Very Strange Problem...

[jmat1980]

Hi,

For about a week now I have been having a problem getting my 2003 S10 Blazer started.

When I go to start it, it wont crank at all, but its not the battery, all of my lights and electrical work fine...headlights are bright, etc...

A few times it started up a few minutes afterthe initial try, but last night it wouldnt start/crank at all, and same thing this morning...again, all the electrical is fine, so im guessing the battery is also good.

Anyone know what this could possibly be??

Thanks in advance!!

[MT-2500]

If the starter is turning it over good.
Then check for good spark to more than one spark plug.
If good spark move on to a fuel pressure check.

What engine?
Will it start with a shot of carb cleaner in intake?
Any check engine lights or security lights?

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold and fuel pressure testing guide line.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak in system.
Post back fuel pressure readings.

[jmat1980]

Any ideas on possible causes??

[DelCoch]

Originally Posted by jmat1980

. . . When I go to start it, it wont crank at all, but its not the battery, all of my lights and electrical work fine...headlights are bright, etc...

. . . last night it wouldnt start/crank at all, . . .

When you say it won't Start/Crank, if you mean the starter won't turn the engine over and the headlights are bright, then it usually is a bad electrical connection between the battery and the starter; the starter is bad; or the ignition switch is bad.

What happens when you try to run the starter? Do you hear any clicks? With the headlights on and trying to run the starter; do the headlights dim, go completely out, or stay bright?

I would start with cleaning the battery cables and battery posts. If you want to pull the starter and take it to Auto Zone, etc, they will test it for free.

Let us know what you find and we can help you further.