Hello: I have a 98 S10 Blazer with a 4.3 engine. It is a 2 door with 4 wheel drive. One day it will start fine and runs great. The next day it will not start at all even after trying time and time and time again. The next day it will start normally and run fine. It seem to have an intermittent starting problem. One time it will start normally and the next time it will not start (but will crank) and the next time it will start normally. Does anyone have any ideas where to start? I am getting confused about this problem. Everyone seems to have ideas, but none help. I certainly would think that I am not the only person who has had this problem. New fuel pump, crank sensor, coolant temp swg, and air flow sensor have been added. Still have the intermittent starting problem.

 

First step is determine if the problem is a lack of spark, or a lack of fuel. You'll need to check it when it's acting up. Spray a half second shot of carb cleaner in the throttle body and attempt to start it. If it starts and stalls, the problem is fuel related. To check spark, remove the coil wire from the distributor cap, stick a small screwdriver in the end of the coil wire and prop it up so there is about a half inch gap between the screwdriver shaft and engine ground. Crank the engine and watch for spark. It should be a blue, not orange, spark. Post your results.

 

WELL.........it did not start today. Cranked and cranked and it would not start. Took off air cleaner housing and poured a little gas into the throttle body. It still would not start. It would crank, but not start. Therefore, it must be an electrical problem. I will have to wait until someone else is here to start checking the electrical system. Any ideas anyone. I will check the coil and spark to plugs when possible. Thanks for the help.

 

I can not figure out why it will start fine and run fine one day and then the next day it will not start. Then sometimes when I let it set for one day after the day it will not start, it will start fine when I have not done anything but put the key in the ignition and start it. It sure is confusing to me and a lot of so called mechanics.

 

Intermittent problems are the most difficult to diagnose, for anyone. Could be a poor electrical connection in the ignition or the fuel system, or a failing part, etc. As mentioned, the first step is figure out if it's fuel or electrical related. The fuel system both fuel & electrical, and the ignition is all electrical. Installing a fuel pressure tester while it's acting up will tell you if it's getting fuel to the injectors. Adding a shot of carb spray will tell you if the injectors are squirting fuel or not. Always better to use carb spray so the engine doesn't flood.

 

Well........I went to check some of the electrical portions of my 98 Blazer that would not start yesterday and guess what............it started like it should and ran like a top. I am getting frustrated with this problem. Every time I go to check something, it starts and when I go to start it to go downtown, it will not start. But after it sets for a while, with me doing absolutely nothing, it will start normally. Really got me confused and frustrated.

 

Does the "security" light in the instrument cluster come on with the bulb check? Does it come on when you try to start it?

 

What do you mean by bulb check. It comes on when I first turn on the key.

 

When you initially turn the ignition to the RUN position, (don't try to start it) the dash lights should come on. Does the orange "SECURITY" light come on for about 2 seconds, and then shut off?

 

When I turn the ignition on (but not start), the security light DOES come on for about 2 seconds and then shut off.