Printable View
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
You should probably start by stating what problems you’re actually having so that they can be addressed before wasting time tuning.
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
So, can anybody take a look? Or I need some logs from good working stock car. I will compare.
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.
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
i know from experience that if your brake booster leaks on an fbody, your brakes barely work at all.. but definitely do check it.
Most likely the booster will be ok.
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?
your TPS is at 1%.... why is your TPS at 1%? it wont try to attain your idle target if the TPS is open.
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.
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.
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
Faulty tps.
Fixed.
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.
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.
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.
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
GM uses the following values for vehicles that were never equipped with catalytic converters:Quote:
Originally Posted by yoheer
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.)
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.
Disabled EGR
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?
You can raise the 'CAT Protect Min Coolant Temp'. Anything over 120°C should do fine.Quote:
Originally Posted by yoheer
Technically, disabling & deleting the EGR Valve are two slightly different things.Quote:
Originally Posted by yoheer
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.
What about fuel tables? It should be leaned a little when the egr if opened. In stock
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.
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?
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.Quote:
Originally Posted by In-Tech
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.Quote:
Originally Posted by yoheer
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.
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.Quote:
Originally Posted by In-Tech
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.
Well if it is so, then i've disabled it correctly.
What about CAT?
Asked & Answered.Quote:
Originally Posted by yoheer
Quote:
Originally Posted by LeMarky Dissod
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.Quote:
Originally Posted by LeMarky Dissod
edited aboveQuote:
Originally Posted by NomakeWan
Quote:
Originally Posted by LeMarky Dissod
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.Quote:
Originally Posted by 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?
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).
What about better intake and headers in vette?
Will modifying theese tables take effect in fbody?
And only 1 knock sensor. Detonation?