94 F-body LT1 solving problems/tune

[yoheer]

Hi everybody
I own 94 TA LT1 4l60e and 2.72 gears
It is stock with some mods for now
-rebuild tranny with corvette oil pump, z-pack and rougher/faster shifting
-trans oil cooler
-engine oil cooler
- 94 vented opti
-k&n air filter
-cat delete
-TB coolant bypass
-intake elbow silencer delete
-oil temp / fuel press / vacuum - gages
-160 t-stat
-fan switch

I want to tune it.
Let's get started

Factory bin file attached

[NomakeWan]

You should probably start by stating what problems you’re actually having so that they can be addressed before wasting time tuning.

[yoheer]

Well
I was cruising and got a SES light with code 44. Left bank lean condition. I had it earlier but i found a problem with HVAC vacuum leak. I fixed it, cleared the DTC.
Today after all I checked the engine for leakes with smoke machine and found one in optispark. I moded 94 non-vented opti to vented earlier as you can see above. I converted it back to non-vented and checked everything again. No leaks. Done.
But I watch throug the Eehack logs and I dont know if theese are normal parameters: (there is no much differences before and after vacuum fix in logs BTW )
MAF is 7.5 g/s at idle
IAC position sometimes 6 to 9 at idle
BLM is on
Also maybe smth is wrong
Here are logs

[yoheer]

So, can anybody take a look? Or I need some logs from good working stock car. I will compare.

[steveo]

i haven't looked at your logs, but with the maf and iac so low you probably have another vacuum leak or unmetered air somewhere. the maf isn't reading much airflow, but the IAC is trying to lower your RPM. it's a very old car so anything rubber or plastic is suspect but also things like your 'intake elbow silencer delete' need to be rechecked.

[yoheer]

New logs. I drove a car all day on my business.
What I found
Sometimes LBLM and RBLM drops less than 110
AVGBLM too
Generally on deacceleration but not always
Checked, for vacuum leaks again. I have no leaks. I'm using smoke machine and I believe i would see if smoke came from somewhere.
The only thing I havent checked is brake booster. I'll check it later, but brakes seems to be okay.
I can attach those logs if needed

[steveo]

i know from experience that if your brake booster leaks on an fbody, your brakes barely work at all.. but definitely do check it.

[yoheer]

Most likely the booster will be ok.

[yoheer]

Idle is 900-1200
replaced the iac with used one
then it rised to 2000
used scan 94 95 to reset iac position
after clicking on that button about 5 or more times it has dropped to normal idle and IAC was about 10-14 steps
after restarting the car rpm is about 750-800
but target rpm is 650
IAC is about 20-25


Faulty IAC?

[steveo]

your TPS is at 1%.... why is your TPS at 1%? it wont try to attain your idle target if the TPS is open.

[yoheer]

Good question. I'll try eehach to measure tps. Scan 94 95 always shows 1%
One more moment. The only leak i have is on the pic below. And I can do nothing with it. TB shaft.

[steveo]

its normal for it to leak a bit there. it looks like you haven't adjusted your idle screw. make sure your throttle plates are closed as much as possible (just not so much that they jam in the bore). after doing all this, pull your PCM BAT fuse for a bit just to make sure ecm memory is clear.

[yoheer]

Now tps is 0. Strange. I did nothing about adjusting that screw. Rmp just raised and thats it. 700. Then 800 in a week. Then 900 and so on

Idle iac is 40 steps. Is it okay?
Idle is 850.

I'll try to install new tps. I dont like how it operates

[yoheer]

Faulty tps.
Fixed.

[yoheer]

Today was a next step with my pontiac
I made mods with ECM.
Installed EEPROM sockets for both sides. I want to say that there is no need in installing credit card pices. And no need to cut the bottom in a socket.
All you need is heated table and heatgun.
If you dont have a heated table you just can use household iron and a paper towel as a spacer.
Everything works perfect.

then I made some "cosmetic" mods:
1. Cat potection disable. I have cat delete.
2. Lowered the overheat enrichment protection
3. Lowered BLM Hysteresis for more accurate idle
4. AC clutch disable within lower TPS

5. Disabled AIR PUMP - DOESNT WORK!!! AIR pump still engages on start. And I see in logs. How to finally disable it?

6.Lower TEMP fans kicking.
7.Lowered IDLE to 500. Works perfect.

[LeMarky Dissod]

5. DISABLE AIRpump
Besides clicking OFF at least two switches / flags, you must ALSO raise the Min Coolant Temp to Enable AIRpump to well over 117.5°C / 243.5°F.

Generally speaking, if you want to disable anything, you often need to take more than one step, possibly two or three or more to do so.

To wit:
1. I think Catalytic Protection can be disabled with only one constant, but just in case, I'd adjust four, as GM did.

[yoheer]

AIR pump done.

Regarding CAT protection
Factory Cat protect AFR is 12.2. Is it bad for the whole engine cooling? And what about torque? I know that it raises a little when it goes to rich. Just about 11.8-12.8

There are Low/High boundaries and Low/Mid/High Pressure parameter. Should i mod them and to what values?

Is it good idea to disable cat protection? Or it's good to leave it alone? If only I'm right in everything that I said above.
I remind that I've deleted CAT.

[steveo]

i honestly don't see much point in cat protect mode even with a cat, but if you have no cat, there's definitely no reason to leave it enabled

[LeMarky Dissod]

Regarding CAT protection
Factory Cat protect AFR is 12.2. Is it bad for the whole engine cooling? And what about torque? I know that it raises a little when it goes to rich.
Just about 11.8-12.8

There are Low/High boundaries and Low/Mid/High Pressure parameter. Should i mod them and to what values?

Is it good idea to disable cat protection? Or it's good to leave it alone? If only I'm right in everything that I said above.
I remind that I've deleted CAT.GM uses the following values for vehicles that were never equipped with catalytic converters:

Min Coolant Temp for CAT Protect = 150°C
CAT OverTemp Threshold (Low Baro) = 1065°C
CAT OverTemp Threshold (Mid Baro) = 1065°C
CAT OverTemp Threshold (High Baro) = 1065°C
CAT OverTemp Air Fuel Ratio = 12.2 AFR

(Although I'd raise the CAT OverTemp Air Fuel Ratio to 14.7 AFR without any fear.)

[yoheer]

you convinced me guyz )))
Want to know your thoughts about egr and BLM locker.

After all Im gonna mod timing, AFR and everything to make the engine more responsible and add some HP.
I will need advices.

[yoheer]

Disabled EGR

[yoheer]

Should i mod smth about deleted cat?
I'm running ~93 octane.
And 160 t-stat and fan temps are lowered (operating temp ~195)
What tables should I pay attention to?

[LeMarky Dissod]

Should i mod smth about deleted cat?You can raise the 'CAT Protect Min Coolant Temp'. Anything over 120°C should do fine.

[LeMarky Dissod]

Disabled EGRTechnically, disabling & deleting the EGR Valve are two slightly different things.
To disable the EGR Valve in the .bin:
Raise BOTH EGR Enable Coolant Temp Thresholds over 120°C / 248°F in C.A.T.S. OBD1 LT1
Raise the EGR Enable Min MAP Threshold over 103KPa
Raise the EGR Enable Min RpM to 5925RpM or the RpM your LT1 engine will never hit, +25RpM)
Raise the EGR Enable Max RpM to 5900RpM or the RpM your LT1 engine will never hit, which also should be under the EGR Enable Min RpM

To physically DELETE the EGR Valve properly, use a blockoff plate for best results.

[yoheer]

What about fuel tables? It should be leaned a little when the egr if opened. In stock

[In-Tech]

Yes, I'm not sure LT1's ever had an EGR circuit that was active, however, all other ecm's have quite a few separate "tables" when the EGR is active. Or I should say, when the ecm thinks the egr is active.

I read all the time where people block their egr and wonder why they have a part throttle lean and knock issue. IF THE COMPUTER THINKS THE EGR IS OPEN IT PULLS FUEL AND ADDS TIMING!!! These are tuneable events and corrections. Changing a cam/exhaust/heads etc drastically alters the egr qualities.

Some egr's are basically on or off, other later ones are pulse width modulated and there are even more fuel tables and spark tables to work with that.

[yoheer]

I've found only timing corrections due egr is opened. But can't find where the condition is leaner with egr engaged. Hit me to that table please.

Also should I correct o2 swing table with cat removed?
Mine o2 swing table is default. I tried to raise the values in this table to get some power in closed loop, but it seems the car accelerates even harder.

How far should I move timing with 93 octane?

[In-Tech]

Are you using the EGR circuit?
I haven't followed this thread closely, can you post the stock .bin you started with so I can find stuff? Most stuff I have seen can usually accept 5 more degrees of timing on a stock timing table if the engine is stock. If much has been changed you have to tune accordingly. Hopefully more experienced LT1 guys can chime in with how much is acceptable, shoot, they have a pretty aggressive timing table from the factory due to the reverse cooling so I creep up on it and do a lot of logging. :thumbsup:

[yoheer]

Are you using the EGR circuit?
I haven't followed this thread closely, can you post the stock .bin you started with so I can find stuff? Most stuff I have seen can usually accept 5 more degrees of timing on a stock timing table if the engine is stock. If much has been changed you have to tune accordingly. Hopefully more experienced LT1 guys can chime in with how much is acceptable, shoot, they have a pretty aggressive timing table from the factory due to the reverse cooling so I creep up on it and do a lot of logging. :thumbsup:

The stock is in the very first message of this thread. Mod list is there too.
I've disabled egr, but hadn't removed it manually. It is installed, but not working because of PCM.

[LeMarky Dissod]

The stock is in the very first message of this thread. Mod list is there too.
I've disabled egr, but hadn't removed it manually. It is installed, but not working because of PCM.Whether you are using MAF Sensor or Speed Density, if you've disabled the EGR Valve operation in the pcm, then it will not apply the EGR spark timing table modifiers.
O2 sensors take care of the rest, provided they are working well.

In the long run, your intake manifold will appreciate that you installed an EGR blockoff plate.

Until you've personally calibrated your spark & fuel tables so that your LTFTs are all between 123 & 133 (123 is slightly better), leave the O2 sensors working.

[NomakeWan]

Yes, I'm not sure LT1's ever had an EGR circuit that was active, however, all other ecm's have quite a few separate "tables" when the EGR is active. Or I should say, when the ecm thinks the egr is active.

I read all the time where people block their egr and wonder why they have a part throttle lean and knock issue. IF THE COMPUTER THINKS THE EGR IS OPEN IT PULLS FUEL AND ADDS TIMING!!! These are tuneable events and corrections. Changing a cam/exhaust/heads etc drastically alters the egr qualities.

Some egr's are basically on or off, other later ones are pulse width modulated and there are even more fuel tables and spark tables to work with that.
By comparing the 1996 LT1 tables (which had an EGR) with the 1996 LT4 tables (which did not), we can see how the LT1's PCM handles EGR events.

The obvious differences are the EGR-related error codes. Easy enough to disable, but only gets rid of the MIL. The LT4 sets the enable temperatures high to disable EGR but otherwise leaves the settings within sane ranges (Min MAP 22.2 kPa, Min RPM 900, Max RPM 2300, Enable Speed 8 MPH, Disable Speed 6 MPH...Enable Coolant Temp 151.25C). EGR Spark Advance is set to between 0.0 and 1.0 (odd they didn't just zero out the table). Those are the only differences between the two calibrations with regards to EGR operation.

It would appear that merely making sure that the EGR enable values are out of a sane range is enough to disable all EGR-related changes. GM certainly seemed to think so.

[yoheer]

Well if it is so, then i've disabled it correctly.
What about CAT?

[LeMarky Dissod]

What about CAT?Asked & Answered.
GM uses the following values for vehicles that were never equipped with catalytic converters:

Min Coolant Temp for CAT Protect = 150°C
CAT OverTemp Threshold (Low Baro) = 1065°C
CAT OverTemp Threshold (Mid Baro) = 1065°C
CAT OverTemp Threshold (High Baro) = 1065°C
CAT OverTemp Air Fuel Ratio = 12.2 AFR

(Although I'd raise the CAT OverTemp Air Fuel Ratio to 14.7 AFR without any fear.)

[In-Tech]

Until you've personally calibrated your spark & fuel tables so that your LTFTs are all between 123 & 133 (123 is slightly better), leave the O2 sensors working.

Yes to the 123, most stock cal's are like this!!! The engine will always respond better with the slightly richer mixture while the computer attempts to remove fuel rather than add.

[In-Tech]

By comparing the 1996 LT1 tables (which had an EGR) with the 1996 LT4 tables (which did not), we can see how the LT1's PCM handles EGR events.

The obvious differences are...Forget about any kind of static ratio pertaining to a dynamic environment. Enable Coolant Temp 151.25C). EGR Spark Advance is set to between 0.0 and 1.0 (odd they didn't just zero out the table). Those are the only differences between the two calibrations with regards to EGR operation.

edited above

[yoheer]

Asked & Answered.


Oh that is clear. I'm talking about back pressure, so O2s can read different parameters without CAT. Any issue or just disabling cat protection(already done) and that's it?
I mostly ask about fuel and timing modifications.

[NomakeWan]

Oh that is clear. I'm talking about back pressure, so O2s can read different parameters without CAT. Any issue or just disabling cat protection(already done) and that's it?
I mostly ask about fuel and timing modifications.
Should be totally fine. The O2 sensors care about what's in front of them, not what's behind them.

[yoheer]

I know, that f-body and y-body engines are the same. 92-94 vette and 93-93 fbody. Same cam and all other stuff is the same. (Correct me if not)
Just headers and intake differs a little bit. And 2 knock sensors instead of 1
So is it good idea to take vette calibration and move all timing and fuel tables to my pcm? Tables differ a little bit. I compared em.
What do you think about it?

[NomakeWan]

Won't hurt anything. The only difference between the two engines is that the Camaros all had 2-bolt mains and the Corvettes had 4-bolt mains. All the other differences were external to the engine (intake design, exhaust design, accessory mounting).

[yoheer]

What about better intake and headers in vette?
Will modifying theese tables take effect in fbody?
And only 1 knock sensor. Detonation?

[NomakeWan]

What about better intake and headers in vette?
Will modifying theese tables take effect in fbody?
And only 1 knock sensor. Detonation?
Changing the exhaust and intake will cause changes in how air flows into and out of the engine. Engines are at their core just air pumps, after all. Much of these changes can be accounted for by the closed loop O2 sensor feedback system. You would have to make much more extreme changes to fall out of the range of what the PCM can account for, which changes to intake and exhaust won't do. If you disabled closed-loop feedback or you just want to adjust the tables yourself, then get a wideband O2 sensor and get to doing your own tuning. There's no magic bullet. But if the question is just "will I blow up my engine if I use the Corvette tables," the answer is no.

No, reducing the knock sensors from 2 to 1 won't cause detonation. On the 94-95 $EE PCMs, whether you have one sensor or two there's only actually one channel being used on the PCM end (the 96-97 PCM used two channels). What's important with regards to the knock feedback system is not the number of sensors, but is rather the calibration stored on the knock module inserted into the PCM. This module is what takes the output from the knock sensor(s) and filters it to tell the PCM when knock is occuring. Making changes to the acoustic profile for your engine will cause this knock feedback system to malfunction, but it's not the fault of the sensor. It's the knock module.

Unfortunately, short of designing your own knock module, you're not going to be able to get around this. Once you start doing custom work in your engine bay, it's best to just disable the knock feedback system entirely and rely on proper tuning, or run an external knock feedback system if you're paranoid.

[yoheer]

Thank you for such detailed answer.
Do you mean that if I have any loud perfomance muffler even with stock headers then i'd better disable knock sensors? Because of false knock.

[LeMarky Dissod]

GM used a different knock module when they upgraded the valvetrain on the '96 & '97 LT4.
The Impala SS Forum's collective experience has shown that using roller rockers and/or headers could cause 'false knock'.
The LT4 Knock Module has been out of production for many years now.

You should be fine with your loud mufflers, though.

[yoheer]

I've made mods to my bin. Lots of vette tables and parameters applied
Here is short log with PE mode and 100% TPS.
Seems to be very lean. Knocks detected. Can anyboby take a look and say what should I move to?

[NomakeWan]

Thank you for such detailed answer.
Do you mean that if I have any loud perfomance muffler even with stock headers then i'd better disable knock sensors? Because of false knock.
Not necessarily. I can't tell you what's going to change the acoustic parameters of your engine, but generally a muffler on the other side of the car isn't going to be what does it. It'll be changes related to the engine bay, or what's immediately nearby the engine bay. Things directly attached to the engine. What you can do is lower the timing on your engine to a point where it won't knock and then test. If you can make the knock reliably appear and disappear by messing with the timing, then it's probably real. If on the other hand you get knock with unusually low timing and/or in parts of the map that have no real load or RPM, it's probably false knock.

And as said, there's no way to fix this in the tune. It's not handled by the tune--it's handled by a physical component, the knock module. So if you find out you have false knock, you either have to make your own knock module tuned to your specific setup's acoustic parameters, or just disable the knock feedback system.


I've made mods to my bin. Lots of vette tables and parameters applied
Here is short log with PE mode and 100% TPS.
Seems to be very lean. Knocks detected. Can anyboby take a look and say what should I move to?
I had a look at your log. The "knock" at 1500 RPM and 40 MAP is probably not real. That's very low load and RPM. There are specks around 4000 RPM, but those could be false too, depending. The fueling at PE looks fine. The closed-loop fueling looks like it wants more fuel, sure, but your log is also pretty darn short, and you don't really cover the whole range without going into PE, so this 'lean' normal operation appears to be well within normal values. The O2 feedback system can handle deviations this small without any issue.

[yoheer]

I have my older logs, before vette tables. There is no knock at about 4000. I'll try to make more cruising logs.
Also I dont like maf readings. 6-7 at idle. I'll try to clean, but I'm afraid he is dying.
No vac leaks. Checked
O2s readings vary to much (left/right)
Rarely I get right or left (dont remember)bank lean condition dtc.

[yoheer]

Btw maybe someone has a good tuned file for stock or like-stock car?
I'd like to compare with stock. Is it noticeable chages in car behavior? I mean can I feel em myself

[LeMarky Dissod]

Here.

[yoheer]

Thank you. Can you write some description about the car, mods and what is made about tuning?

[LeMarky Dissod]

Thank you. Can you write some description about the car, mods and what is made about tuning?Absolutely OE, no mods, no tuning.
You asked to compare with stock. It's stock.

[yoheer]

Nope ) I do have lots of stock files. I asked tuned file for stock car.

[yoheer]

here is my combined bin
I will be grateful for the analysis and corrections.
To those who have f-body. It would be cool if you try this tune and say what corrections are required.

[yoheer]

Guyz.
I compare corvette and f body trans tables. Can't understand one thing.
95' vette 2.59 gear vs 95' f-body 2.77 gears
Vette pressure table values are higher in all range.
But. Vette modifiers are much lower and even have negative values. F-body modifiers are higher and positive values.
What is it for?
Does it mean, that vette has softer shiftings and f-body has rougher shifting?
Why vette pressure is higher but it is gets lower with modifiers. What is the sense of all this?
Vette=high pressure+low modifiers
F-body=low pressure+high modifiers
And as a result pressure is somewhere at about same values. But the way cars gets this values differs. Why?

[LeMarky Dissod]

Guyz. I compare corvette and f body trans tables. Can't understand one thing.
95' vette 2.59 gear vs 95' f-body 2.73 gears
Vette pressure table values are higher in all range. But. Vette modifiers are much lower and even have negative values.
F-body modifiers are higher and positive values. What is it for?
Does it mean, that vette has softer shiftings and f-body has rougher shifting?
Why vette pressure is higher but it is gets lower with modifiers. What is the sense of all this?
Vette=high pressure+low modifiers
F-body=low pressure+high modifiers
And as a result pressure is somewhere at about same values. But the way cars gets this values differs. Why?Good question, I can only guess at an answer, and my guess success rate is not good enough for me.

I.E.: the 4L60E line pressures for LT1 Caprices RoadMasters & Fleetwoods do not protect those 4L60Es from enthusiastic driving, at least not for very long.
Only notable exceptions are 9C1-LT1 Caprices and V4P 7000lb tow package Fleetwoods.

Since your car is probably heavier than a 'vette, I'd use the higher base line pressures & carefully study where & when the negative modifiers are applied.
My GUESS is that you can probably safely raise the negative modifiers to zero preemptively with no danger.

[yoheer]

And what if i will apply higher vette pressure tables keepeng f-body positive modifiers?

[yoheer]

Log analysis
Here is highway logs.
Dunno if i'm right but it seems to me lean. Blm ~135
If it is so then what are the next steps?

[LeMarky Dissod]

And what if i will apply higher vette pressure tables keeping f-body positive modifiers?Start slow, make small incremental changes, save your previous version, see what happens.

Were I you, I'd use the 'vette base pressures AND raise all the negative modifiers to zero, based on my experience with several Caprices and a few Fleetwoods …
… but remember that I'm not there testing your car in real time with you.

Your shifts will probably get a bit firmer.

[NomakeWan]

Here is highway logs.
Dunno if i'm right but it seems to me lean. Blm ~135
If it is so then what are the next steps?
Either use the "Analyze" function in EEHack to give suggestions on changes, or export a CSV by clicking the "Main" tab and then clicking "Export CSV" so that you can feed that data into Trimalyzer. Note that in Trimalyzer you must change the default "Trim Input Type" in the upper-right corner to "+/- Percentage" in order to correctly read CSVs from EEHack in Trimalyzer.

Also note that if you have the MAF enabled, you cannot adjust the VE tables. EEHack/Trimalyzer will not give you accurate data for the VE Tables with MAF enabled--they will only be able to give you MAF adjustment data. If you want to tune the VE Tables--and you should if you haven't--then disable MAF mode and start there first. Once your VE tables look good, then switch back to MAF tuning. Or just tune the MAF and see where that gets you, I ain't yer daddy.

[yoheer]

Thank you for the info. This is the only place where I can ask for help. Im trying to do all my best

[steveo]

Dunno if i'm right but it seems to me lean. Blm ~135

remember, a blm of 135 doesn't mean you're really running lean, it just means it was lean for just a moment and the ECM had to add about 5% more fuel to fix it. it's nothing to worry about. that's what closed loop is for. you could add 5% of fuel to that area so next time it doesn't have to adjust.

[JD1964]

To the OP, thanks for posting you factory bin. I snagged it for storage. I had not saved a factory bin from my Z28 PCM before I sent it off to a tuner. I've since been tuning my own stuff but it's nice to have a stock F body bin to look at if I need to. Especially a TA bin because I might be adding the performance mode for transmission stuff.

[steveo]

http://fbodytech.com/tutorials/bin-files/

there are a lot of factory bins here, if you're interested in checking them out for comparison

[yoheer]

I can't figure out with detonation in PE mode.
Main spark table is modified, but it seems to be almost okay.
Extended spark table is stock. Retard @4200 is up to 10 degrees. Commanded afr is really rich in PE. ~12.0 . It should be at least.
Im running 93+ octane. MAF car. No vacuum leaks.
Short eehack log below. (remove ".txt")
any ideas?