My '96 Chevy K1500 has fuel issues that have me somewhat confused. If the truck sits, it is haaaaard to start. I have to cycle fuel pump repeatedly and crank...and crank....and crank...before it finally starts. Once it's been running for five minutes, it restarts quickly every time.
The truck has 240k miles, and I think it's on the original fuel pump. Filter is not original, but god knows how old it is. I was originally thinking fuel pump and bought a new tank/pump/sender unit from Rockauto, figuring that since the fuel guage was inaccurate anyway, I would be frustration ahead to replace the whole rusty conglomeration rather than try to pull the old pump out and drop a new one in the old tank. I haven't put it in yet because the truck is too big for my garage and it only got warm here recently.
The other day, I tried to start it and it started up almost immediately. I put a fuel pressure gauge on the port on the engine and it showed 62 psi (stock range is 60-66). Two days later I couldn't get it to start at all...and it still showed 62 psi on the gauge.
Am I correct in thinking it's the pump? The pressure readings have me wondering. I've also seen references to NOID lights in diagnosing these, and I have no idea what a NOID light is or how to use one. Any input is appreciated.
When it does the crank-no start, will it start on spray? Need to make sure it's a fuel issue, and not a sparkie issue.
When it is hard to start, will it start easily if you flood start it (WOT while cranking)? The fuel pressure regulators can leak down and flood the engine although it is usually only cylinders 3 and 5.
Is your distributor original? It isn't too hard to get the cap off on these (if I'm remembering right) although you might need to climb in the engine bay to reach it, pull an intake coupler and a couple of torx screws I think. Take a look and see if you've got a bunch of dust and soot trails inside. If you're getting 60 psi pressure your fuel pump sounds like it is doing well. Also this time of year there's a lot of moisture in the air which can make a marginal distributor struggle more.
Mine needed a cap and rotor at least twice. This is sound advice replacing them.
That and look for bad wires I had a little lightning storm going on where the wires are close to the floor in my old van. It was hard to believe that it even ran.
55 psi is the minimum needed for the poppet valves to open, if you get a no start at 55 psi keep the pump and just give it the spider upgrade. This replaces the poppet valves with injectors.
Spider injectors are a common failure point and it sounds like you might have that issue? Usually it manifests as a misfire first.
Curtis said:
Spider injectors are a common failure point and it sounds like you might have that issue? Usually it manifests as a misfire first.
This is what I was thinking.
psteav said:
i've also seen references to NOID lights in diagnosing these, and I have no idea what a NOID light is or how to use one. Any input is appreciated.
A noid light can be a 194 bulb with the wire contacts pulled out straight. Plug the wires into the injector harness and see if the light flashes. If so, you're getting an electric signal to the injector. Move on to your next diagnosis.
