Fuel coming from exhaust

TechAngel

Member
Apr 9, 2020
21
1
13
Kentucky
Hello All! This is my first (re)post here on StangNet and I was hoping to find some guidance. I’ve got a 95* Mustang GT with the 5.0 V8. I just recently got the car and knew it needed some work. Just a quick look over the car I saw a few things. AC lines are all cut, some wires are janky, O2 sensor wires are cut and hanging from the bottom of the car, Etc. When I first drove the car, it was running rich and smelling strongly of fuel. I read I could change the fuel pressure regulator and that can help, so I did. The richness cleared up immediately (no more smoke) and the gas smell faded. Then one day as I was about to leave work, I started it up, and it was back. And really strong. I got the car home and noticed there was fuel coming out from the inside of the exhaust, right below my door. ( I made sure it wasn’t just dripping down anywhere by getting under the car with a flashlight). I’m really stumped as to what it could be. My guess would be a stuck injector, as it’s only on the passenger side. My dad said it could be a vacuum leak as well, which I hope isn’t the case, I’d have no idea where to start to track it down. Any help would be appreciated, I really want to drive my car! Thanks in advance.
 
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First order of business is to check for codes, be prepared, you're gonna have a bunch.
Next thing is to install the 02 sensors and figure out what the (dumb ass) previous owner did to the wires for them.
I hope you are not driving the car around, until you get the fuel dumping thing resolved it's a rolling Molotov Coctail.
You can rent a fuel pressure gauge from a parts store, some will loan them of you have a credit card. Note the pressure with the key on, engine not running, and engine running with the vacuum line off and plugged.
Tell us what you find.
 
First order of business is to check for codes, be prepared, you're gonna have a bunch.
Next thing is to install the 02 sensors and figure out what the (dumb ass) previous owner did to the wires for them.
I hope you are not driving the car around, until you get the fuel dumping thing resolved it's a rolling Molotov Coctail.
You can rent a fuel pressure gauge from a parts store, some will loan them of you have a credit card. Note the pressure with the key on, engine not running, and engine running with the vacuum line off and plugged.
Tell us what you find.
I’ll have to try checking the codes again, I had to pull the gauge cluster to put a bulb in the check engine socket, as the previous owner took it out. ( no idea why :chin, he definitely didn’t want me to see that light come on lol)
I did however go ahead and check my injectors. I pulled them out and did the ol 9 volt battery trick, and every one of them clicked. I’m still planning on replacing them just to be safe, if not future proofing. I’ll let you know what codes it shoots sometime tomorrow. Thank you for the advice!
 
First order of business is to fix what you know is broke. If the O2 sensors are dangling out the bottom of the car, then the fuel pressure isn't likely the problem. Get the O2 sensors installed properly, and then we can start looking at the janky wiring.

Kurt
 
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First order of business is to fix what you know is broke. If the O2 sensors are dangling out the bottom of the car, then the fuel pressure isn't likely the problem. Get the O2 sensors installed properly, and then we can start looking at the janky wiring.

Kurt
I read somewhere that you could either have your MAF sensor or your 02 sensors, and it’d try to correct it and adjust itself. I don’t know how accurate that is, but it definitely wouldn’t hurt for me to fix them. I’ve gotta jack her up today and see what all has been cut, I don’t even know if there’s still a connector under the car :shrug:
 
Here’s before and after I took the intake off
 

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I read somewhere that you could either have your MAF sensor or your 02 sensors, and it’d try to correct it and adjust itself. I don’t know how accurate that is, but it definitely wouldn’t hurt for me to fix them. I’ve gotta jack her up today and see what all has been cut, I don’t even know if there’s still a connector under the car :shrug:

The car runs best with both. There are limp modes to run without certain items so that the car will still run if a sensor fails. Anything modified, and all the tuning tables for limp mode are going to be completely off.

Kurt
 
So I drained all the oil, and swapped it with some used oil just to test and see if the oil pan was still filling up with gas. We reassembled everything, and I replaced the fuel regulator which was covered by a lifetime warranty. Ran a NOID light on all the injector connectors and everything checked out. So I started it up, and checked for dripping. There were 2 drops, then it stopped. Looked at the dipstick and it was in a good spot, then I ran it for a while and checked the dipstick again. It didn’t change so there wasn’t anything pouring into it. Checked for more drips, no more came out. I took it for a test drive and it seems to be doing quite well, although I went ahead and ordered the o2 sensors and the connectors I needed to fit to the wiring harness. That’ll be here tomorrow, and I’ll install them.
 
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It’s very tough to see but if you’re looking at the back of the connector on the passenger side it goes: light blue/gray - red/gray - yellow/gray - black. That’s starting from top left and working clockwise.