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Chevy Blazer GMC Jimmy Maintenance and Repair



  • repairdogrepairdog Member Posts: 948
    97 known for faulty ignition switch module in the steering column - search and the info is there. First place to try with those electrical problems. Front drive shaft always spins and there is an axle coupler on the front pass side that engages the pass side. Axles splined to the hubs. 4HI only couples that axle and 4LO engages a lower gear in the transfer case as well. Check the vac lines as I just poeted above in #2385. Then on from there.
  • sharon77sharon77 Member Posts: 1
    I have taken my blazer to be repaired numerous times. I had to replace the cat converter, which collapsed, the muffler, o2 sensor, mass air flow sensor and it still hitches. My mechanic suspected the egr valve but it didnt set a trouble code. He cleaned it, free of charge, but it didnt make a difference. It seems to get worse the further I drive and gives the most trouble going uphill. Any suggestions? Its a 96 with a 4.3.
  • repairdogrepairdog Member Posts: 948
    Think you mean surges/bucks/shakes/spits which with heat could be the coil. Was the Blazer put on a scope/analyzer and the firing pattern looked at? Did they test the fuel pressure as the pump gets old it could heat up and pressure could drop and if lower than 54psi would be a problem running. Fuel filter OK?
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  • bntapplebybntappleby Member Posts: 1
    My Jimmy's AC blows only through the defrost vents. Can anyone help me figure out what is wrong? Thanks!
  • repairdogrepairdog Member Posts: 948
    The selector on the dash goes to a vacuum operated driver that moves a door in the heater box so would look behind the glove box and see if the vac lines are connected to it and then a few metal rods move and could be stuck or disconnected. Models differ and some use a cable not vac and climate control ones (temps marked on selector and auto settings) also have an electric blend motor on the heater box. Any AC shop should be able to fix this.
  • kmbsinkhornkmbsinkhorn Member Posts: 1
    A couple of weeks ago my blazer got to where some times it would take several turns before it would start. It got better, then worse. Most recently it took about 6 turns. Today it quit all together and when I tried to turn it over it clicked several clicks. It did this several times. 25 minutes later it started fine. I've heard everything from starter to fuel filter to battery cable. Any guesses?
  • repairdogrepairdog Member Posts: 948
    Would test the battery first - sounds like its dying or has lost a cell so take it to an auto store and they will load test free. Is the alternator still charging (13-14V on the gauge) and store can test free too. If those 2 are good then same store should see a high current draw when you start and pinpoint the starter. If starter is going the bearings/bushings wear down and the armature drops and if you give it a good rap with a hammer (3 lb one) and it then starts - its starter time.
  • ladydemonsialadydemonsia Member Posts: 5
    i have a 92 s-10 blazer 4.3L 6cyl that seems to idle irractically and will stall at full stops (only some times). sounds fine during acceleration. the vehical responds the same whether hot or cold. We have replaced the plugs, wires, map sensor, fuel filter, air filter and egr valve. we have NOT replaced the O2 sensors yet. nothing seemed to help except the map and egr and that was only temporary. someone suggested cleaning the maf sensor, but i don't know where this is or how it should be cleaned.
    we also get heat coming out from the floor vent with the a/c and heat off. is this from the climate control or heater core? there was another post with gurgling and i wasn't sure if the issues are related? we are planning to replace the digital dash, so it would be a good time for the heater core anyways...
  • jnkraabjnkraab Member Posts: 2
    I have a 96 chevy blazer with the 4.3 vortex v6, and after getting my fuel injectors cleaned, the truck started great and ran good for 2 weeks, now it all of a sudden it takes a couple of cranks to get the truck to start, after it does it runs fine, but when it does start from the back of the truck it seems like its running rich from the fuel you can smell from the cranking. also if you shut the truck off and start it again it will start fine, but if you let it sit awhile, you have to crank it like up to six or seven times to start again. any ideas? is it a fuel regulator that is not holding back the fuel on start up?

    thxs for any help
  • repairdogrepairdog Member Posts: 948
    You don't have a MAF - you got the older model with the map - any codes on - SES or check engine light on? Did you repkace the cap/rotor too I hope. The older CPI injection can leak under the intake and may require replacement (search above and many posts) but you should be smelling a heavier gas small than normal - look on the dip stick too and smell that for gas. Check fuel pressure cause low will cause bed idle or be related to the CPI.

    Believe the older model have a heater control valve in the line in the engine compartment that may be frozen on allowing hot coolant to always circulate (nwer models do not have this - always flows).
  • repairdogrepairdog Member Posts: 948
    Check the fuel pressure - requires 60 psi cold start and 54psi to run. Possible that the cleaning damaged the regulator or injector poppets - cheap design with mostly plastic parts. As for the cranking - have to ask but how is the battery and alternator - get them tested at the local auto shop its free and a failing battery/alt can cause many problems on Blazers with a lower voltage. Don't assume fuel only. In hot climates I only get 3 years from a 3 year full warranty battery so been there often. Alts average about 60-80k as norm on Blazers too.
  • jnkraabjnkraab Member Posts: 2
    the battery is 6 months old and alt is 1 year old, battery cables were replaced 2 summers ago...this morning the truck started better on 2 cranks to go but still seems harder to start then there any way to know if its the regulator or poppets? or should i replace both?...also the poppets, are they the injectors or part of them and can i buy these parts seperate and are they hard to replace?

  • repairdogrepairdog Member Posts: 948
    Check the fuel pressure first if thats the orginal fuel pump. The CSFI system has 6 separate injectors each a plastic tube with a small poppet or injector on the end that clip into the intake under that plastic upper intake cover - these are fed by the central assembly or spider that has the regulator and the electronics that distributes the fuel - the fuel rail is bolted into this (see the 2 metal lines from the rear of the engine) and this has a test port to check the pressure. Each piece is not cheap but if this turns out to be bad GM now has a new replacement system called MFI that bolts right in and replaces the whole mess as one piece (redesign). Search the internet on this and you'll find the system - not allowed to get other links on this forum and the article is in pdf so can't paste it.
  • kennedbkennedb Member Posts: 3
    Original Post: (2382)
    Vehicle stopped running while moving down highway. Attempted to restart and will not. Battery just replaced. When attempting to start the engine vibrates/shimmys like crazy. Thought it was the timing chain...checked it and it looks good.

    Update: Installed new fuel filter still won't start.

    Observed another thing when attempting to start: When Key is in On Position Gas guage shows full and when attempting to start (turning engine over) the gas gauge shows empty.
    Is this the on-board computer giving a hint or code as to what's wrong?
  • pgurganuspgurganus Member Posts: 12
    i have a 2000 blazer.when i give it gas slowley it accerates fine till about half way of the pedal then it will lack on power and sputter. when i punch it it just sputters and dont want to go. today my wife and i went out in it and barley made it home it was like it had no power at all changed 2months ago cap roter wires pulgs fuel fliter ran injector cleaner in it still same service engine light is on.if that helps.also took out all 3 o2 synsors and tried it same thing. can some one please help me
  • auto9999auto9999 Member Posts: 86
    I would doubt a clogged exhaust system
  • repairdogrepairdog Member Posts: 948
    Just saw some info on the defrost problem - if the controls have lost vacuum they default to defrost so look under your hood on the drivers side and see if the vac hose 5/32" is rotted/broken. It feeds off the intake to a T and to a reservior in the fender and I have had to replace all these lines on my newer models also. You can get your hand to the reservior hose with a few trys, really. That plastic line that Ts off should go to the heater controls so if the lines under the hood don't solve it you will have to get to the back of the heater conrols and make sure the line is plugged in. Let us know if that works.
  • repairdogrepairdog Member Posts: 948
    Check the fuel pressure at the rail test port. Key on engine off should be 60psi. When you turn the key on (not try to start can you hear the pump running?
  • repairdogrepairdog Member Posts: 948
    Fuel filter change (under inside frame rail under drivers seat area). Is the air filter clean. Clean the MAF sensor above the filter with spray MAF cleaner or brake (not carb cleaner and be careful don't break a wire on them). Then fuel pressure test as posted many times above. Then I would get it to a shop and put it on an analyzer/scope and look at the ignition circuit/firing pattern and rule that all out first - yes bad plugs/cap/rotor/wires - can happen. Or a sensor failing but should get a code then. Report the fix for others or can feed you more to look at.
  • pgurganuspgurganus Member Posts: 12
    new fuel filte , plugs are a week old, wires cap, roter are less than 3 months old new air filter. when i got the plugs changed they put it on a analizer and no misfires,all firing is good and she starts right up,only on accleration it acts up. funny thing is its not getting a far as the 02's took them out and same thing and didnt even get a service engine light when i took them out.the place i took it to told me maybe a bad computer but i dont think so i think he wanted me to spend money if u know what i
  • pgurganuspgurganus Member Posts: 12
    auto9999 did u say u would doubt or wouldnt doubt a cloged exhaust like maybe a clogged cat
  • lbp47lbp47 Member Posts: 2
    Did you find a solution to this problem? I have the same problem and am looking also. Any help would be appreciated. Thanks
  • pgurganuspgurganus Member Posts: 12
    i think i found the problem,i unpluged the 2 synsors on the air in take from the filter 2 the carb and no more problems so i am going to assume that was the MAF? CORRECT? now my service engine light is on so i am going to go get those 2 synsors can someone tell me what these 2 are. 1 of them is a box like deal the outher is a verry small one that goes inside the breather tube. she is running better but not quite like she should but no more sputtering and she will go
  • kennedbkennedb Member Posts: 3
    Have not checked the pressure at the rail test port. When key on (not trying to start) I hear nothing...don't hear the pump running.
  • repairdogrepairdog Member Posts: 948
    Small one is the intake air temp that is high resistance when cold so a high voltage (5.0) to the PCM and it drops as it warms. The honeycomb with the small resistor is the MAF or mass airflow sensor. I would suspect the MAF but clean it before you replace it and try it out (use MAF spray or brake but not carb cleaner). A new MAF is $150 or so and some sites have trobleshooting tests info on them like autozone.
  • repairdogrepairdog Member Posts: 948
    Only runs hard till pressure up and may be less noise after a few seconds - but look at the fuse box under the hood for the "ECM B" fuse for fuse pump/ECM/oil pressure power and see if its good, then replace the "F/PUMP" relay and see if it works. If its the pump in the tank its drop the tank and $300 for a pump (dealer is $450) plus labor.
  • pgurganuspgurganus Member Posts: 12
    yeah i brought it to autozone and the guy put the diagnostic test on it said that the maf is not bad so i showed him what i was talking about and pluged it in and got him to ride with me in the parking lot we got in i floored it and all it did was sputter then i got out and unpluged it floored it and lit up the tires.he didnt have anything to say then.lmao ..... so i changed more problems. thanks 4 all of your help with this problem. i have changed the MAF instead of cleaning it because i didnt need to pay 4 it lol.... thanks again 4 you all's help...............oooooooyeahhhhh back on the road again :):)
  • repairdogrepairdog Member Posts: 948
    If you are still working on this one here's some info I came across that may be your problem on starting and shutting off:

    "The ECM operates the fuel pump relay for three seconds or so when the key is turned to run. Then, as long as the ECM is receiving a signal from the crank sensor that the engine is cranking over, it will continue to operate the fuel pump relay.

    There is another system to power the fuel pump directly, once the engine starts, and that is an oil pressure switch. As long as there is at least 4 PSI of oil pressure, that switch will send power to the fuel pump, weather the ECM operates the relay or not."

    This all means the crank sensor could be bad or wires/connector bad(front of engine below the timing cover look from underneath) or oil pressure sending unit/wires(located in the back of the engine by the dist) may be bad or when you start this is there oil pressure on the gauge?? No pressure and its doing what it should - shut down. Let us know if you get this one fixed.
  • becky81becky81 Member Posts: 1
    Please help! I've asked several mechanics where the timing wire is on a '95 Blazer (4.3L). Every time, their answer has been wrong. This is about to drive me crazy! Please help!
  • repairdogrepairdog Member Posts: 948
    The #1 spark plug wire is the front drivers side one where you connect the timing light to trigger off. This is the one you mean: (pulled from search online)
    "2 versions on 95. If your ECM is under the hood on top of the coolant recovery tank (1st revision ODBII), then no, you cannot time it(ECM handles timing). If your ECM is under the dash then disconnect the brown or tan wire behind the passenger side carpet on the firewall to disconnect the distributor from the ECM, set to 0 degrees TDC, look at the crank pully, you will see 2 grooved marks on it. Use the one on the left to time with. When complete, reconnect the brown or tan wire behind the passenger side carpet".
  • the_jimmythe_jimmy Member Posts: 1
    How can i tell if the wheel hubs are bad? I have a 1999 Gmc Jimmy, when in 4 wheel drive the front tire wont spin. Like in mud or Snow. But i can feel the engine bog down. i feel the Transfer Case engage, and all the good stuff. But if any one can help me that would be great. :cry:
  • titanic1912titanic1912 Member Posts: 2
    We have a 1999 Chevy S-10 Blazer which we have now replaced the fuel pump 10 times in the last 2 years, we've also replaced the CPS, TPS, Rotor, Cap, Plugs, Wires, Ignition Module, Fuel Pump Relay, Fuel Pressure Regulator & electrical connections on fuel pump. We've also replaced the fuel filter after every pump change. The last pump lasted only 3 days. We have checked for recalls and there are none for the 1999 S-10 Blazer fuel pumps. Does anyone have any further suggestions on what to try next? We are desperate. We appreciate any advise we can get. Thanks!!
  • repairdogrepairdog Member Posts: 948
    Are you buying the Delco pump or aftermarket and who is putting these in? Is the return line crushed or blocked - by doing a pressure test at the rail the specs are 54-64psi for a new pump and if the line is a problem its goes up to over 70psi. Voltage at the pump correct?
  • repairdogrepairdog Member Posts: 948
    Hubs contain the wheel bearings and the front CV axles are splinned into them - they grind/grate when failing and are not the problem. Sounds normal to me.
    All power goes thru the transfer case even the rear wheel only or 2HI, The case engages 4LO gear by an encoder motor. For 4HI (and all 4wd modes) an axle coupler on the pass side engages or locks the axle (look under and see the cable and sensor on the front diff). The front diff is open or has no posi unit so only the wheel with the least traction drives - same with rear unless you have the G80 option (look in glove box). If you have the 4th button "Auto" then the trasfer case has a posi type clutch pack unit in it that allows driving on pavement in any condition - it can slip or allow diff front rear wheel speeds. Front drive shaft always turns too for all 98up models for shift on the fly. Try a hard start on a loose dirt road and have someone watch the front tires for spin - one should at least.
  • mstafformstaffor Member Posts: 4
    I was reading posts on rough idle on GM products. What is a "CPI" unit and how does the "pop valve in the CPI injector work"? I have replaced the IAC, EGR, MAP, throttle position sensor, fuel pressure regular, and 02 sensor as well as the distributer, cap, coil, wires, and Throttle body. I still have a rough idle (not always) and it gets worse the longer it idles (93 GMC p/u with a 5.7 liter, 350 CID engine). Off idle and under a load it runs great! Vacuume at idle is fine. The fuel injectors (2 each) and the enginer computer are all I can think of that are left in the system. It does idle better with the airconditioner on for some reason. No codes. It feels like a lean idle condition from a carburator system (lean roll). If the engine were not a new GM engine (2000 miles on it) and I had not had the problem on my last engine I can think of lots of things that could cause this.

    Any suggestions?
  • bivenserbivenser Member Posts: 2
    First off I am glad I found this forum. There is a lot of great information here.

    Now to my problem. Long story short, 2000 blazer stalled out and would not restart. Engine really struggled to run at all before it died. Then would not start. Got it home and had it running by putting gas in the intake. Then would start on its own and ideal but dies when in drive and the gas pedal is touched. I changed the fuel filter, checked the fuel pressure, changed the fuel pressure regulator, MAP and TPS. All of this with no service engine light. After all that it popped on. Got a reader and it stated intermittent crankshaft sensor P0339. So I switched the sensor. No luck. I am going to check the voltage into the sensor to check the wiring but other than that I have no idea. Any ideas or advice would be greatly appreciated. Thanks,

  • repairdogrepairdog Member Posts: 948
    All those are s-10 blazers with 4.3L motors.
    You have the 5.7 with throttle body injectors I believe - correct (looks like a carb or throttle body with the small injectors sitting on top of it with wires feeding it)so would guess its the idle air control valve on the throttle body but been awhile since working on these. AC on ups the rpms thats why it helps. Check the online auto store on this part.
  • repairdogrepairdog Member Posts: 948
    Unplug the connector to the MAF sensor in the intake above the air filter (larger connector of 2 - other is air temp sensor) and see if it runs better. If so clean or replace the MAF. If this is not it reply and I'll look up the crank sensor relearn procedure that may help.
  • titanic1912titanic1912 Member Posts: 2
    Thank you for your quick reply. Originally we replaced the GM pump with a Delphi which we have now put in 7 of them, then we switched to Carter & have put in 3 of them. Carter is the pump on it currently. The return line is not crushed or blocked, voltage at the pump is correct. We had an ASE certified mechanic who has worked for a GM dealer check it the first few times, then we had a local ASE mechanic change it the last 2 times. PSI is always in the proper range. We have even thought about contacting GM direct and sending the receipts of everything we've replaced to them. If you can be of any further assistance we would greatly appreciate it. Thanks once again.
  • tthomsontthomson Member Posts: 3
    Had a similar problem with mine after installing a new rt front hub/bearing. Had to do this 3 times. The first caused a knocking sound when turning. Replaced that with a second..the knocking went away but when applying the brakes over 40 mph the ABS would activate and pull it dead left (big time problem almost wrecked it). Hooked it up to a code reader and drove it. All wheels read fine till it got over 40 mph then the rt front would drop to like 20 mph. This made it think it was in a skid anytime the brakes were applied. Turns out that hub was bad too (theres like 200+ pins in it that the abs reads and some were damaged). Went with a new hub manufacturer and all has been well since. Hope that helps!
  • tthomsontthomson Member Posts: 3
    Have a 96 Jimmy with a strange grinding/whirring sound from the passenger side that comes and goes (sounds like a piece of plastic rubbing on a tire). The sound will come from out of nowhere and follows the speed of the truck in intensity. Usually if I pull off on the side of the road it stops and doesnt come back. Shifting to neutral does nothing but shifting to 4wd silences it but then I get a steady banging sound in the same spot in the front (sounds like driving on a road with expansion joints). It may happen once a week or once every two to three months not for any particular reason. The hub/bearing up there is new and the problem has happened before and after its replacement. It doesnt seem to come from the transfer case so I was thinking the differential or cv axles. Any help would be greatly appreciated.
  • repairdogrepairdog Member Posts: 948
    See if the CV boots on the out/wheel end are intact and if grease has been flying out. Diff check the 80w-90 gear oil level thru the upper plug. Is the 4wd acuator vac line OK and the axle coupler not partly engaging. Then if its random pull the brakes and look at the caliper slide bolts and grease them, check the stainless metal plates that insert/sit in the bracket that the pads slide on and make sure they are clipped in cause if they are partly out you get a noise as they contact the top of the rotor (on the vented rusty area). Try touching the brakes when the noise happens and see if if then lessens. See if the pads have the anti squeal shims on the backs (piston side) and if not apply the permetex blue stuff. Dry climates cause noise problems sometimes as well as sand/dirt in the brakes.
  • repairdogrepairdog Member Posts: 948
    That should have turned the ABS light on - if you remove the 2 sensor bolts and the sensor on the hub you can look in and see the square cut cogs that the sensor looks at and turn the wheel to look at all of them. I'll remember this one.
  • bivenserbivenser Member Posts: 2
    No luck with the MAF. If you could dig out the relearn I would appreciate it.
  • pspiesmanpspiesman Member Posts: 6
    Recently I noticed a relatively quiet noise when I apply my brakes. It sort of sounds like this... "fffffitt fffitt fffitt fffitt." I hear it when I apply pressure to the brakes and even a little after I have let up. It does not always do it, probably 70% of the time though. I checked my pads and they are good (its a not really a squeal anyways). Anyone have any ideas what to check next? Maybe its always done it and I just noticed it but I don't think so....

    Thanks in advance.
  • repairdogrepairdog Member Posts: 948
    Reread yours and the relearn is driving cycles which if yours does not run you can't do - only a scan too can help. But lets start again. Fuel pressure was good at 60psi key on engine off - correct - thats the start psi then if it runs 54psi lower. The crank sensor and cam sensor (in dist) send signals to computer to time it all and GMs have had pin problems so tighten the crank sensor connector pin connectors in the plastic connector (gently bend together) and try to start again. Did you disconnect the battery for 10 mins plus to reset the computer yet also. Check the wiring on both and trace for stripped or breaks (cam connects to back of the dist). Try those.
  • repairdogrepairdog Member Posts: 948
    Grease all the caliper slide pins front and rear - rears are always missed and they get stuck often and wear a rotor on one side - usually the inside that many don't look at. Start there and then the calipers should release fully and float/slide/adjust as required as the pads wear and brakes are applied. The pads are held close to the rotors by the caliper seals retraction and as you see the pistons are only on one side of the calipers so movement is required or noise happens - also make sure those stainless inserts in the bracket are clipped in (pads slide on them) and make sure the pads can move on the inserts and brackets - rust can hinder that under the inserts - had this on one that was from a northern salt use area.
  • jpmccrjpmccr Member Posts: 31
    I have a 01 Blazer LT (85,500) and love it. I have a few problems I read about in here and I am debating on fixing them. The issue with the blinking 4WD lights. It works so no problem right now. Not sure if I want to have the encoder replaced just yet. The gas gauge thing; so far it does not bother me that much. My daughter has the S-10 P/U and the same thing. However . . .

    In the morning sometimes when I try to start my truck, sometime I get nothing. Nada, zip. No lights, no radio, nothing. It is almost like the battery doesn't exist. I check my cables for tightness and low and behold the little engine compartment light comes on and and tada! everything is fine. Then there are the times it starts but it will not run. It is almost like it is flooding itself out. Drop it into Drive and it stalls. So I shut it off, give it a few seconds and insert the key and start it and hold it over a brief second and it runs great.

    I have also noticed that my instrument lights flicker at night when my lights come on. I turn the lights off and they stop. Bad rheostat switch? That is an easy fix. . .

    Would absolutely love to know if you have any ideas on this. Thanks. . . . .
  • nebulisnebulis Member Posts: 2
    Every once and a while the blazer will turn on the abs light and the parking break light. When this happens i have no power to the overhead console, power windows, vents, stereo or wipers (front or rear). What could the issue be?
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