Injuneer

Here’s a way, from Shoebox to see if Opti signals are reaching the PCM, and being sent to the ICM (white wire in the ICM connector):

4th Gen LT1 F-body Tech Articles

The second part is a check to see if the PCM is providing the correct voltages to the power wire and signal wires. If the Petris Opti has a permanently attached harness (no harness connector), you have to check at the gray connector on the bracket on the passenger side of the intake manifold.

If aIf the voltages from the PCM are OK, then you need to check for the signals from the Opti. That can be done while cranking the engine. Best way requires a small oscilloscope, but can also be done using the AC voltage function on a multimeter.

scope513

The harness to opti isnt fixed to the opti.
https://petrisenterprises.com/collec...32075760992310
This is the exact kit I installed. The details is what sold me. Ill have to check the voltage when my multimeter gets here tomorrow. I saved that link you sent for testing values. I just wish my obd2 would connect so I can scan for codes. Thanks again (Fred I assume from other threads I've read).

scope513

Getting the correct readings, except for voltages on opti A and B. No dc voltage to them.

scope513

So im thinking theres a bad ground somewhere.

Injuneer

Did you measure key on, the PCM end of the harness connector, between pin A (5V, red/black wire) and pin D (ground, pink/black wire). Ditto pin B to pin D?

scope513

I measured with it grounded to battery key on, I will connect those pins tonight or tomorrow (its cold in ohio). Should be on ac scale correct? Also out of curiosity I checked fuel pump relay and when I got the carpet pulled back I noticed a white wire on the left side checked voltage to see if it was a live or dead wire, i got 12v dc going through it. The owners son before me did have a neon underglow setup that he took off. Maybe its the power wire that fed it? Pic below.

scope513

DrewHMS97SS

Not having power to either the feed or coil side would prevent the pump from being able to run.

scope513

Is there any info on which wires on the relay connector and what their voltage should be?

Injuneer

All voltages on the Opti connector are DC. You need to measure the A and B voltages using pin D in the connector as the ground. All those wires come from the PCM.

The fuel pump relay wiring is shown in the 1996 factory service manual I linked in post #4. Can be hard to locate. Normally I would access the manual from my laptop PC and provide wire colors and volts, or at least the page #. But I'm not at home right now. I can’t access it until tomorrow around noon time. You can’t reference the diagram for the earlier years, like the 95 diagram on Shoebox because in 96 they switched from a 4-wire relay to a 5-wire.

Injuneer

1996 Factory Service Manual - Page 6E-457. Note, there should also be a schematic in section 8A - Electrical Diagnosis, but it is missing from the downloadable copy.

There are 5 wires attached to the relay:

Pin 87A - red wire - 12 volts from the fuel pump prime connector, only when a power wire is attached to the prime connector

Pin 87 - orange wire - 12 volts from fuse #3 (PCM BAT) in instrument panel block, hot at all times

Pin 86 - black/white wire - ground from chassis ground G110

Pin 30 - gray wire - 12 volts to fuel pump, only when prime connector is powered, or if PCM is supplying 12 volts to relay

Pin 85 - dark green/white wire - 12 volts from the PCM, but only if the PCM detects the "fuel enable" signal (part of VATS) from the BCM, and detects low res pulse signal from the Opti

No white wire.

scope513

Could have been the corroded terminals on underhood fb.

scope513

Or the jacked up after market alarm install?

scope513

Or half of a hack job radio install? (Im assuming some bare connections could have been touching to drain and or short out battery?)

scope513

Replaced ign. Switch, still have to put column back in.

Fuel connecter fixed (not burnt anymore)