Chevy Blazer Starting and Stalling Problems



  • repairdogrepairdog Member Posts: 948
    Should be setting body code DTC B2960 and is for 98-01 blazers. Look up GM bulletin 01-08-56-001A and its 5 pages long so detailed - Passlock is getting incorrect sensor voltage to the BCM (body control module). Could be broken wire, connector, bad terminal, insulation rubbed thru, etc. Main wiring from column to all so it could be anywhere almost so suggest a GM dealer - they have done these and few others have. Sorry.
  • preludeboy1preludeboy1 Member Posts: 3
    After checking the usual steps for ignition spark when cranking, if there is a spark then I would be suspicious of water in your gas tank. With the stupid problem of GMC fuel pumps burning out with low levels in the gas tank so ownes filling up with at least 1/4 tank all the time, these GMC trucks/cars are susceptible to water content build up in the tank causing spluttering and non starts when cold. Water is heavier than gas so lies at bottom of tank feeding the engine first and never mixing with gas. Remedy is to run tank to safe low limit and add water dissolver solution at next full fill up. Do this once a year in the winter when condensation/water build up is more likely. This is more common in colder & humid climates.
  • sands53042sands53042 Member Posts: 3
    Just wanted to thank repairdog for the advice on the no start condition on the 2000 blazer. It turned out to be the cap and rotor causing the problem. Everything is fixed, and working fine! Thanks again! :)
  • repairdogrepairdog Member Posts: 948
    Great! Glad you got it. Finding more and more aftermarket parts for the Blazers are not up to par and failing very fast so Delco ones are best or many are made by Standard Motors Corp so they have been holding up.
  • myblazemyblaze Member Posts: 3
    I just bought a used 2000 Blazer TODAY ... and, it's sitting in a parking lot right now. My son, a very new driver, went to get the car while we were paying the bill at a restaurant ... and, the next thing I know, the SECURITY light is flashing and the car won't start.

    The owner's manual led me to the Passlock section ...
    I followed the instructions ... waited 10 minutes ... tried again ... but, no luck.

    Any suggestions?

    David in Detroit ([email protected])
  • myblazemyblaze Member Posts: 3
    Awesome. We left the vehicle in the parking lot overnight and we're going to see what we can do today. Thanks VERY MUCH for your help. David in Detroit
  • myblazemyblaze Member Posts: 3
    The vehicle needed a jump start and there were no problems with the flashing SECURITY lights after it sat for 24 hours. Many thanks to everyone for the help.

    Any opinions about dealer service vs. a good repair shop?
  • buzzsaw1buzzsaw1 Member Posts: 1
    Ok, my truck seems to stall out for no reason. There is fuel and spark. When it stalls i lose all power. no power steering, brakes, stereo, dash, and all power everywhere. i think it has something to do with the ground because when this happens all i have to do is, pop the hood and shake the battery a touch. everything will turn back on and it will start right up. i am not sure what else i am supposed to check to fix this. i have checked the battery terminals and followed the cables to the grounds. they are all secure. Can i get some better ideas???
  • repairdogrepairdog Member Posts: 948
    Check the cables with a meter and shake them as someone watches - bad cable, terminal block, connector, or a battery or alternator problem - get them tested at most auto stores free. Also look at teh starter cables and solenoid connections for bad or loose wire.
  • larrysbarlarrysbar Member Posts: 3
    when the temp outside is below 40F it can take up to 10 try's to get the old girl started after that she runs great
    starts warm just fine
    is there a cold air sensor that is going bad ?
  • repairdogrepairdog Member Posts: 948
    Could be low fuel pump pressure or yes there are sensors. One for the gauge and one by the EGR for the PCM to sense temp - newer 98up only use one sensor for both.
  • larrysbarlarrysbar Member Posts: 3
    also looking to change the fuel filter after reading some post could be related to my problem ??
    how do I release fuel line pressure ?
  • repairdogrepairdog Member Posts: 948
    If its been sitting awile just slowly loosen the rear threaded line to the filter - it will drip no matter what so wear safety glasses. Believe the line end is metric and then filter US so get the right sizes and do not stip that nut on the line. Front is unclip type. Have to remove the plastic holder bolt to get filter out of it usually and new one back in it.
  • colorado2028colorado2028 Member Posts: 1
    :confuse: Okay, here is an interesting problem I have been trying to figure out and thought I'd bounce it off of everyone here. I have a 98 Chevy Blazer, 100,000 miles, 4 wheeled drive, 6 cylinder. Replaced thermostat, alternator and fuel pump over the past 2 and a half years. Do regular oil changes, etc, but when the ambient air temp is usually above 70 degrees, the truck doesn't start. The starter tries to work but nothing catches. Like no fuel but you could start smelling the gas after a while. When you can get it running, it runs fine with no problems excellerating or idling. Another thing just FYI....I live in Colorado Springs and we are in a high altitude area. The sales stickers on the truck from the dealer show it originally came from NY state but a high altitude region there as well. In the winter, works like a dream and it never over heats. Any ideas what it could be or how to fix it?
  • allicromallicrom Member Posts: 1
    Having major problems with my 2001 jimmy, Sometimes it will start with no problems at all, but usually it won't start with no crank, no nothing as if there was no charge in battery.(battery is at full charge) brought truck to gm they check thoroughly, they told me everything is working fine. starters fine, charging system fine etc... even got them to disengage remote start, no change. funny thing is when at gm garage, hooked up to their huge charger it started fine everytime??? been asking other mechanics for opinion, most usually said starter, crank sensor or even for me to run a secondary battery??? which if not necessary, im not gonna try.(haven't tried any) so after multiple towing and gm shop charges, i am still scrathching my head. Please help, any information will be greatly appreciated.
  • repairdogrepairdog Member Posts: 948
    If no SES codes, a full tuneup with a new cap/rotor, plugs and wires would be a good start. Then fuel pressure check, new fuel filter, air filter, and check the air temp sender in the air intake. Possible relay problem so switch the fuel pump relay with same type under hood ( believe 3 same ones). This assumes you are not loosing coolant into the motor due to a leaking lower intake gasket so watch the reservior for dropping/lose.
  • repairdogrepairdog Member Posts: 948
    First is put a new cap/rotor on - Delco or Standard not aftermarket cheapos - have to rule them out as often the cause and many dealers replace them as last step when no codes and random starts. Then check all cables and make sure the ends are all clean and the nuts tight. Check the rear pass side ground strap firewall to rear of block. If all are good then you have to suspect the coil or crank sensor having random problems.
  • jgoldencardjgoldencard Member Posts: 1
    I have a '97 Chevy Blazer (120,000 miles). A few months back, the car turned off and turned back on as I was coming to a stop sign. When this happened, the dash lights turn off, and the gauges all stop reading. It has only gotten worse since (turning off while I am on the freeway...), and now it will turn over, but doesn't want to start. When it finally turns on, the dash lights come back on, as well. I have replaced the cap and rotor, plugs, and gas pump, along with the fuel and air filters. I took it into the Chevy dealership and they couldn't find anything wrong with it. I am pretty sure it is electrical, but I don't know where to look. I am going to check out the wiring to the key switch, but is there anything else I can check while I am at it? PLEASE HELP! :sick:
  • rkmalone1rkmalone1 Member Posts: 2
    Figures...the thing is nothing but problems and one right after another, too. But today, I went to leave work and it wouldn't start. 97 Blazer LT, 4WD, 4.3 Vortec(God, I could recite that in my sleep.) 152,000 miles. Never has the thing done this to me before. 2 different shops have quoted me 500 bucks and the other a grand to change out the fuel pump. (Because I'm female ???) Either way, that isn't going to happen. So I know it isn't getting fuel and the first thing to think is the pump...BUT...could it be the relay instead? I was told that it's under the hood, against the firewall, now I'm reading that it's in the glovebox and on the left...Help.
    PS..anyone want to buy it? It's for sale and CHEAP. ;)
  • dougerwindougerwin Member Posts: 2
    For the past year I have been dealing with a starting issue that has finally come to an end. I have to turn the key to the run position, wait 2-10 seconds for my indicator lights to come on then it will start w/ no problem. If my brake indicator light doesn't come on with the rest of the indicator lights it will not start. lately it will just die and I will have to go through the process again, sometimes while driving all my gages will stop working for about 1-2 seconds then go back to normal, sometimes truck will die but not usually. Now, will not start at all- no indicator lights ,but, stereo, lights ac/heat, wipers window wash all work. Now when key is in run position will not even shift out of park, will crank but no power for fuel pump. could this be a computer problem or ignition?
  • repairdogrepairdog Member Posts: 948
    There can be several reasons but the most common the 97 ONLY has a known defective ignition switch which is actually the wiring and connector in the steering column (not the key/tumbler) that causes many strange electrical problems.
  • rkmalone1rkmalone1 Member Posts: 2
    No kidding? That's good to know. The problem I wrote about with it not was the fuel pump. $700.00 later, it's on the road - again. I am seriously losing faith in this truck. But what you've just told me is actually happening, too. There are electrical things going on with it as well. I can't move my seat or use the clicker on the keychain to lock or unlock it. It is a fuse that's big enough to look like a relay switch and I went to the Chev dealer in town to get it. It was fairly cheap...but once I put it in the fuse box, I have about 3 seconds to adjust the seat before that fuse is too hot to touch with my fingers. So it sits in the change holder till I need to use it. That, and sometimes my driver side window doesn't want to go up.
    Gotta love Blazers. Not really...but I can't get things done on it fast enough so that I can get it sold.
  • dougerwindougerwin Member Posts: 2
    Thank you very much repairdog I'll start there.
  • jtemple42000jtemple42000 Member Posts: 1
    I have been beating my head against the wall on this one. 4.3 V-6 Blazer, 130000 miles Over the course of the past few days I have dumped just over $300 dollars into parts and nothing has changed. No Codes other than a P0452 Evap low code(been getting this one for a while, but hasn't created any drivability problems.) The problem started while I was driving. The truck would run fine down the road then when I let off the gas to stop it would die. It always starts right back up. In two days it went from dying a couple times, to dying every time I stop. I have replaced the IAC, EGR, and the MAP sensor. Used a fuel pressure gauge on the fuel system and pressures are good. Used a scan tool to check other systems, MAF, IAT, TPS, etc, everything looks good. Heres the odd thing though. The new MAP sensor is giving some really strange numbers, same thing the old one did. Haynes book says 1.5-2volts at idle, I get 1.20v, and 4.5volts full throttle. As I depress the gas pedal, this number goes down, not up. The more pedal I give it the more the voltage goes down, never higher than 1.0 voltsand as low as .5volts. I'm going to try to swap out the new MAP sensor for another new one and see if I happened to get a bad MAP sensor, but if this doens't work, I have no idea what to look at next. PCM???
    Any help would be greatly appreciated.
  • scott7002scott7002 Member Posts: 2
    My truck recently started running like all cylinders weren't firing. This happened before and salvage yard said it was a vacuum hose that was cracked. Any idea what name might be of this hose?
  • preludeboy1preludeboy1 Member Posts: 3
    I would rule out the Map sensor & I'm assuming you checked the common ignition switch and cap/rotor issues with this vehicle. If your ICU is not throwing up a code then I would strongly look at the ignition system. Specifically your ignitor could be on the way out. It can overheat and stop premutely with this age/mileage. Once it cools down it works again but it's close to death. The only other thing is the oxygen sensor which is also close to dying which is typical at 120K+ miles. When the O2 sensor gets 'slow' it's still within the computer's acceptable range so doesn't throw a code until it dies completely, but it's bad enough to choke the engine temporarily. Does it happen when the engine is warming up in the first 5 mins? You can rule this out by disconnecting the O2 sensor temporarily and seeing if the engine dies again with same scenario (it might run slightly rough but it shouldn't stall with 02 open circuit). Ideally you can hook the 02 sensor output to an oscilloscope and check it's swinging cleaning and fast between 0.2-0.8 volts if you or a shop has the equipment. The fuel pump and/or filter is the only other outside thing I can thing of.
  • repairdogrepairdog Member Posts: 948
    Vac lines all run off the PCV tap on the intake so follow them over to the drivers side and repair all rotted ones - 5/32" are smaller ones. Now if you smell gas then perhaps its the classic CPI and nut kit (fuel lines under the intake) that are leaking. Search that and see the post answers.
  • scottd2scottd2 Member Posts: 1
    In regard to the power seat issue, where is the fuse or relay located that you replaced?
    I've been trying to figure out why the power seat on my 96 jimmy isn't working & I haven't been able to locate any fuse or relay for it.
  • cubanswmmrcubanswmmr Member Posts: 2
    hey could you tell me what the connector or wiring harness that is causing the problem is called, i am having the same problem and need to know what it is called thanks
  • repairdogrepairdog Member Posts: 948
    Power seat wiring.
  • larrysbarlarrysbar Member Posts: 3
    My 95 s10 Blazer is hard to start when cold it can take up to 10 try's (SHORT BURST)but so far always start's
    It seem's to start as the key goes off but sometime it will start first try even after sitting a week
    I changed wires ,plugs ,rotor,cap,fuel and air filter
    Cleaned injectors, rail, MAF,and EGR
    Tested fuel pump and coil
    Always starts warm 1st or 2nd try and runs great
    120k miles on gets 22mpg on a 300 mile trip
  • repairdogrepairdog Member Posts: 948
    The older models have 2 temp sensors and the one for the PCM input for cold start is by the EGR valve so that could be it.
  • jimmy6jimmy6 Member Posts: 1
    My 2000 GMC Jimmy 4WD automatic will not start on occasion. Car has 96,000 miles. Battery is new. When I try to start engine, all electrical seems to work fine - just no cranking (not even sluggish cranking). NOTE: this problem occurs intermittently! First time it happened last year, I called for a tow but by the time he arrived, the car started just fine (Tow guy checked battery/electrical anyway and said all was fine). No problems for about the next 3,000 miles, then the problem resurfaced yesterday. This time, I moved the shift lever to NEUTRAL and the car started fine. Same problem a few hours later - so I jiggled the shift lever in park and it started right away. So, I'm guessing this is NOT a PASSLOCK problem but rather something to do w/ a safety sensor relating to the shifter. Is there such a device and, if so , how can I verify this - rather than PASSLOCK - is really my problem and is there a sensor/part which I can replace?thank you. Jimmy6
  • repairdogrepairdog Member Posts: 948
    Transmission has an adjustment on the drivers side and must be in park or N to start so get it done at the shop in about 5 minutes.
  • nmurielnmuriel Member Posts: 4
    I have a unique problem my 01 S10 Blazer with 113,000 + miles, 6 cylinder. Last year during 90 degree heat my Blazer stalled on me for the first time, it started right back up and we didn’t give it a second though. While I was driving down the road it started to chug while getting up to speed and the bumper to bumper expressway traffic didn’t help this situation at all. After traveling around 100 miles I could barely get the vehicle past 30 mpg so we pulled it in to a gas station where my husband thought it was either water in the gas tank or a bad fuel pump. Vehicle sat while he went in search of a fuel pump. Friend advised that the same thing happened to him down south and that it was the air conditioner that caused our problems. He told us to disconnect the battery wait 3 minutes reconnect the battery and the computer would reset itself to get us home, and to not run the air conditioner. He advised that we needed to change the O2 sensors and some other things and that would fix the problem. It did, and while I work at GM and have engineers at my disposal they all thought I was crazy and said my air conditioner would not have caused this problem.
    Well it happened again yesterday 95+ out side, we had air conditioner on and in stop and go traffic it started to chug and stall. My husband disconnected the battery and we waited but it did not fix the problem. We chugged so much it disconnected the battery and everything went dead. We were able to pull over and try this procedure all over again and it worked this time. We waited longer and it seems to me the vehicle sat for some time before we did it the first time last year. Anyway it still stalled at every light or stop sign so I kept having to put it in to neutral and revved the engine a little to stop the stalling, but we made it home.
    Today it is fine, although it did give me a little hard time starting and I did not run the air conditioner. Basically when this happens tack bounces all over the place, and vehicle stalls when stopping. If vehicle had a carburetor I would tell you the choke was stuck open or closed. My husband is wondering if it is a vapor lock but why would just the air conditioner cause this. I can tell you it does not happen unless it is above 80 and the air is on. Any idea’s as to what is causing this?
  • sfpbcrsfpbcr Member Posts: 1
    I have workin fuel pump, fuel lines not clogged, new wires, plugs, regulator, ignitors, and something else escaping my memory. I am however the proud owner of the vehicle that has my mechanic telling me to take the headache back after two weeks. He has tried everything he can think of. He has spoken with other mechanics and with chevy dealers. I think pushing it off the side of a mountain sounds like a plan at this point.
  • repairdogrepairdog Member Posts: 948
    Computer tells the idle air control (IAC) valve on the throttle body to step idle up when AC on but if you turn AC off does the idle stablize - if so could be it and the port behind the IAC does get dirty and the IAC is about $75 for the part and I've had them fail intermittently even with AC off and when vehicle goes to idle just stalls and can be restrted, thats usually IAC, but ignition such as cap/rotor/plugs/wires etc needed by 100k. Now could be many other things as temp must be running about 200 or lower or cooling system problem, good fuel pressure tested at the fusl rail, clen fuel filter, air filter, and of course no codes or SES light on.
  • repairdogrepairdog Member Posts: 948
    Hope he tested the fuel pressure key on engine off and min of 58-60 lbs or no cold start on these. Need a scan tool to test all the sensors for an intermittent faults also so try a GM dealer. Dealer can also look at the PCM (computer). If it runs after starting with gas would sure point to pump, filter clogged, regulator, tank connector not getting correct voltage etc.
  • stilestile Member Posts: 2
    My truck started over heating on the 7th and won't stop no matter how much fluid i put in it. on top of that it won't start without giving it gas and it won't stay started for long without my foot on the gas.

    I have a new fuel filter for it but i don't know how to replace it or even where it is located on the truck can anyone help me?
  • stilestile Member Posts: 2
    io had a similar problem with my blazer a few time. I know this sounds stupid but try tightening the battery connections. sometimes my connections vibrate loose and i can't seem to tighten them enough to prevent it.
  • nmurielnmuriel Member Posts: 4
    No when you shut AC off vehicle starts to chug tack bounces all over the place while you are trying to get up to speed and after awhile the vehicle the vehicle will not maintain the speed.
    From another persons point of view it probably looks like I am using a clutch and keep popping the clutch because the car jerks wildly while trying to get it up to speed.
    My husband said we had to replace the map sensor as well as both O2 sensors the first time.
    Why does the combination of extremely hot day and air conditioner cause this issue.
    PS: Had check engine light on for long time, it went off now. Go figure. I am just going to by a horse and be done with it. ;)
  • cubanswmmrcubanswmmr Member Posts: 2
    hi repairdog thanks for the info but my problem is i do not have a power seat my problem was with the wiring harness i believe and that was the part i was hoping to find, hopefully you can help out again thanks,

  • bigfoot5bigfoot5 Member Posts: 1
    I had the same issue with my 01 Blazer and it was the distributor cap and rotor. My truck only had 56K miles but the rotor looked like it had 150K when I opened it up. It’s worth looking at. So much for quality GM parts.
  • david565david565 Member Posts: 7
    I have a 98 Blazer and understand how to change the fuel filter on it (having the same stalling problems as the earlier discussions - drives fine but when I slow down the car stalls. Had the same problem years ago and had the fuel filter replaced, which fixed it), but how do you release the pressure before you change the filter?
  • repairdogrepairdog Member Posts: 948
    Not really necessary - just slowly lossen the nut end and pressure drops- always drips anyway. Really stupid design and place and I always get gas on the arms and wear safety glasses and be off to one side that helps. Have to remove that one bolt holding the bracket on as the filter always is stuck in the plastic bracket. Enjoy.
  • david565david565 Member Posts: 7
    Thanks repairdog! Will cover up and go for it!
  • ga_boy1ga_boy1 Member Posts: 3
    hi,i have a chevy blazer 4.3L..and the other day i was coming home and it lost all power and shut off on me,not your average spit and spudder stall out...just up and shut off,so i coasted to side of wondering what would make it do this?my brother showed me it wasnt getting fire.we bought a coil and still no fire..any suggestions,help ..clues..thanks
  • tommyd2tommyd2 Member Posts: 2
    I have a 96 Jimmy. Just started stalling out when acelerator is pressed to the floor like its starving for gas. Have a fuel smell in cab as well. Runs perfect otherwise. Changed the fuel filter, ran the codes and get a fuel volume regultor control circuit open and o2 sensor low volts bank one sensor 1... DId notice a time or two back a very loud whine coming from fuel pump. Now it does not do it. The error codes were on for a long time and ran fine... I am leaning towards a fuel pump with the ordor and milage more than sensor and fuel reg. Anyway to quick test?

    Thanks, Tom
  • bigal6bigal6 Member Posts: 1
    Hi there, I just had the same problem and am trying to figure it out myself. If I do I will let you know. I hope you'll do the same for me. Thanks.
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