I have massive amounts of raw gas pouring out of my exhaust. I just did a total engine rebuild. All the vacuum hoses are correctly hooked up. All the grounds are correctly hooked up. There is a new fuel filter in the truck as well as a new fuel regulator and a cold air intake. There is no defaults on the ecu scanner showing. I have an ase certified mechanic and a nasa engineer who knows motors superbly scratching their heads. I have been working on cars for 35 years and I'm in serious WTF mode right now. Antone out there got a clue what this is? Sure would appreciate any input anyone may have.

 

First, on a cold start up, it is not uncommon for WATER to come out of a tailpipe (condensed from the last run). I'll assume you're confident it's gas.

I also assume it's running like crap. Put your timing light on EACH spark plug wire, to see if each plug is actually firing (if the plug doesn't fire, the gas goes somewhere).

Disconnect your CSI (electrically). This only checks for a stuck CSI power circuit; if the CSI is stuck open mechanically it could also flood the engine.

Are you sure you have the correct vacuum to the FPR? If you have atmospheric instead of vacuum at idle you will be flooding the engine. (The Fuel Pressure-up does this under ECM control; if yours is stuck it's a problem)

Is the fuel return plumbed correctly? If blocked, it will raise the rail pressure.

Last, could you have a stuck injector? The injectors click when they open, but that won't do you much good on the passenger side. I would still pull plugs looking for a wet one.

Good luck.

 

scope 103,
thanks for the reply.It is definitely raw gas coming out of the exhaust. Every plug is wet with gas and fouled, they are new by the way. There is probably a pint every minute and a half coming out of the pipe. Possibly even more than that. I don't know if a csi could even flow at that rate. Got gas in my oil pan too, big time! As for the vacuum I am positive it is right. Been over it 6 times OCD style. Any ideas?

 

scope 103
By the way the fuel return is th factory set up and hasn't been toucked

 

scope 103
Thanks for the reply. It is definitely raw gas coming out of the exhaust. Every plug is wet with gas and fouled, they are new by the way. There is probably a pint every minute and a half coming out of the pipe. Possibly more than than that. I don't know if a csi could even flow at that rate. Got gas in my oil pan too, big time. As for the vacuum I am positive it is right. Been over it 6 times OCD style. Any ideas? By the way the fuel return is the factory set up and hasn't been touched. Keep in mind that this is a fresh motor that has not even ran for 5 minutes. Did not have this problem when the motor went down.

 

Dumping that much fuel How can the engine even run??

If your getting spark how is it that it has not flashed in the Exhaust system

Just what engine ?? You never did mention

Did you do the engine work or someone else

Was anything done to the injectors ??

All of them stuck open at once ??

 

I think it's called mainlining J/Kiding guys, that's just crazy.

 

it is a 3vze 6cyl. the plugs are firing because the thing is actually cranking and running for a bit. Then it drowns itself out and dies. How in the world it's not catching fire or blowing up is a complete mystery to me. And this ain't my first rodeo boys. I have about 7 total engine builds under my belt. Some of those builds were 1000 hp hot rods. This is my first v6 yota though. Nothing has been done to the injectors but wiped off and cleaned. They worked fine at the time the motor was torn down. For the life of me I cannot believe that they all just up and decided to stick open at the same time. Keep in mind that I have done some surfing around on this issue with this particular truck and other people have had this problem. Any insight would be welcome. I know when I'm over my head.

 

If your fuel regulator (new, huh?) isn't working right, you could over-pressurized the rail. It will start and run fitfully until it floods out (and gas pours out the tailpipe).

Not a sure diagnosis until you put your pressure gauge on it. You'll need a 1.25mm adapter like this one: http://www.ebay.com/itm/251254996574

 

scope103
Thank you for your help with the link to the pressure adapter. I do agree that a pressure test is in order. I picked up the new regulator and installed it yesterday right before I started asking for help on this forum. It's doing just as you said, it starts, runs fitfully then drowns out. I have looked up the rail pressure numbers already so I will check that today. I'll let you know what the outcome is.

 

Any updates ?? I am quite curious about this one.

 

okay Wyoming9,
here's the situation as it stands. After a good bit of research, educating myself thoroughly on Toyota fuel systems as well as talking directly to a dealership tech and a couple of fuel injector experts this is my best hypothesis. Between the time my 4runner went down and I pulled the motor to rebuild it it sat for about 2 years. After the injectors sat for that length of time with fuel in them the fuel likely turned to varnish. When I finally lit the freshened up engine with the old injectors in it I think at least 3 of them hung wide open. I have a new set coming and they should be here Wednesday afternoon.
As it stands now there is a good fuel pump, new filter, new regulator , proper pressure in the fuel rails and electrical current turning on and off in the injector plugs as it is supposed to. Near as i can figure the only thing left in the fuel system is the injectors themselves. Also there are no stuck valves. Got good compression in all 6 holes. When the injectors are installed and the thing is finally running properly (optimism) I will most definitely come back and post the outcome on this tread. If anyone else ever encounters this I want them to know what to do about it and not struggle like I have. Wish me luck!

 

I was also curious myself and your theory makes sense, luck to you!

 

If you are going to replace (or even just service) injectors, now is a good time to replace the electrical connector TO the injector (yeah, I know, MORE work suggested). https://www.yotatech.com/forums/f116...ectors-290886/ At the age of our rigs, those connectors are succumbing to the heat.

You can buy connectors with "pigtails" that you crimp/solder to the old wires, but you'll get a much cleaner, more reliable job if you replace and crimp just the connector as I describe above. And it's not too expensive.

 

Okay everybody here is the final report on the raw gas in the exhaust issue. Now I have to start by saying that I am a little embarrassed but much relieved. Now in my own defense I am not the only person who has had this exact problem. The one thing that dawned on me that was a common theme with everyone having this problem is that they all had to remove the plenum for one reason or another. Obviously there is something we are all doing wrong when we reinstall the plenum. On the passenger side of the plenum where all the vacuum lines connect there is also the fuel return line. If you hook that fuel return line up to a 6mm vacuum port it will vacuum out massive amounts of gas from the tank and dump it directly into the plenum and right out the exhaust. DUH!!! Now I have to say that I have worked on engines for entirely too many decades to make a rookie mistake like this but I sure did. Part of the reason that I am so generously sharing my stupidity with everyone here is in the hopes that I am sufficiently embarrassed enough to make me pay more attention to what I'm doing in the future.HA! Hey it's either laugh or cry. If any of you fellas ever hear of anyone having this problem please share this information with them. Thank you all for your time and input here. It really is appreciated.

 

Speaking for myself thanks for coming clean

How many people do you know who have installed hundreds of clutches only to reinstall the old clutch disc ?? That was the reason for the new clutch kit

 

I'm having the same issue. Could you post a pic of where the return line should be going? It's been troubling me all week and I cant figure out what's going on

 

Fuel return line: it attaches to the bottom of the fuel pressure regulator, located on the firewall end of the fuel rail, and the other end goes into the firewall.
http://www.toyota-4runner.org/classi...ml#post2246678