no datalogger connection and No start

[DongeR]

This happened about a week ago while I was on my way to a buddies place. I saw that the gas light was on and it went on about 1/8 above the "E" mark and I decided to get fuel. I was literally 10 feet from the pump and the car died. I was like "oh hell" and decided to crank it up because I didn't want to push it ten feet. No start and the logger read 17 volts on the alternator so I didn't want to chance it. I pushed it up ten feet to the pump, put 5 gallons of gas into it and rolled it back and called AAA for a tow. Called my friend up at Winchester Auto and he got me another alternator that day and exchanged it with warranty. I upgraded the power wire of the alternator to a 0/2 gauge and added an extra ground from the alternator tensioner (4 gauge).

I can't get a connection with the logger to the ecu. All I get on MMCD is Serial Comm Error and on Pocket Logger, a corner with the X. I tried the palm on another VR-4 and it works fine. I swapped ECU's and still no connection to the logger and still no start. (maybe two bad ecu's?)

I checked the voltage on the ECU harness side with the key in the ON engine off position (KOEO) and this is what I found:
Pin 3 - Turbo meter (pressure gauge) - 10.3 volts
Pin 18 - Vehicle speed sensor - 4.7 volts
Pin 23 - Power supply for sensors (5volts) - 0.12 volts
Pin 56 - Control relay (Fuel pump control) - 11.23 volts
Pin 62 -Purge control solenoid valve - 11.26 volts
Pin 64 - Engine warning light - 11.28 volts
Pin 66 - MPI Control relay - 11.29 volts
Pin 103 - Power supply for backup - 11.17 volts
Pin 109 - Ignition pulse detect-Fuel Pump Control - 11.20 volts
Pin 110 - MPI Control Relay - 0.17 volts

Now with the Key out, I checked for continuity and this is what I found.
Pin 1 and 13 are connected
Pin 17 and Pin 24 are connected
Pin 104 are connected with 101, 108 and 106.
Pin 106 and it is connected to 107
Pin 108 is connected to all except 105 and 109
Pin 51 are connected together with 52 and 60 and 61.
Pin 62 and 63 are connected.

So basically, I'm stuck. I have no idea where to go from here..
does everything above look like its functioning or the correct values. There is a slight voltage drop due to having the battery in the trunk.
HELP!!!!

 

[steve]

I checked the voltage on the ECU harness side with the key in the ON engine off position (KOEO) and this is what I found:
Pin 3 - Turbo meter (pressure gauge) - 10.3 volts
Pin 18 - Vehicle speed sensor - 4.7 volts
Pin 23 - Power supply for sensors (5volts) - 0.12 volts
Pin 56 - Control relay (Fuel pump control) - 11.23 volts
Pin 62 - Purge control solenoid valve - 11.26 volts
Pin 64 - Engine warning light - 11.28 volts
Pin 66 - MPI Control relay - 11.29 volts
Pin 103 - Power supply for backup - 11.17 volts
Pin 109 - Ignition pulse detect-Fuel Pump Control - 11.20 volts
Pin 110 - MPI Control Relay - 0.17 volts

That fact that you were measuring 0.17v on pin 110 is interesting you should be seeing battery voltage when the key is in the RUN position. Not so interesting if the key was in ACC.

You should be measuring 63 or 66, 102 or 107, and 103. At the MPI relay pins 3, 4 or 5, 8 and 10 are interesting initially and 2, 7 and 9 when the car is cranking. You should also be watching to see if the CEL turns on during bulb check and if the boost gauge moves.

All this tells me is that the ECU isn't turning on but not why.

 

[DongeR]

with the help of quasimondo, he helped me figure out it was another bad ecu.

I had another ecu that went bad without it even having the car in the start. The third ecu worked like a charm.

what should I do about pin 110?

thanks for helping.

 

[steve]

If the car started I think you'll find that pin 110 is now measuring correct. It can't work otherwise.