Chrome user having major issues and out of ideas!

[Jimvr4]

Not the FPR because your symptoms change simply by disabling closed loop

[Jimvr4]

From my Chrome Tuning Experience thread:

If I'm not wrong the right bank is 1,3,5 and the left is 2,4,6. So according to the service manual my 1995 harness has:

Front (O2 housings)
Right bank - pin 75
Left bank - pin 76

Rear (O2 in downpipe)
Right bank - pin 60
Left bank - pin 79

According to what I can find the 99 ECU needs:
Front (O2 housings)
Right bank - pin 72
Left bank - pin 71

Rear (O2 in downpipe)
Right bank - pin 74
Left bank - pin 73

I currently have pin 71 wired to 75 and 72 wired to 76 so these are backwards. The downstream sensors are wired OK already.

[twinspoolin94]

From my Chrome Tuning Experience thread:

I have a Jester ECU and original harness though, so if there is an issue it will be inside the ecu related to the jumpers right?

[Jimvr4]

Yes it would. In the electrical schematics for a 96 (both turbo and non-turbo) car I find the following. Note the O2 sensor heaters all have individual wiring unlike my 95 where they are hardwired to a single pin.

Right bank is 1,3,5 and the left is 2,4,6

Front (O2 housings)
Right bank - pin 75, heater - pin 35
Left bank - pin 76, heater - pin 34

Rear (O2 in downpipe)
Right bank - pin 73, heater - pin 43
Left bank - pin 79, heater - pin 42

According to what I can find the 99 ECU needs:
Front (O2 housings)
Right bank - pin 72, heater - pin 4
Left bank - pin 71, heater - pin 3

Rear (O2 in downpipe)
Right bank - pin 74, heater - pin 27
Left bank - pin 73, heater - pin 26

For the jumpers to work properly I believe they have to take into account both the sensor and the heater wiring. At least the heaters all have to be hooked up and I'm not sure what logic the ECU uses to decide whether to enable them. I do know there is a test mode that can be disabled in the Peripheries. You definitely want to do that.

I wonder if the heater wires are hooked up properly. Without that the O2 readings are worthless. And based on your results with closed loop I'm leaning to this as the cause.

[twinspoolin94]

Yes it would. In the electrical schematics for a 96 (both turbo and non-turbo) car I find the following. Note the O2 sensor heaters all have individual wiring unlike my 95 where they are hardwired to a single pin.

Right bank is 1,3,5 and the left is 2,4,6

Front (O2 housings)
Right bank - pin 75, heater - pin 35
Left bank - pin 76, heater - pin 34

Rear (O2 in downpipe)
Right bank - pin 73, heater - pin 43
Left bank - pin 79, heater - pin 42

According to what I can find the 99 ECU needs:
Front (O2 housings)
Right bank - pin 72, heater - pin 4
Left bank - pin 71, heater - pin 3

Rear (O2 in downpipe)
Right bank - pin 74, heater - pin 27
Left bank - pin 73, heater - pin 26

For the jumpers to work properly I believe they have to take into account both the sensor and the heater wiring. At least the heaters all have to be hooked up and I'm not sure what logic the ECU uses to decide whether to enable them. I do know there is a test mode that can be disabled in the Peripheries. You definitely want to do that.

I wonder if the heater wires are hooked up properly. Without that the O2 readings are worthless. And based on your results with closed loop I'm leaning to this as the cause.

I did some reading on your thread, the real long one, pretty interesting but some of it is over my head. I see you are running a different flash ecu than I am. With the Jester ecu there is no adapter harness. The harness that hooks to the ecu is the original harness the car came with. So if there is a problem with the hookup it would be inside the ecu itself and that is one thing I am unclear of is how the jumpers should be set up. moving the one jumper required to switch from fed to cali (how it should be set and how it is shown on jesters website) gives me opposite lock on the o2's and didnt seem to help the issue? ill see if I can get in touch with him agian and see if he has any ideas.

[Jimvr4]

I see you are running a different flash ecu than I am. With the Jester ecu there is no adapter harness. The harness that hooks to the ecu is the original harness the car came with. So if there is a problem with the hookup it would be inside the ecu itself and that is one thing I am unclear of is how the jumpers should be set up. ill see if I can get in touch with him again and see if he has any ideas.

Yes, I am aware the Jester ECU does the switching internally. There are 4 O2 signals and 4 heater signals and probably other differences between years so I'm not sure how 7 jumpers handles everything that is needed. The heaters may be overlooked because they are not individual wires on 91-95 cars. Only the 96-99 years have individual heater wires and obviously the 98/99 years need no changes there.

I wonder if anyone with a 96/97 has had success with the Jester ECU. Or I could be completely full of crap and the problem is in your car with your harness or sensors.

[twinspoolin94]

I am wondering the same thing now, it makes sense when you think about it. ill try to disable the 02 heater functions and see if that makes a difference. Any 96 VR4 Jester ecu users now is a great time to chime in!

This would also explain why the car seems to run ok when the car is cold but gets worse as it gets warmer

[twinspoolin94]

One thing I have that would help me test this theory is a 96 to 95 ecu converion harness with safc 2 pigtail on it from when I was running a hybrid setup. I would need to do some work on the harness to remove the safc extension and ensure all the o2 wires were correct but I could set the flash ecu up to run as a 95 federal spec.

[Jimvr4]

I'll try to disable the 02 heater functions and see if that makes a difference.

I don't think you mean that. The O2 heaters MUST be running or the sensors will not work properly. I think only the diagnostic test is disabled by the periphery.

[Chris@Rvengeperformance]

its not the fpr...