Miss on aftermarket EFI

[clint78z]

I am usually quite good at tracking down things on my Accel DFI. I have a miss at idle and light load can't seem to track it down.

 

Here is what I use for different stuff

370cc injectors with stock FPR

Mustang TB no IAC

ZXT fuel pump with DFI controlled factory wiring and relay

88 chev Electronic spark timing igntion module with case grounded directly

this hooks to stock reluctor.

 

I am usually quite anal about wiring so I will give an indication how I wired the unit. 8 gauge with gold terminal from 12+ve to a gold plated fuse block 50amp fuse (gold). This provides power to ECU, injectors, O2 sensor all hooked together. The switched power for the ECU came from old coil +ve. All grounds come back to common ring terminal, which goes a short distance with 10 gauge to starter ground. If you see problems here please tell me.

 

Weird things I notice is my dfi voltages swings up and down one volt, not sure if that's normal. Also when I turn on my signal light I notice the idle swings up and down more. The noise of the fuel pump seems to change.

 

I am not sure if it's electrical, fuel, ignition. I hate these little intermitant things. I am pretty good with a multimeter. I would like to talk more about ground loops and try to diagnose this problem.

[TOMAHAWKZ]

the voltage drop when you turn on your signal sounds like a ground problem, try checking your grounds for corrosion and make sure where they connect is clean bare metal. also how old is your battery ground cable? they have a bad tendency to hide corrosion inside the strands, white powdery looking stuff evil will cause all kinds of electrical system havoc. remember new feul injection technology uses milli volts and milli amps so they can use smaller wires to save weight in the newer cars, this in turn makes connections of the utmost importance.. let me know what ya find...