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Chevy Blazer Fuel Pump and Pressure Regulator Problems



  • nmonk83nmonk83 Posts: 1
    a shot of ether and runs for a few seconds then quits,i have had 7 pumps in it. the last one was put in 2 months ago. any thoughts?
  • I have a 96 s-10 blazer that had what sounds like the exact same problem. they changed the fuel pump, the filter they checked the regulator also it turns out it was something called the spider injector im guessing its the fuel injectors they changed that and it started right up i don't know if the 2000 is much diffrent from the 96 so check it out might work for you too.
  • I have an 02 Blazer with 150,000miles on it. It had been doing the same thing, Real tough to start then it would only start with ether then to the point where I was killin the battery and having to recharge it before she would start.. I knew it was something in the fuel system but nobody could figure it out. I had changed the fuel pump and fuel filter and it was fine for a couple weeks then the same thing again. So a family friend was over and has a 96or97 blazer I was telling him about the problem. He said that he had gone through a few fuel pumps before he figured out what caused his to do the same thing. Turned out that he had to replace the spider injector set-up because it is plastic and had cracked therefore it was leaking fuel into the manifold. To do this repair you need to take off the upper manifold, while you having the upper manifold off you need to also changed your fuel pressure regulator which is also under the manifold on this vehicle. I have mine in the shop as I am writing this so I should have it back early next week... I will follow up on this post for anybody else having a similar problem.
  • bonedog16bonedog16 Posts: 1
    i have a 96 blazer it pudders and hesitates to go after i stop then go like after a stop light or stop sign but it eventually kicks in then its fine like if im the highway its ok my truck doesnt have a catylac converter it has a flex pipe wich is hoocked up to a pipe that connects to my muffler wich the pipe going from my muffler to the flex pipe isnt quite connected all the way its clamped but not all the way and my exsaust is loud my cousin says it might be because i dont have any back pressure im not sure really also my gas and temprature gauge doesnt work i checked all fuses and they seem fine i dont know how much gas i have in it or wut the temp of the motor is also there is a really bad squeek noise coming from my passenger side maybe a ball joint or idler arm not sure wut do i do
  • redddogg1redddogg1 Posts: 2
    I have a 1995 blazer ..For some reason I'm not getting power to the fuel pump .. Cant seem to understand why ..I know it works fine because I used some wires test it .But plug it to the harness it don't work ..Doing the work myself don't have the money for a Mechanic!!!!!
  • jondevilsjondevils Posts: 1
    Replaced fuel pump on my Blazer bc thought it was bad (which it was not). Have new pump in but still won't come on. Checked all relay switches and fuses they are all good. Checked connections to pump all are connected and each wire is getting fire to them. Blazer will turn over but will not start and fuel pump won't come on at all. Can put fuel in throttle and it will start but shut off as soon as it burns fuel off. Have no clue on what else could be causing the fuel pump to not come on. Please help lol. Please post on here and please e-mail me as well at
  • stealthnystealthny Posts: 25
    I have a 1997 Blazer that I have been trying to fix for 6 mos. It just wont start on its own. I have repalced the pump ( which they said was bad but never pressure tested at the filter. when i pour gas down the carb it starts right up but will only run as long as the gas I pour in lats then stalls. someone told me that means the injectors are out of sinc. I am trying to replace the fuel filter now. nobody has tested the pump pressure other then holding down the FPV and saying there is alot of pressure there. anyone ever of the injectors being out of sinc
  • 2002 Blazer V-6, 4WD, auto. The gas gauge floats back and forth. Been doing that since a few months after I bought it 2 years ago. Started getting a double code about 8 months ago, (evap code, and I don't have the code here, but I think it was P0049 that suggested evap system). Could it be a vacuum (line) problem.

    I have a friend with a 1998 (or 96) that has the same problem. They've replaced the fuel pump 3 times but it (the CEL) still happens.
    I've replaced the gas cap and the purge valve but the codes keep coming back.

    If it's happened to 2 vehicles, it's probably happened to more. Does anyone have experience with this problem?

    Thanks, Rick
  • jlflemmonsjlflemmons Posts: 2,242
    See the answer I posted to your question in Maintenance and Repair.
  • Do you know what page or have a link to the page?
  • tidestertidester Posts: 10,059
    I believe this is it:

    tidester, host
    SUVs and Smart Shopper
  • cramcamcramcam Posts: 1
    I have a 2000 blazer with 4.3l CSEFI engine that won't start. I can get it started with starting fluid, and it will run after that but it hesitates from time to time, nearly stalling.

    After I shut it off, it will restart if I try within 10 minutes. After that, it won't restart without using the starting fluid.

    I hooked up a fuel pressure gauge. When I turn the key and the engine is cold, it reads around 48-50 PSI. At this point it won't start. When I start it with the fluid and it's running, the pressure goes up to around 55 psi. When I shut it off and turn the key back on the pressure reads around 58psi. But if I leave it off for about 10 minutes that pressure drops back down to below 50 PSI again and it won't start again.

    Is this problem my fuel pump? I have already replaced my fuel filter.

    Any suggestions?
  • My blazer won't start when it sits for over 6 hours. Hooked a pressure gauge up and it is 54 psi key on, running 56, and after 30 min it drops to 50. I have replaced filter and no leaks visible. Any help would be grateful.
  • have u check your fuel pump or fuel pressure regulator. if im no mistaken the 4.3 fuel system should be at or above 60 psi. im looking at the same problem on my 97 chevy c1500. im about to change my pressure regulator since i just replaced my fuel pump 2 years ago and the regulator is a hell of a lot cheaper. i'll try to let u know how it turns out.
  • i have a 2001 chevy blazer 4wd 2 dr changed fuel pump,fuel filter,cap and rotor sparkplugs . truck wont run have to pour gas to get it to run ,but this only last's for a few secs and we dont hear fuel pump prime like as before . any ideas
  • I have read all the posts and am still confused where my next step is. my 2000 4door blazer (TBI) would not start after an extended idling period,everything pointed to the fuel pump. I replaced the pump and after prime it started. I drove it to get gas and to the car wash and then home, started every time. it sat two days and now it will not start again! I hear the pump running but to me that means nothing after all of my reading. I did replace the harness when i replaced the pump as well as the the fuel tank pressure sensor. this blazer only has 60k and fuel is gettting to the Throttle body.
    ANY IDEAS?? Can i add a secondary pump to bypass the factory setup to rule out the pump all together?
    All ideas welcome and appreciated.
  • duntovduntov Posts: 133
    If the engine will not start after a period of idling or after the engine gets to operating temperature, it could be a temperature related ignition control problem..

    Replace the ICM (Ignition Control Module) and heat sink. Use new mounting screws.

    Replace the fuel pump relay.

    Replace the fuel line filter.

    Always check the fuel pump pressure after a fuel pump is replaced,. If the fuel pump pressure is not to spec the engine may not start when it reaches ooperating temperature. You should always replace the fuel pump wiring harness and fuel pump screen when the fuel pump is replaced. The better fuel pump kits include a new harness and pump screen.

    Replace the fuel pump regulator.
  • if the fuel pressure regulator located outside of intake plenum it must under it next to fuel injector pack that the way it is on the 1995 blazer
  • check fuel pressure will running shut engine off for a few minutes to half hr. to see if pressure holds up. If it doesn't could be regulator . If there is a strong smell of gas fumes could be fuel injectors
  • chris10hchris10h Posts: 1
    i had low fuel pressure in my also. changed fuel pump worked for a while. changed fuel filter and pressure regulator. still same problem.

    In the end the fix was to drop my gas tank and rinse it out with gas. then i vacuumed up the old rust that was in the tank. put it back together and no more problems. better gas mileage and power. hope this works. gl
  • duntovduntov Posts: 133
    It is recommended you should also replace the gas tank when the fuel pump, wiring harness and screen is is replaced. A new gas tank cost $100 and it is a cheap insurance. The fuel filter should last 30,000 miles if you have a clean tank.
  • iamuncacoiamuncaco Posts: 3
    My 2003 Blazer will not start, I replaced the fuel pump in the tank per a dealor, still will not start. Just turns and turns. I checked the relay and it is good. I tested the old fuel pump and it still pumps. Seems like no power to the pump. I also checked in the steering collum all wires look good. No visible wire damage under the truck. Any ideas?
  • iamuncacoiamuncaco Posts: 3
    I have same issue on a 2003, have you found the answer yet?
  • iamuncacoiamuncaco Posts: 3
    edited May 2011
    Thanks I will try this with my mechanic. I have only had issues with the dealer whom I bought this vehicle, now I can't even get a call back from them. Last I heard from them I put another bad pump in the truck. Thanks again, I will let you know if that works.
  • After taking my blazer to several mechanics I am still stuck! I have a 97 chevy blazer 4wd Lt model. When we run it too long it shuts off and it wont start back for 30 mins. It idles hard, if we are at a stop light to keep it running I have to hold the brake down and slightly push on the gas. We ran a fuel pressure check it come back normal (60 psi), they replaced the 02 sensor, and we had a tune up done. I just want to know what is wrong with it and what needs to be replaced so that it wont do this anymore. Someone help me please?! :cry:
  • duntovduntov Posts: 133
    The fuel pressure should be steady between 60 - 65 lb. with the engine running and not drop below 55 lb. for 5 minutes after the engine is shut off. If the fuel pressure is not steady or it drops rapidly after the engine is shut off, the pressure regulator is bad.
    AC Delco fuel pressure regulator #217-2251...$45

    If the fuel pressure is good, the ICM (Ignition Control Module) may be breaking down when the engine get hot.
    Poor hot engine operation indicates the ICM is bad.
    ACDelco ICM, #D579....$97
    ACDelco ICM mounting bracket, #10457979....$21
  • cliffy3cliffy3 Posts: 3
    I have found that chevrolet has a very unique wireing arrangement
    I had a fuel problem and after changeing many parts
    I studied the wireing diagram ,and found chevy has a emergency shutdown of the circut of the fuel wireing , The brales and oil preasur sender are wired to the fuel pump hot wire
    A long story short
    THE fuel pump wireing includes a internal ground
    If the ground to the BODY is lost ,the brakes and rear tail lights draw there ground thru the fuel pump
    To fix thids problem I have done what chevy should do
    I attached a ground wire dirrectly from the battery to the frame of the truck
    to try a quick check and see if this will help
    simply attach a jumper cable from the NEGATIVE side of the battery , and the other end firmly grounded to the frome
    Get in step on the brake first then start your engine !!
  • I have same issue on a 2003, have you found the answer yet?
  • freakistfreakist Posts: 4
    The fuel pressure regulator is very likely leaking, and contrary to many supposed experts on the subject, you do not have to replace the entire fuel "spider assembly" in order to regain normal results. the part is different for vehicles made between 92- 96 and those made after 96, and the change actually started in 95 and a half, though the 8th digit of the vin code for either model will be a W. your model has a plastic intake manifold, and the fuel pressure regulator will be found underneath it, held in place by a simple clip. it will require draining some of your coolant and removing various connections fo vacuum, electrical connections and the like in order to remove the manifold, yet once this is done, you'll find the part is brain dead simple to exchange for a fresh unit at a cost of around 50 bucks, as opposed to 3-500 for the whole system depending on who is trying to rape your wallet. DIY and you will learn some stuff along the way, a knowledgeable driver is a roadworthy driver. be advised also, the fuel pump MUST put out between 58-62 psi when engine running for the system to function properly. a cost effective pressure tester is available from harbor freight, which will easily attach to the provided relief valve near the injector inlet on the drivers side of the engine near the firewall. be sure to tighten it well before turning on the key, so u get an accurate reading and avoid spraying fuel around. with key on, engine off you should see something over 62, perhaps 65 or more for a brief moment, do it several times like this to make sure its not getting bad numbers due to air in the gauge. if the pressure drops rapidly after the pump stops, it is 1 of 2 things, the check valve in the tank mounted pump, or, more likely the aforementioned regulator. find the rubber section of fuel hoses, and pinch off the return line (skinnier) with vise grips over a rag and if the pressure still drops rapidly (say, less than 5 minutes), the problem is the check valve in the fuel pump (replace the pump). If pinching off the return line stops the pressure loss, the problem is a leaky regulator.
    have fun! SAVE SOME MONEY!
  • duntovduntov Posts: 133
    edited July 2011
    A separate fuel pressure regulator is not avaolable from GM for the 1992-1995 4.3L V6 "W" code engines with Central Port Injection (CPI). You must purchase the entire fuel injection "spider" assembly from GM which includes the fuel pressure regulator at a cost of $613 MSRP plus labor.

    However, by 1995, Dorman Products saw a market for producing a fuel pressure regulator that is separate from the entire CPI spider assembly. The CPI fuel pressure regulator is Dorman part #55162 and costs $37. It will require about 5 hours for a competent auto repair technician to replace a fuel pressure regulator or about $325 to $400 in labor cost. I suggest that a person go to an auto repair shop in a small town of less than 15,000 population and you can get it done for half that cost. It may even be cost effective to have your Blazer towed a small town to get major repairs.

    The "W" code CPI systems are failure prone and is why they were only used from 1992 through 1995. I am fortunate to have a 1991 S10 Blazer 4x4, 4.3L "Z" code engine with a TBI (Throttle Body Injection.) The TBI system was uised from 1986 through 1995. The TBI is simple enough that I can even rebuild and replace it in an afternoon.. I prefer certain 1992 - 1995 CPI "W" cylinder heads and I therefore installed a pair of 1993 CPI "W" engine cylinder heads on my 1991 S10 Blazer LT.

    IMO, the 1986-1995 TBI system is fool proof.
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