99 Suburban fuel pump problem?


bendam1
05-28-2005, 11:47 PM
I have read many posts, but still not sure. I have a 99 sub 5.7 and it died on me twice. First time in the parking lot of Best Buy, wife thought it was an omen. But after it died I waited a couple minutes and it started right up. I went inside Best Buy then came out 1/2 hour later. Started right up. I noticed the gas gauge read a 1/4 tank so I went to the gas station and filled it. Again no problems @ all starting or driving. Drove it home. Took it to work the next day again no problem. FYI 180 miles round trip. The next day died on me on the freeway. Since then it turns over but doesn't start. When I turn the key on the fuel pump comes on and shuts off like normal. The reason I think the fuel pump is because when it was running before all of this it sounded like it was priming all the time. That's how loud it was. Can the pump be bad and still come on? Sorry about the length but wanted everyone to get an idea. Thanks for any help.

777stickman
05-29-2005, 10:32 AM
Check fuel pressure. 55 to 60 psi. Go from there.

010175
05-30-2005, 10:29 AM
I just checked my fuel presser and here how to do it if you donít know. Sears, NAPA and some parts stores sell a fuel presser gage that go on a shrader valve for about 35 to 40 dollars. You have two silver colored lines that rise up from the left rear of the engine and make their way to the centre of the intake. One of these lines has a schraeder valve on it to plug a pressure tester to it. For this type of application the pressure should be 60-66 psi. If you have 58 or 59, that is not enough for the engine. This information that I received from //2000CAYukon and Chuck help me a lot and I hope it helps you. Dave

oneillchick
05-30-2005, 10:55 AM
my mom has a 99 suburban and when her fuel pump went out a month or so ago......it wasnt like the symptoms you just described. it wouldnt turn over at all .... you turned the key and just nothing. also...it didnt have any problems before...she just parked it one night and the next morning it was dead......cant say for sure that its not your fuel pump...but i hope this helps

bendam1
05-31-2005, 02:39 PM
I just went and bought the fuel pressure gauge @ Sears. When I tested it it was only showing 9#'s pressure, after many times going over it and went ahead and changed the fuel pump, since I already had it. The fuel filter was already changed the day before as well. I will let you guys know what I experienced just in case you guys want to tackle it yourself. I loosened the 2 hose clamps on the drivers side for the filler hose and the hose next to it. I undid the tank straps just 2 bolts about 5" long brought them down evenly. I set the tank on my ladder because I didn't have a trans. jack available (if you can get one do it) Anyways once the tank was down I unplugged the harness to the pump both of them pretty straight forward there. I undid the main breather line from the tee. Then tried to get the fuel lines off of the pump. This I couldn't do because the tool to take them off wouldn't fit into the fitting because the way the pump housing is made it blocked half of the tool to go inside the line both of them. So after screwing with them for about 20 minutes, I just broke them off. Keep in mind you do need to depressurize your system or you will get fuel sprayed all over not fun. After they were off I pulled the tank out w/ the ladder. I did have to go back and retrieve the broken pieces in the hoses. Just use your fuel disconnect tool and jam a screwdriver or torque bit or equivelent with the disconnect tool and @ the same time pull them out. Once that's done I cleaned off the top of my tank with a towel real well. My fuel pump was being held down with a snap ring pretty easy to take out. Did it with a screwdriver. Then pulled the pump straight out. Once that was done I cleaned inside the lip where the pump sits alot of crap there. Once cleaned I grabbed the new O-ring and pump. Make sure to lube the O-ring if you don't I don't think you'll get it to go in. I used Baby Oil. Anyways popped it in. You will need to use a bit of pressure to make sure it's seated properly. Put the snap ring on, put the tank back up under the Sub plugged the lines back in. FYI mine was noted blue on the return line. Plugged the harness back in made sure to put the lock back on the one harness if you see it you'll know. Then with a ladder, scissor jack and jack stand, I put the tank back up.Use your imagination I know I did. Strapped it up put the hoses on the filler neck and smaller back together. Fired it up and worked. I then read the pressure again but it's only showing 55 psi. So I'am going to replace my pressure regulator next in a couple days. I'll let you guys know. I hope this helps anybody out there.

chuck's
05-31-2005, 11:39 PM
Before diving into changing the pressure regulator check your pressure when you cycle the key on.This is where you should read the 60-66 psi.I have checked my fuel pressure and got a reading of 54 psi WHILE RUNNING.When I check the pressure when I only cycle the key on,the pressure is up to 62 psi.I am interpreting your post that the engine was running when you checked the pressure?Check into this before doing some unnecessary work.
chuck's

bendam1
06-01-2005, 07:34 PM
Before diving into changing the pressure regulator check your pressure when you cycle the key on.This is where you should read the 60-66 psi.I have checked my fuel pressure and got a reading of 54 psi WHILE RUNNING.When I check the pressure when I only cycle the key on,the pressure is up to 62 psi.I am interpreting your post that the engine was running when you checked the pressure?Check into this before doing some unnecessary work.
chuck's


Thanks for the advice I was so happy to get it running that I forgot to do it correctly. So I tested it today and Yes when I cycle the key on it does go to 60 psi. then when running it goes to 55 psi. Thanks for the help.

pflyman
12-27-2008, 05:32 PM
Just read the post on fuel problems with burbs. I'd like to thank you guys for making my job easier. My 99 burb 454 just gave up the ghost. I went through the job of changing the fuel filter ( in the snow) no help there but I guess you have to start somewhere. My symptoms are a little different than most, because my truck will fire right up every time after a ten minute wait, it will fire up and run for 4 and 1/2 minutes time after time. This makes running a quarter tank of gas out a little easier, which I'm doing now in anticipation of a fuel pump change. (in the darn snow). While I had the filter off, I connected a hose to the fuel line from the tank and turned the key to "on". Seemed like good gas flow for the relays 2 second pulse and again when I turned the key to "off". put in new filter and started truck. Died in the 4and 1/2 minutes. Does anyone think that this may not be the pump but the ignition Mod. I know I need to do a pressure check and I will tomorrow. Just thought it strange that I have no problem starting my truck at all. I also have an o2 light on, could a sensor shut off the pump? Just thought I'd ask since it sounds like all of you have been through this nightmare already. I use my truck to plow this weird Northern Mich. snow daily. If I don"t get this running soon, I'll be stuck in my cabin till spring. (with my wife) PLEASE HELLLLP!!!!!! Thanks again

chuck's
12-28-2008, 02:42 PM
I'm hoping I'll be able to help.The engine shuting down consistatly after 4.5 minutes sounds very puzzling.Would you possibly have a plugged catalytic converter?Is that the o2 sensor code you are getting??When the engine does shut down,have you checked for spark when trying to re start the engine.Does your suburban have the security feature?If it is malfunctioning,I don't know for sure if it will cause a shut down after 4.5 minutes.Sorry if I'm not much help,but you do seem to have a unique problem.

Chuck's

pflyman
12-28-2008, 06:51 PM
Chuck
Thank You for giving me another avenue for resolving this delema. To be honest it makes perfect since. I have never had a cat replaced in the 7 years that I have owned my burb. It gives me alot to check out tomorrow. I will run her until it pukes and have my wife turn it over to check for fire at the dist. If there is none I guess I can seperate the cat from the exaust and try again. It is a unique problem from all I've read and may not involve fuel at all. I would not have thought of that at all. I sure hope you are right. I will certainly let you know how it turns out. I really appreciate your input.
Dan

pflyman
12-28-2008, 07:04 PM
Chuck,
Thanks for your input. It certainly gives me a lot of things to check out. Tomorrow I will run the engine until it pukes and have my wife turn it over while I check for spark. It certainly makes perfect sense, since I've had the truck for 7 years and never replaced the cat. If I don't have spark I suppose I can disconnect the cat from the exhaust and try again. If I do have spark I will pursue the fuel issue. Thanks again for giving me another avenue to pursue. I will certainely let you know how this turns out. It may be helpful to someone in the future.
Dan

maxwedge
12-28-2008, 08:27 PM
Gentlemen you have revived a 3 year old thread, per forum rules please look at the age before posting, start a new thread here, thanks.

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