Loading up Running rich
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
Loading up Running rich
I have a 85 Corvette I have eliminated the o2 and AC. It has a performance chip
For some reason if i am in traffic or @ idle It wants to load up and run rich. After it Idles for a few when I take off i see black smoke. (and smell fuel)
I am also having issues with it surging @ idle and some times not wanting to idle while in gear. (seems to be more prevelant when the motor is hot)
I dont smell Gas in the oil.
I am thinking EGR? Any Ideas?
For some reason if i am in traffic or @ idle It wants to load up and run rich. After it Idles for a few when I take off i see black smoke. (and smell fuel)
I am also having issues with it surging @ idle and some times not wanting to idle while in gear. (seems to be more prevelant when the motor is hot)
I dont smell Gas in the oil.
I am thinking EGR? Any Ideas?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You can't get into closed loop mode without an O2 sensor.
Your ECM is looking up values for fuel and spark from tables in your chip and guessing. Without going into closed loop mode the ECM can't calibrate the BLM table and will use the default values. You're screwed. It would take a LOT of data logging and tuning to fix this setup in its current configuration.
Your ECM is looking up values for fuel and spark from tables in your chip and guessing. Without going into closed loop mode the ECM can't calibrate the BLM table and will use the default values. You're screwed. It would take a LOT of data logging and tuning to fix this setup in its current configuration.
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
People have run open loop tunes but not without aftermarket wideband o2 sensors (or at least they shouldn't) to make sure it is a solid tune. This is definitely something that will take a lot of iterations and burns to get right.
Why did you eliminate o2 and keep EGR?
Put back the o2
Why did you eliminate o2 and keep EGR?
Put back the o2
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
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Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
I have a 85 Corvette I have eliminated the o2 and AC. It has a performance chip
For some reason if i am in traffic or @ idle It wants to load up and run rich. After it Idles for a few when I take off i see black smoke. (and smell fuel)
I am also having issues with it surging @ idle and some times not wanting to idle while in gear. (seems to be more prevelant when the motor is hot)
I dont smell Gas in the oil.
I am thinking EGR? Any Ideas?
For some reason if i am in traffic or @ idle It wants to load up and run rich. After it Idles for a few when I take off i see black smoke. (and smell fuel)
I am also having issues with it surging @ idle and some times not wanting to idle while in gear. (seems to be more prevelant when the motor is hot)
I dont smell Gas in the oil.
I am thinking EGR? Any Ideas?
Codes?
Other mods?
Injectors ohm tested? hot & cold?
Cold start injector checked/verified not leaking?
Fuel pressure verified?
Is it going into closed loop?
Base timing set correctly?
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
[QUOTE=96GS#007;1581158565]
Data logs? None
Codes? Not a one
Other mods? Nothing but a Cat Converter Test Pipe
Injectors ohm tested? hot & cold? (no clue how to do this)
Cold start injector checked/verified not leaking? (also no cloue on how to test this
Fuel pressure verified? Not yet
Is it going into closed loop? No idea how do i tell
Base timing set correctly? As far as i know but also no clue how to check
Data logs? None
Codes? Not a one
Other mods? Nothing but a Cat Converter Test Pipe
Injectors ohm tested? hot & cold? (no clue how to do this)
Cold start injector checked/verified not leaking? (also no cloue on how to test this
Fuel pressure verified? Not yet
Is it going into closed loop? No idea how do i tell
Base timing set correctly? As far as i know but also no clue how to check
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
[QUOTE=shamdave;1581159349]
Data logs? None
Codes? Not a one
Other mods? Nothing but a Cat Converter Test Pipe
Injectors ohm tested? hot & cold? (no clue how to do this)
Cold start injector checked/verified not leaking? (also no cloue on how to test this
Fuel pressure verified? 42lbs and drops normal after motor is off
Is it going into closed loop? No idea how do i tell
Base timing set correctly? As far as i know but also no clue how to check
I am thinking the EGR Solenoid From Zip
"The solenoid fails at a much higher rate than the EGR valve and typically causes your C4 Corvette to stall, experience rough idle, engine knock and surging or hesitation during acceleration."
Data logs? None
Codes? Not a one
Other mods? Nothing but a Cat Converter Test Pipe
Injectors ohm tested? hot & cold? (no clue how to do this)
Cold start injector checked/verified not leaking? (also no cloue on how to test this
Fuel pressure verified? 42lbs and drops normal after motor is off
Is it going into closed loop? No idea how do i tell
Base timing set correctly? As far as i know but also no clue how to check
I am thinking the EGR Solenoid From Zip
"The solenoid fails at a much higher rate than the EGR valve and typically causes your C4 Corvette to stall, experience rough idle, engine knock and surging or hesitation during acceleration."
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If you removed the air pump and you didn't seal up the Headers, it'll suck air pass the O2 which will then be lean. The ECM responds by dumping a bunch of fuel it doesn't need; ie, it ends up rich. Scan it to see what the Block Learn is. If it's Lean, I'd start at the Headers first if only because that's one thing you've changed. You might make sure that the Check Valves are intact too - air should only flow in the direction of the Headers. To a lesser extent, a vacuum leak does the same thing and these earlier years used vacuum as part of the controls for the Air Pump. Make sure that line was plugged.