94ZinEdgewater

I've been fighting with my 94 Z28 for years and have finally got stumped. First the starter would not engage. I found voltage drops all through the circuit. Replaced the fusible link, ignition switch/connector, jumpered the relay, still would only work randomly. Ended up adding a relay to the power and that cured it. Fuel pumps (have2) wouldn't come on and found the (2) orange wires for the battery power to the PCM had no power. Cut the wires and ran them to the junction with a 10A fuse like in the fuse box. Now it runs for 3 sec and the fuel pressure drops to 0 and it dies. After it dies, I can hear the fuel pumps running again. Tried to connect my laptop with TunesCats as I've done a million times and it wouldn't establish comm. It seems like the C100 connector has issues since all the suspect wires run through it. It looks fine though. Any ideas? Thanks

Injuneer

Need to clarify the "suspect wires". In a 94 the fuel pump relay ground, PCM BAT power, and theft deterrent starter relay wires pass through C210. C100 is A/C, injectors, AIR pump, fans.

http://shbox.com/1/harness_connector_faces.htm

94ZinEdgewater

Where is C210 located? It seems like the one in the firewall by the clutch pedal. Have you ever heard of the starter circuit having too high of a resistance causing the starter not to engage? I have a racing starter that I replaced with the same model about 3 months before all of this acted up. The first one would get lazy when it got hot. Also, another issue that might be related to the electrical issue. At the track, the first pass goes great. 10.80 at 125 or so. Next pass, it dies half track. I restart it and it goes but at limited power. Last time it backfired through the blower and blew the air filter off like it ran out of fuel. The next time out I was going to record the fuel pressure meter.

94ZinEdgewater

I think that I found the C210 connector. Under the kick panel on the passenger side. I had previously jumpered the purple wire trying to fix the starter issue.

Injuneer

Look carefully at the Shoebox link I posted. At the bottom of the first page are tabs for each of connectors. Open the tab for the connector, and the shape and location of the connector is shown at the top of the page.

94ZinEdgewater

Found the connector. What's the common cause for the fuel pressure to drop after 3 seconds? I've read that the Y-body cars have a fuel output that can be disabled. The F-body one controls the theft deterrent relay which I have permanently grounded. I still use the relay input for my park/neutral switch.

Injuneer

Shoebox has info on the PASS-Key II system:

4th Gen LT1 F-Body Tech-PassKey/VATS

Sounds like the fuel pump is shutting off. If the engine was shut down, but the pump was running when it shut down, there should be residual pressure.

From your description, there are a huge number of mods to the engine and wiring, including dual pumps. Are you running both pumps, in parallel, at the same time? Are both pumps relying on the stock relay? That would include a setup with a second relay in the back, signaled off the 12V wire to the stock pump.

Might want to add a "signature" so we know the extent of the modifications. The more we know the easier it is to help you.

https://www.camaroz28.com/forums/lt1...nature-879835/

94ZinEdgewater

I have the dual pumps from Lonnies performance. They're powered by their own relays connected to the battery junction. I'm hoping that the ignition switch and connector will fix it since I've heard so many stories about them. The switch didn't look too bad and the connector was a little discolored. I now have the second pump connected to a Hobbs switch as Lonnie has preferred.