As i mentioned in an earlier post, my fuel pump started the typical whine about 2 weeks ago but only when it was colder than -12c out. The colder it got the louder it was. Well today i was on the highway and was passing a slower vehicle and i thought he started to speed up, when i looked down my RPM's were dropping a little so i stepped on the pedal a bit more. When i did that it kinda popped through the intake a bit and continued to slow down. Each time i tried to accelerate it would do the same thing. I pulled over and could hear this noise OVER the radio and the heater blowing on high, so i shut off the radio and could hear the fuel pump INSIDE the truck with the heater on high it was that loud. So i turned around and started nursing it home cause it was still running. I could not accelerate past approx 40 km/h if i gave it too much throttle it would make that popping sound through the intake and just slow down. so i just gently feathered the throttle to gain the best speed possibly and get home. After i got closer to the city i stepped on it to see if anything had changed and it accelerated fine. The problem had gone but not entirely and the fuel pump was now alot quieter. Then a short time later i could smell raw fuel really strong and it was coming fom my truck , not some beater in front of me. It ran fine and accelerated almost fine , no engine light on or anything and the fuel smell went away after about 5 mins or so. I say it accelerated almost fine because to me now it seems to be a little "off" in the way it accelerates. I am dropping it off at a garage tomorrow morning on my way to work to have it looked at and quite possibly have the fuel pump changed (OUCH!!!) (nothing will be done without my consent). Because of a previous problem i was having the truck has a new fuel pump, has had the injectors purged and the combustion chamber cleaned at the same time, new plugs and wires, cleaned the TB and the IAC as well as a new pcv valve. I was just wondering if any of you guys have had a similar expierence or if you had and suggestions or opinions. Thanks,

Ken.

Several thoughts-the popping in the intake was due to the truck running lean due to the fuel issue.The fuel pump whining that loud due to cavitation(pump trying to pump fuel,but can't).Was the tank drained and the inlet filter changed? Sounds like you have something in the gas tank that the filters won't pass.

I agree with Bronco2. The pump is trying it's best to supply fuel volume but for some reason can't maintain the demand. The pump probally is good but the suction and/or the discharge is constricted. It will ruin the pump in short period of time if it has to work harder, plus the amperage draw with go up.It's a roller vane pump (simular to a centrifugal pump) not a P.D. (positive displacement) so it will cavitate. Good news is I know where you can get a rebuild kit for the fuel pump module instead of having to buy a complete module. About $70 compared to $350. In any case you should take tank out and see whats up with the suction.

Had a GM Tech tell me to either replace the fuel filter at 25k miles or
replace the fuel pump at 75k miles for big bucks.....said the filters gunk up and cause the fuel pump to wear out.

Noticed my fuel pump's whining too. Got to thinking this has something to do with my intermittent stalls too. Hoping this ISN'T the case since it only does it when there's a low idle.

Well i just picked it up from the garage and the diagnosis..............nothing found. Fuel pressure checks out ok , no codes, if it was a fueling issue such as being starved for what ever reason it would have thrown a lean code. They scanned it and there was no codes and since it is not doing it now i guess i will have to wait for it to die completly on me since i am tired of spending money on trying to diagnose friggen gremlin problems that dissapear once i get it to the garage.

Sounds like garbage/gunk in the fuel system, the best and I think only good way to fix it is to drop the tank and make sure it's clean of dirt and debris and then to flush the fuel lines from the rear to the front. Money permitting maybe also replace the fuel pump since it's life was surely shortened during the freeway drive.

Check your e-mail, I sent you the e-mail link of the chevy parts guy who stocks the rebuild kits.

Those all sound like great possiblities. Water in the fuel......ice build up due to water in the fuel.......something restricting fule flow in SOME way. But every single garage , even GM say that if they get starved for fuel the curve will change and cause a lean condition and it will throw a code. Trust me. if this was a fuel starvation problem for one reason or another it should have definitly thrown a code. I could not give it any amount of throttle because it would just seem to cut out on me and the rpm would drop. I could barely get 40 km/h out of it. Like i said i guess i will just have to wait till it dies on me because i am tired of throwing money at it just to find out what the problem is.

Well it has been about 5 days that the fuel pump has been quiet and it is still cold, -16c to -32c and it is quiet. All i did was dump a bottle of isopropyl into the tank. If it was a water issue in the tank it does not make sense because a GM tech and the garage where i usually go for repairs both said that if it was being starved for fuel for any reason it would throw a lean code. Like i said , there was no engine light or anything........will keep you guys updated if it staye quiet. Thanks for all the suggestions/opinions.

Ken

Just an update, it has been almost a month and the fuel pump is still as quiet as ever.