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Chevy Blazer GMC Jimmy Maintenance and Repair



  • First time posting to this list which has been a great help in the past. I'm the second owner of the truck, I've had it now for about three years. It's high millage with 160,000 miles but at the time I purchased it with 150,000 miles I considered it a good buy because before it was owned by a group of sail plane pilots who kept every record on the truck and it was very, very well maintained. In early Dec. of last year my Jimmy which has the 4.3L Z engine died on me but after a change of plugs, wires, cap and rotor, fuel filter and the addition of a Jacobs Electronics Ultra Coil the truck up until last week ran better then ever. It now dies at idle and when I go to accelerate it is very low on power although it seems to be firing on all six cylinders. when it shifts it's at high revs and the truck lurches and top speed seems to be about 35 mph. I've once again changed every thing I did back in Dec. and on the advice of an engineer at work I changed out the oxygen sensor with no improvement. I'm at wits end am sadly without a code reader. Any ideas would be greatly appreciated!!
  • repairdogrepairdog Posts: 948
    Advance and Autozone and most stores will read the codes for free (this assumes the SES light is on so a posted code). They also have a free handout that tells you how to read them out yourself cause thus is a 90 so believe old system and you can get the light to flash the code out. Very common is the old CPI and nut kit which is the injection under that upper intake - it leaks and does what you stated so do a search on CPI and Blazer and you will find many answers.
  • Thanks for the speedy reply repairdog. I see that you have been a great help to many. I've been pouring over my Chilton manual this morning trying to find any info on the CPI unit but with no success. I've done the search as suggested and have come to guess (probably mistaken) that CPI stands for Central Port Injection. My jimmy being a 1990 model is equipped with the Rochester TBI unit. :confuse: Would this still have the CPI and nut kit (supply lines)? Again, many thanks!!
  • repairdogrepairdog Posts: 948
    Sorry, missed that 90 date. No CPI on the TBI models only the electric injectors on the throttle body. You have the book so now check the fuel pressure to see if fuel pump related or relays.
  • No problem repairdog, figured that out this morning. have done a host of things mainly checking and re checking things in leu of having much to go on as far as diagnostic tools. I've noticed that there is no fuel entering the top left throat of the TBI. Is this the secondary? Noticed a pinched wire leading to the injector. Wire integrity seems ok, have insulated it the best I can. Have wired in a Jacobs FC 1000 ignition module and it starts with no problems so I can rule out any problems with the ignition system. I work at Mallory Electric so I guess I can talk to a few people there and maybe find out more.
  • I’ve been having a front diff. actuator problem with my 4wd ’02 blazer ZR2. With the vac. line above the driver side fender plugged in the actuator won’t engage below 35mph. While on the highway above 35mph (roughly) the actuator engages. It will not engage with the vac line unplugged at that speed. Are there any long term effects leaving the vac line unplugged while only in 2wd and does the speed have any effect on the vac switch itself? Is the vac switch the source of my problems? Thank you for any help
  • repairdogrepairdog Posts: 948
    Can't say for sure but if you disconnect the vac line under hood to the 3 port you must plug the engine side off (golf T is great). The 3 port switch on the case is about $20 so try that first (based on 3 button 233 case - tag on case - not the 236 4 button Autotrac case). Check all lines under and up to the front actuator that the vac engages and that pulls a cable to lock or coupler the pass side axle. Then at the same time (when you select 4Hi) the encoder motor on the case steps and engages the front driveshaft. So, once you select 4Hi axle couples and front shaft engaged and light on dash stops blinking and goes solid on 4Hi - if not the TCCM (4wd computer) did not get readings from the sensors on the axle and case confirming status.
  • repairdogrepairdog Posts: 948
    All mine are newer models so this is a reach back. The fuel pressure per Haynes is 9-13psi. Assembly has the throttle body and fuel metering controlled by the throttle position sensor(TPS) on the throttle butterfly shaft which signals the PCM that then determines the mixture. 1 injector is primary and 1 secondary as I recall (had a 350 Suburban TBI). Also an idle air control (IAC) on the TBI that maintains idle by air mixture. $15 Hayes shows most of this.
  • frschevyfrschevy Posts: 2
    I have a 04 chevy blazer 6 cyl 4 wheel drive.
    I purchased in Jan 07. (39,000 miles)
    Its been back to the dealer 4 times for stalling.
    I'm just driving down the road and its shuts off.
    I still have power but the engine quits.
    so for all that has been done is (replaced)
    the distributer cap and roater,the coil and something attached to it. They can't figure it out. I don't get any
    check engine lites. Im pritty sure the problem is electrical,but who knows. Can anyone help this is driving me crazy.
  • jlflemmonsjlflemmons Posts: 2,242
    Crank shaft position sensor??? If intermittent it will not set a code. But the fail mode is that it thinks the engine is not turning and will shut off the fuel and ignition. One way I have isolated it is to try this. When the engine quits, WITHOUT TURNING THE KEY OFF try and start the engine. If it will not fire, turn the key to OFF, count to ten seconds or so, then see if it will start. If it fires right up, you may have an intermittent sensor. I have seen this on late 80's and early 90's, but the discription you give does seem similar.
  • repairdogrepairdog Posts: 948
    I agree that is often the one - my daughters 01 just did that and I replaced the CPS (use a Delco or standard motors sensor - many others are slightly off and effect timing). Then also if that simple $60 part that takes 2 minutes to change is not it, look at the idle air control (IAC) valve on the side of the throttle body - its electric and controls the air to keep the idle stable - connector can be kloose or ther IAC or passage all full of crap. Then GM has had some failures in many models due to the PCM seeing a voltage drop in the ignition switch (actually the wires and connector in the column) that shuts the engine off. Often associated with blinker being on at the same time and only fix is replace that ignition switch (again not the key/tumbler). This last one is not common and only a real electrical guy has any hope of finding but the dealer should have seen info on this. If the other 2 fixes don't do it insist they replace the ign switch. Hope you are still under warranty. Post the final cure so all know please.
  • auto9999auto9999 Posts: 86
    Last few days, the heated seats of my 2000 Chevrolet Blazer are always on, regardless of the position of the switch. Is there an easy fix? (I know that the easiest fix would be to remove the fuse.)
  • repairdogrepairdog Posts: 948
    Cheap plastic switch and the back retainer clips all break. On my 99 LT I poped the side off and added a nylon twist tie to hold it in place - but also pulled the fuse under the hood in the block - its also for the lumbar so thats a personal choice but the switch was always getting turned on and in FL a might tooo warm for me!
  • auto9999auto9999 Posts: 86
    Hello, Repairdog. For some reason the heated seat problem fixed by itself. I will keep your advise for the future. Thank you very much for your advice.

    By the way, Host Mr_shiftright, I see too many threads and find it almost impossible to read a thread to obtain general information. I enjoyed reading this thread to forecast my future problems but I cannot now. Also there are so many threads that deal the same topic and the the number of topics is proliferating.
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,328
    Would this "view" be of any help.

    I got this by using the "browse by vehicle" drop down window on the left of this page.

    I'm not your host on this board, but I'm glad to help and I'm sure the regular host will as well, if you need more assistance.

    WE also have a "help" feature at the bottom of this page, and you can also e-mail any host by clicking on their name (preferable to posting navigating questions here).


    Host Wandering Around

    MODERATOR --Need help with anything? Click on my name!

  • tidestertidester Posts: 10,059
    Also there are so many threads ...

    We have moved away from the "single topic" model which resulted in many of our topics exploding into 10's of thousands of messages. That made it difficult for people to find what they needed. With the current "polytopic" model it should be easier to pin down the right topic but, as you point out, the topics do proliferate!

    I would ask everyone to search through the existing topics before creating a new one. The hosts try their best to avoid duplicate topics. In any case, those topics with one or two messages should trail off into obscurity while the more popular ones will remain near the top of the topic list.

    tidester, host
    SUVs and Smart Shopper
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,328
    DUH! I told him about the "view" for searching but didn't include it.

    Okay here it is. Maybe this will be helpful!make=Chevrolet&model=Blaze- - r

    MODERATOR --Need help with anything? Click on my name!

  • auto9999auto9999 Posts: 86
    Thank you, Hosts Tidester and Mr_shiftright, for your prompt replies. Taking this opportunity, I would like to thank you for your nice work to run this very informative and enjoyable forum. I believe that many Blazer-lovers are feeling the same way.

  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 57,328
    See post #2966 and see if that helps.

    MODERATOR --Need help with anything? Click on my name!

  • mporubcanmporubcan Posts: 2
    Have a 98 blazer with 280,000 miles.
    Recently. at steady speeds above 25 mph or so it with have a brief (< 1/2 sec) hesitation. This will happen every few seconds or so (not consistently). This hesitation is slight enough than even sometimes the passenger will not feel it. Generally the motor starts/idles and accelerates without issue. There are no trouble codes coming up. Any Ideas?????? Thanks!
  • repairdogrepairdog Posts: 948
    Nice going on 280k! Assume 2wd.
    At that mileage it could be a multitude of things but right off I'd look at the vac lines underhood drivers side for rot and follow to the reservior in the fender. Then check PCV and hoses. Clean the MAF sensor in the air intake. Then if the fuel pressure is in limits after an actual test and filter is new, I'd look at the throttle body if this is off the line pause - there is a throttle position sensor (TPS) and an idle air control (IAC) sensor so that requires pulling the throttle body off and cleaning it. That IAC often sticks and air seat all crapped up and you get the engine doing a slight rpm quiver or actually dies then instant restart - IAC is controlled by the PCM for mixture and thus idle rpm. Assumes good cap/rotor (Delco or Standard Motors Product not cheapos), plugs and wires, and a clean air filter. This is a small list to start with. The injection system could have a dirty or sticking poppet but that usually gets a rough or intermittant idle shake and you feel that on accel and most oftem get the code for a misfire.
  • bgdobrobgdobro Posts: 1
    repairdog this is for you, had my 95 in for oil line replacement, and inquired about lower intake manifold leakage as this unit has 184k miles and it appears that most of the trouble in this area rears up at about 100k miles. Repair tech said that I had the old type paper gasket which was much less prone to leakage. It would appear that this was a very early 95 as it was a manufactures lease vehicle; does this fit with your experience in this area.
  • Ok... OEM stereo cd and speakers in my 1998 Jimmy. I was playing Metallica really loud but only so loud that it wouldn't sound distorted. The driver side rear speaker stopped working and the driver side front tweeter stopped working. All other speakers work fine. is there a crossover for the component setup? if so where is it? Or is that not the problem? I don't have time to figure this one out... but i do know it's not the speakers... tested them and they work fine. Help :(
  • repairdogrepairdog Posts: 948
    Sounds right as 94-95 had a torque of like 36 lbs while the 96 and newer went to 11 lbs! If you torque the newer one higher the block can distort so I'd guess a block redesign about then - 4.3 went thru many changes and theres 10 pages on differences. Keep it running! Thanks.
  • repairdogrepairdog Posts: 948
    First upgrade to any of these is all 4 new speakers - the stock unit sounds pretty good then and for another $150 you can get the newer aftermarket unit with aux inputs for ipods. All 4 speakers are 6.5" and all the majors have the GM connector so they connect without cutting wires. The rears actually are heard more than the fronts by the driver. The stock unit commonly only loses the CD drive in total.
  • cairnscairns Posts: 4
    I have a 96 Jimmy and the wipers are doing just that, thank you for the tip. Excellent
    Regards Ron
  • eagleeyeseagleeyes Posts: 1
    I had a similar problem. I could not shift out of park unless I removed the boot and used the manual override and shifted.

    I just talked to the mechanic and he is saying that it is the stop light has failed and prevents me from shifting as a safety precaution.

    Anyone heard this one before?

  • repairdogrepairdog Posts: 948
    2 parts to that switch - one for brake lights other tells system you are stepping on the brake so let them shift. Manual has the clutch safety switch.
  • jmbeazjmbeaz Posts: 5
    Looks to be electrical problem, but where? Battery, alternator, starter all good. When I turn the key the dashboard does not show warning lights. Cranks but it will not start. I tried to talk to the computer, but it will not respond. What can the problem be?
  • repairdogrepairdog Posts: 948
    Could be many things but the 97 only model has a known defective ignition switch (really the wiring and harness in the steering column) and that can cause any of the things you stated so sorry, thats #1 to do.
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