sure we can figure it out.

[Big don]

Thanks, I tried moving the bin to desktop and reflash but no luck. The speed still reads about half or less of road speed and looks unstable as in not linear . I dont know what else might be wonky. The same numbers work in tunercat.

I built that stand to work out wire loom and check engine light issues before installation. It sure makes a new install a lot easier when the engine will start, not leak, and no lights come on.

[Big don]

Thanks a lot. I did download the tunercat bin from the car renamed it and put it in desktop and it now works in tunerpro and flashes back with no speedo issues.

I have found that many things would be a lot easier if I just knew what I was doing.

Thanks for the help. now on to more tuning stuff.