93 3.4 V6 malfunctions
 

Hey all! Def new to this group so excuse my dumbness as far as trying to navigate the site lol
Ok so here’s my problems and hopefully yall have some answers. Got a 93 V6 automatic car. It’ll start but dies. No security light ever! Checked bulb it’s good. Will run off ether but not its own gas. Tons of parts have been thrown at this car before I got it (new injectors, fuel pump, most sensors on front of engine, ignition switch, plugs, wires, coil packs, prob more I’m forgetting). I’ve checked absolutely every damn thing I know to check and I’m still stumped. Replaced key switch (vats wires in switch) bypassed TDM ( bought a voltage reducer and supplied 2.5 volts to PCM, bypassed starter lockout etc), tried different PCM and same thing, no power to the fuel relay on the signal side but straight wire and pumps all day (new pump), there’s no signal from the PCM to the injectors or the fuel request side of the relay. I need some better minds to assist if y'all wouldn’t mind! Please and thank you!

I would start by checking the ECM connector - does it have power and ground where it's supposed to?

You need a schematic and/or the pinout. I am not sure where it would be, I just got here myself, but that's a general diagnostic step I would take.

Ive chased more wiring than I care too lol I’ve got the pinouts and checked voltage and grounds over the entire front of the car and not gotten anywhere. Luckily this is a nostalgic toy and not my daily!! 🤣

I am thinking you may have a wiring fault to one of the sensors. That way, sensor can be new, but still produce no signal. Maybe something like the crank sensor.

Do you have a scanner that can monitor sensor data? If you don't have that and are running old-school with a test light and a multimeter then maybe the thing to do is look at the schematic and test wiring from crank sensor to PCM.

You may be on to something. I’m old schooling it lol first OBD 1 I’ve had to mess with in a long time that wasn’t diesel! I’ve checked several sensors but not all yet. Gotta get underneath and check oil pressure sensor as well. Why gm decided it was a good idea to tie it into the fuel relay I’ll never know…the thing that gets me is there aren’t but maybe a handful of shops around here that can check old school sensors like this 93. I’m not really in a place to just throw parts at it like owner before me did so it’ll be back to the drawing board this evening.

I'm not sure about oil pressure, and I haven't done this on a 93, but I have run into lack of crank signal doing something like that on a different GM product. So, it's a guess, but not a totally wild one.

Yea it’s a wild shot but supposedly it’s supposed to kick oil pressure up to 5lbs to show ECM it’s has pressure enough to fire. I have oil pressure when cranking but third wire could be messed up, loose or who knows what. I do believe I’ll check crank signal either this evening or one day after work. It’s frustrating the crap outta me for sure.

Electrical issues are always like that.

Yup I agree. This is the first one I’ve had to have someone else’s opinions on if I’m being honest.

if you have not done so yet download a factory service manual for 93 here https://www.mediafire.com/?40mfgeoe4ctti its for the firebird but other then a few body parts its the same for Camaro.