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Chevy Blazer GMC Jimmy Maintenance and Repair



  • repairdogrepairdog Posts: 948
    That front drive shaft always is engaged and the transfer case only switches a gear for 4Lo. When you push 4Hi (or Lo or auto) the left (passenger side) CV axle is then coupled to the front differential via a vacuum actuated switch under the battery that pulls the cable to the axle coulper. So, you have a motor (encoder), a computer (transfer case control module-TCCM), switches, sensors, actuators and vac hoses that all must work and sent proper signal to the TCCM. On a 98 first look at the vac hoses from the intake to the reservior can on the drivers side for rot and then trace down to the actuator - most common. After that it gets harder to find/fix.
  • my question is this, I am not getting any pressure even when the regulator is out of the equation. I have a "T" that attached to the output of the fuel filter. The filter is on one side the gauge on the center and I plugged the other side. And I am bypassing the relay so the key has no effect on whether or not the pump is getting voltage. I have 65k on the truck. With this setup I am still only getting around 30 psi. It should be able to get much higher than that. It would be like clamping off the return hose from the regulator so that it can't release the pressure.
  • repairdogrepairdog Posts: 948
    Interesting setup but if you T the line the regulator wil still control the pressure cause its a closed circuit with a supply and return. If you simply put the pressure gauge on the output of the filter then you would get full pressure from the pump but not sure how safe this is - 2 person test with fire suits! The fuel rail test port is the correct place to test this and this will give you the real operating pressure.
  • I found the problem. Quite by accident. I was using the fuel pump to empty the tank so I could lower the tank and check for correct voltage at the pump connection, and while I was doing that I was removing the skid plate and loosening the support rails. I slipped and the wrench hit the exhaust pipe. when this happened the pump revved up. I did it again and got the same result. I reconnected all the fuel lines and had my roommate try to start the truck while I held a wrench from the frame to the exhaust. The truck started up, pressure was fine and there were no problems. I removed the wrench and it died. Long story short, the ground from the battery to the frame needed to be replaced. Now it runs fine. Thanks for your help though.
  • Hi, I have read a lot about Ball joint problems in this vehicle. I have just replaced the front ball joints because of a clunking noise on the right side of the front. Two different mechanics told me this was the problem. I still have the same noise in the same place. It is a loud and irritating noise. Does anyone have any ideas what the problem really is? I don't have the funds to keep trying any more. I really love the vehicle otherwise and have had no other problems. I have the diamond edition and would like to solve the problem rather that giving it up. Please help me. This is my first forum so have patience with me. Thanks.
  • nicanica Posts: 4
    Thank you for that information, it is helpful!! Could there be a chance that the noise could just go off by itself? Also My service engine soon light keeps coming on reading code 00446 which indicated that it needed new spark plugs so they were fixed but the service engine code still comes on reading the same code any suggestions?
  • repairdogrepairdog Posts: 948
    Doubt it but maybe - turn the radio up!
    The P0446 has nothing to do with spark plugs, the code means: "Evaporative Emission Control System Vent Control Circuit Malfunction" so it could be the gas cap or the canister up front or the vent above the gas tank that may be defective. Posted this answer a few weeks ago. For all readers these codes are easily found with a simple search and most auto stores do free code readouts and clears - if you get a code write down what it was and then have them clear it as a first free test cause it may not come back!
  • repairdogrepairdog Posts: 948
    I'll remember this one - the switches in the doors have this same problem and the windows and locks quit till a ground is added to the door from the frame due to the crappy pins/bushings we all replaced at least once! Good find!
  • burnout3burnout3 Posts: 1
    I bought this 91 S-15 Jimmy and i can get it to start after sitting a day or two. After that it won't stay running it dies right after it starts. I've changed the plugs, plug wires, cap and rotor. Oh and fuel filter. I pulled the plug from the #4 and it was blacker than well you know. It looked liked it was in there for ever, A new plug looked like that. After that I checked the oil and it was 4-5 quarts over. I drained it and put new oil and filter on it. It still does not want to stay running or start up half the time. I looked at the end of the tail pip and it rusted away so under the right rear corner its black like it was in a fire. A ralitive said it might be the O2 sensor or the EGR valve. What is the problem.
  • mongo1mongo1 Posts: 49
    Hi Jimmyowner, Yes, ball joints are a problem on these vehicles. But a more prevalent problem is the wheel bearing hub. These are not like NORMAL wheel bearing set ups. They are a press fit into a separate hub and, depending who you talk to, go bad anywhere from 35,000 to 75000 miles. I just replaced my right front bearing assembly at 100,000 miles. Lucky I guess. My Jimmy is a 2000 4WD and was making a similar noise as you describe. To check, jack up the front end and spin each wheel. It should spin free with no noise. If you get a clicking sound, or the wheel does not spin freely at least one revolution, you probably will need to replace the hub. You can do it yourself, but if it has seized to the spindle, you are going to be in for the fight of your life. Avg. cost to have it replaced is about $400.00 per side. GOTTA LOVE THEM #$@%&; GM ENGINEERS. :confuse: By the way, you need to check this out quick, it is dangerous to drive around if the bearing is bad. Hope this helps, good luck
  • repairdogrepairdog Posts: 948
    There are now 2 little cone shaped washers the dealer sells that go on the hood hinge bolts that often fix this dealer part #12383460 about $5 each and easy to install. Try these before anything else! Easy test is to open hood and put small towels in the hood/fender gaps and close - if noise goes away thats wghere it came from.
    Then there are the brake caliper slides worn or needing grease, the sway bar mounts, the shocks, a-arm bushings, hubs as you were warned (but these are usually a grating sound and if you turn left putting most weight on the right front wheel it would be louder - opposite for the other side). There are also the the spring isolator pads (2wd) or torsion bars (4wd) that can clunk. Then on the 4wd also have the CV axles, front diff, and transfer case. As an added item if you have the 4 button Autotrac 4wd, the transfer case fluid has been a problem and is now blue dealer only item and the clutch packs in the transfer case can clunk. And finally, on my 99 4wd, after backing up and on speed bumps, after I checked all these and replaced many - still have the small clunk, so..... possible body or fender hardware problem. I am used to it.
  • repairdogrepairdog Posts: 948
    No way 4-5 qts over - if so those plugs are probably fouled out so replace again. Do you have any fuel pressure at the TBI (throttle body) cause sounds like starts and then stalls may be fuel pump. Rust in the tank? Which motor is this cause the 4.3 had fuel injection problems and leaking regulator all located under the plastic intake cover. 91 so do you even have a spark at the plugs? Need more info - could be coil, ignition module, etc and this baby ain't too new is it and wasn't taken care of it sounds - at all.
  • pete6266pete6266 Posts: 1
    Replaced water pump,thermostat,antifreeze.Only time I get heat is when temp control is fully clockwise.
  • zippo99zippo99 Posts: 1
    I have a pulsing/clunking noise when braking coming from my front right wheel on my 1999 Chevy Blazer 2-door 4wd V6. Normally I would assume that a pulsing means a "warped" rotor, however, I replaced the front two rotors and pads with no change. Then I thought that the guide pins/bushings might be allowing the caliper too much play to "jiggle around" so I replaced the bushings, no change. Then I noticed that the caliper was very rusted, but after changing the right front caliper, surprise, no change. I even tried removing the ABS fuse to no avail. I had the rotor checked to see if it was "true" and it is. The rotor I replaced on the front right side had a lot of glazing and pits on the inner side. Also, the tire has a good deal of wear on the inner tread but not on the outer. After an exhaustive search on the net and this thread, I think it might be either the control arm bushings or the wheel bearing or hub. This only happens when braking. When I go to step on the brake at around 35+mph, it pulses violently and quickly, and as it slows down, a clunking noise gets louder as the pulses get slower. Any suggestions?
  • impalacabimpalacab Posts: 11
    Hi, I´ve checked switches and sensors, they seems to be ok, and have power. I´ve checked the vacuum actuator, and it seems ok, pulls the wire real strong. I´ve raised the car and, but still no rotation on the front wheels. Since the the vacuum actuator works and pull the wire, should the problem be in the front differential?? I don´t have an exploded view over the front differential. How do the wire activate the differential? Is it possible to fix at home? Is it fixable without taking it away from the car? Could I download an exploded view over the front differential from somewhere? Etc? Have a nice day.
  • repairdogrepairdog Posts: 948
    Did you flush the heater core? Most Blazers lose this at some point and GM knows that the Blazer line is the most prone to Dex Cool core clogs due to air getting in the cooling system. So, to flush, my method (opinion, not GMs) is to remove the ends of the heater hoses at the engine side (follow the 5/8 and 3/4 hoses from the firewall) and unclamp them, then using a garden hose simple hold the hose end on one hose and let the water run out the other. (don't get the dist all wet so cover with a plastic trash bag if you make a mess like me) Why this way - a chemical flush always takes the core out within a short time (pin hole leaks start) and you will smell the Dex cool in the air vents - not very good for you and Dealer charges about $600 to replace - dash has to come out. This limits the water pressure too so you don't blow the core yourself.
    Hope you did a good flush before the new WP, cleaned the reservior out, and changed to an after market cap. Keep the reservior at the Hot level when the Blazer is Cold to ensure no air in the system - and speaking of air - is the temp OK now cause air in the system causes temp swings so watch that - may have to bleed the system.
    Next, is this a Climate Conrol Blazer (temps on center dial) cause the electronic blend motors fail and the control head can too big $$ so search earlier posts.
    Another thing is rent (free) at an auto store a cooling system pressure tester and pump the system up and see if it does not leak - another possible area.
    Let us know what else you need or the fix for others.
  • repairdogrepairdog Posts: 948
    Did you check all 4 discs? Rears can sound/feel like fronts. Rears need turning with the fronts and the single piston calipers are junk so get rebuilts on a brake job. To check the hub jack the Blazer up and support under the lower a-arm so the CV axle can freely turn - you will feel and hear the grating if its bad - really bad can clunk but did you do the lower ball joints yet - #1 Blazer clunk area and you can't usually feel any movement with the front jacked up. Most alignment shops can test these and then alignmnet should help the wear - run at 35 psi and rotate regularly on Blazers. The idler arm can allow wear on Blazers too - frame to tie rod arm and you can see/feel movement with a side to side tire hand wiggle (all have alittle I mean see/feel the arm flex up) -again the shop.
  • repairdogrepairdog Posts: 948
    Yes, there are diagrams on some online parts stores but I am not allowed to give you the links per this sites rules. After looking at the first post, what makes you think the 4wd was not working - will the selector on the dash engage and the light go solid on 4Hi and then 4Lo? Means alot to resolve. On that front axle coupler the cable pulls a gear to connect that passenger side right axle - seen posts of the gear sheared/worn bit again more indications?
  • taiu476taiu476 Posts: 2
    Can anyone tell me where all (3) O2 sensors are located on my 2001 blazer? I know where 1 on the air intake is located but I have no clue about the rest of them. Also, does anyone have any ideas on what could be causing vibrations at about 65 mph? I dont think it is suspension or tires, etc. Are CV joints a possibility? What about all this talk about ball joints going bad on Blazers? Well, I am very new to this posting of questions, but I will thank all of you in advance for any responses I get.
  • repairdogrepairdog Posts: 948
    That one on the air intake is an air temp sensor, not O2, and the other is the MAF. Look on the exhaust for all the O2 sensors - see them 3" long screwed into it. 1 on each side right below the exhaust manifolds and the other behind the cat converter. The SES light will come on if they go bad normally, so has mileage dropped or what? As to ball joints and vibrations, search the forum for many recent posts on them, in fact scroll up a few pages and many are there.
  • impalacabimpalacab Posts: 11
    The selector on the dash turns to solid light on both 4Hi and 4Lo. When I have the car raised and engine running and put in gear in 2Hi, the rear drive shaft rotate and the rear wheels turning. When I put in a gear in 4Hi or 4Lo, the front and rear drive shaft rotates, but only the rear wheels spin... There are no visable damage anywhere on the front differential, axle, tubes and so. The vacuum activator pulls the wire, and I can pull the wire by hand when I disconnect it from the activator (but it´s hard to move).
  • taiu476taiu476 Posts: 2
    Thanks repairdog, for the info. Yes the service engine light has come on and I have lost a lot of gas mileage. Could O2 sensors be responsible for running slightly rough too? Is there any way of testing o2 sensors or do you just go ahead and replace em any way? I have almost 90,000 miles on Blazer so is it a good idea to go ahead and replace em? Also, I am planning a tunep. planning on new spark plugs, New K and N filter element (Old one hopelessly dirty), and replace o2 sensors. Is there anything else anyone can think of that would be a good idea to check into? Thanks repairdog and all else who reply.
  • repairdogrepairdog Posts: 948
    First go to the auto store and get the codes read out to tell you if one is bad. If that air filter is that dirty a new one may be the fix, plus your MAF sensor is now probably really dirty so spray it with MAF cleaner (or electriacl contact or brake cleaner) and that may fix mileage too. The K&N works great but don't over oil it or it sucks onto the MAF sensor. Plugs (platinum) and a new cap/rotor, PCV, fuel filter (every 30K min)and check the plug wire resistance and be careful and rotate the ends before pulling off the plugs or you will be buying wires!
    Hope you flushed that Dex cool by now and got a new cap too - many posts on that issue. Don't forget the trans (and xfer case if 4wd)fluid change.
  • Have 92 S10 Blazer V-6 4X4-It was hit on side and totaled. I found a 92 donor without eng or trans w/ good body. I have already removed eng from one wrecked. The wiring harness on donor has been cut in eng compartment. Looking at eng. compartment and to the left and below A/C you have A wire harness that enters the vehicle. How do I go about removing that harness? I am also going to pull ECM.
    Thanks for any help. :confuse:
  • repairdogrepairdog Posts: 948
    Mine are 98up 2nd gen Blazers but most of the harnesses come thru a firewall grommet and the plug end (ends) is behind the dash or kick panel - not much help here. Hope someone replys with help but keep searching. Seems like mostly newer Blazers on this forum. Splicing may be risky cause thats a high moisture/heat area with AC and wheel well splash.
  • jimmy94jimmy94 Posts: 6
    vortec 4.3 in a 94 blazer has no power
    it takes me several miles to get the thing up to 55 mph
    and it does not go over 65 mph
    rpms and temperature are good, so is compression and fuel pressure
    the engine sucks down the gas because i have to keep the pedel on the floor when on the highway
    the trany seems to be shifting ok, overdrive, locking torque, and is in 2wd
    i also checked timing and spark
    i am guessing TPS or maybe something wrong with the cpi and the popet nozzles
    if any ideas please let me know
  • repairdogrepairdog Posts: 948
    That actuator pulls a gear to couple the right pass axle so from what you say I would suspect that is the area to examine. When that axle is coupled and the front drive shaft is turning you should have at least one axle/wheel turning thru the front diff -if that was bad then you would have grinding. Its a 98 so 3 button 4wd I assume (not Autotrac or 4 button cause that is not engaged until wheel slippage sensed via the ABS sensors if selected and the transfer case has clutches in it).
  • hey can anyone help me on this i am trying to figure out how u replace the front side turn and parking lights. i throught i could get to it by takeing the battery out but there is still no room to reach it . is there an easier way of doing this . ? thanks
  • Hi all! I own a 96 blazer with a miraculous amount of miles on it and it's been a good vehicle but my DRL's flicker when the lo beams are on, and when I use my turn signals. It doesn't do it when the hi's are on. It also doesn't do it when only the DRL's are on in the daytime.The relay also clicks to match the flickering which is alot like a strobe light. I've replaced the relays,bulbs,on/off switch and checked the wiring.Could it be the multi function switch that controls the dimmers, wipers, etc.?Please help! I actually have people pull off the road for me because they think there is an emergency lol.
  • impalacabimpalacab Posts: 11
    Yes, it´s a 3 button 4wd. And there´s no abnormal sounds at any speeds, no humming, grinding or anything. I suppose there´s some kind of fork or something like that, that´s pulled by the wire and couple the right axle? I think next step for me would be to drain the front diff and open it to have a look inside.
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