Lost Fuel Pump after Battery Change

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Lost Fuel Pump after Battery Change

Postby OrlandoSonomazr5 » Thu Apr 23, 2015 10:46 am

I recently had to change my battery as I found my truck dead last Saturday, I jumped it got it running and drove it quite a bit but eventually parked at work. When I went to leave work the battery was again dead, I looked at the battery and it was from 2007 (which I will say is great for a Walmart battery to last 8 years), but it needed to be changed so off to Advanced Auto for a Silvertop Battery.

After changing the battery the truck failed to start. It would turn over all day long and I was getting spark(A little starting fluid confirmed that) but no fuel. I could also no longer hear the very high pitch whine of the Fuel Pump anymore which we all know you can hear clear as day on these trucks.


Initially the truck wouldn't start so after the battery change I let it sit overnight cause I had to head to work in my 69 Impala instead(not fond of driving my baby to work but no choice). The very next day I went out turned the key, and it fired right up with no issues and I could hear the fuel pump working fine just like it should.

Which brings us to today as I went to leave I first noticed I did not hear the Fuel Pump Prime, secondly the truck refused to start again. I tried a little starting fluid and she started for a moment so I know Its not spark so I'm right back to the fuel pump.

I've gotten no MIL codes

So my questions are.

Does the security system disengage the ignition or the fuel pump to keep the vehicle from starting.
Has anyone else had these Issues?
Could it just be the fuel Pump is going bad and that's why its been so noisy?
Any input or help will be greatly appreciated.
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Re: Lost Fuel Pump after Battery Change

Postby HenryJ » Fri Apr 24, 2015 6:47 am

Fuel pumps should make noise. The buzz lets us know it is working. Avoid Chevron fuel. The Techron additive is a contributor to the woes for our fuel pumps. Any additive that traps contaminates. Always run on the top half of the tank. Fuel is the cooling media for the fuel pump. Use a good cleaner additive every other oil change. Some swear by Mystery oil as a treatment.

Fuel pumps die and sometimes without warning. GM has determined that the small terminals were restricting the amperage and contributing to the fuel pump failures. The Delhi replacement pump addresses this with a new pigtail and connector for the fuel pump.

Some of your problems with the weak battery could possibly contributed to the pump failure. That may be a stretch though and kinda sounds like something the dealer might say trying to get out of a warranty repair. Sorry.

Best to diagnose the pump, regulator and injectors. There is a good thread that has all the steps. Rent , borrow or buy a fuel pressure gauge. Well worth the investment.

I have yet to see one of these trucks disabled by the security system. It is possible, but it would require using a key without the correct security "chip". Even then the security light would be flashing and then on steady.

New battery. Hopefully it did not take out the alternator. The 105 amp have a plastic bushing for the front bearing and are prone to failure when heated. Try not to push it hard and consider upgrading to the AD244 at some point if you keep the truck.
Test the fuel system. A new pump may be in order.

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Re: Lost Fuel Pump after Battery Change

Postby OrlandoSonomazr5 » Fri Apr 24, 2015 9:16 am

Found the issue.

120,000miles has taken its toll on the Fuel Pump Its dead. Funny gave it a few hits with a shovel and she primed right up. So its either the connections or the pump. I'm just gonna replace with a delphi pump to escape the problem.


Thanks for the help again.
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Re: Lost Fuel Pump after Battery Change

Postby HenryJ » Fri Apr 24, 2015 9:23 am

Banging the bottom of the tank can jar it and sometimes get you home. I have had more than one rig do this and get by once or twice. The last was a Jeep Cherokee? Got her home twice doing that.

The connector is usually not loose. GM argued that the terminals used were not sufficient and the lack of amperage was destroying the pump. I think they just wanted to use the same pump as the full size does and made us change connectors. Last few I have installed I changed to the bigger connectors and have had zero returns. Guess even if it is "voodoo science"...it works , so I will follow :)

"Speed doesn't kill, suddenly becoming stationary does." - Richard Hammond
"Speed is just a matter of Money - How fast do YOU want to go?"-Mechanic from Mad Max-
If at first you don't succeed - Don't take up Skydiving!
- ThunderII KE7CSK
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Re: Lost Fuel Pump after Battery Change

Postby OrlandoSonomazr5 » Fri Apr 24, 2015 10:36 am

Thanks!!!
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