I am new to this forum. Not new to Fs Chev/Gmc tho.
I have a 90 Gmc Jimmy 4x4 350 Tbi. Absolutely love it, seems to hate me.
Here is my issue right now, It was running fine, then just stalled on me. I have spark and I can hear fuel pump when I turn key on. Will not start tho. I searched other forums and similar issue were fixed with a new ign module. But... not mine.

More background on mine. Im running a Msd 6al box, Blaster ss coil, Msd wires and msd pro billet distributor. I have a adjustable fuel pressure reg on it and a pressure gauge before the Tbi unit. CFM tech throttle spacer. K&N x-stream air filter, Also hedman elite headers w/ no cat (we dont smog up here). Had Jet chip until 2 months ago. (got expensive running 91 octane) Others stuff but thats mostly it for motor. Has ran fine for years with this setup.
Last sunday it stalled and fuel pump was not working. Installed new sending unit due to hacked up wiring. (pump was fine) Ran great again. But this sunday it died and wont start.

Today I tried another ign module and then had both of em tested. (a stock one and pertronix) both tested ok. I would have replaced pickup coil but Msd isnt same as stock setup. The local parts store didnt have in stock.
tried another pump relay also. checked wiring @ tbi seems fine. replaced the ECM and put Jet chip back in. Im not getting any pressure reading from gauge at back of tbi. Injectors arnt squirting. Can Hear pump and I have half tank of gas. I tried bypassing Msd box and had spark both ways. cap and rotor are good. fuel filter is 2 months old, maybe 5 tanks thru it. Not throwing codes cept for Brake icon flashing on dash.

Running low on patience and cash. I know Im missing something. This is my only vehicle. Plz help. cant affoard to let a mechanic test theory on it either..
Would a failed fuel pressure reg send all fuel down return line?
I love my truck but it seems to hate me sometimes. All input greatly appreciated. I know there are some sharp guys on this site.. Thanks

I forgot. It will fire with Starting fluid so I know its a lack of fuel

 

I stumbled across some info that did not make me happy at all.. Googled MSD 8366 problems. Sounds like my issue exactly.. I always thought MSD was good stuff.. Now im thinking otherwise.

 

Sparkk or Fuel. If you have a timing light you can check spark on any plug wire and the coil wire. Connect the pick up of the timing light to the wire of your choice and crank the engine. If the light lights you have spark.

You can aslo pour a small amount of gas directly in the TBI and then crank it. If it starts and runs a little bit you have a fuel problem. I believe you stated in your email that your fuel pressure gage is not showing any pressure. That would lead me to believe that you have a fuel delivery problem. You could have a clogged fuel filter, or something going on in the tank even though you hear the pump running it may not be pumping fuel for some reason.

 

I've heard nothing but problems with MSD ignition systems installed on these 350 TBI motors. Ditch the MSD system put back the stock. If the pump is good and when you dump fuel down the throttle body and the engine still won't run, then you have a spark issue. Either the distributor needs to be replaced or the MSD stuff needs to be removed. Or maybe a combination of both those things. I had a similar issue with my Blazer last winter and it turns out it needed a new distributor.

 

Its fixed.. I had two issues tho. I had spark and the injector were getting voltage and pulse, but no fuel.
So figured it was fuel pump not actually pumping just making noise. Found out the pump had started to lean away from the sending unit and was barely connected. I replaced the pump and fixed the leaning issue. Didnt start. The pump would prime and that was all it seemed.
Checked for power before and after the relay. Since I had already ordered em I put Ignition module and pickup in the dizzy. Fired right up and idled great..
I drove it at highway speeds for over 60 miles this sunday, No hiccups or trouble codes.