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Chevy Silverado and GMC Sierra Fuel Pump/Fuel System



  • hiscokidhiscokid Posts: 4
    I'm have a problem with my truck. It was running fine and the next time I went to start it, it wouldn't. The vehicle cranks over fine, I check the fuel pressure and its between 60 and 70 psi at the schrader valve. I've got plenty of spark at all the spark plugs, it just seems like there is no fuel getting inside the combustion chamber. Anybody have any ideas? This baby's got 191,000 miles on it.
  • Spray a liberal amount of carb cleaner into the throttle body, then try and start it. If it starts briefly there is a fuel delivery problem. Pressure at the rail checks ok, so injecters are not firing. Most likely cause is a bad cam sensor. Other causes are an open circut from the oil pressure sending unit, security issue. If you have a security light on your dash that says security. After turning your key to run position, the light should not blink. Using a scan tool may be helpful. If you remember the last time you were driving it, if the check engine light came on during the drive. It is usually the cam sensor. Once the engine is shut off, the PCM can't find TDC and doesn't fire the injecters.
  • hiscokidhiscokid Posts: 4
    Thanks for the tips mickeymouse2, I ordered a scan tool and am awaiting its arrival. The check engine light had gone on a few times before it did this so you're probably right. Does it usually throw a code for the cam sensor then? If it is the cam sensor do you know if the pcm requires a relearn program once I replace it? Thanks again.
  • Does it usually throw a code for the cam sensor then? Yes. Once your code indicates a bad cam sensor, it should still be checked with a graphing meter. However, thats expensive and the sensor is probably only 45.00. No relearn needed. Once a cam signal is seen by the PCM it will fire the injecters. Your check engine light may take awhile to go off by it self, or just do a clear code reset with the scan tool. If for some reason you disconected your battery and lost any stored information. You can reset the trouble codes by cranking the engine for at least 10 seconds, and any codes pertaining to no start up will reset if there is still a problem.

    Also, special note. If the new cam sensor has a small piece of cardboard stuck on the end of it, size and shape of a dime, dont take it off. Thats for adjusting the air gap when you bolt it in. I don't think yours has this, its just a bolt in plug and play type. Good luck
  • My 1993 4.3L Silverado suddenly runs badly. Air filter is clean. All fuel lines appear ok. Only 1 fuel pump installed.
    Just filled gas tank earlier that day. Reputable, high volume station, never any fuel quality problems.
    Engine acts like it is starving for gas.
    What should I check first?
  • obyoneobyone Posts: 8,054
    easiest would be fuel filter
  • How often should fuel filters be replaced? Mine was last replaced in 04/2003.
  • obyoneobyone Posts: 8,054
    I would think that should be done on an annual basis depending on your mileage however most wait till so little fuel passes that it causes problems prior to changing. It's a cheap part and fairly easy to replace so I'd start there.
  • hiscokidhiscokid Posts: 4
    hello, I just wanted to update you on the truck. I got my scanner and plugged it in, got no codes. Decided to see if the truck would start and it did, I did nothing to the engine. Once it started It was misfiring alot but it seems like its progressively getting better. Does anyone have any other Ideas what it could be? Also does anyone know of a cheaper way to do a fuel injection cleaning other than bringing it to the dealer? thanks.
  • biga4biga4 Posts: 2
    I had a similar problem last week. Truck starts fine when cold but hard starting, or won't start at all when at operating temp. Did some research and found some answers at A lot of the people posting there had the same issues. Found out the hard starting was caused by a leaking fuel pressure reg. On these 98-01 Sequential fuel injection Vortec engines the spider assembly and FPR are located under the upper intake manifold. once the FPR starts leaking, the fuel collects in the intake manifold and sits there flooding the engine. If the truck sits long enough the fuel will evaporate and the engine will fire. The fix for me was to purchase the upgraded Spider assembly for SFI vortecs, instead of just a FPR. This upgrade does away with the poppet style injecters and replaces them with real injecters and is complete including the FPR (GM#93441235) and is a direct bolt-in. From what I gather GM had to develop this because of problems and a recall in CA with the poppet style injectors getting clogged because of the additives in the fuel there. Since I had it installed I noticed the smoother idle, starts with just a touch of the key, and better throttle response. Haven't checked fuel milage yet but should be back to my normal 17-18 mpg city
  • hiscokidhiscokid Posts: 4
    My truck just started up the other day and is running fine now, it misses every once and a while but I'm thinking it was bad gas. Where can this upgraded spider assembly be purchased? I heard these poppet style injectors are nothing but problems. thanks.
  • biga4biga4 Posts: 2
    I got mine at a local AC Delco supply store, 1/2 price compared to what any dealership wanted. I heard of other people ordering from for around $260
  • mac53mac53 Posts: 2
    I have a 2000 Sierra 4WD with just over 99000 miles. It has developed a problem with the ABS. At slow speed stops on a dry surface, the ABS kicks on just as the truck comes to a stop. It goes off when I pump the brakes. It doesn't do this on hard stops.
  • Check for a small stone stuck in one of the pulse rings, throwing the sensor info off for one of the sensors. Also check for for a mechanical reason that one of your wheels is turning slower than the others at slow speeds.
  • My 2000 Silverado had a recall on the ABS sensors. They did pretty much the same thing. Call a dealer and have them check. While you're at it, have them check for recall service on the tailgate cables as well; I had mine snap while standing on it! The bad part is I received the recall notice at least a month before that happened. :mad: at myself
  • bigd41bigd41 Posts: 1
    My 2001 1500HD with a 6.0 Liter has been getting harder and harder to start to the point of having to floorboard the pedel to get it to crank. The truck has approx 182k miles. After that it would run Ok but a little rough idle. I thought it was my fuel pump and my mechanic confirmed it. I have been reading some issues here where some people were just replacing the "fuel regulator" at a fairly low costs. How hard is it to replace the fuel pump and what is a ball park cost for doing it? :)
  • sierraz71sierraz71 Posts: 1
    Have a 2001 GMC Sierra 1500,5.3L with 144k miles. Recently developed hard starting problem. No trouble codes present.Cranks with no start until 3rd attempt. Probably would start with one attempt if I didn't let up on starter. Prefer 3 short attempts to avoid damaging starter. Occurs after shutdown of approx 5 minutes or overnight. Will start OK if you shut down and restart immediately. Fuel pump and filter was replaced at 120k miles. Runs fine otherwise from idle to WOT. Have noticed after shutdown,can hear noise in the fuel tank that sounds like fuel pump is still operating or more likely pressurized fuel is returning to the tank. Replaced original plugs and wires since they were long overdue. Truck has run flawless since purchased new. Any ideas where I can start to troubleshoot ?
  • scout8scout8 Posts: 1
    I have a 96 GMC sierra that speeds up it's idle not at first,but as soon as it warms up,to about 1400 rpm. I also seem to have an excessive amount of vacuum or just very strong vacuum. Other than that it runs well.
    This is a 305 with central sequential injection.
    Any feedback is highly appreciated!
  • hi, i have a 95 Sierra as i took off from a stop sign it suddenly starting sputtering and then died,restarted it and got home after alot of effort.replaced the fuel filter,no will sit there and idle just fine,rev's up good just when i put it in gear it will bog down and then do a surge of running good,then bog down again.fuel pump or something else?i am at a loss,need some advice badly.thanks
  • jeffsayersjeffsayers Posts: 15
    I had a similar set of symptoms on an old car once. I found that the air duct going into the intake was cracked between the air sensor and the manifold. Everything was fine untill I put it in gear, then it would bog out and die unless I VERY SLOWLY fed the gas and built up speed.

    The replacement was pretty expensive from what I remember. If this is the problem, a half of a roll of duct tape will work just as good as a new air duct!

    Good luck, let us know!
  • jpmoorejpmoore Posts: 2
    Yesterday out of the blue all of a sudden my truck started bogging down, and the fuel gage went from half a tank down to E so I turned around and pulled into the gas station put 20 bucks in and started out of town again....well it didn't stop it kept bogging down especially when I would go to take off....then it took forever to get home, cause I had to go really really slow to get up a hill and had to roll back down one cause it just wasn't going. I checked the fuel filter and it seems fine. Do you have any ideas??? There was no warning it just started bogging down when I accelerate. I'm going to check it out again here in a sec, any ideas would be greatly appreciated.....Thanks! it acts like its not getting enough gas or something.
  • mickeymouse2mickeymouse2 Posts: 161
    Make sure your fuel pressure is with in specs. Running a vehicle low or out of gas over heats the electric pump and will sometimes cause it not put out enough fuel pressur. Curious that you had a fuel guage issue prior to this. I think that the fuel pump and sending unit are one assembly on the year.
  • jpmoorejpmoore Posts: 2
    Thanks, we went and got a fuel pressure gage, and we are going to check it now. If the pressure isn't accurate shoule we replace the fuel pump? Thanks again for your reply.
  • Strange problem. Noticed during warm weather fuel pump would not come one unless i reached under and "jiggled" the connection. then fine. I checked it yesterday and it is getting really Hot at the connector as the truck runs. I cleaned the connection and checked that the ground is still good. Fuel guage works fine. During winter I have less or no problems with this. Right now if you start and run for 10 minutes, the connector and grey wire (power) are very hot to the touch. The diagram shows a capacitor in the pump, what are chances it is bad and discharging all the time? After running for awhile and shutting down, I will have to "jiggle" connection again to restart. Trying to avoid new pump if possible. Thanks guys.
  • quimbyquimby Posts: 2
    I now have identical problem with my 2000 Sierra 4X4. Dealer is estimating $650 to replace hub, etc. Too bad, as only have 70K miles and bearings are fine. Others are telling me to clean the sensor, once I have access to it. I am most interested in the recall issue. I have never received recall notice on this issue. Did you learn more about a recall? What was your resolution of the abs problem. Thanks
  • mhwebmhweb Posts: 1
    The recall I believe was limited to vehicles in the northern states (salted roads). Chevrolet did not send out notices to every owner, regardless of what state you lived in. I took my 2002 Siverado in maybe two years ago for this and had to argue with the service manager on if this year was covered. It appeared that if you cleaned the ring and coated it with lacquer and adjusted the sensor you might get by if the sensor was not tore up. I was told the rust build up was the problem.
  • quimbyquimby Posts: 2
    Thanks for input. Yes, my vehicle is in Maine, road salt capital of U.S. Learned dealer did serviced abs 3 years ago in accordance with a GM bulletin that they did not tell me about. Basically, it seems they remove it, clean it and reinstall. I did the same the other day myself. No rust, no apparent dirt, with a lubricant on ring and sensor. But, problem at slow speeds persists, although it is always intermittent. Looks like I must replace entire hub - too bad as seems the bearings are fine. Basic design flaw in my opinion.
  • cooey5cooey5 Posts: 3
    I have a 2003 Silverado 1500 ext cab...ran fine one morning going to town, but on the return trip wife said it started sputtering and bogging down. It finally died on the highway after about 15 miles. I went out there and changed the fuel filter but would not start. could not hear the fuel pump run. towed the vehicle home and the next morning tried to start it and the fuel pump would come on and the truck would start and run for about 15 seconds or until I hit the foot feed. Any ideas?
  • cooey5cooey5 Posts: 3
    After trying to start it a few times now the fuel pump will not come on at all. I'm not much on these newer models.
  • bailey18bailey18 Posts: 1
    Hi, I have a 2003 Silverado 1500hd (My Bubba :blush: ). I used to get 15mpg city 17-18+ hwy. In the last 6 months my mpg has dropped to7-8 city, 9-11hwy. I have had my regular tune up, also fuel system tune up, oil change regularly, front end ailgnement and tires balanced an rotated. I have no problem with starting issues, no gas smell, little sluggish but it was when purchased(used). Dealership said O2 senser is fine and so is cat. converter. Is there something they are missing? I love my Bubba but don't want dealership to nickel and dime me to death trying to find a solution. It has also started to shake at around 72mph. Any input would help and thanks.
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