Im having starting issue with my blazer. in the mornings it starts up fine but when I leave for lunch at work about 5 hours later is has a problem starting sometimes. it takes awhile to crank sometimes other times it starts right up. my resting voltage is between 12.7-12.9. any ideas?

 

Are you saying the engine does not turn-over at times or is it that the engine turns-over but does not start?

In the first case suspects could be the starter or the ignition switch. To determine which, would require you to measure the voltage at the solenoid terminal during one of the no turn-over conditions. If the voltage is good at the terminal, then the igntion swich is good and is likely the starter.

In the second case suspects are fuel pump, rotor, dist cap, fuel injector, fuel pressure regulator, spark plugs, plug wires....and probably more. Will require further troubleshooting to determine fault.

 

It will always start its just sometimes it has a hard time starting like it takes a second. theres no ticking noises just the sound of it trying to start like in the mornings when I leave for work boom starts right up no problem but when I leave to for lunch about 7 hours later it hesitates to start but it will start.

 

I have been having the same issue... Its driving me nuts to be honest. I replaced the spark plugs, tried to crank it and the battery dies. I replace the battery it cranks, but now it strains when I press the gas and acts like it doesnt wanna go at all, I get a loud clunking noise when I get up to 3000rpms, and then a burning odor comes through the vents.

Today I went to crank it, and it turns but wont crank up at all. I haven't replaced the fuel filter, and the pump sounds like its working... At this point im just so stressed out with the damn thing I feel like selling it.

Sorry to rant on your post I know im not helping, but I cant seem to find many answers either...

 

By inference I'm getting you two have completely different problems.

Xaldwyn, you need to start your own thread or there will be confusion of biblical proportion. Yours is going to start with a complete fuel system diagnosis.

99bblazer99 you didn't really answer LannyL81"s question. What I'm getting is that in the AM the motor will crank and start, at lunch the starter kind of binds but you can get it to go then after work it seems to crank fine and starts.

You need to do some electrical tests to confirm whats going on. First thing I would do is watch some youtubes on voltage drop and amp draw. If you would like to just start some stuff start with cleaning grounds. The one from the battery to the block being #1.

If I had to "GUESS", something I hate to do, is that you will find you need a new starter. There are some bushings in the starter. They get worn and out of round. When the motor is at it's hottest, Lunch time, they have expanded by a fraction causing binding, by time you leave they have cooled down and shrunk so it turns. Same goes for the AM.

Look with search terms like "starter diagnosis" and you can watch or read all about it.
If you do decide to change the starter get a Hitachi style aka short starter. There have been certain difficulties with OEM's do to clearance issues.