So who wants their ECU's "Chromed"?

Just remember that any PIN 35 custom out will create a new "FORK" of code as that code will not be compatible with a 1998 or 1999... Pin 35 is used for the EVAP Vent on the 1998 and 1999 . . . unless it is switchable via the peripheries . . .

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Originally Posted by saiteiman

Just swapped out my ’95 Fed ECU with a ’99 ECU purchased from Brett. Chromed the ECU with V2 and disabled the following bits under Periphery2 as a common procedure for ’95 and earlier models:

bit. 15 P0443, P0446, P0403, P1104, P1105 Solenoids Test – Off
bit. 11 P0135, P0141 P0155, P0161 O2 Heater Test - Off
bit. 10 P1400 MAP Sensor Test - Off
bit. 09 P0403 EGR Solenoid Test
bit. 03 P0136, P0156 Front Rear Secondary O2 Sensor – Off

Now, most of the CELs are gone except P1300 Ignition Timing Adjustment Circuit Malfunction. Not able to find Periphery bit for this CEL. Is this a common problem for a ’95 Fed model?

After everything are ready. Started up the car and got 17-18 A/F ratio during idle and cruise. Logged via EvoScan2.9 on both Front O2 (3E) & Rear O2 (13). Front O2 tends to stay around 0.01952V and fluctuates to 0.03904 if I blip the gas pedal. Rear O2 tends to stay between 0.89792-0.95648V. At the same time, Front O2 (STFT) logged with 12.5% steady and Rear O2 (STFT) logged with -15% steady. Forget about F&R (LTFT) as they both are crazy too.

Re-flashed ECU by disabling Periphery0, bit.02 Dual Narrowband Fuel Bank Trim (basically, front O2 sensor). Now the ECU runs only on the Rear O2 for all 6 injectors. The A/F shows around 13.9 – not too bad. Logged both Front O2 (3E) & Rear O2 (13). Front O2 stays around 0.8xxxxV. Rear O2 now swings between 0-0.9V (perfectly normal).

Before I swapped my ’95 Fed ECU, my A/F ratio stays between 14.6-14.8. In another word, both my O2 sensors are in good shape.
Can someone please help/advice?
Jim

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Jimmy, I sent you a PM reference your car and the above problem.

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Originally Posted by 99 vr4

Just remember that any PIN 35 custom out will create a new "FORK" of code as that code will not be compatible with a 1998 or 1999... Pin 35 is used for the EVAP Vent on the 1998 and 1999 . . . unless it is switchable via the peripheries . . .

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The custom pin outputs use the stock code when switched off and the new code when switched on. I remember this because I wrote it this way to retain the stock functionality. :p

Jimmy, I verified your VIN. Your car is a FED spec car. P1300 is not a valid DTC for this platform. Are you logging this DTC with EVOScan 2.9? Please download EVOScan v2.6 and check the DTC with the older version. The newer version does not report the DTC correctly. We are trying to get this fixed but this is an EVOScan issue.

Also can you please tell me what bits 13 and 14 are set to? These should be off. If you change the bits, you will need to use EVOScan v2.6 to check and CLEAR any DTC's.

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Originally Posted by Greg E

Did I give you V2? I don't recall seeing you on the donation list.

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I downloaded directly from your website. Just donated, please verify;)

Yeah evoscan 2.9 is messed up with reading DTCs. If you try to read them even when the CEL isn't on, it'll still show you erroneous codes. I've given Hammish a heads up with this but haven't heard back. :(

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Originally Posted by saiteiman

I downloaded directly from your website. Just donated, please verify;)

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Got it! Thanks man.

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Originally Posted by 99 vr4

Jimmy, I verified your VIN. Your car is a FED spec car. P1300 is not a valid DTC for this platform. Are you logging this DTC with EVOScan 2.9? Please download EVOScan v2.6 and check the DTC with the older version. The newer version does not report the DTC correctly. We are trying to get this fixed but this is an EVOScan issue.

Also can you please tell me what bits 13 and 14 are set to? These should be off. If you change the bits, you will need to use EVOScan v2.6 to check and CLEAR any DTC's.

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I'm logging DTC via Matco OBD2 scanner, not from EVOSCAN2.9.
Periphery0, bit13 off, bit14 on.
Periphery2, bit13 on, bit14 off.

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Originally Posted by saiteiman

I'm logging DTC via Matco OBD2 scanner, not from EVOSCAN2.9.
Periphery0, bit13 off, bit14 on.
Periphery2, bit13 on, bit14 off.

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Ah okay! I question the accuracy of that device too. I can say this with a lot of confidence, if you don't see the DTC in the peripheries, its not used in the code. Best to use evoscan 2.6 for reading and clearing codes.

You should also turn bit 13 off in periphery 2. Your periphery 0 setup is correct.

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Originally Posted by Greg E

Ah okay! I question the accuracy of that device too. I can say this with a lot of confidence, if you don't see the DTC in the peripheries, its not used in the code. Best to use evoscan 2.6 for reading and clearing codes.

You should also turn bit 13 off in periphery 2. Your periphery 0 setup is correct.

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Okay, just turned off bit 13 in periphery2 and observed the following symptom:
Now the A/F goes up to 17-18 with F.O2 (3E) at 0.0xV & R.O2 (13) at 0.8xV. At the same time, F.O2 STFT is at -15.xx% and R.O2 STFT at 12..5%.
A moment later, A/F goes down to 11 with F.O2 at 0.9xV & R.O2 at 0.0xV.
It is apparent that both front & rear O2s don't agree to each other.