Backfiring and fuel smell

Post by **Eck** » Sun Apr 12, 2015 4:34 pm

So after driving about 50 miles today, I was getting close to home and started to hear some backfiring and specifically if I really tried to get on it. It also seemed sluggish. Pulled it into the garage and could smell gas. I checked for leaks at the fuel rail but couldn't see any. When the vehicle is running, I'm getting at least 30-40 psi but as soon as I shut it off, the pressure drops to 0 immediately. It used to hold pressure and slowly drop.

Any ideas what to check for? Obviously I'm running EFI- and no codes or check engine issues.

Post by **Rox Crusher** » Sun Apr 12, 2015 5:29 pm

I would check the fuel pressure regulator which is mounted on the fuel rail.

See if the vacuum line to it is still connected and in tact.

Post by **Eck** » Sun Apr 12, 2015 6:02 pm

Rox Crusher wrote:I would check the fuel pressure regulator which is mounted on the fuel rail.

See if the vacuum line to it is still connected and in tact.

Yep plugged in still. The truck idles fine- didn't die. I checked both pumps and those are running fine. When I try to turn the truck on, it doesn't fire right up anymore like its starving for fuel- which leads me to believe that somehow the system isn't staying pressurized or the fuel isn't getting to where it needs with the right mixture?

Post by **landshark** » Sun Apr 12, 2015 6:21 pm

Maybe tap on the fpr and see if your pressure changes After shut off. Is the fpr new or from the jy?

Post by **Rox Crusher** » Sun Apr 12, 2015 6:38 pm

It sounds like the fpr is bypassing too early.

You've got enough fuel pressure to idle, but not enough to feed it under load.

They are cheap to replace.

Post by **Moab Mike** » Sun Apr 12, 2015 6:58 pm

I would check your dizzy again.

Post by **Eck** » Sun Apr 12, 2015 7:01 pm

76fordbronco wrote:I would check your dizzy again.

Check it for what? It's not sending a cam sensor code. And I have oil pressure.

The FPR is from the JY. I'll try to replace that and see if it helps.

Post by **landshark** » Sun Apr 12, 2015 7:09 pm

Fpr is cheap. Mine went out on the 76 about a month after I got it running. Jy parts are hit and miss sometimes.

Post by **Moab Mike** » Sun Apr 12, 2015 7:14 pm

I didn't see your second comment. I was thinking if your fuel pressure was at 30-40 PSI your FPR was good.

It makes sense if your backfiring you are running lean but that doesn't explain why your not getting lean codes. It your FPR is bad that would explain 0 fuel pressure.

Post by **Viperwolf1** » Sun Apr 12, 2015 9:22 pm

Look for leaks at every connection of the fuel system. Injectors to rails, regulator, lines to rail, pressure gauge, etc.

Post by **B.O.B.** » Mon Apr 13, 2015 5:16 am

Mine did the same thing and I had some leaking injectors. My old ranger had a bad fpr and fuel was leaking out the exhaust. Probably one of the two. Since it just started I would get fpr

Post by **landshark** » Mon Apr 13, 2015 6:49 am

Sometimes you can pull the plugs to see if one is running "rich" sometimes an indicator of an injector leaking down.

Post by **Rox Crusher** » Mon Apr 13, 2015 6:58 am

With the rig cold

Cycle the key off and on a few times, which will trigger the pump to pressurize the system.

Then crawl all around the engine bay and underneath looking for leaks at all the connections.

If you locate it, clean it up or let it evaporate before starting so you don't have a fire in your hands.

I had a small leak at the fitting where the fuel line connects to the fuel rail. It was hard to see / find.

Post by **Digger** » Mon Apr 13, 2015 3:06 pm

Check FPR.

I've had two get old, rupture and dump fuel straight into the intake via the vacuum line. They are not bulletproof.

Post by **Eck** » Mon Apr 13, 2015 8:00 pm

New FPR did not cure me. I am fairly sure I sprung a leak somewhere towards the back of the engine. Hoping to remove the upper intake and cycle the fuel pump to see if I can figure this out...

Post by **Eck** » Tue Apr 14, 2015 7:33 pm

So I had a bad fuel injector in my #2 hole. (Let the jokes commence). Was able to soak up the intake, blow out the spark plug hole, change the oil and fire it up. The engine runs much smoother now than it did before. It seemed like the entire engine vibrated.

The stupid thing is that when I last rebuilt the engine I decided to go with professionally rebuilt injectors instead of JY parts. Now I have a JY injector back in.

Big thanks to Phil for fielding my call and walking me through what to do.

Post by **kbank6** » Tue Apr 14, 2015 8:24 pm

Let it go....let it go.......

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