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Hi, so I've just installed a chromed ecu from jester and for some reason all 4 of my oxygen sensor heaters do not work. I keep getting the same 4 check engine codes for them. I've already checked all the wiring and replaced the MFI relay in hopes to remedy the problem. Nothing has worked so far.

I know Jester chrome ECU is able to wire in an AEM wideband signal, and then its scaled in EcuFlash so the computer understands the inputs. I have a 1994 cali base model, and it says to tap into pin 77 for the wideband 5v signal.

Only problem is pin 77 is one of the wires for my oxygen sensors, and the connector has a wire in that spot. Also, there is no option available in EcuFlash to connect/ scale in a wideband signal anywhere.

I've searched everywhere and have been testing all the electronics in my car but cannot find any answers. I've also talked with Adam from Jester but I haven't gotten a solid answer. If I can input the wideband I can just disconnect all of my other sensors and run off the aem one and the car would run great again.

Any help is appreciated. I know creating new threads is annoying, but I couldn't seem to find any answers.
 

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Hi, so I've just installed a chromed ecu from jester and for some reason all 4 of my oxygen sensor heaters do not work. I keep getting the same 4 check engine codes for them. I've already checked all the wiring and replaced the MFI relay in hopes to remedy the problem. Nothing has worked so far.

I know Jester chrome ECU is able to wire in an AEM wideband signal, and then its scaled in EcuFlash so the computer understands the inputs. I have a 1994 cali base model, and it says to tap into pin 77 for the wideband 5v signal.

Only problem is pin 77 is one of the wires for my oxygen sensors, and the connector has a wire in that spot. Also, there is no option available in EcuFlash to connect/ scale in a wideband signal anywhere.

I've searched everywhere and have been testing all the electronics in my car but cannot find any answers. I've also talked with Adam from Jester but I haven't gotten a solid answer. If I can input the wideband I can just disconnect all of my other sensors and run off the aem one and the car would run great again.

Any help is appreciated. I know creating new threads is annoying, but I couldn't seem to find any answers.
You need to turn off the O2 monitors in the peripheries. Kinda figured that would already have been done if the ECU was listed as being for that car... the 94 O2 sensors heaters are not controlled or monitored by the ECU, so it's setting codes because they aren't there...

You also need to confirm that yours is specifically for a Cali car... The O2 sensors on 94-95 Cali cars are wired backward of Fed cars.
 

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Discussion Starter #3
I did see that option in the peripheries, thought that would only turn off the check engine light but I'll switch them off next time i get the chance. The car still runs a little weird off the two narrow band sensors, which is why I wanted to go off the wideband, which would be better for tuning anyway.

And on the Ecu, the sticker does say 94-95 SL Cali spec. 94-97vr4 and 96-97 SL. Although when I connect to ecu flash in the first box that identifies the car it says 1998 3000gt SL. Not sure if that's generic or not
 

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I did see that option in the peripheries, thought that would only turn off the check engine light but I'll switch them off next time i get the chance. The car still runs a little weird off the two narrow band sensors, which is why I wanted to go off the wideband, which would be better for tuning anyway.

And on the Ecu, the sticker does say 94-95 SL Cali spec. 94-97vr4 and 96-97 SL. Although when I connect to ecu flash in the first box that identifies the car it says 1998 3000gt SL. Not sure if that's generic or not
You won't get it to run any better or different with simulated signals from a wideband controller... The ECU doesn't know the difference.

What are your fuel trims doing? Are they taking off in different directions? I would definitely follow up on determining if it is identifying the O2 sensors correctly.
 

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Discussion Starter #5
You won't get it to run any better or different with simulated signals from a wideband controller... The ECU doesn't know the difference.

What are your fuel trims doing? Are they taking off in different directions? I would definitely follow up on determining if it is identifying the O2 sensors correctly.
I'll definitely check to see if its seeing the o2 sensors. That might just be my problem.

I haven't checked my fuel trims yet. When the car is started on cold start, it'll run to roughly 14.5 afr for a minute but then drop to around 11.5-12.5 afr. last time I really drove it, the readings would only steady out when the car was hot.
 

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I'll definitely check to see if its seeing the o2 sensors. That might just be my problem.

I haven't checked my fuel trims yet. When the car is started on cold start, it'll run to roughly 14.5 afr for a minute but then drop to around 11.5-12.5 afr. last time I really drove it, the readings would only steady out when the car was hot.
If it's in closed loop, you need to just ignore the wideband... The ECU is controlling the mixture, and the fuel trims are where you need to look to see if that's in line.

The wideband will always read 14.x as the sensor is warming up... Once it warms up and starts moving, then you can believe what it says. Cold start is always commanded rich, and tapers off to stoich as the coolant temp warms up. That's normal behavior.
 
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