Hey Guys,
I've been researching this for days, but can't seem to get any definitive answers. Here's the situation: (95 4WD Vortech V6 Chevy Blazer)

We replaced the fuel lines a few months ago, both the main line and return line. The truck worked fine after that for about 2 months, then it began to not start after sitting for awhile. If you left it for 10-15 minutes, it would start right up, and work fine for hours. Then if you tried it after shutting it off, it probably would not start again.

Now it cranks all day but won't fire. I thought it might be a vacuum leak, but we replaced the lines going into the tank and the charcoal cannister, with no change. Truck has plenty of spark..........leads me to think a fuel pressure problem? I need to pick up a gauge and check the pressure at the Shraeder (sp?) port, but anything else this could be? I've read about the Security fuel cutoff system, but have found no information on how to disable/bypass this system?

Also, if this is a 95, does that mean it only has one injector (W vin code)? Another thing, the fuel pump was replaced less than 2 years ago, and you can hear the pump running/priming when you turn the key. Fuel also comes out of the pressure test port on the back of the intake plenum when you press in on the needle, so it appears the pump is working.

I'm stumped, and have been at this off and on for weeks, PLEASE HELP ME!! I WILL GLADLY DONATE!, haha thanks.

Mike

 

So after some more reading last night, I found this post:
https://blazerforum.com/m_24348/tm.htm

I forgot to mention in my original post that I also just replaced the ignition lock cylinder. My problem was that Passlock must have been disabling the fuel, and not allowing proper ignition. The truck starst every time now and idles great!

Thanks Swartlkk for that post, and Rammer for finding the TSB in this post:
https://blazerforum.com/m_63388/tm.htm

Mike

 

Glad you got it fixed!

 

Hey again,

I had hoped it was completely fixed, but this morning it kept turning over with no start. We did the re-learn procedure again, and it started right up?!?!?!

Does this mean the ignition switch is likely on the way out?

Mike

 

Hey, me again, with another related problem!

I replaced the ignition switch/module in the steering column, thinking that the Passlock sensor was the problem. Now the truck will start, but appears to have a horrible vacuum leak, from somewhere under the hood it appears.

Can anyone help me out with a vacuum diagram for a 95 4wd 4.3 blazer? It's a W vin code, which is the single injector fuel system.

Thanks for any help guys, I've been screwing with this for about a month now!

Mike