Scrufdog

Referred here by the moates.net support site

First the info...

1995 Chevy C2500 Suburban 5.7 4L80-E, 16197427 ECM, BNKM, $31


I've had my APU1 hard mounted and hard wired in my 95 Suburban since June 2014. I use it daily to feed my Nexus 7 with ALDLDroid, and to tweak the tune as needed. Yesterday I went to start the Burb and it stalled right out. I restarted it and the idle was high and unstable, check engine light on and sometimes flickering, and when I drove it, it was stuck in second gear, aka Limp Mode.

I tried to pull codes with a paper clip, and no response. ALDLDroid showed Checksum Mismatch when trying to connect.

At that point, I grabbed my laptop and connected to the APU1 with TunerProRT. It connected fine, I read the BIN in the APU1 and it was correct. I reuploaded the current BIN from the saved file, turned off the truck, pulled the ECM fuses for 5 minutes to reset things. and tried restarting... same rough idle, etc...

At that point I shut it down, pulled the fuses, pulled out the ECM and APU1 and plugged the stock chip directly into the ECM. Truck fired right up just fine. I than hooked back up the APU1, and the truck fired up fine, as it should. I drove it around, no problems, and went on with my day. Figured maybe something just needed to be plugged in tighter or something.

Today went to start the Burb, and it wouldnt start at all. I went straight to the ECM, pulled the stock chip off the APU1 adapter, and plugged the stock chip directly into the ECM, everything was fine. I went about my day, it drives ok, but I imagine the BLMs are maxed out.

The only thing I can think is that the past few days it has been pretty hot outside, and maybe the heat is finally getting to the APU1. I've checked all the cables, especially the ribbon cable, and all seems fine. As I said earlier, it was all hard mounted in my dash, no wiggle on the APU1 itself or the cables.

So, basically, it seems the APU1 responds fine to reading and writing the emulated BIN, even when it wont start properly, and the ECM itself is fine.

Any ideas or what might be going on?

I am a professional automotive and industrial technician with multiple certifications and such, which means I can do whatever testing you can think of, including checking things with an oscilloscope.

Thanks

84Elky

The battery chip in the APU could be weak but not dead because you were able to get a BIN from the APU. Call Moates and they will ship new one generally at no charge. Also, if you are using a Zif socket for the cable from the APU to the ECM, make sure the connection is rock solid. Have had problems with this in the past. Remove, reseat and all OK.

Scrufdog

From what I've seen on the moates site I don't think the APU1 has a battery. I know some of his other stuff does. I will check if no other ideas are brought up here.

84Elky

I got 2 battery/clock chips from Moates 3 months ago because my AutoProm would not retain the BIN. Replaced chip and all OK. Battery has a limited life. My AP was approx. 4 yr. old. Programmed on a BENCHMARQ, bc4013YMA-70, 0445-H,4BZ002W. HTH.

Scrufdog

OK. Good info. I was just looking for a more standard looking watch battery.

Scrufdog

Contacted David at moates and he is sending me another chip when they get some back in stock.

Thanks again.