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having problems with 2004 chevy tahoe fuel system. dealer ...
Sent to Car Experts August 19 03:15 PM

having problems with 2004 chevy tahoe fuel system. dealer replaced fuel pump twice
now i'm getting a vacum leak kind of sound out of the lh fuel rail when you cycle the key.
i believe they still haven't fixed the problem and just waiting to get stuck with it again.
can you help?

 

Optional Information:
2004 Chevrolet tahoe v-8

Already Tried:
taking it to the dealer 3 times this week

Customer (name blocked for privacy)
Status:  Closed   Value: $15
Answer
August 19 3:19 PM (3 minutes and 50 seconds later)
         
REPLIEDCheck Mark

Do you smell gas?

Do you have access to a fuel pressure tester?

Does it sound like air running through the fuel lines?

Hit 'Reply' (not 'Accept') to answer OK?

Russ



Russell S Wydra
Picture
Wydranator -- Auto Mechanic -- 100% Positive Feedback on 82 Car Accepts
30 years experience in automotive, motorcycle and small engine repair.
Reply
August 19 3:37 PM (18 minutes and 35 seconds later)
         
Reply to Wydranator's Post: don't smell gas
no fuel pressure tester
yes it sound like a 5 second vacum leak or air leak
at the spot on the rail where the cross over pipe is
Customer (name blocked for privacy)
Answer
August 19 3:45 PM (7 minutes and 31 seconds later)
         
REPLIEDCheck Mark

Thanks for the info.

This noise only happens when you turn your key to the On/Run position right?

Does it sound like the noise is coming from the fuel pressure regulator?

Russ



Russell S Wydra
Picture
Wydranator -- Auto Mechanic -- 100% Positive Feedback on 82 Car Accepts
30 years experience in automotive, motorcycle and small engine repair.
Reply
August 19 3:50 PM (5 minutes and 44 seconds later)
         
Reply to Wydranator's Post: yes

i assume that is a regulator on the rail right there.
1 steel line coming in
1 steel line going to the rail on other side
with a regulator or switch right there
Customer (name blocked for privacy)
Answer
August 19 3:57 PM (6 minutes and 37 seconds later)
         
REPLIEDCheck Mark

OK, we need to narrow the noise down.

Take a long screwdriver or long ratchet extension and holding one end to your ear and the other end to different parts of the fuel rail (starting at the regulator) have someone turn the key off and on until you isolate the noise. (also, check any solenoids or vacuum check valves OK?)

Russ



Russell S Wydra
Picture
Wydranator -- Auto Mechanic -- 100% Positive Feedback on 82 Car Accepts
30 years experience in automotive, motorcycle and small engine repair.
Reply
August 19 4:09 PM (12 minutes and 24 seconds later)
         
Reply to Wydranator's Post: it's coming right from the top of the regulator where the 2 steel lines are.that's the only place.
the original problem was when you would start the truck, it would spit and sputter for 5 sec. then clear up. that was the first symptom. the next day it would not start had to be towed to the dealer.
they put a new fuel pump in because they said it had erratic fuel pressure. she left the dealership, picked our son up from school, and it was running worse. took it back they replaced a intake gasket that they said was leaking. same problem.
now finally today the answer is that we got bad fuel in the tank and it ruined the new fuel pump they just put in.
truck runs ok so far ( 10 miles maybe) but this leak or noise was never there before.
i don't believe they fixed the problem and my wife is going to get stuck with this again.
appreciate the help.
Customer (name blocked for privacy)
Answer
August 19 4:25 PM (15 minutes and 42 seconds later)
         
REPLIEDCheck Mark

For starters, the dealership evidently has unqualified mechanics, and unfortunately, you had to pay for their incompetency. (I know that doesn't make you feel any better, but I just had to say it because it makes me mad)

OK, I'm better now.

The sound you are probably hearing is the gas being pushed past the regulators diaphram. It can't be vacuum air because the engine is not running. (by the way, try listening while the engine is running to see if it still makes that noise)

if the truck is running like it is supposed to, other than changing your pressure regulator, I would drive the truck locally under different driving conditions and see if I could get it to act up...and then take it back to the dealer and raise cane, or to a good mechanic and see what he thinks. (Dealers are not the only place to get quality work done)

Keep me posted OK?

Russ



Russell S Wydra
Picture
Wydranator -- Auto Mechanic -- 100% Positive Feedback on 82 Car Accepts
30 years experience in automotive, motorcycle and small engine repair.
Reply
August 19 4:36 PM (10 minutes and 47 seconds later)
         
Reply to Wydranator's Post: I've been in the heavy duty truck industry all my life. parts dept, service dept, sales dept, and one thing i know is that most mechanics these days are parts changers, if the computer doesn't recognize the problem when they plug it in their screwed. so they guess at the customers expense.
just one more question. the gas should not be pushed past the regulator and that is probably the original problem. now with another new pump it will keep enough fuel pressure anyway for a while. am i right in that thought?
Customer (name blocked for privacy)
Answer
August 19 4:47 PM (11 minutes and 24 seconds later)
         
ACCEPTEDCheck Mark

Actually, fuel does pass through the regulator. When you turn the key on, the pump pushes fuel to a closed diaphram. The diaphram has spring pressure behind it and once that spring pressure is maxed out, the excess fuel is returned to the tank by way of a return line.

To answer your other question, I always say, "If it ain't broke, don't try to fix it." And as far as worrying about your wife breaking down, I worry too...and I'm a mechanic!

You never know when a car these days is going to stop running....so we just do the best we can.

A friend of mine bought a new car and the dealer has had it longer than he has!

Again, keep me posted OK?

Russ



Russell S Wydra
Picture
Wydranator -- Auto Mechanic -- 100% Positive Feedback on 82 Car Accepts
30 years experience in automotive, motorcycle and small engine repair.
Reply
August 19 4:50 PM (2 minutes and 35 seconds later)
         
Reply to Wydranator's Post: thanks i appreciate the help.
Customer (name blocked for privacy)
Answer
August 19 4:56 PM (6 minutes and 30 seconds later)
         
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30 years experience in automotive, motorcycle and small engine repair.
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