Stock tune TA -94 TunerCats

[scaryeyes]

Hi
Im new here on this forum. Looks alright the forum.

First of all the background. I had some injector issues and wanted to go E85 and blower. So the issue with injectors lead to #42. Then I could start tuning for hard liquor. And then later for the blower.....was my thought. Before the injector swap, my opti went for holiday. So the focus had to be there. Found an aftermarket richporter (think it was) that has a -95 wentted cap on a -94 body.

I mounted the injectors and the damned thing woudnt run smoothely. The only change I did was the constant of injectors in the program. Backfires a big deal at startup. Missfires sometimes at constant speed and sometimes it suddenly wants to die at idle.

My stock tune that I pulled was on my harddrive. And the harddrive ofcourse went crap. So I now have a tune pulled from internet.

I found here 2 stock tunes for Z28. Is it an idea to compare these tunes to mine?


But I believe I have to minimize the ammount of fuel at startup, as the machine gets too much. There I have an issue with backfire and lots of black smoke.

/magnus from sweden

[dawdaw]

Hi
Im new here on this forum. Looks alright the forum.

First of all the background. I had some injector issues and wanted to go E85 and blower. So the issue with injectors lead to #42. Then I could start tuning for hard liquor. And then later for the blower.....was my thought. Before the injector swap, my opti went for holiday. So the focus had to be there. Found an aftermarket richporter (think it was) that has a -95 wentted cap on a -94 body.

I mounted the injectors and the damned thing woudnt run smoothely. The only change I did was the constant of injectors in the program. Backfires a big deal at startup. Missfires sometimes at constant speed and sometimes it suddenly wants to die at idle.

My stock tune that I pulled was on my harddrive. And the harddrive ofcourse went crap. So I now have a tune pulled from internet.

I found here 2 stock tunes for Z28. Is it an idea to compare these tunes to mine?


But I believe I have to minimize the ammount of fuel at startup, as the machine gets too much. There I have an issue with backfire and lots of black smoke.

/magnus from sweden

LOL man you are all over the map..... if this is for real and your not a computer, what is your complete set up from oil pan to throttle body... An introduction thread with your modifications would be nice :D

[popo8]

Im hoping its just because he is from southern Sweden

20823

Co-Owner/Admin @ LTXtech.com

[scaryeyes]

Oh excuse me. My car is all stock -94 TransAm. No changes exept for injectors and budget opti. And about the tune, all I did was the injector constant and deleting of air pump.

[firebird_1995]

Did you change the opti and injectors at the same time?
Was it backfiring before the opti or injector swap?
Is the backfire in the exhaust?
Do you have 42# injectors in it now? If so what brand are they?
You mentioned in your tune, all you changed is the injector constant, what did you change it to?


Initially I'm ASSUMING that the problem you said you had with the original injectors was due to the bad opti, if its bad it wont fire the injectors. So you changed the opti, upgraded the injectors?

[scaryeyes]

The injector problem went back years. Had some codes and the original opti was bad. So that was changed. And waterpump and cables at the same time. Sparkplugs too.
For some years it was almost ok, with some irritating missfires and rough idle. But not much. I measured the stock injectors and found out some differences, maybe 1-2 Ohm overall.
Acouple of years later when I decided to change the injectors, the opti went to hell. Again. (AC Delco Opti). Engine was dead as soon it got warm.
Then I changed the opti and it ran a little rough. Didnt know if it was the new opti. If i mounted it wrong or just leaking injectors. Thats why I started with the injector swap. Just to see difference. But as the backfire (plenum backfire) only happens sometimes, its hard to put the finger on it. First I thought I mounted the opti wrong, as I heard on american forums, that is possible and people seen many times.
To me its totally impossible to mount it wrong on the splines, as one spline is twice the thickness as the others. Was hard to find the right spline though, but after some time it sat there.

The tune, I changed it to 42#. At first I tried to run it on E85 and just find a constant for the injectors, reading the auto log. Was down to 34# in the constant, and then gave up. And maybe I need a pair of new oxygen sensors as well. I cant get even readings between the banks in closed loop. And even it wants go open loop at idle. Thats another mystery.....

Sorry if I write un-understandable. I dont speak your language very well.

[firebird_1995]

Acouple of years later when I decided to change the injectors, the opti went to hell. Again. (AC Delco Opti). Engine was dead as soon it got warm.

Have your replaced the icm/coil or did the modification to move the assembly off the head?

[scaryeyes]

No I did not yet. First I didnt see an issue with that, cause not everybody has had problems with it. But it doesnt hurt. And even get a bigger heat sink would improve cooling. I did however mount it with some washers so it got away from direct contact with the head. But as you suggest, it should be relocated.

[firebird_1995]

Washers alone are generally good enough. But if the icm was fried before it was spaced off the head it could be bad. You probably don't have a buddy down the street you could swap icms with?

[scaryeyes]

I did swap it. I bought a used one from a guy that had several working ones. Mad no difference. So I counted that out.

[scaryeyes]

The thing is.... The engine is running great! Its shooting on REAL good. Very low on milage, but damn good response as long as the problems doesnt show. It gets a LOT of fuel. Im gonna change fuel filter. Change fuel regulator. I have a second one layin around. I know I can test the membran with the vacuum line to a bottle. Test that first.

[firebird_1995]

Ok, just wanted to make sure that was addressed. I think it would be best to put some stock injectors in until you can narrow down the cause of the backfire. A backfire in the intake means either the air fuel mix is too lean, timing too advanced, or an intake valve is open during an ignition event. It could be held open by a rocker arm being adjusted too tight, or the valve could be bent, burnt, or cracked causing it not to seal.

[scaryeyes]

The rocker arms... Dont they just go to the bottom and the adjustment in the lifters? Vever had the valv cover off. Im a pontiac guy, so never was very interested in chevy parts. Until now.....
But cracked valve.... well firing too lean must mean welding in the seat.
The thing is. I suspect timing way too advanced. But how can that be? Then it shod be that way all the time. Half of the times cranking, its normal. And sometimes it just takes like 10 to 15 seconds of cranking to start. I didnt have as much backfire this year as last year. Just that the engine goes very hard on the starter. Hydro lock? It can turn like 5-10 revolutions and then it nearly stops. Like suddenly too advanced timing OR hydro lock.

I could do a compression test.

And I know the air/fuel is not right. It seems to lean out on one bank a little. #2 cylinder is much colder than the rest of cylinders, according to a cheap IR temerature meter on the headers.

[firebird_1995]

Valve lash in these engines is adjusted in the rocker arms.
Do you have a way to datalog the car?

[scaryeyes]

Oh, good info here! Didnt know that. Jupp, Datamaster. Unfortunately, Im going to mexico for about 5 weeks, and I dont have time to pull a log, but if you dont get too tired of waiting, I can do it when I get home? And even upload the tune Im running.
To be honest, I didnt expect this engagement so soon. But thanks very much. Seems to be a great forum! My self have been a little passive about the car, since I started another build. But with a LS1, so have to learn that too later. The trans am are gonna be sold later on, but then it has to run perfect. But until then, Im gonna use it as every day car in the summertime. I have been earlier years, but last year I drove my -97 cadillac almost all summer. Had to do with my family. (whife dont drive race cars....)

[scaryeyes]

OK good info there!
As I mensioned, I never had the LT1 apart. I have the books though, but didnt read em through yet.
Im off to mexico in 2 days, so the datalog from DataMaster have to wait til august when I get home again. Hope its ok. I didnt expect this engagement. Very nice forum. I thank you for that! Thats makes a welcoming.
I have a log from last year in my laptop, but that one is not like it runs now, so that isnt reliable.
As it is it spins at 60 miles an hour during kick down and i have michelin pilot sport 285 40 17 on the rear.
So runningwise, its ok.

[popo8]

i dont like the "tune pulled from the internet" thing.

What was the source?

Co-Owner/Admin @ LTXtech.com

[scaryeyes]

Me neither. Cant find the source rihgt now. Looks like a dead link. I know its there, but the file I tried to use is a no working file. Im using the one I modifyed. Then I tried to modify it back again, using files I found on internet, since my own file went dead. There is one file around here that sais stock automatic and 3:23, but its fucked up. I have came across that file several times. Makes my car start in 3 gear. Etc

[scaryeyes]

I am lookin for a stock tune. Pulled from your own working car. Thats what Im asking for. A -94 trans Am automatic. I dont know if the tune for the camaro can fuck it up in a trans am????? Its F-body... And as the vin nubmer is ok, all is ok?

[popo8]

we have a tune repository...i believe its stickied in this section.

Co-Owner/Admin @ LTXtech.com