Fuel pump works...then doesn't.. then does...then...

[Frank Enstein]

I always cross the grounds off the list first thing. On an older vehicle doubly so. They corrode, break, fall off, and get left off way too often.
Take them off, clean until shiny on both the ground strap and where it bolts down on every ground you can find.
THEN start diagnostics.

+1 on Shurkey. He can come off a bit gruff but he really wants you to have the best chance of fixing it right the first time.

I however, am long winded and like to double space because my eyes aren't what they once were but my goal is the same as Shurkey's to make sure you go down the right path to getting your truck fixed with minimum financial pain.

Also please include year, model, engine, and transmission in your posts. It can help with diagnoses.

 

[454cid]

I always cross the grounds off the list first thing. On an older vehicle doubly so. They corrode, break, fall off, and get left off way too often.
Take them off, clean until shiny on both the ground strap and where it bolts down on every ground you can find.

The ground is on the frame rail back by the gas tank... not sure of it's reachable with the box on, but it sure would be a good idea to try. That location is bound to see much more weather and neglect.

I however, am long winded and like to double space

Lol, same. I often think, will people read all that???

 

[tinfoil_hat]

I don't understand why you don't just replace the relay. It's not an expensive part and then you can cross it off your list. I was having the exact same issue you are having until it finally stranded me. I replaced the relay and never had a problem since.
You have to realize that on a site like this you are talking to a lot of guys who made their living as professional mechanics. They have been taught not to just throw parts at a problem because it wastes time and money. For the average DIY guy it might make more sense to just replace a suspicious relay and see what happens.

 

[mudpie]

Don't be so fast to push Schurkey away. Yes, he can preach, but he knows his stuff.

Lot's of smart people in the world that aren't going to talk to you like a seven year old.

With regard to the relay, it's a year old and came with a lifetime warranty, so I presume it's of fairly decent quality. When I got to the parts store with my jumper wire in, I put the relay back in and the truck started right up. I was willing to make the assumption that the relay wasn't actually the problem. Not any kind of brilliant diagnostics, but I just found it unlikely that the fairly new relay was bad.

Anyway, I pulled the fuse box and looked at the wiring. The orange wire was frayed, and the grey wire had some discoloration that I presume was from heat. Also, the grey wire had clearly been replaced at some point. I went to the junkyard, pulled some wire, cut these two out and soldered in replacements. I haven't had a problem with it in the 4 days since. Hopefully the problem is solved.

So, for anybody doing a search in the future, check your wiring before you spend the money on a fuel pump.

Thanks everybody

 

[mudpie]

And of course an hour after I posted, it won't start.

I jumped the fuel pump relay terminals 87 and 30 and get nothing. That should be a direct connection to the fuel pump, right? No fuse or anything, just 12v straight to the pump? I tried several times over a couple hours and got nothing, so I'm assuming at this point that my fuel pump was on the way out, and I was in fact on borrowed time, and now my time is up. I assume the wiring "fix" was just coincidental.

I must say though, I really appreciate the truck dying right in my driveway. Saves me some hassle. Is there a patron saint of Chevrolet's?

 

[1997]

if it breaks down at home, it doesn't count ...
both mine have done that, 95 ECU flame out, 97 twice, rear brake line blow out, then a poppet failure on cylinder1.
must be a GM thing

 

[454cid]

And of course an hour after I posted, it won't start.

I jumped the fuel pump relay terminals 87 and 30 and get nothing. That should be a direct connection to the fuel pump, right? No fuse or anything, just 12v straight to the pump? I tried several times over a couple hours and got nothing, so I'm assuming at this point that my fuel pump was on the way out, and I was in fact on borrowed time, and now my time is up. I assume the wiring "fix" was just coincidental.

I must say though, I really appreciate the truck dying right in my driveway. Saves me some hassle. Is there a patron saint of Chevrolet's?

Now would be the time to try the trick I mentioned earlier..... bang on the bottom of the gas tank, right below the pump. It's just about inline with the fuel filler.

 

[HotWheelsBurban]

And of course an hour after I posted, it won't start.

I jumped the fuel pump relay terminals 87 and 30 and get nothing. That should be a direct connection to the fuel pump, right? No fuse or anything, just 12v straight to the pump? I tried several times over a couple hours and got nothing, so I'm assuming at this point that my fuel pump was on the way out, and I was in fact on borrowed time, and now my time is up. I assume the wiring "fix" was just coincidental.

I must say though, I really appreciate the truck dying right in my driveway. Saves me some hassle. Is there a patron saint of Chevrolet's?

Might be; my Burb decided its starter and battery were done at the garage, after I had them change the oil pressure sending unit. They couldn't get it started,to back it outta the bay! Good thing it was a pay week (and most parts for 400s aren't super expensive).

 

[mudpie]

if it breaks down at home, it doesn't count ...

Not only did it break down in the driveway, it broke down in the shaded part of the driveway. I'm thinking this is probably a good day to buy some lottery tickets, as my luck seems particularly strong at the moment. It's almost like the truck is begging to be worked on.

You must be registered for see images attach

Now would be the time to try the trick I mentioned earlier..... bang on the bottom of the gas tank, right below the pump. It's just about inline with the fuel filler.

I wacked on it a few times and I get nothing. The standard procedure lately when it dies has been to pull the relay, stick the jumper wire in, pump works fine, then put the relay back in. That process makes it kind of difficult to tell if it's the relay or the pump. Now it's been sitting overnight and I still have nothing from the pump when I put the jumper wire in place of the relay, so it kind of has to be the pump at this point, right?

I'm going to pull the bed and check it out,

 

[HotWheelsBurban]

Not only did it break down in the driveway, it broke down in the shaded part of the driveway. I'm thinking this is probably a good day to buy some lottery tickets, as my luck seems particularly strong at the moment. It's almost like the truck is begging to be worked on.

You must be registered for see images attach

I wacked on it a few times and I get nothing. The standard procedure lately when it dies has been to pull the relay, stick the jumper wire in, pump works fine, then put the relay back in. That process makes it kind of difficult to tell if it's the relay or the pump. Now it's been sitting overnight and I still have nothing from the pump when I put the jumper wire in place of the relay, so it kind of has to be the pump at this point, right?

I'm going to pull the bed and check it out,

Fix me daddy, please.....