I'm using an Innovate Motorsports LC-2 wideband and when I compare the fuel error between it and the IEGOs, they seem to move in opposite directions. When I adjust fueling based on the IEGO error, both improve so it seems like my wideband error calc is inverted. I looked at the definitions and they seem to be correct.
I am running open loop in idle as the HEGOs seem to go cold at idle.
Wideband and HEGOs behaving opposite
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danielt
- Posts: 16
- Joined: 2021 Mar 16, 22:26
- Location: McKinney, TX
- Vehicle Information: 1990 Ford Mustang 5.0LX Convertible
5-speed, stock drivetrain
Wideband and HEGOs behaving opposite
- Attachments
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- 2026-0716 drive 3 - autozone.xdl
- (183.02 KiB) Downloaded 1 time
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- cobra_20260716_mod1.bin
- (56 KiB) Downloaded 1 time
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danielt
- Posts: 16
- Joined: 2021 Mar 16, 22:26
- Location: McKinney, TX
- Vehicle Information: 1990 Ford Mustang 5.0LX Convertible
5-speed, stock drivetrain
Re: Wideband and HEGOs behaving opposite
Missing build information:
B302 30lb injectors
Pro-M 75mm bullet MAF with 24lb calibration
stock shortblock
B303 cam
GT40- 306X (58cc) heads
1993 Cobra intake
Equal length mid length headers (Factory Five Cobra side exhaust)
HEGOs mounted in collector on both sides, LC2 is mounted in collector on passenger side and tied into EGR
B302 30lb injectors
Pro-M 75mm bullet MAF with 24lb calibration
stock shortblock
B303 cam
GT40- 306X (58cc) heads
1993 Cobra intake
Equal length mid length headers (Factory Five Cobra side exhaust)
HEGOs mounted in collector on both sides, LC2 is mounted in collector on passenger side and tied into EGR
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decipha
- Posts: 6953
- Joined: 2021 Feb 15, 12:23
- Location: Metairie, LA
- Vehicle Information: Work Truck
'25 F-150 5L
Re: Wideband and HEGOs behaving opposite
Im not going to get any free time anytime soon to take a look at the log but...
how much pipe do you have after the o2s ?
wideband is useless for idle and should only be referenced at half throttle on up. Anything below that especially idle its not uncommon for the wideband to be wrong, usually reporting falsely lean.
If the wideband reports rich at idle then id suspect the o2s cannot control fuel properly.
Being a fox ecu are you sure your hego enable ground reference is secured to a clean bare ground?
how much pipe do you have after the o2s ?
wideband is useless for idle and should only be referenced at half throttle on up. Anything below that especially idle its not uncommon for the wideband to be wrong, usually reporting falsely lean.
If the wideband reports rich at idle then id suspect the o2s cannot control fuel properly.
Being a fox ecu are you sure your hego enable ground reference is secured to a clean bare ground?
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danielt
- Posts: 16
- Joined: 2021 Mar 16, 22:26
- Location: McKinney, TX
- Vehicle Information: 1990 Ford Mustang 5.0LX Convertible
5-speed, stock drivetrain
Re: Wideband and HEGOs behaving opposite
Thanks Decipha for the guidance!
There is about 5-6 feet of pipe after the collector. About 10-12 inches then a large radius 90 degree bend, then another 4 feet, of which most is a straight through glasspack muffler. It is loud!
Yes, when in closed loop, the O2 feedback was dead lean driving lambse down until the engine flooded, especially when cold. Setting it to OL at idle per the Tuning Tips section fixed that up nicely.
I double checked the grounds for the harness. It's a Ford Motorsport engine harness (M-12071-A50). I see 2 grounds in the wiring harness:
- System ground connected directly to battery, per the wiring schematic this is the ground used for the HEGOs through pin 49 on the EEC
- Pin 4 in the 8 pin body harness - this is for grounding the ECM case and the shielded wires leading to the TFI Module.
I'll also go back through the grounds for the Wideband since it is on it's own wiring harness.
I appreciate the advice on wideband at idle. Since both were giving inconsistent readings at idle, I tuned the fuel to where it seemed happiest by adjusting the low slope slightly. You had a history table that shows fuel correction vs. imaf vs. Pulse width and i notice all the readings below 2.5ms were consistent, so seemed easiest to just adjust the low slope. What was most interesting. As I increased the low slope up, which should reduce fueling, the HEGOs went from permanently at zero V to now being .5-.8V and the wideband went from .72 to .78 Lambda. My theory is that as I'm leaning the fuel mixture out, the exhaust is now hot enough to get the narrow bands to operate.
Hope you are staying busy with friendly and paying customers! Have a blessed and safe weekend.
There is about 5-6 feet of pipe after the collector. About 10-12 inches then a large radius 90 degree bend, then another 4 feet, of which most is a straight through glasspack muffler. It is loud!
Yes, when in closed loop, the O2 feedback was dead lean driving lambse down until the engine flooded, especially when cold. Setting it to OL at idle per the Tuning Tips section fixed that up nicely.
I double checked the grounds for the harness. It's a Ford Motorsport engine harness (M-12071-A50). I see 2 grounds in the wiring harness:
- System ground connected directly to battery, per the wiring schematic this is the ground used for the HEGOs through pin 49 on the EEC
- Pin 4 in the 8 pin body harness - this is for grounding the ECM case and the shielded wires leading to the TFI Module.
I'll also go back through the grounds for the Wideband since it is on it's own wiring harness.
I appreciate the advice on wideband at idle. Since both were giving inconsistent readings at idle, I tuned the fuel to where it seemed happiest by adjusting the low slope slightly. You had a history table that shows fuel correction vs. imaf vs. Pulse width and i notice all the readings below 2.5ms were consistent, so seemed easiest to just adjust the low slope. What was most interesting. As I increased the low slope up, which should reduce fueling, the HEGOs went from permanently at zero V to now being .5-.8V and the wideband went from .72 to .78 Lambda. My theory is that as I'm leaning the fuel mixture out, the exhaust is now hot enough to get the narrow bands to operate.
Hope you are staying busy with friendly and paying customers! Have a blessed and safe weekend.