I hope this is where this goes... In August '09 we had a valve job done on my wife's 99 blazer, v6, 4.3, 2wd. We also replaced the spider inj and IAC, Throttle pos. sensor, map, mass air flow, pcv, crankshaft pos sensor, temp sensor...
We do NOT have a service engine light, but now, eight months later, the engine cuts out after idling for 5 minutes. Starts back up fairly quickly, but cuts out soon after. When it does cut out, the component directly behind the intake manifold makes buzzing, clicking, whirring sounds for a few seconds then goes quiet. It feels like it is trying to do something, but can't keep the engine running. It happens whether driving it or not, accelerating/decelerating/idling. It surges, revs real high, drops down, bogs down and cuts out. Sounds alot like it is shorting out too. I am going to remove the entire upper intake manifold cover piece tomorrow. What should I be looking for? Is this where the problem is? There are no codes, again, the service engine light is NOT on. I don't know all the jargon, but I can figure things out pretty good... just need some advice.

 

Don't go removing anything just yet.

Why did you replace all of those parts?

Is it consistently 5 minutes worth of idling and then the stall?

Have you replaced the fuel filter? Tested fuel pressure, especially when it stalls?

Can you take a picture of the top of the engine and point out what it is that you hear buzzing/clicking/whirring? Maybe a video?

 

We kept getting a code that said it could be one of those parts, so we replaced all. Turns out it was a crankshaft pos sensor and noone was resetting the code to see a new one pop up... live and learn. It is consistently several minutes of idle will do it. Fuel filter was replaced when we had the valve job. Had a tune up first hoping that was our original problem, it wasn't. I do remember when the mech put in the spider he showed me the old piece in the box... I don't remember ever seeing a pressure regulator... and the noise is coming from the large plug at the top of the CPI? unit just behind the intake manifold. Have not tested fuel pressure. I can hear the pump priming when I turn the key. Sorry no pics, I'm not that savvy with all this.

 

Something doesn't sound right. You should not hear much of anything coming from the injector pack, especially if the engine has died.

The pressure regulator was on the back of the spider. And your engine is an SCFI engine, not a CPI engine.

 

Check your air breather duct (hose) clamps. Mine were loose and caused the exact same problem. Now they are tight and no problem. I hear similar noises like relays clicking and the fuel pump buzzing when I turn the key on.

Jim

 

Not the pressure regulator, it's the Fuel Pump... The fuel gauge acted crazy the other day bobbing back and forth erratically. Problem with return line. Thanks for the advice though.

 

I do not think the fuel gauge has anything to do with engine issues. The fuel gauge acting erratically is probably from the junk sending units that GM uses in the tank. Did you check the clamps on the intake boot. I know it sounds too simple, but a loose seal will cause problems.

 

I checked every bolt, clamp, screw and anything that could be tightened or otherwise... Everything is as tight as... Mortgage lending... you thought I was gonna say drum, huh? No, seriously. The fuel pump is bad. We run the blazer with a quarter tank or less all the time because we use so much gas and try to conserve it in it at the same time... I know it is confusing, but it stays at or below a quarter all the time, so I think the pump just gave out. I know it relies on the fuel in the tank to keep it cool, just don't have the money needed to keep it full enough (hence my comments). It's original factory pump and I think It just got old... like current Economic theories... just OLD. But keeping the tank fuller has become a priority now... Definitely can't afford this again. Thanks for the input, I do appreciate it.