Chevy S10 Blazer Engine Won’t Start – Turns Over But Won’t Ignite

Reader Question

I have a 1994 Chevy S10 Blazer and after a trip i arrived back home and casually turned it off. When i tried to turn it back on, it turned but there was no response. I then went to a next door neighbor who is a mechanic and he said the biggest problem would be the fuel pump.

He hit it once with a hammer and on cranking the car it started. So we deemed the problem to be the fuel pump. I replaced the fuel pump myself and it now turns on when the key is on the ON position and the fuel lines are pumping fuel. (I checked it on the engine.) But after i replaced the fuel pump and checked that it was pumping fuel i tried to start the car and it gave the same response. So it turns over but just won’t start.

I have since checked the spark plugs and they seemed to produce spark. (I checked them by opening the wire connecting to the spark plug sticking a screwdriver inside and touching the metal part to a “ground” like the top of the engine, and it produced sparks) So what could be the problem now? What could cause the engine to not start after the fuel pump has been replaced and the spark plugs checked?
-Please respond,

Whats up Abel,

I am not sure I understand your email, BUT the first thing I would do is check the fuel pump PRESSURE. The pump might be pumping enough fuel into the lines that you can see it, but if it is not pumping hard enough the engine won’t start.

There is a place to check fuel pressure on the back of the engine with a manual screw on gauge. Hitting the tank with a hammer is a great and easy test to kick start a weak pump, but not a very accurate test. Could it have been coincidental? Maybe just the time it took to get the neighbor solved the problem and when he hit the tank you guys just assumed it was the pump?

Checking spark the way you did is ok, but it does not tell you if the spark was strong enough to ignite the fuel, it just tells you there was some kind of spark.

I would check fuel pump pressures and recheck your installation. If you used a cheap aftermarket splice in pump, I would be suspicious. Can you hear the pump prime itself when you turn the key to the on position? Are you sure the pump was installed correctly?

I would also check the spark from the ignition coil, and test the ignition module.


Austin Davis

Posted in: Won't Start Issues

29 Comments on "Chevy S10 Blazer Engine Won’t Start – Turns Over But Won’t Ignite"

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  1. chad says:

    I have a 91 s10 blazer that wont start im getting fuel but no spark from the coil or plugs it started at the when i put gas in it i cranked it and it ran fine and i put it in gear and it died

    • Austin Davis says:

      91? With a distributor? Start from the source, battery power to distributor, power to coil, distributor gear is turning, ignition rotor and cap are good etc. If no distributor, check ignition coil and crank sensor and camshaft sensor output.

  2. laura says:

    I have a 1993 Chevy s10 blazer 4.3 vortex. I’m running out of options here. When initially died was sounding like it wasnt getting enough gas, put more in, tried turning over, then battery dead.. started to jump start after few mins charging, tried turning it over but battery kept losing power then starter went. Was towed home started to start repairs. Battery tested good. Starter,tested bad, replaced. Fuel pump, fuel fuse, fuel filter, plugs, wires, coil pack, distributor, distributor cap, rotor, ignition module, idler air control valve, o2 sensor, mass air flow sensor, checked fly wheel it good. It will start, idle rough, I smell gas (almost like too much), then min or so will dog down n die, won’t start back up for while. I’m wanting to replace fuel regulator, but I’m honestly clueless. I need answers not guesses. I’m a single mom and its my only vehicle. I can tell its almost there just still missing something, the oomph to stay running.

    • Austin Davis says:

      Does sound like a full control type of problem, could be a fuel pump or you might have a bad fuel injector. Some of those vehicles used a “spyder” fuel injector that had 6 hard plastic fuel lines that attached to each cylinder. The lines would leak, causing a drop in fuel pressure…and cause a raw fuel smell….and even a fire under the hood.

      Get a local mechanic to check and see if you have one of these main fuel injectors with the hard plastic lines, and then check for a leak in the lines if you do. They used to make a repair kit for it from the dealer. Buying a new injector is expensive and labor time extensive.

      keep me posted as to what you find out

    • laura says:

      Changed the fuel regulator and replaced intake gasket, turns over but won’t fire up.

      • Austin Davis says:

        Missing something, fuel pressure, ignition timing/spark, and compression. fuel pumps are common failure on those older S10’s

  3. joseph says:

    I have a 94 blazer s10 vin w. Its been sitting for like 6 months and it would not start. So I change the spark plugs fuel pump and It started up and ran for 4 days then cut off. I have compression from the spark plugs my fuel pump is turning on my relay and everything’s working all my fuses are good. I got a brand new distributor it is a gm 23. and for some reason I feel pressure is only 12 to 13 ps i’s and yes I know that is not right trust me 41to 55. Firing order 1-6-5-4-3-2. If someone could get back with me I would really appreciate it

    • Austin says:

      And you still have spark at each spark plug now? If you are reading 12-13 PSI at the fuel rail under the hood, that is too low and I can only suspect you have a fuel pump issue or a problem inside the fuel tank. I have seen a few stopped up fuel pump screens, and have seen a few broken plastic hold down clamps that hold the pump to the fuel tank. This allows the pump to move around the tank and bang into the tank, which kills it. Might want to replace the fuel filter first before you pull the tank down again.

  4. Thomas says:

    i have a 1992 chevy s10 blazer with the 4.3 vortec. i was driving and it died at a stop light and now cannot get it to start back up. had module tested, coil tested, rotor is spinnin but no spark. where do i start to look next?

    • Austin says:

      Are you sure about no spark??? These vehicles are suspect of bad fuel pumps, so I would check fuel pressure at the engine next to rule that out. Sometimes you can bang on the bottom of the fuel tank with a block of wood AS someone is cranking the engine over. This can jump start a weak fuel pump. Testing for spark should be done with a nano light tester which will flash when spark is present. Check for spark at each plug. But spark can be missleading if there is no fuel injector pulse. I would rule out lack of fuel pressure first.

  5. blazertommy says:

    I have a 1990 blazer and it is hard to start every time. It also revs way up every time you crank it wether it’s crank it cut it off and start it right back or wait hours in between. Any Ides, im getting tired of wondering if this thing is going to crank every time.

    • Austin says:

      In most cases one of the following is to blame

      1. Bad fuel pressure regulator
      2. Weak fuel pump
      3. Bad fuel injector
      4. Bad idle control valve
      5. Vacuum leak under the hood somewhere

      I would first start with checking fuel pressure at the engine with a manual fuel pressure gauge and go from there. You most likely have a “spyder” type fuel injector which is one big injector with a bunch of small plastic tubes feeding each cylinder fuel. These injectors leak fuel usually at the back of the intake manifold causing a drop in fuel pressure and hard starts. Once the engine starts it takes a second or two to burn off the excess fuel causing the fast idle speed.

  6. camelTl247 says:

    john with the 1999 S10 Blazer……….had a friend w/the same prob and it was the fact alrm the bran box had to get it fixed at the dealer

  7. camelTl247 says:

    1,2,3 all good the alrm light keeps falshing on the dash it starts then cuts right off

  8. camelTl247 says:

    02 chev,s10 2.2L no start i know the prob but not sure how to go about fixing it it has alot to do w/the fact alrm cutting off the fuel at the injetors……….what color is the ground wire that i need to hoor up fram ground to

  9. veronica says:

    I have spark and gas going to it and it won’t start turns over but won’t start? I have an 01 Chevy Blazer.

    • Austin says:

      You need 3 things

      1. Spark to ALL spark plugs
      2. Proper fuel PRESSURE, not just a trickle of fuel
      3. Compression on all cylinders

      These vehicles have a history of weak fuel pumps and leaking fuel injectors. I would suspect you do not have enough fuel pressure if you have spark and compression. Bang on the bottom of the fuel tank with a rubber hammer or block of wood AS someone is cranking the engine over. If it starts you most likely need a new fuel pump inside the fuel tank.

  10. John says:

    1999 S10 Blazer will sometimes start and run for 1-2 seconds then die. After waiting EXACTLY 10 minutes, it will start every time. Anyone with similar problems?

    • Austin says:

      Would be awesome if you could get your mechanic to check for spark and fuel during this no start time period. My first instinct is lack of fuel due to a fuel pump problem which is fairly common on these. Sometimes banging on the bottom of the fuel tank with a block of wood as someone cranks the engine over can jump start a weak fuel pump.

      If you do not have spark going to the spark plugs you could have an ignition module or ignition coil issue. You are missing either spark to the plugs or fuel pressure, so try to rule one out.

  11. tory says:

    I had the same problem as Bryan no lights, I did the same, hit the steering wheel lights came on and it started… turns out it was a short in my switch wiring!!

  12. HuieJay says:

    hey i had the same problem change your sparkplug wires mine were shorting out i changed my fuel pump and that wasnt it everyone told me it was but my wires had a short and were grounding now its back in acting and it would have saved me like 200 dollars

  13. Bryan says:

    have the same problem the lights never came on and I use to get really mad and I gave the steering wheel a smack or two and the lights would go on. I’ve been doin that for almost a year and I know its not good. WOULDNT A GOOD IDEA BE TO GET A REMOTE STARTER????? would that work Im not familiar with those things much

  14. jimmer says:

    replace the ignition module first dont be confused by the ecm electronic control module also known as the computer but check all conections first and the battery must be good

  15. zach - Answer says:

    Oh, two more things:

    1: if you have a tbi you can pour a little fuel in the top and try to start the engine. If it starts, your problem is in fact fuel.

    2: if fuel is coming out of injectors, but it is very weak, it could be a weak fuel pump, clogged up fuel filter, pinched fuel line, or fuel pressure regulator (located just previous to the fuel injectors).

  16. zach - Answer says:

    I had this problem and found the solution. I had a TBI but it may not make a difference.

    First thing check all fuses.

    After that, first, fuel must pump out from your injectors. Verify this is happening by putting a cloth or paper in front of an injector and try to start the car. If fuel came out of the injector, fuel is probably not the problem.

    If fuel did not come out, next check to see if fuel is even making it up to your injectors from the tank. The way I checked that is to disconnect the fuel line from the back of the engine (which lets out any fuel sitting there). Then re-connect it, and attempt to start. Then disconnect it again and see if new fuel falls out of the line again. If no fuel comes out, either no fuel is pumping out of the tank or your line from the tank to engine is clogged. Most likely it is your fuel pump failing in some way. Look up how to deal with that (not hard).

    If fuel does come out, fuel is at least reaching the injectors. If it is your injectors, first thing to check is if they are getting the signal to inject the fuel. This can be verified by testing the injector pulse with a $3 test light. (look up that sentence for exactly how to do it – not hard). If they fail that test, you have some kind of computer/sensor/electrical problem and further testing is needed to narrow that down.

    If they pass that test, then they are probably stuck/clogged. People clean these things, etc, but it’s very hard and doesn’t give you a new injector, just a clean, old one. So in my case I just bought and installed new injectors at this point and it started right up perfect.

    Hope that helps!

  17. joe says:

    really? take it to a mechanic?! Great car advice website mac.

    • admin says:

      ummmmm, ya. Did you actually read the reply I gave to the original email? DId you happen to read how many items the owner has already guessed at and figure up the cost that has already been spent on GUESSING? I would bet its at least $200 in parts cost….not including his time to actually do the work. So my LAST followup suggestion after he had already done what I first suggested him to do was to go to a qualified mechanic and stop guessing. You can get a mechanic to diagnose the problem for you and you can go home and do the work yourself but stopppppppppppp guessing!

  18. David says:

    I am having the same problem in my 93 blazer, i have tested all of the same things and replaced those and more, but my blazer is still not starting. Any help would be appreciated


    • admin says:

      Sorry for my delay, have been on vacation all week. Spent $100 and get a qualified mechanic to diagnosis this for you….trust me it will be cheaper in the long run.

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