2000 Chevy Suburban

There are a lot of things that would cause a fuel smell, I am going to ask a few questions to try to help you diagnose your issue. They may not seem relevent, but please give me the most clear, presice answers you can.

Have you noticed any loss of fuel economy since the symtom began? Have you noticed any puddles of fuel under the vehicle? Is the smell worse inside or outside of the vehicle; is it worse at the front, center, or rear of your vehicle? What part of the country do you live in? Have you ever replaced the park plug wires? Have you has the fault codes read since the knock sensor & plugs were replaced and if so, what were the fault codes (letter with four digits such as P0301) were retrieved?

I realize that that is a large amount of questions, but the more information you can give us, the better diagnosis I/we can give you. The possibilities range from a leaking fuel injector, leaking fuel regulator, leaking fuel line, leaking intake, poor ignition alowing unburnt fuel to get into the exhaust system to name just the top five of the usual suspects

I will watch for your reply so we can hopefully get you a quick diagnosis.

Thank you.

There is a service bulletin that was issued by GM, released March of 2006 (Bulletin/Recall numer 05027A) that may pertain to your vehicle. It has to do with a faulty connector to the fuel pump module and may cause a fuel smell, as well as several other problems. Check with your local Chevrolet dealer, with the vin number from your vehicle they will be able to tell you if your vehicle is part of the recall.

Another possiblility with the information you provided is you may have a faulty fuel pressure regulator. This can be checked by removing the vaccuum line from the regulator. Is there is raw fuel at the connection point between the regulator and the vaccuum line, the diaphram in the regulator has a hole in it and is leaking. This would cause a missfire and give you the fuel smell without a puddle of fuel under the vehicle.

You may also have a fuel injector that is starting to leak. Check the area around each injector and remove the connector from the injectors to see if they are damp with fuel.

I ask about where you live, because if you live in an area that get snow, the chemicals (salt etc.) That are used to melt snow on the roads can rust or corrode you fuel lines ad cause them to begin leaking. Asmall leak in one of the lines (just begining to leak) could cause a fuel smell without a puddle of fuel under the vehicle and cause your fuel smell symptom. If this is the case and you plan on repairing this yourself, I strongly recommend using direct fit lines. The fuel pressure is approx 65 psi, old school rubber fuel line is not designed to handle that much pressure. There is a high pressure fuel injection rubber hose you can purchase but it is extremely difficult to get a good seal to the old fuel line with it. Also be carefull, the brake fluid lines are ran with the fuel lines, if the fuel line is rusted and leaking, the brake lines are most likely rusted and weak as well. With the symptom that the smell is worse when you start it up, if it is a leaking fuel line; I would guess it to be the return line that is leaking.

Again, sorry for the large amount if information. These are just a few ideas, things that I have seen that match your symptoms. I hope they help, let me know.

Thank you,

Dan