Ok...I got the new pump and still no go

I don't think it's getting power as I hear nothing when the key is turned on and have ZERO pressure.

Anyone have fuel system power schematics they'd be willing to share?

Does Chevy switch the +12 line or do they switch the ground?
Is there a fuse for the pump?
I know bad grounds are common on this vehicle, can I grab ground from anywhere or does it have to come from the computer?
Digging back into it tomorrow

 

have you replaced the relay?

 

Not yet, I haven't dug into any electrical as of yet, working in the driveway on my back and it was getting dark

Replaced pump and filter

 

Hey Raybz- My '97 is in the same mode apparently, but I didn't spring for the pump yet (see my previous post re: full tank). Sorry yours didn't work out, but you may have saved me some $$. The ground from the pump apparently is attached to the cross-member above the spare tire. I cleaned that to no avail.

@Chris 015- do you know which relay is for the pump? There are 3 in the glove box and 3 more on the firewall. I switched both groups around like a 3 card monte but no change. Also, I thought I read that the relay is vacuum actuated, and didn't see any indication of that on either location.

My pump seems to be totally non functioning now, but I can hear something happening under the hood right when the ignition is turned off. swartlkk said in his post(s) that the pump should run for 2 sec at that point. This electrical and injection system rocks when it works, but right now I long for the old days of mechanical pumps and float valves, LOL! I have an old pump tester, but it only reads to about 16 psi. I am off to get a higher rated guage for it. Keep us posted on your progress, Raybz, and I'll do the same.
Above all else, Keep Calm! ( I am also on my back in the driveway)

 

I believe the fuel pump relay is under the hood on the firewall, but it may be in the glove box, not certain on '97 The fuel pump relay has 5 wires attached to it, check the relays until you find this combination of wires:

Orange: Must show battery voltage at all times.
Black: Must show less than 5 ohms resistance to ground at all times.
Green with white stripe: Must show battery voltage for ~2 seconds when the ignition is turned to the RUN position.
Grey: Goes to the fuel pump. Must show battery voltage for ~2 seconds when the ignition is turned to the RUN position, then drop to zero volts.
Red: There should be a loose terminal on the end of the wire, (near the relay). The other end goes to a terminal in the relay socket. When the relay is installed, and the ignition is in the OFF positon, apply battery voltage to the terminal and the fuel pump must activate. Post your results.

 

*** Have someone hop in your truck roll down window, and put key in ignition. Meanwhile you get underneath your truck [drivers side by gas tank] and listen carefully. Have helper, turn key to just before turning over. You should hear a very loud and distinct buzzing sound (this is the fuel pump priming). If you don't hear this, then your fuel pump is History.

 

Thanks for posting, Captain. My local parts guy, who also used to have a '97 s-10, says there is no relay listed for the pump. Strange, but I borrowed his pump circuit tester and the electrical side checks out OK. I have the truck elevated now and need to lower the tank enough to remove some fuel through the tank inlet. (couldn't get a hose to navigate the fill tube). I will look for the relay you describe first and do those tests, but I am pretty much resigned to needing a new pump. I was hoping to see a post from Raybz with a success story before I continue. Oh well, thanks again!-bd77

 

Better find a new parts guy The relay is about 1" cube. 98 and newer it's located in the underhood fuse panel and only has 4 terminals. 97 and older has 5 terminals and could be either on the firewall or near the glove box.
Buy ACDelco Multiuse Relay D1703A at Advance Auto Parts

As for siphoning fuel through the filler neck, it ain't gonna happen. There is an anti-siphon ball in the filler neck, about the size of a ping pong ball. You'll never get a hose past it. If you end up dropping the tank, take a look in the lower end of the filler neck, you'll see it. If the ball gets stuck, it takes forever to fill the tank... I'm just saying

EDIT: When/if you drop the tank, check for voltage on the grey wire, and ground at both black wires at the module connector. Grey should show voltage for ~2 seconds and blacks must be less than 5 ohms to ground at all times

 

Happy to report that I found my problem and the truck is running.

I was an idiot! I know better than to trust the provided crimp on connectors, yet in my laziness I used them during the install. The grey wire wasn't connected.

NOW I found that there is a leak in the filler tube. Headed to the bone yard to pull a new-to-me one on Saturday

Thanks for the help guys

 

Thanks for posting, Raybz. I am still at it, having a little hassle getting the 18 gal of gas out of the tank is no fun on the ground. I need to loosen the filler tube(s) from the crossmember and then it will be easier to manage. I was draining the gas from the tube into a basin type container, but it got real windy and I had to wait for a while for calmer weather. Better now, so back at it. What pump did you get, and how much, if you don't mind me asking?