Nitehawke:

I was getting so confused. Since it finally went to a hard fail were you able to find out if it was spark or fuel or did you just decide to let the shop handle the whole problem?

George

 

Just going to let my mechanic deal with it. I did tell him change the fuel filter regardless as the former owner (next door neighbor, as it happens) tells me it's been about 3 years.
I should know tomorrow what the problem is. Hoping for something cheap and easy to fix. I need my ride back, lol.
I'll update the thread when I know more so it can serve as future reference for others. The video on testing the ignition switch is handy, though, as it literally sounds exactly as mine does. The only difference is that whatever's going on with mine began as intermittent failure. I've never known a fuel pump or computer module to fail in this manner so I'm hoping it's a sensor or clogged fuel filter. Something, as I said, cheap and easy to fix.

 

Nite hawk:Good luck.

Chuck750ss: We want to help you here but in the future if you have your own unique problem please start a new thread.

George

 

So, my mechanic finally got to my Blazer today. He hopped in and turned the key to see what it's doing......and it started right up. Smh.

We're both leaning toward fuel. I'm mostly leaning toward crap in the tank or filter intermittently blocking the fuel pump screen or filter outlet. This might explain why it starts after sitting (loss of pressure allows the obstruction to fall out of the way or, in the most recent instance, the vehicle being towed "washing" the obstruction out of the way with the movement).

I also apparently have a fuel leak somewhere. Not excessive but it needs to be fixed. So I've told him go ahead and replace the fuel pump, fuel filter and fix the leak. I've never known a fuel pump to fail in this manner ( I've been driving professionally for over 30 years and haven't paid more than $1500 for a personal vehicle in that same time period) but the professional says he has.

if he finds something during repair that seems definitive, I'll update. If it breaks down again after repair, I'll update. Otherwise, anyone reading this can assume we found the problem.

 

Here is a diagnostic work flow which may come in handy if you still have the problem. Travel with a fuel pressure gauge and spark tester to catch the problem when it happens. Good luck:

https://blazerforum.com/forum/2nd-ge...rticle-103750/


George

 

Thanks for all your help, George. I really hope the fuel pump, filter and leak repair takes care of the issue but diagnostic article might come in handy if it doesn't.

 

How did you rule out the ignition switch? I'm having no start issue jus cranks for months an im about over the entire situation. I need it running like yesterday lol

 

Your starter engages and you have spark at the plugs so the ignition switch is not your problem, at least not the voltages for the starter and ignition. It may still be your problem due to the integrated hall effect sensor and passlock resistor function which we have covered. The resistor hack takes the ignition switch/passlock module out of the system completely and it no longer matters if that part has issues. Has the security light behavior returned to normal after the resistor hack and relearn process? If not then the process may need to be checked/repeated or you may have a BCM problem. I believe that you also reported the minimum 55 psi fuel pressure after 10 min so next up is to check for injector pulses with a test light or noid light. If your security system is malfunctioning then this will most likely be your issue because that is what gets disabled.

The way to solve this problem is to eliminate most possibilities and pursue the possibilities that come up as issues, starting at the top:

1) Spark - -you have confirmed spark so all kinds of issues are off the table including the ignition switch starter and ignition voltage functions

2) You have adequate fuel pressure (I think) so a bunch of stuff is off the table, fuel pump, regulator, leaking injectors, ...

3) Next up would be fuel injector control pulses. I suspect this to be your problem. If i am wrong then its on to ...

4) Bad gas

4) Timing

5) Mechanical problems


George

 

If you still want to test your ignition switch then follow post 6 and the associated video link.

George

 

I am pretty sure it was after he had put in the resistor is when the security light had went back to its normal function. It will show briefly as all lights do when first turn the key on and then all lights will disappear as they should. I still haven't tried the re learn thing yet because my battery light is on and I'm trying find a battery charger first so I dont get almost done doing relearn and battery dies on me or something stupid like that. But shoukd be able too get a charger on it this week. So I will let you know how it goes. I still have a screenshot of the relearn directions you posted.
Guessing from battery being so low, now when I try start it it dont even try it just clicks. But all dash lights come on like normal... but again will get charger hooked up to it and will test battery to see if it's still good.