Disabled EGR
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?
THEY are NOT Lying to You.
You are NOT Even Lying to Yourself.
You ARE Being Lied to ... by Your SELF.
The Last Psychiatrist, aka ... Alone ...
Technically, 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.
THEY are NOT Lying to You.
You are NOT Even Lying to Yourself.
You ARE Being Lied to ... by Your SELF.
The Last Psychiatrist, aka ... Alone ...
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.
Last edited by In-Tech; 08-26-2021 at 12:34 PM.
-Carl
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.
-Carl
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.
1990 Corvette (Manual)
1994 Corvette (Automatic)
1995 Corvette (Manual)
Well if it is so, then i've disabled it correctly.
What about CAT?
THEY are NOT Lying to You.
You are NOT Even Lying to Yourself.
You ARE Being Lied to ... by Your SELF.
The Last Psychiatrist, aka ... Alone ...
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