Chevy Blazer Fuel Pump and Pressure Regulator Problems

leliaslelias Member Posts: 1
edited July 2015 in Chevrolet
i have a 1997 chevy Blazer, won't start by just turning the key i have to dump fuel down the top of it. i was told i have to replace the fuel pressure regulator and i can't seem to find it. Can someone guide me where to find it and if any other idea's what could be my problem please let me know.

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Fuel Pressure Regulator Repair



  • danlucentedanlucente Member Posts: 2
    I am having problems with the fuel pump on my 97 Blazer. I am not getting the whinning noise when turing the ignition on. I have checked the relays, they are clicking, but not getting power to the fuel pump. I verified this by disconnecting the plug form the fuel pump and checking the 12 line, I get nothing.

    This happened the other night also. I was working on a problem I had with the trailer wiring, and I believe the problem came from leaving the ignition on too long.

    Anyone have any ideas on what to check next??? I am stumped.

  • penizzlepenizzle Member Posts: 104
    just because the relays are clicking doesnt mean that they are good. Put in a new fuse and relay and give it a try.
  • repairdogrepairdog Member Posts: 948
    You can switch relays with the same # in the underhood box and retry also. Pump only comes on for 2 sec as you turn key on to pressurize - need to put a pressure tester on at the fuel rail (Actron sold at most stores for under $40) and see what pressure if any really there. If when you put the key in and turn to run the security light should go out after 5 sec - if its blinking you acivated passlock.
  • skippybobskippybob Member Posts: 2
    I didn't hear the fuel pump come on when key is on so I assumed pump was shot. Replaced pump , relay, still no buzz from the pump. I don't have a fuel pressure guage, but at the port on the fuel line right behind carb, if you press it in you should have fuel spurt out,right? Also, at the 4-pin connector on the pump, I have 5 volts on purple wire, good ground on 2 black wires. What should the gray wire do?
  • repairdogrepairdog Member Posts: 948
    Per the Haynes diagram for a typical V6 CPI the black is ground, the purple is the sender unit to the gage, and gray is the hot from the relay. There are 2 parallel paths for gray, 1 thru the fuel pump relay and 1 thru the oil pressure switch and both run thru the ECM fuse. Check the fuses. Input to relay shows black/white ground and dark green/white ign hot to energize the relay and then orange feeds hot thru from the ECM fuse to gray. Caution - your colors could be different - this was the typical wiring diagram - best I have. Post back when you get it going so others know.
  • morgan420morgan420 Member Posts: 3
    H i i have a 92 s10 blazer and its a fuel problem. i have replaced fuel pump, fuel filter, and the cmfi unit, "you know the little spider thing". And now it will run for like 15 20 minuts and then it just shuts down some where. Please anybody can you help me.
  • repairdogrepairdog Member Posts: 948
    Replace the fuel pump relay or switch with one the same # and see if its that. When it shuts off are you sure you have no fuel pressure? Could be spark? Have to test.
  • morgan420morgan420 Member Posts: 3
    well i pulled a spark plug and it was getting spark. And when it dies I sprayed a little starting fluid and it ran just a little off that you know fired off the stuff. I did that b/c i dont have a fuel pressure gauge. Yea and where is the fuel pump relay switch I cant find it for nothing. thanks
  • repairdogrepairdog Member Posts: 948
    92 should be under hood drivers firewall and if CPI injection and no throttle body inj (TBI) you need 60psi to start and 53 to run so you have to test the pressure sometime toi rule it out.
  • morgan420morgan420 Member Posts: 3
    Wow is it one of those two relays right on the firewall driver side? I'll check them, but I have a chilton manuel and it says its behind the dash man i tore half my dash out trying to find it. But ill check thoses two and the pressure. Thanks hope i figuer it out. I mite be back. lol
  • grantimangrantiman Member Posts: 1
    I have a 1987 chevy blazer K-5. I just put in a new fuel pump and the pump won't run. I have power all the way to the gas tank, could there be a bad ground somewhere?
  • joe132joe132 Member Posts: 1
    When I turn the ignition on the fuel pump runs continusly the engine runs fine when you start it but when you turn it off the fuel pump runs for another five seconds then stops???
  • repairdogrepairdog Member Posts: 948
    Believe it runs for about 2 sec after the ign turned off by the relay but there is a secomdary path that runs off the oil pressure switch which will power it until oil pressure drops (believe to about 5 lbs) - all is OK.
  • hank4312hank4312 Member Posts: 4
    Fuel pump stopped working and I replaced it. New fuel pump worked for about 1 week and then stopped again. If I crawl under the vehicle and unplug the 2 electrical connectors on the fuel pump and plug them back in again it starts working for about a day.
    Any advice would help before I drop the tank again.

  • repairdogrepairdog Member Posts: 948
    97 has a known problem with the ignition switch which is the connector and wiring in the steering column that all power goes thru. Fuel pump relay maybe failing. Connectors on the pump maybe corroded. Ground maybe bad to pump.
  • mk97blazermk97blazer Member Posts: 5
    Ok, so after reading all of these posts and talking to my mechanic it sounds like I have the same problem with my 97 blazer. However, I'm a young blonde woman and I often have difficulties with mechanics because they like to over charge me. This time I'm doing my research. Can anyone give me a good estimate on what this should cost to have the garage fix? They've already had the car for a day and barely looked at it... Thank you!
  • repairdogrepairdog Member Posts: 948
    At Advance part is $100 - Part No. S193 GP Sorensen Ignition Starter Switch so add labor (don't have the book on it sorry). Shop will use their local part brand and add some markup. They can give a full quote once the repair is confirmed as the needed one. I've found the dealer is pretty good on Blazer repairs cause they do the same ones all the time, have the scanners, and the tech bulletins.
  • hank4312hank4312 Member Posts: 4
    I replaced my fuel pump again and this time the new fuel pump came with different pig tail connectors. When changing out the new fuel that lasted only a week, I noticed that the sending unit was loose on the fuel pump itself. Replaced the old pig tails with new ones and the fuel pump itself, no problem so far
  • mk97blazermk97blazer Member Posts: 5
    Well they just quoted me at $800. It's the fuel pump not the starter switch.
  • hank4312hank4312 Member Posts: 4
    New fuel pump for my 97 Blazer was $289 from advanced auto parts… Took me about 2 ½ hours to install…. Not sure why they are charging $500 extra. Could be a more expensive pump or high labor cost…
  • mk97blazermk97blazer Member Posts: 5
    doesn't it seem like $500 is a bit much extra to charge? They've already done the work though. What do I do?
  • hank4312hank4312 Member Posts: 4
    If they have already done the work than you will have to pay them to get your car back… I am sure that they will give you an itemized receipt of the work. Car repairs are expensive sometimes. It’s a good practice once you know what to the problem to call around. However, this is something that I think we have all learned the hard way…
  • repairdogrepairdog Member Posts: 948
    Ask for pump brand and price breakdown. Delco pump list price is over $400. Make sure they give you a one year warranty on the part/work too because some aftermarket pumps fail early.
  • mk97blazermk97blazer Member Posts: 5
    Thanks everyone. Just a word of warning to all of those replacing fuel pumps to definitely ask around to other places. I ended up paying $775 to replace mine ... $500 for the part and $225 for the labor (3 hours of labor). I was quoted at another place for around $575 but I was at the mercy of the garage I was at because I was away from home and since the car would not start, I would have had to pay for towing again. I definitely have learned the hard way and I don't think anyone should have to pay over $600 to have this done.
  • jfleming1jfleming1 Member Posts: 2
    So I have determined that the fuel pump is not working. I have powered the test lead and still fuel pump did not run. I dropped the tank and broken one fitting on the sending unit and also on the other end of the tank where I could not see when dropping the tank I borke another little plastic fitting thingamaboob. I can replace the sendingunit and fuel pump.....But know one understands what I am asking for when I discribe the thingamaboob. Does anyone know what they call this thingamaboob? Also I unpluged the fuel pump and vierifed that I was getting power at the pump when the key was turned on. I also verified that I had a good ground......So with all this I have to say that the pump is bad.....I still need help I dentifiying the thingamaboob......

    Thanks in advance
  • repairdogrepairdog Member Posts: 948
    Go online and look at some of the pics at sites like rockauto and gmpartsdirect for help on ID.
  • jfleming1jfleming1 Member Posts: 2
    I have taken a look at thoses sites and not much luck......

    I think it is called a Fuel Tank Vent Valve.........

  • toby35906toby35906 Member Posts: 1
    This has just started thought the fuel pump went out replaced complete pump and float canister. Still didn't work checked fuses blown 20amp max fuse. Replaced fuse cranked right up. Drove it about 15 miles blown fuse. tried new fuse blew fuse. towed home waited couple days decided to try again replaced fuse cranked right up. drove 25 miles blew fuse again. any help why fuse keeps blowing.
  • repairdogrepairdog Member Posts: 948
    If this was a Chevy Blazer I'd say look at the relay and the wiring and connector to the pump. Relays go bad and connectors get loose and corroded. Also check the ground wire probably pump to frame which means the engine to firewall strap (on a Blazer) must be in place. I don't do Fords.
  • jbodden6977jbodden6977 Member Posts: 9
    I know how it can be. I am a mechanic that quit working because customers disrespected me simply because of the abuses they suffered from other dishonest and or simply incompetent mechanics. Not everybody who can buy a wrench is a mechanic, and that goes for those with computer programs that can print out fancy looking mechanics licenses etc. to hang on the wall.
    Try this. Besides doing your homework (always a good idea regardless of fixing a car or a disease) and getting a second opinion, try carrying a digital recorder and take lots of 'notes' while you are at the mechanics place of business. Don't shove it in their faces, but don't hide it either.
    Odds are good that they will suspect that you likely work for a bureau of auto repairs (California) or some other agency. Can't hurt, eh? ;)
  • jbodden6977jbodden6977 Member Posts: 9
    Install a manual switch to disconnect/reconnect the fuel pump without having to drop the fuel tank to get to the wiring?
    Modern Detroit engineering is a validation of the old adage that cousins should not be allowed to marry ... their mothers.
  • jbodden6977jbodden6977 Member Posts: 9
    lady wants me to fix her Blazer. Told her sorry, it was trashed at the factory during design and manufacture. Who builds this (cant find an angry word that is bad enough).
    Everything you need to get to is under a bunch of other stuff, you need fingers like needlenose plier and elbows like swivel socket adapters.
    The fuel pump is list at Napa for 324 $ and change, plus taxes of course.
    Fuel pump runs for two seconds and quits - pressure is built but NO GAS ARRIVES AT THE ENGINE!
    Have disconnected gas line from filter and from fuel input at engine - compressed air passes freely.
    Am about to install an inline impulse pump to see if the vehicle will run on that. Advise lady to sell this so someone that she really hates and has the punishment coming - and buy a Dodge 74 van. Fixable and reliable even in the desert.
    Modern cars are trash - and their design lends validation to the adage that cousins should not be allowed to marry - their mothers.... :mad:
  • repairdogrepairdog Member Posts: 948
    GM pump is designed to run for 2 sec as the prime as pressure on 96 up should be tested at the fuel rsil port and be min 60psi, then drop 2-3 lbs as the pump shuts off. Fast drops indicate a bad regulator or pump. So, after the 2 sec prime (note: then key off for 10 sec it will run again for 2 sec) no gas at where? What year? 96 up are injected diff than 95 earlier with CPI and earlier with the throttle body injection, back to a carb. Let me know what you need.
  • wuddarushwuddarush Member Posts: 3
    My 98 chevy blazer was running fine. I drove it to work and when i tried to start it to leave it would not start. It sounded like it was the fuel pump was not pumping. I turned the key on to listen for the HUMM noise of the fuel pump and i couldnt hear it. A friend from work told me to try banging on the bottom of the gas tank so I went out and banged all along the fuel tank with my hand/fist and then i got back in and turned the key , then i heard the HUMM kick in and long behold it started right up. Not sure if this might help anyone but it sure helped me to get it back home. Still probably need to replace the fuel pump but at least its not stuck at work.
  • repairdogrepairdog Member Posts: 948
    Correct, pump going or bad connector on top of tank.
  • blazer68blazer68 Member Posts: 2
    My 2000 Blazer was running fine when I went to work a couple of days ago. When I got in it after work it wouldn't start. I couldn't hear the fuel pump running so I assumed it was the pump. I took the tank apart and got that same pump running for a day and then it happened again. It rolls over but will not start. I put some primer in the air intake and and it ran like that. I replaced it with a new pump and a new fuel filter and now have alot of fuel pressure but it still won't start. I am getting fuel pressure up to the engine at the pressure check valve area. I have tried everything I can think and now I am lost as to what to try next. Does anyone have any suggestions?
  • blazer68blazer68 Member Posts: 2
    My Blazer started but I'm not sure for how long it will run. Last time I got it running for only about 24 hrs by replacing the connector that accepts the clips from the outside and the inside of the tank. This time I installed new wires (black and gray) inside the tank, from pump to the connector that sits beside the fuel lines and I am using the same pump that the Blazer first broke down with. I still don't quite trust it for long distance driving because I'm afraid of getting stuck out in the middle of nowhere.(I live in the sticks in the far Canadian North). Hard to find parts up here so I always have to trouble-shoot every problem before buying expensive parts. I hope it stays running from now on. By the way, is anyone reading this?
  • ixxixxiixxixxi Member Posts: 9
    I have noticed lately, my blazer seems like its starving for fuel. one case, when I get below half a tank, i try to accelerate, but the RPM goes down and it doesnt even want to move. Or when I go up a hill, I cant even keep up with the speed limit! I changed fuel pump in tank 2 months ago. I changed fuel filter a month ago. When I fill up the tank completely, then it seems to do ok, sometimes. I had to fill up today at 3/4 of a tank and it still decided to not give any power, and yesterday it dipped below 1/2 tank and had to pull over on the side of the road and get a 5 gal can of gas to fill it. Is there another fuel pump besides the one in the tank that may be going bad? when i search fuel pumps on google, it shows me a different one that goes in the tank. its getting frustrating not being able to move on the raod and fueling up all the time. Any help would be wonderful!
  • jlflemmonsjlflemmons Member Posts: 2,242
    Something that specific may be a dealer only item. Their books (or computer screen) should show the part.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Ah, your friend has taught you the GM Tank Kicking Two Step. A new fuel pump is in your future. This is a very common method of getting an intermittent fuel pump off it's butt and get you back home. :shades:
  • ozman316ozman316 Member Posts: 1
    i have a 2000 jimmy , replaced fuel pump, filter, i am not getting fuel to the engine im guessin. no pressure at port and will start with starting fluid sprayed at filter im guessin my spark is good. i do know i get fuel from the tank and to the filer becouse i have tested that.any ideas or suggestions for me id like to fix it if i could. and i do have to think about the costs here too so any id like to do all i can first
  • delluchidelluchi Member Posts: 3
    A night before i set on a journey from Switzerland to Germany my car show yellow warning light which warn about fuel, power etc the symbol look like a videocamera diagram.

    After about 3 hour drive the car stop to accellerate. I listern to the fuel pum sound it sound fine but road patrol said the fuel dont run to injector. What can i do before i buy a new pumb whch cost about $1150 equivalent in Swiss Franc (Sfr.1350-)

    Befoe then i notice my car jeck for fuellike when the fuel suppply is cutting mostly when i break in a traffic light and some time it run so low that it switch off.
  • riverrat15666riverrat15666 Member Posts: 1
    You said the pump was replaced...I think you have a 4 door Blazer pump installed in your 2 door Blazer. Ain't the same... but it will fit and look the same..The 2 door has a module (the white thing on top where the hoses connect) with a sticker marked SGK which is correct for a 2 door(19 gallon tank) A 4 door has a module marked TCH (18 gallon tank). A 2 door tank is mounted between the back frame rails...A 4 door tank is mounted on the drivers side to make room for the spare tire.
    If someone sold you a pump that is supposed to fit got ripped off.
  • delluchidelluchi Member Posts: 3
    You such a great help. I have ordered a new fuel pumpfollowing your advice..God Bless you. Plsdo you know where i can buy a good repair manual? or where to download one for free
  • tidestertidester Member Posts: 10,059
    Try these:

    Online Repair Manuals

    Where To Find Your Car Owner's Manual Online

    tidester, host
    SUVs and Smart Shopper
  • thumpingonethumpingone Member Posts: 2
    I have a 98 Blazer I bought a few months ago... I have been getting very frusterated trying to figure out this problem.

    The truck feels like I'm towing a trailer all the time, however the odd time it seems to lighten up. All the bumps on the road are very hard, very rough ride and when I go over bumps it bounces all over. Now when I put it in 4WD and hit the gas, I hear a cluck from the front left wheel. It almost sounds like a CV joint on a FWD car. But louder and harder.

    I feel like these problems are all related to the same thing, but I can't find it. I've checked if any of the brakes are draging there all good. It possibly needs an alignment. If anyone can help, please do before I sell this thing!

  • rdp2rdp2 Member Posts: 1
    I just came across this old message you left for a guy who had replaced his fuel pump. i've got a 97 2dr Blazer, just replaced the fuel pump, and she won't do any more than idle. very little pressure at the pressure valve on the rear of the engine. the pump was listed as a MU112 E3953M. do you know if this was this the wrong pump? i don't remember what sticker was on it. sure would appreciate any help. thanx
  • nicsandnicsand Member Posts: 4
    Ive been having problems with this for truck for months now. I would be driving down the street and the car would just stall. No warning it just cuts off. A mechanic replaced the modulator.(Think thats what its called) It ran fine for about a week and a half. Then it started again. Only now its stalling all the time. I couldnt make it down the street without it stalling 3 or 4 times. The fuel pump would come on and stay on. It hums the entire time the car is on. Ive smelled fumes also. Now the truck doesnt start at all. It will turn over but wont start. Like it cant get gas. Had mechanic replace pump about year ago. Could it be the fuel pump or something else????

    Thanks in advance!
  • nicsandnicsand Member Posts: 4
    Dont know if ur still trying to find out about that fuel pump but u can go on ebay motors. They have the two door listed as MU1063 E3954M. Hope that was helpful if you still need the info.
  • bitterbitter Member Posts: 22
    The fuel pressure regulator on the 4.3 eng. is located @ the back of the intake manifold, behind the throttle body. The manifold has to be taken up to be replaced.
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