Hello Everyone!

Sorry for the long post, trying to provide as much info as I can here, I am assisting my brother (Mike, I am Rob, made the account under his name, as it's his truck) with a "no start" issue. Vehicle is:

1995 S10 Blazer, 4 door
"push button" 4WD
Automatic transmission
Vortec/CPI 4.3L.

I'm not going to lie here, truck is a little rough...I digress.

When last the vehicle ran, he was driving "very low" on gas (a "no-no", I know) and tried to execute a 3 point turn, front end dipped about a foot lower than the rear in a storm runoff (picture a paved road with a dirt shoulder that tapers off around 25-30° or so), and the truck stalled. From that point forward, it would turn over but not fire. At this point I was thinking the change in angle exposed the fuel pump pick-up and it sucked air. We pushed the truck out of the "ditch" (yeah, that was no fun) and got it level, still no fire. Tried to cycle the fuel pump a few times by turning the key from off to on with no effect. Added a couple gallons of fuel, tried the key thing, nothing...called a tow truck and had it hauled home (thank god for friends AAA, am I right?)

Once home, we added more fuel (truck now sits at a smidgen under 1/2 tank), tried the key thing a few more times and still no fire. Turns over fine...figured maybe the fuel filter was clogged, hadn't been changed in recent history, key trick a again, no fire. Here is a list of things I've tried:

Pulled a spark plug wire, plugged a spark plug into it, turned over, verified there is spark.

Removed fuel filter, turned key on, verified fuel pump is moving fuel/can be heard.

Pulled air filter, was a little dirty but not bad overall. Re-installed.

He killed the battery on the side of the road (we jumped it with my truck while trying to diagnose on scene), it took a charge and has held for a few days now.

Been reading tech threads on this site, can anybody verify for me that this vehicle has the "fuel line purge valve"? I looked but did not see it, want to verify I'm getting fuel to the engine. I want to check fuel pressure, make sure he didn't spank the pump, a common point of failure.

I also seem to remember hearing that the vortec fuel injector can be a common point of failure for these vehicles, any thoughts on how to troubleshoot that?

Can you think of anything I've overlooked here?

In summary, we have fuel in the tank, we have fuel to the filter, fuel filter is new, there is spark, and there is nothing impeding air flow as best I can tell. It turns over fine but no hint of fire.

Thanks in advance for any assistance you can provide!

Rob

 

These engines are finicky when it comes to fuel pressure. If you do not have enough pressure it will not start. The pressure valve should be at the back of the engine. Two steel lines with a valve. I believe that engine should be in the range of 58-64psi

 

Thanks, I will look again. I presume it's behind the intake plenum, near the fuel injector assembly? Everyone says top/rear of the engine, all I saw back there was what I believe to be the distributor and some heater hoses. Is it necessary to remove the aluminum plenum?

 

Figure I'd offer a little follow up to anybody that may find themselves in my situation, that would be a newb trying to sort out an issue on an unfamiliar vehicle.

The "schrader" valve isn't exactly like the shrader valve on your tires, it almost looks kind of like a bolt on the base of the intake manifold, it is to the left side of the intake manifold near the back of the valve cover. Look at the brake booster, then look 2" toward the engine, kind of has a pointy tip to it...

Anyways, Autozone will let you "borrow" a tester, but you aren't walking out of the store without leaving a $160 deposit, fortunately in my situation, Dad is a bit of a tool fetishist and had no problem spring for the $45 shade tree mechanic grade unit they sell there.

Ran the test, was topping out at 10 psi. Pump technically works, but nowhere near good enough to allow the vehicle to function. Changed the pump, vehicle runs fine...

To all newbs that didn't know, save yourself some grief, NEVER drive around with less than 1/4 tank...

Thank you "burned" for the input!

 

After changing the fuel pump, the vehicle seemed to be running fine; except for when trying to fire it up again after driving it approximately 5 miles or so.

It now only tries to turn over again, only this time it makes the vehicle slightly rock. Given a day or so, it will proceed to fire up again, like nothing ever happened.

After re-inspection of the tank and all the lines connected to it (I even re-fastened all the lines and the newly installed fuel filter to ensure there were no leaks), I cannot see a problem that would prohibit this vehicle from starting as it should.

I am the "newbie" (idiot) that drove this vehicle at 1/4 tank, and my mechanical inclination is extremely limited (obviously). Any suggestions anyone may be able to provide to resolve this matter would be greatly appreciated, I'm all ears.

Thanks!

 

Re check the fuel pressure and make sure it holds. The pressure may be bleeding off.

 

If you didn't use a ACdelco or delphi pump you may be replacing it again. Usually the cheap pumps last a little longer than that, but these engines are very picky when it comes to aftermarket pumps. Good luck.

 

Next time you are in a ditch with an issue like this,bang on the underside of the fuel tank with something with a bit of weight(soft hammer or ?),sometimes in a last ditch effort(unfortunatly for me it didn't work) you can get a pump shook'n back to life and limp to a shop/home.

 

+1 recheck fuel pressure. Did you have to replace the electrical connector going to the pump? If so, recheck it also. Something may have come loose or shorted out.