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No fuel pressure after backfire & engine fire

Vehicle: 2000 Chevy Express 3500 passenger van 5.7L
History: Low fuel pressure when starting. If the van sat longer than 24 hours it wouldn’t start without a squirt of starting fluid. I suspected it was the fuel pump but didn’t get around to changing it. My wife put in “extra” starting fluid one afternoon and tried to start the van - there was a small explosion which blew up the air cleaner housing and started a fire. She put the fire out with an extinguisher. The fire was restricted to the air cleaner media and housing and burned for about 45 seconds.

Repairs: I cleaned up the extinguisher material and replaced filter housing and media. I checked the fuel pressure at the fuel rail - pressure gauge read zero. I checked the relay and all of the fuses - everything was in good shape. I looked for a fuel cutoff switch but the Chevy tech I talked to said there isn’t one on that year of van - he recommended that I disconnect the battery for 5 minutes to reset the system. I did that too. Still no fuel pressure. Replaced the fuel pump and fuel filter. Still no fuel pressure.

Current Status: The engine will crank and if I put starting fluid in the van will turn over and run as long as there is starting fluid. When the accelerant is gone the engine stops running. Again, it will crank but there is no fuel pressure at the rail. The manual says the pressure should be 85 lbs with the key on and engine off and then 45 - 55 lbs running. Any thoughts?

First of all take the starting fluid cans to the hazmat disposal site in your area. It has no place around modern cars. You’re lucky the starting fluid didn’t bust open the plastic intake manifold on your engine.

So, is the fuel pump operating when you try to start the engine? If you’re able to replace your own fuel pump you must also have a voltmeter. Get a wiring diagram and find the power feed to the pump. If I recall it’s gray, but don’t hold me to that. While cranking the engine make sure you have battery voltage going to the pump. Also make sure you have a good ground at the same connection. There should be almost no voltage on the ground wire. From this test, we can find out if the trouble is at the tank or somewhere else.

If pressure at the fuel rail is zero, then your pump’s not running. Look for a bad ground back at the tank or no power out of (or into) the relay. If it were my truck and I was paying the bills, I’d put a pressure gauge on the fuel rail & intermittently apply +12 volts to the output of the fuel pump relay. I would take steps NOT to catch the whole place on fire, though.

I doubt whether the starting fluid fire damaged anything.

Sounds like the fuel pump picked that time to give up the ghost completely.

The fuel pump relay is good. And while I hate dropping the fuel tank to get to the wire harness on the pump, I am going to do that this morning. The question that plagues me is this: what else is there in the in the fuel pump circuit that could interrupt the circuit?

The harness was in good shape when I changed the pump (should have checked it with the multimeter though). The pump ran, albeit poorly, prior to the disaster. Now it doesn’t run at all. Is there a sending unit or emergency switch that may be grounding out? Is it possible the the fuel pressure regulator is causing a problem?

Anyway, I’m dropping the tank and checking the harness. If anyone has a thought on the rest of the circuit, I’d be very interested. Thanks a million!

One additional symptom that seems noteworthy - this van has been plagued by fuel pump failure. When the first one failed it was a result of my wife running the vehicle out of fuel twice (at least that was my assumption). She doesn’t do that anymore. Nevertheless, I have changed the pump in that van a total of four times. I just assumed that the Airtex pumps I was putting in were poor quality. This time I went to Napa and got a Delphi OEM pump. Thanks for your thoughts.

@Pinwheel, are you checking that the tank doesn’t have all sorts of rust and dirt in it?
In other words, when you’re dropping the tank to replace the pump, are you making sure to take a good look inside?
Have the rebuild kits includes a wiring harness pigtail. On many GM vehicles you have to snip off the fuel pump pigtail and install an updated one. The old pigtails tended to overheat.

Have you been installing these?

http://www.rockauto.com/catalog/moreinfo.php?pk=1975360&cc=1358636

Sop is to use starting fluid when van sits for 24hrs AND ur wife is ok with this? Whew. Step back to Pre-explosion days. Van sits for awhile. U pull engine cover and spray starter fluid down intake? U could hookup fuel pressure gauge on dash for giggles but even with good fuel pressure you still need starter fluid? Does it have the weird GM spider fuel rail?

@Stoveguyy, the van definitely has that “weird GM spider fuel rail”

It’s called CSFI, by the way. Central Sequential Fuel Injection

Thanks for the input. Problem solved before I dropped the fuel tank again. There is a 15 amp fuse - basically a fusible link - on one of the wire harnesses coming out of the fuse box under the hood. That fuse had blown and when I changed it out the new pump worked fine.

So u don’t need starter fluid now after 24hrs of sitting?

Congratulations. There’s an old saying, “nobody ever checks the fuses”. It’s true of all of us.

Happy motoring.

@thesamemountainbike

Do you know this acronym?

CTFFF

I’ve been guilty also.

I’m unfamiliar with the acronym, but I’d bet we’ve all failed to check the fuse at one time or another.

check the . . . fuse first