Alright, this has been years (yes, years) of headache but I'll try to keep it brief. Also note I'm not a "car guy" and beyond changing oil or changing tires I don't know anything. About three years ago my fuel pump went out - ok, it happens. Got it replaced. About a year later, it happened again, local shop chalked it up to an unlucky faulty pump, so yet again, replaced it. Then, ONCE AGAIN, it lasted about a year, which was around November 2018. Still under part warranty so I kept taking it back to the same shop. This is when we figured out that if you knock around on the gas tank it'd start most of the time, but they simply replaced it without really looking into why, they just said the voltage was good, relay and fuses were good, etc. Fast forward to last month, and yeah, again - won't start. Cranks and cranks but you gotta whack the tank a time or two and it'll get it to start up, for a little while - eventually it gets to the point where no amount of hitting it helps.

Anyway, I was tired of that shop thinking they were overlooking something or doing something wrong, so I find a new place to take it. He replaces it, also replacing filter, fuse, whatever else, and he emptied the tank and cleaned it (which apparently shop #1 never did, so new shop figured it was due to dirty tank/gas). I thought all was well until today. It lasted two weeks. Still again though, it'll start if you hit the tank. New shop says they have absolutely zero idea or direction on what the issue is because they cleaned/replaced/fixed all components involved and all readings looked good, they'll offer a full refund but won't do anymore work on it. Told me I should "take it to a dealership where they'll charge me thousands of dollars."

So I'm at a loss, don't know what to do or where to turn, so I'm hoping someone has at least a thought about what's going on here. I know its not worth a lot now, so I don't want to spend thousands at a dealership, but I don't want to get rid of it either, especially without knowing whats up. If it were a bad transmission or blown motor then yeah I'd be likely to part with it, but this mystery stuff is killing me. Thanks for your time and assistance.

 

Bad ground; bad (imported fuel pumps) it's hard to say. I'd take the refund, (this was very nice or them on their part) and find a really good shop on Yelp or word-of-mouth. The dealers do charge much more, but you tend to get a better warranty and service so its a bit of a toss-up. What brand of pumps were used, if you know?

 

I can't imagine you keep getting bad pumps. Something electrical has to be going on. You've already narrowed the problem down to the tank area. If you don't want to spend money on dealers or more repair shops, you'll have to become a car guy. You have to start somewhere, right? Drop the tank and try to reproduce the problem. If the pump won't turn on, wiggle some wires, if it turns on, you're getting close. Pinpoint where the problem is from there. If that doesn't work, tap the pump. If it starts, maybe it is bad. Check the wire connector for corrosion and bad pins. Look for damaged wires. Find the grounds connections and derust and clean them. Check voltage to connector. Check resistance. These are all things the dealer will do and will charge you more than the car is worth.

 

What brand fuel pump has been installed? Airtex, at one point, at a bad reputation. Some were bad out of the box. About a year ago I had to have the fuel pump in my '06 Ram 1500 replaced. Shop installed a Carter pump. No problems to date. Shop owner said they called Airtex pumps "yo-yo's" as in put them in and take them right back out.

 

Yeah when changing a fuel pump; pumping gas out; dropping the tank, ect, I only care about putting a top-of-the line pump back in. Don't want any do-overs at all.

 

does the tank appear collapsed/sucked in. any hard to fuel fill/ slow fill issues. if the evap vent path is blocked the tank can't get air in as the fuel is pumped out. This stresses the fuel pump.


you should be replacing the external fuel filter. when the pumps are changed..early cobalts had external filters and intank filters.