99' Silverado 5.3 - flooding/not starting

[nixtux]

been fussing with this since yesterday. A friend and I replaced the 02 sensor (bank 1 2nd sensor.) Now it won't start at all. It just floods out. Remove spark plugs, dry them off, pull fuel pump fuse/crank it over until it stops pushing fuel out. Put plugs back, it'll fire but shortly after it floods out again. No mis-fire codes (although 4/5 did show up on 1 scan yesterday.)

It did drive yesterday with no O2 sensor. Still missed though. maybe the coil for cylinder 4/5 would fix it up? Can one or two bad coils cause the whole engine to flood out. The problem is in all cylinders.

Any ideas/suggestions. Thanks

[nixtux]

Attached is a screen from HP tuner scanner. Might be some useful info for someone. No DTC's. It just cranks, fires a little, when it does run it blows some nasty smelling blue-ish smoke. It won't start and stay started any more. Doesn't matter how well the plugs are cleaned up. They get nasty too. If we remove the plugs and crank it, it takes about 5 or so revolutions before all the fluids are pushed from the cylinder.

The O2 sensor was replaced. A fuel regulator was replaced 10-15,000 ago. The fuel filter was replaced (35 miles ago). Prior, it had about 9500 on it when replaced promptly. New fuel pump about 8-10,000. Plenty of fuel pressure. If you open the line it sprays and when it was running it stayed running. We were going to do a compression test today but couldn't get it started and warmed up.

Any advice would be awesome. Kind of at a lose. It's a tight situation. I don't have any money and my friend doesn't. Can't be wasteful replacing shit that is good. It sucks.

[robertisaar]

was the engine running at all during in that graph?

[nixtux]

was the engine running at all during in that graph?

No it wasn't running. I tried saving the data but it kept crashing so I lost that. It ran decent yesterday. About 35 miles. Ironically without a O2 sensor. The stupid thing stripped so we had to tap it. There was a DTC, P0137 HO2S circuit low. I don't think it was bad but we took it to a shop that hooked it up to a super-bad ass scanning tool that didn't say anything we didn't know. He said, change the O2. It was also missing on cylinder 4 and 5. There was some DTC's about random misfiring but that never happened after the exhaust blew some large orange sparks. They were burning on the road. However, it started running much better after that. Annoying trying to troubleshoot a issue. The coil packs are expensive for that truck.

The plugs are fairly new. But they are real dirty. Gas (I think) and so they may need to get replaced. But I don't want to replace them just to repeat it. We did clean them up, pulled the fuel pump fuse, cleared the cylinders and it killed off after 45 seconds. It also ran rough, backfired, and had some sulfar smelling blue smoke.

[pocket-rocket]

Stuck open injector? Toss a fuel pressure gauge on there and see if it holds pressure after the pump primes.

[nixtux]

Stuck open injector? Toss a fuel pressure gauge on there and see if it holds pressure after the pump primes.

Could that cause the entire engine to flood though?

Every cylinder gets flooded. All plugs are gassed and blow out a stead stream with no plugs. It seems to have good compression. The force from it kind of hurts the hands a little. It probably doesn't help that it's blowing gas hah. Car issues, they never end.

[sil]

sounds like what my car is doing......and i got bleach in the tank.........not fun

[nixtux]

sounds like what my car is doing......and i got bleach in the tank.........not fun

Ouch. I can't imagine bleach was put in the tank. However, it started acting up after fuel was put in at a mom-pop gas station. That's been in the back of my mind that maybe the fuel was bad. We did replace the fuel filter and drained the fuel into a glass. It seemed to burn pretty good. Hopefully it wasn't bad fuel.

The plan for the day, get two new coils for cylinders 5 and 4 and check the fuel pressure to see if it's a stuck injector. Hopefully it's either a bad coil pack or a stuck injector. Fairly cheap fixes assuming it's only two coils or the injectors.

[86FieroSEv6]

All the cylinders get wetted? You are definitely pumping fuel into the engine. Did you pull the pressure regulator vacuum line and check for a blasted diaphragm?

[nixtux]

All the cylinders get wetted? You are definitely pumping fuel into the engine. Did you pull the pressure regulator vacuum line and check for a blasted diaphragm?

All the cylinders get soaked with fuel. The plugs, nasty black and soaked. If we pull the fuel pump fuse, it takes about 5-10 cranks before it clears the fuel. A nice steady mist comes out.

I'm not sure what you mean about a blasted diaphragm. If the vacuum is pulled on the fuel regulator, I believe it sprays fuel. My friend did something based on something a mechanic friend of his told him to do. Hopefully that makes sense.

The release valve on the fuel line/rail, will blast fuel if you push it. I don't have a fuel pressure gauge handy. I'll go get one today. See if it loses pressure after it primes.

Could a stuck injector or two bad coils cause it to flood out like that.

On another note, we clean and dry the plugs, before it would run, but now it won't. I suspect we may need to replace them if we can get it to stop flooding. However, replacing them if it stills flood seems pointless.

[walterdude]

"All the cylinders get wetted? You are definitely pumping fuel into the engine. Did you pull the pressure regulator vacuum line and check for a blasted diaphragm?"

X2!!
Tom...
Ninja.... Ninja....
If the FPR "sprays" fuel when you pull the Vacuum line I'd say THAT'S a problem!!!
I'd make sure your oil isn't contaminated with fuel also.. What happens is the diaphragm in the FPR gets a hole in it. Fuel gets through the hole and fills the Vac line. From there it "can" start to fill the plenum with raw fuel... And on to the plugs...

[86FieroSEv6]

If you pull the vacuum line off the fuel pressure regulator, does any fuel squirt out of the vacuum port on the regulator?

[nixtux]

If you pull the vacuum line off the fuel pressure regulator, does any fuel squirt out of the vacuum port on the regulator?

Yes, fuel comes out the vacuum and when it was running it would stay running. Also when running pushing the release valve on the fuel line, that sprays fuel and it stays running. When it runs, it runs pretty crappy which is why the guy at a shop told us to replace the stupid O2. But it got a signel on the HP tuner. A DTC would come up with low voltage but other than that, it still reported similar numbers to bank 2 O2 sensors. I really don't think the O2 was the issue. And it was a waste of $74.00.

[robertisaar]

if fuel is coming out of the vacuum port of the FPR, that is a serious problem.

[nixtux]

if fuel is coming out of the vacuum port of the FPR, that is a serious problem.

It comes out the vacuum line, not the regulator itself.