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Chevy Blazer Starting and Stalling Problems

I have a 1974 Blazer with a 305 in it, I just replaced spark plugs, cap, rotor, wires, fuel filter, some hoses and PCV valve. It starts up strong, runs fine for a bit - drive it around the neighborhood - then once I come to a stop it basically dies on me, sometimes it will start right back up again - sometimes it will just crank and crank.

What other things should I be looking at, fuel pump? Can a bad coil cause this??

I would appreciate any help, thank you.


  • tidestertidester Posts: 10,059
    I changed the title of this discussion to make it more general.

    tidester, host
  • repairdogrepairdog Posts: 948
    This is reaching back, but no computer and manual fuel pump with a carb. Float level and needle/seat would be one to look at - does this have an air idle solenoid on the carb? Isn't there a small brass filter in the carb base where the line screws in too. Fuel pressure should be checked (believe 9-11 lbs but check online to be sure). Coil could heat up and die as well as wiring to the key switch could be loose.
  • bigjoe85bigjoe85 Posts: 5
    I have an 01 blazer 4.3 vortec and Im having trouble I think with the fuel system. When I would pull up to a stop light and sit there longer than 5 min. it will cut off on me and and now its shutting off while im driving down the road. I have no problem starting it backup though. Fuel pump or possibly injectors?
  • repairdogrepairdog Posts: 948
    That or coil, sensor, MAF, vac leak, cap/rotor/wires/plugs etc - mileage? First when was the fuel filter changed - first place to look and its $15 ($75 with labor). Air filter not too dirty? Fuel system has a test port on the metal line that requires a special valve to connect and then ckeck the pressure. 60psi min with key on engine off (start pressure) and 54psi running. If those check out then on to electrical/sensors/etc. Any SES light on and codes?
  • well the milage is about 83,000 havent checked the fuel filter yet(where is that located by the way) air filter looks good and also can i go to a local parts store to have the lines checked?
  • repairdogrepairdog Posts: 948
    Fuel filter should be changed every 25-30k miles and is under the drivers seat area under the frame on the inside. Its always a pain to change up there - $10-15 part and about $50 labor. One end is quick connect squeeze tabs to release (after pressure released) and the other end requires 2 open end wrenches. Have to take the bolt out of the plastic holder also to get the filter out.
    Pressure test NOT normally done by auto stores but they may have a free reantal tester to use at home or take to a shop and they will do that and the filter plus analyze the problem so you don't throw too many parts at it.
  • repairdogrepairdog Posts: 948
    First change the fuel filter a $15 part, then if problem still happens test the fuel pressure at the test port on the metal line at the top rear of the engine. Its a special tester and once you have it or get a shop to do it the pressure should be 54psi when running or alittle higher (but not lower than 53) and if there is a starting problem its 60psi with the key on engine off. Also check all connectinons at the top of the tank and there is a fuel pump relay in the fuse box under hood.
  • Ijust got a fuel filter for my 01 blazer and i need help on switching the old one w/ the new one. How hard is it, should I let a mechanic do it, and what tools do I need if I replace it?
  • P.S. very limited funds.
  • repairdogrepairdog Posts: 948
    One end is a snap or quick disconnect that you squeeze the 2 tabs and it pulls off (after pressure released). The other end requires 2 open end wrenches. The bracket it is in is held on by one 13mm bolt to the frame that has to be taken off to get the filter out of the bracket and the lines are simply snapped in to the top of that bracket. You will get gas on you and its kind of a pain but shops charge about $35-50 to change so up to you.
  • When I drive down the road sometimes when I step on the gas the engine bogs and stalls, if I quickly put it into neutral and restart it will have all kinds of power for a few miles then do the same thing. I relaced the fuel filter, fuel pressure regulator EGR valve, spark plugs and cap, I put a fuel pressure gauge on the test port and it reads with KOEF 65lbs. and with the KOER it reads 58lbs. I also put a vaccuum gauge on engine and could find no leaks. Why does this do this and how do I correct the problem? Help this is a safety issue, my family uses this vehicle.!!
  • repairdogrepairdog Posts: 948
    What year and mileage? Aby codes (SES light on) and if so post them.
  • No codes come up until after it happens then it comes up oxygen sensers port 1 and port 2. You can step on the gas and the engine just bogs it has absolutely no power . Put the car in neutral ( while still moving ) count to 3 and restart and have all the power you want. Tried Hi test gas , fuel additives, still happens! This has me totally confused. Need help, someone told me to replace the computer.
    The mileage is 124000 and the year is 1996
  • repairdogrepairdog Posts: 948
    Clean MAF sensor - tells computer mass airflow or rich/lean settings - could trigger the O2 sensor code if too rich. Check/clean EGR. This does have the newer style injection so could be fuel pump heats up and pressure drops - have to test at test port. Coil could be failing due to overheating due to ignition module never shutting off so always a low voltage to it. On from there.
  • Last night on my way home from a friends house I stop'd to put gas. I parked did the usual routine and as I came back from paying for my gas I lined up my car. I turned it off and when I finished I got back in my car and tried to start it. The thing was that it wouldn't start. It cranked but no ignition. So I got a jump from some guy and still no luck. The Battery light and the Service Engine light is on. And another thing is my power windows still work when I take the key out of the ignition. Please Help...N-E-one! :mad:
  • Replaced the Mass Air Flow sensor today. Very Costly and STILL does it. !!! Doesn't do it all the time, sporaticly, but it always happens when you really need to step on the gas in traffic, what now? How many sensors do I replace? This is baffling me as well as others. If the fuel pump is over heating, wouldn't that be dangerous being in the fuel tank? Plus, the fuel pump was replaced by the dealer 6 months ago. Please any help would be appreciated!!
  • repairdogrepairdog Posts: 948
    That was why I suggested clean it! Clean the EGR also. Most repair manuals list details on these and also coil testing. If the pump is 6 months old and a Delco doubt it could be that - fuel pressure test is required to be sure. Did you check all vac lines also for rot. If you keep getting O2 sensor codes there should be 3 of them - 1 in each exhaust in front of the cat and 1 behind it. There are many things that could be causing this . Have you looked at the injectors where they plug into the lower intake to see if they are not cracked or clogged - plastic squeeze connectors hold them in but this requires removing the upper black plastic intake to check which is not easy if never done before.
  • I did have the injectors checked and even replaced the fuel pressure regulator . I checked the fuel pressure and it's KOEO 68lbs and with the engine idleing it'd 54lbs. which is within spec. I'm at wits end , the wife said if it's not fixed by weekend it's GONE, HELP, I LOVE THIS TRUCK!!! :cry:
  • I have a 00 blazer with the 4.3L vortec. Driving home one night from work it just died on me. I got it towed to a local shop and the found it to be the ignition rotor spun off hte shaft and put a hole threw the cap. So once this was fixed I started noticing that the truck didn't want to start all to easily. I've tested power and vacum lines. I've found that its not holding fuel pressure when the car is off. Any ideas on how to fix and whats involved? Any help would be appriciated. Thank you in advance...
  • repairdogrepairdog Posts: 948
    Have you taken it to a Chevy dealer yet - once a local shop can't find it thats the next step - trying to find an intermittent problem is a pain - GM seen them all and Blazers have many.
  • repairdogrepairdog Posts: 948
    Standard fix is a new fuel pump assembly in the tank, or possible pressure regulator on the injection assembly under the upper intake. Have to test at port on fuel rail with a pressure tester and watch the pressure to see if its within specs then if it drops with the key off (key on engine off should be min of 60psi and running 54psi). As a test turn your key on, wait a few seconds and see if pressure builds then start - anything lower than 60psi (from the articles on this injection type) state that it will not be enough to fire all 6 injectors in a rich start state.
  • The dealer put the new injectors and fuel pump in. I think I'm capable to change a SENSOR BUT THE DEALERS CODE READER SAYS THE SAME AS MINE. Maybe I should try another dealer???
    Changing the coil this morning.
  • samm00samm00 Posts: 6
    Did you solve this problem yet - our 01 is also stalling gen when the temp outside is hot - told the pressure in the fuel pump is good?? Any advice welcome???
  • No it still does it. The other nite it did it and I again had to put it in Nuetral while moving and then restart and I had all the power I wanted. I can't figure it out and it's really frustrating!!! Any one with any help would be greatly appreciated
  • samm00samm00 Posts: 6
    We were told we have a Vapor lock - but they didnt know how to get rid of it?
  • I was always under the understanding that fuel injection eliminated that problem. Now don't quote me on that but I'm 80% sure thats the case.
    Sounds like your emissions system isn't working properly or your fuel filter needs to be changed.
    Is your service engine lite on ? If so have your dealer or mechanic check your codes to see where the problem may lie
  • samm00samm00 Posts: 6
    This started after our 01 Blazer ran out of gas, now stalling happens on going down hill and seems to be in hot weather, the fuel guage is also inacurrate - any links - ideas - we also had intermittent O2 sensor codes in the winter?????? We had a new filter and the fuel pump has been checked!
  • HOnda prelude cranks but wont start. Havent been driven for quite some time. Left parked in the summer heat.Worked for a while Drove for two days and shut off while driving.. Advice would be appreciated.
  • repairdogrepairdog Posts: 948
    If fuel pressure was 60psi key on engine off and then 53psi up running its OK. Possible crankshaft position sensor failing or back connection - under front of engine there is a plug in connector (under harmonic balancer /water pump area - you'll see if from underneath. They are magnetic and tell the computer when to fire the plugs - when they fully die no spark and no SES light so a pain - about $60 part held in by an 8mm bolt - easy to do. Cheap one to do and rules that out. Check coil wire also with ohm meter and make sure its OK and also no arcing to metal anywhere. Then the coil itslf should be tested if this continues.
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