I know, I know, he should get a Ford. His dd is a ranger, but got this at a steal for towing his boat.

Anyway, it's a 1995 Silverado Z71 with the 5.7
He's been having this problem where the truck would start and run fine, then when leaving work or wherever it wouldn't start. It would turn but not fire. Left him stranded a few times. But he could go out there a day or two later and it would fire right up. So he parked it bc he was told it was the fuel pump.

Well, I changed out the fuel pump today, fuel filter, and put new plugs in it. It will turn over, but not fire up. If you spray starting fluid in it, it will attempt to fire, but not run. Which leads me to think fuel.

What else would you check to dianose this thing?

I know the pump is working bc I turned the key with the filter disconnected and fuel sprays out.

Battery seems weak, but I've hooked my jump box to it, and still won't fire. I've kind of ruled out spark since it will attempt to fire with starter fluid, but could it still be a spark or power issue, or is it definitely fuel?

I'm at a loss here.


-Josh

 

Perhaps a fuel cut-off switch that's malfunctioning? I had that problem on one of the wife's old rides and it would be real intermittent like that.

 

its spark. pull the dis cap off and have a look there first.

 

Definitely in ignition somewhere because you can actually run (not just start but run) an engine with starter fluid (I would not do it but have seen it done) if you have good spark. Starter fluid is HIGHLY volatile and will fire off when nothing else will.

 

Those trucks are known to get moisture in the dis cap. The rear seal on the hood gets work out or some people just take them off and moisture gets in. A coworker had the same problem and couldnt figure it out for awhile.

 

If it's a moisture problem shoot a bit of WD40 on the ignition system. SP wires, distributor, and coil. The WD 40 will suck the moisture out.

 

Cap and rotor. When I worked in the GM parts department we sold them like crazy. My brothers chevy used to do it all the time.

 

FML...

Changed out the distributor cap, rotor, and ignition control module. Still doing the same thing. Turns but doesn't start. Will still half-butt start with a shot of starter fluid, but not actually run.

He changed out the nuetral safety switch the first time it wouldn't start and it fired right up. But is now back to the same thing. Could the new one possibly of gone bad already?

Any other thoughts? Fuel pump relay, fuse, One of the injectors on the throttle body?

I'm about to

 

95 was an ulgly year for GM. They switched from OBD I to OBD II kinda mid year and also have an OBD I.5.

I have an S-10 Blazer same year, but it's a V-6.

Anyhoo they need gobs of fuel pressure to work, so start with a fuel pressuer test.
Next GM wiring components are junk at best. Any corrosion in the wires that controll the fuel injection will give you fits, so check all the plug-ins and grounds.

That's where I'd start, good luck.........I HATE CHEVYS.

 

Like jgger said those GM's need around 54 psi at start up if I remember correctly. I would check the fuel pressure regulator. Since it's the only thing left in the fuel system besides wiring.

 

.
It's a GM, it would be strange if it HADN'T!

 

Changed out the battery and it fired right up. Going to let it sit, and try again tomorrow to see if it was a fluke, or that was the problem.

 

Son of a gun. Let the truck sit for 30 minutes, went back out and same thing, turns but won't start.

 

What do you mean we're not going to have trouble with this vehicle? It says "General Motors" right there on the door jamb!

 

Check for a bad ground on the gas tank/fuel pump