Digital inputs 1-5 not working | AEM
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digitalsolo
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Digital inputs 1-5 not working

So, working on tuning my car and I've discovered that my digital inputs don't appear to work. It's an Infinity 10 on a Coyote with a custom harness.

I have the intake cams on Digital 1 and 2 (C1-22 and 23) and the flex fuel sensor on Digital 5 (C1-26). I have them wired with 12V (Batt+, switched from the ECU relay via my digital PDU) which matches the ECU adapter harness pinouts from Ford/AEM.   All of them show zero feedback in InfinityTuner software. Firmware is 96.1. 

Anyone have any suggestions? Maybe I'm an idiot... everything else on the ECU appears to work fine (other than my boost control solenoid, but I don't think that's related).    It's problematic because the VVC feedback for the intake cams can't function without sensors, and I'd really like to get my flex fuel content sensor working.

AEM_SB
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Joined: 06/07/2014 - 14:29
Those are pretty simple

Those are pretty simple circuits. Each pin uses a separate transistor chip, so it's unlikely for all three transistors inside to fail at the same time.  The transistor basically tells the ECU's processor if the input is above or below a trigger threshold, going from memory I think that's about 1.0V.  If the signal voltage is always below 1.0V  or always above 1.0V (but never crosses) due to ground offsets between the ECU and sensor, that could cause the problem you're describing.

Hope that helps,

SB

digitalsolo
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That's very useful.   I'll do

That's very useful.   I'll do some testing, I may just have to scope it and see exactly what the outputs are doing.    I'm glad to hear these are separate channels;  I'll dig into it more.   Thank you for the insight.

digitalsolo
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So, I've done some testing

So, I've done some testing and I have cam sensor bank 2 (C1-23) working, and I've validated that reads on C1-22 work (I moved sensor connector from C1-23 to C1-22 to test).   Apparently my sensor on intake cam bank 1 is bad, wiring tests good and ECU is working.   That's good news.

Flex Fuel input is still causing my headache.   I've validated I have 12V IGN at the sensor, and ground.   I'm getting power from my chassis digital PDU (ECUMaster PMU16) which is enabled (for this output) by the AEM relay control output (PMU feeds injectors, etc. as well, on multiple sets of outputs).  Power is clean and >12V and my battery is fresh and well charged.   When I initially prime the pump, I see a brief "blip" of data in InfinityTuner on Digital 5, with a random number, generally around 30-90 for a second or two, which then goes away and it sits at zero as soon as the car starts.   I have validated that the 12V and ground are solid and consistent in accessory/prime, crank and run.

I've tried the following:
2x brand new sensors, one from an autoparts store and one from GM
1x tested good sensor pulled from a friend's working car (his car is a ProEFI Pro128)
New power wire
New ground wire
New lead from ECU to flex fuel sensor
Moved (new) lead to Digital 4 instead of 5 and reconfigure wizard for Digital 4.

No change in behavior.   I'm pretty confused on this one as this should be a "just works".  :(    I'm clearly missing something, but I'm about out of ideas.

All tested sensors are the newer style Continental sensor that look exactly like the one AEM sells.   I'm going to design an Arduino circuit to read the sensor shortly and validate 100% that the sensor works, but I mean, they work in a friend's car, so it would be weird that they just don't like my trunk.  :)

Appreciate any direction that can be given, this (and 1x more cam sensor) are about the last things not working in my build at this point.

AEM_SB
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Joined: 06/07/2014 - 14:29
Very interesting. Have you

Very interesting. Have you tried tapping the signal wire directly to ground and watching the ECU software to see if it registers? Some old batches of 30-7101 ECUs had digital input circuits that triggered at a very low voltage threshold, possibly 0.5 V or lower.  If you have one of those ECUs our repairs department can modify the circuit so it should work better with most signals. Post your serial number or email it to InfinitySupport@aempower and I can check it.

digitalsolo
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Joined: 12/28/2016 - 08:31
Weird.  I replied to this and

Weird.  I replied to this and it disappeared.   At least I thought I replied.   Anywho.

This is a replacement that I received in May, after I sent my old one in for repair for some issues.   Serial: 7107-0013

Thanks!
Blake

AEM_SB
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That's a pretty old ECU build

That's a pretty old ECU build, very low serial number. The voltage threshold is around 0.5V, possibly a bit lower depending on the transistor temperature. We've heard of others having trouble with that hardware and flex fuel sensors, probably best to contact the tech guys for an RMA and send it in.  If you're skilled at soldering small surface mount components and want to save some shipping time/cost you can email InfinitySupport(at)aempower(dotcom) for a copy of the hardware update instructions.

digitalsolo
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Joined: 12/28/2016 - 08:31
Oof, so I need to pay again

Oof, so I need to pay again to RMA the unit that I paid to RMA like 6-8 weeks ago because the replacement I was sent back (my original was replaced because it was too old and had some type of unidentifiable issues with DBW and other systems) is too old to function properly with my flex fuel sensor?    Seriously?!?!?

I appreciate the insight into the issue, so don't get me wrong, but I'm not thrilled to be spending 100/month to try and hope I get an ECU that works.   It's a bit frustrating.   I'm capable of surface mount solder work, but I don't know if I want to risk a ~$3000 ECU to that skillset.

digitalsolo
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As an update to this, AEM is

As an update to this, AEM is updating the ECU to hopefully resolve the issue with the digital inputs.    I'm optimistic this will clear up the issue and I can get the flex fuel sensor working.    Hopefully this is the end of my weirdness with the digital inputs.