2000 Silverado fuel pump install

[Beck]

Sunday I installed yet another fuel pump in my 2000 Silverado. This is the 3rd time in 92k miles. The 2nd replacement (1 year ago) was a wrong diagnosis. I still had that pump so reinstalled it. That is where my problem starts.

Yesterday (Thursday) the Service Engine Soon light came on. The code says it is an EVAP vac leak. After thinking about this fuel pump replacement... Is there supposed to be an O-ring on one of the lines? I didn't see it when doing the reinstall and didn't think about it. It may have stuck in the vent line and still be there, or it could have fallen out when fighting the pump under the truck bed.

Was there supposed to be an O-ring? What else could it be? Did I crack a hose? I had to drive a different vehicle today so I don't know if the light will return. I reset it last night.

[wayne petty]

i had a friend with a repeated P0456 that no matter what i did would not go away..

turned out.. that the new aftermarket gas caps are not as closely calibrated as a factory gas cap.

there is a spring and check valve in there to allow pressure to be held and vacuum to be filled.. but at a specific rate..

it took a  smog tech with a EVAP testing machine and an advanced scan tool to control the solenoid valves..

they could not find a leak.. the top of the fuel sending unit had cracked and the fuel pump hanger had been changed..  that was part of the previous leak..

when they tested the cap... it failed the computerized test ..  he went to the dealer and came back with a factory replacement cap that i made him verify came in a factory box.. not an open stock cap that might have come from the parts store as a fast sale..


on another i believe it was a 2000 chevy tahoe...  there was a similar code.  on the fuel tank vent line up from the tank.. there is a test port with a green cap..  some shop had found codes for EVAP issues and i think air injection issues... expecting to clean up big with a hefty estimate..  nope... the customer traded in the truck where my friend bought it.

he got massive estimates also.

as my antique OTC scan tool would work on this model i was able to go thru the factory data stream.. far more advanced than OBD2 data stream many scanners can access..

well.. the little olive green cap on that tube actually had been left loose..
that causes the small leak that set a P0456 on that truck..  but it also had a air injection code??? that truck had a device over by the right hood hinge.. with a few small vacuum hoses to it..  i seem to recall its the electronic smog pump.. it all looked great..  but when i got into testing.. i could not command it and make it work properly..

when i got out my hand vacuum pump..  i found the manifold vacuum supply hose was hooked to the vented hose barb...  where it should have been connected to the sealed barb with the solenoid off.

yes.. this truck was tampered with..  its not the first one i have found to have been tampered with.  

i found a late 70s fuel injected seville that had worked perfectly till the oil was changed running horrible.  and a huge estimate written by the other shop..  close inspection found just the computer ground connection fastener had been loosened slightly.. both of them the same amount..

was yours screwed with.. hoses hooked up backwards..  incorrect calibration on the gas cap..

other failure.   cracked hose... missing oring..

i usually keep 2 packages of orings.. for GM fuel lines and fuel filters..

GP sorensen 800-9214 and 800-9215...  the larger version fits the pressure lines and the fuel filter connections  the smaller one fits the return lines connections..  there are other places i also use the smaller ones..  but that is way off thread..  these are in stock at most AZ stores.. and i know how many of you feel about them.. but i have 5 within 5 miles to choose from including a hub store.. where the PB and Oreilly stores usually only have 40% instant fill rate and their delivery is hours away..  even my professional parts stores are only at 40% instant fill rates for my strange collection of friends cars.

i hope this helps cap your issue..

[Beck]

The code has not returned since I reset it.

I did have to install a new pump again today. The used one that I had reinstalled was noisy, just like the one I replaced. The new pump solved the noise issue. The old pump (AC Delco) had a year warranty. It lasted 11 1/2 months. It was replaced for free. Well not quite free, I had to pay return shipping and shipping back to me. Total cost $31.