Hi Everyone,
I have a 2000 GMC Sierra truck. It is called the 'new model' because it was made near the end of 2000 and it has the same design as the 2001. It is a Sierra 1500, 5.3, 4wd, z71 extended cab. It has less than 120,000 miles on it, all highway miles. This truck has never been taken off road and it has never worked - it is my wife's occasional vehicle and we have owned it since new. The problem is that for the past year we've barely been able to get it to run and when it did run we are too afraid to take it far from home because it probably would need to get towed back home. Now it does not run at all. We've been to 2 different reputable garages and to a GM dealer. I used to be a mechanic myself. When I try to start the truck it seems to immediatly start and stop and no amount of trying will get it to start and run anymore. When I spray starting fluid in the motor it immediatly starts and runs for about 2 seconds - so it seems to be a fuel problem, but then again it could be the computer sensing a problem and just shutting down the pump. There is spark at the plugs. When you turn the key on you do hear the fuel pump run for 2 seconds. I've put a test light in the fuse box port and it does light up for the same two seconds. Fuel pressure is 50psi when cranking. I've changed the fuel pump twice with Napa pumps and it is still 50psi (not 49 psi) at the Shrader valve. Is 50 psi when cranking good or not ? I've also changed the fuel filter, changed the crankshaft sensor, changed the fuel pressure regulator, changed the fuel relay, pulled and checked all the fuses, checked the vacum lines, checked and cleaned every electrical connector I can find including underneath the truck, made sure that the battery is good, made sure that the starter is good. I also cleaned the 3 grounds between the body and frame. Almost a year ago I had the garage change the tumbler in the ignition switch even though there is no chip in the key. There is no vapors released when I open the gas cap. I've made sure that everything at the gas tank is good with connections and lines. I changed the gas in the tank twice. So at this point I am so frustrated that I almost feel like sending this beautiful looking low milage truck to the scrapyard - considering that this nonsense has gone on for about a year! I've pretty much run out of ideas. I've not cleaned the injectors and I don't know how to do this at home, and because it does not run I really don't want to have to tow it to a garage to clean the injectors, unless I'm told that it is really necessay - in that case I will. I've not changed the camshaft sensor and I've not changed the airflow sensor and I don't really want to simply keep changing stuff for the sake of change. There is one thing that I am suspicious of: When I first took out the gastank I made sure that it was very clean on the inside. When I took the tank out again to install the second fuel pump I noticed that there were some little bits of rust inside the plastic tank. So I'm wondering where that came from - maybe from the fuel lines or the rail ? I did not change them and the dealer told me that that they never need to change these. The garage said that there are no error codes from the computer and that the computer is good. But at this point I am pretty much fed up and out of ideas. Does anyone have any thoughts on this ? I've been also doing a lot of online research and it seems that a lot of peope are frustrated with these trucks with starting problems.
I have a 2000 GMC Sierra truck. It is called the 'new model' because it was made near the end of 2000 and it has the same design as the 2001. It is a Sierra 1500, 5.3, 4wd, z71 extended cab. It has less than 120,000 miles on it, all highway miles. This truck has never been taken off road and it has never worked - it is my wife's occasional vehicle and we have owned it since new. The problem is that for the past year we've barely been able to get it to run and when it did run we are too afraid to take it far from home because it probably would need to get towed back home. Now it does not run at all. We've been to 2 different reputable garages and to a GM dealer. I used to be a mechanic myself. When I try to start the truck it seems to immediatly start and stop and no amount of trying will get it to start and run anymore. When I spray starting fluid in the motor it immediatly starts and runs for about 2 seconds - so it seems to be a fuel problem, but then again it could be the computer sensing a problem and just shutting down the pump. There is spark at the plugs. When you turn the key on you do hear the fuel pump run for 2 seconds. I've put a test light in the fuse box port and it does light up for the same two seconds. Fuel pressure is 50psi when cranking. I've changed the fuel pump twice with Napa pumps and it is still 50psi (not 49 psi) at the Shrader valve. Is 50 psi when cranking good or not ? I've also changed the fuel filter, changed the crankshaft sensor, changed the fuel pressure regulator, changed the fuel relay, pulled and checked all the fuses, checked the vacum lines, checked and cleaned every electrical connector I can find including underneath the truck, made sure that the battery is good, made sure that the starter is good. I also cleaned the 3 grounds between the body and frame. Almost a year ago I had the garage change the tumbler in the ignition switch even though there is no chip in the key. There is no vapors released when I open the gas cap. I've made sure that everything at the gas tank is good with connections and lines. I changed the gas in the tank twice. So at this point I am so frustrated that I almost feel like sending this beautiful looking low milage truck to the scrapyard - considering that this nonsense has gone on for about a year! I've pretty much run out of ideas. I've not cleaned the injectors and I don't know how to do this at home, and because it does not run I really don't want to have to tow it to a garage to clean the injectors, unless I'm told that it is really necessay - in that case I will. I've not changed the camshaft sensor and I've not changed the airflow sensor and I don't really want to simply keep changing stuff for the sake of change. There is one thing that I am suspicious of: When I first took out the gastank I made sure that it was very clean on the inside. When I took the tank out again to install the second fuel pump I noticed that there were some little bits of rust inside the plastic tank. So I'm wondering where that came from - maybe from the fuel lines or the rail ? I did not change them and the dealer told me that that they never need to change these. The garage said that there are no error codes from the computer and that the computer is good. But at this point I am pretty much fed up and out of ideas. Does anyone have any thoughts on this ? I've been also doing a lot of online research and it seems that a lot of peope are frustrated with these trucks with starting problems.