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Thread: Chrome ECU 2x Wideband logging and Fan Control

  1. #1
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    Chrome ECU 2x Wideband logging and Fan Control

    Hello everyone!

    I'm looking into datalogging my 2nd Wideband with Chrome and Evoscan and also did run into an issue with converting to ECU controling radiator fans, they never engage.

    1991 GTO.
    MAF-T + 3"GM MAF,Denso C.O.P, 15G Turbos, 550 RC Inj, Prophane+Buthane injection, Jester ECU with Chrome for 91+GTO, full car rewire.

    Being a GTO it only had 1x NBo2 which was wired into the rear NBo2 (Pin76 ). I got myself one Wideband with WBo2 + NBo2 output and replaced the stock NBo2. So far so good, wired into pin76 and pin55 of the jester ECU and I can see NBo2 and WBScaled logging in EVoscan.

    Now I got a second WB, welded bungs at the "precat" Downpipes (empty pipes on a gto, right after the Turbos going down to the downpipe) and plugged the default o2 spot. Wired the second NBo2 output to the pin75 for NBo2 front.
    Changed peripherals and can see the front NBo2 in Evoscan.

    But where do I put the second WBo2 so I could log it?
    Obviously pin 54 is for a MAP sensor (which I don't utilize). All the other custom pinouts are not scaled, just triggered? I though about using the pin54, set the scale as good as possible (can't set 20, only 20.1) and change the name conversion in evoscan to AFR? but now the output is 16afr when it should be 20 in evoscan (Gauge and swapping sensors will say 20 afr when engine is off). guess I need to play with the strange string in the definitions table?

    Is there some dedicated pin for a second WB I could use? Or is the MAP pin my only way, and if yes - could I get it to work in evoscan with just copy pasting the string from the WBscaled field?


    My Sensor at the radiator got faulty and I thought now it's time to get chrome to do it's job, plugged the sensor at the radiator. removed sensor wires and connected the radiator fan relay grounding pin to pin 53 in Jester.

    I rewired the fans, basically both run together and I want only one speed settings (full). Resistor is gone too.

    Now When I toggle the switch grounding the relay, the fans run.
    When I toggle the actuators in EVOSCAN the fans do run, depending on how I hooked them up (low,high or spliced into both).
    But when I let my car run the fans never activate at all. Tested and let my temp raise to over 105C(!) and fans didn't activate, tried to wire to low,high and both pins and no fans starting, no relay clicking.

    Even unplugged the pin and measured impedance on the pins on the ecu.

    Actuator test: impedance get's close to zero at the pin to ground. .
    Temp around 60C when the car is warming up, impedance is high but not 100% capped at both pins.
    Temp around 100C when the car is hot, impedance is high but not 100% capped. at both pins.(Stock temp tables)

    Now I see TEMP in EVOSCAN it moves from 30C to whatever and updates pretty fast when I activate the fans with the switch, I also put in a new sensor by the thermostat housing. So I can rule out that the Jester doesn't see temp?

    I played with the fan temp tables because I wanted to achieve "low speed" to engage sightly earlier and keept the gab in mind) - so I assumed I did something wrong, but even when loading up stock settings, nothing.

    Fans don't turn on

    Any idea why? Relay related maybe? Should I switch ground and +12v pin 85 and 86 supply?
    Also is it the best practice to just splice the wires for both pins, or should I wire in just "high"? (I'm not sure if low pin disables and just high keeps grounded at a certain threshold or both are on?

    Do I need to activate something i overlooked in the chrome pheri?

    Last edited by enkaio; 05-31-2019 at 03:47 AM.

  2. #2
    I lack color... verified
    Feedback Score 1 (100%) Greg E's Avatar
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    For the wideband, I only coded one input. There are only so many inputs and multiple demands for them so only one WB input was setup. Unfortunately copy/pasting the values from the MAP input will not work.

    As for the fans, the ECU hardware side isnt my forte and its been about 8 years since I looked at the setup for it but I vaguely recall Adam telling me the ECU triggers a ground for all the relays and solenoids. Not power. Meaning you have ignition power going to the trigger relay and from that to the ECU pin.

    I would confirm this with the 3000GT wiring diagrams before taking that on my word.

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    Thanks Greg.
    I will try mess with the map abit more, if it's just offset but linear, I might be able to correct the logs with a Formular later. (and cross verify that it actually has sane values - switching front and rear sensor). If it doesn't work out, it's no big issue to me. Might look into ldbc or use other means to log it directly.

    Doing a full rewire of the car spread across 8 months might did confuse me at some parts. Maybe it's really that simpel and I accidently switched power and ground. Thanks for the push I will go back and look into the oem circuit.

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    Concerning the FANS.
    Experimented with EVO Scan actuator tests and LOW Fan pin is activated with High FAN Speed. So basically for me - I just take the low pin no need to splice into the high.

    I did was to take out the relay and manual bridged the pins of the relay. Tried to switch the relay pins for the control circuit 85 and 86 (just in case it would have an undocumented diode in there, chinese make is always full of suprises), tried (even thought it makes no sense) to ground pin85 and having pin86 just connect to the ECU. so basically ground - ground. Nothing.

    Basically putting all back like it was.

    Set the LOW and high speed tables in chrome to 188F (87C) to enable, disable at 175F(79C) . Fan started turning at 202F (94C ) and turned off at 185F (85C). (Measurement taken from evoscan logging - so what the ECU actually sees). Tried it another 5 times and it works, still confused why it turns on at such a random number - aaaand even turns on at all in contrary to before (and worried if it would later at higher temps turn off suddently).

    So keeping my fingers crossed for now.
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    Thermal Engineer- Mmbr Since:8/2005 verified Feedback Score 0 Alex3000gt's Avatar
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    Sounds like progress man, nice!


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