Hey guys, Just bought a new to me mustang, seemed like just a fuel pump problem but after that fix it has turned into much more. Looking for some trouble shooting advice.
Originally my GT would require a bunch of fuel pump priming and then it would start and sort of run for a minute or so then stumble and die. It wouldn't rev up, was missing like crazy. Fuel pressure was really low and would bleed off so I replaced the fuel pump and fuel filter. Now the car seems to be over fueling like crazy. It floods a few cylinders so bad it requires minutes worth of cranking over and it then runs on the fuel in the cylinders for a couple minutes, then as it is going to die if I allow the fuel pump to run it will stay running. Any load what so ever causes it to stutter then flood. Tons of smoke from over fueling. It didn't do that before the pump replacement. I have discovered the alternator diode is bad, I have fixed that, I have checked the crank sensor and cam sensor ohms and volts. The number 4 cyl seems to be not getting quite enough fuel. The number 5 cyl is getting way too much, it literally makes the spark plug drip fuel when its removed.
I have replacement spark plugboots and injectors on the way. The fuel in the tank was super old and nasty looking; was a bit yellow. The thing that really bothers me is when I am using the Torque diagnostic app on my phone to read the o2's they both read 0v. The fuel trim is massively high. Like 42% constantly it dips down to 32% on occasion. I am at a loss of what to do. Once my new clean injectors and boots are installed I plan to drain the tank and fill with new fuel and then see if I can get the engine to run long enough to get to operating temp to run a compression test and leak down test, I am worried about cyl 4. No matter if spark or fuel is disconnected it doesn't change the idle. If the car is brought just above idle it will chug along and stay running. If it is left at idle it surges from such low rpm it knocks and clanks to jumping up to 1000 rpm and back down over and over.
Any advice would be appreciated. I am really running out of diagnostic ideas here. Is there any way to reliably do a cold engine leak down or compression test if I can't get it to run long enough? I really hate running the car this over fueled. It has to be causing engine damage.
Once I get it cleaned up and the ghetto chromed out 18's off it ill post some pictures
:
Originally my GT would require a bunch of fuel pump priming and then it would start and sort of run for a minute or so then stumble and die. It wouldn't rev up, was missing like crazy. Fuel pressure was really low and would bleed off so I replaced the fuel pump and fuel filter. Now the car seems to be over fueling like crazy. It floods a few cylinders so bad it requires minutes worth of cranking over and it then runs on the fuel in the cylinders for a couple minutes, then as it is going to die if I allow the fuel pump to run it will stay running. Any load what so ever causes it to stutter then flood. Tons of smoke from over fueling. It didn't do that before the pump replacement. I have discovered the alternator diode is bad, I have fixed that, I have checked the crank sensor and cam sensor ohms and volts. The number 4 cyl seems to be not getting quite enough fuel. The number 5 cyl is getting way too much, it literally makes the spark plug drip fuel when its removed.
I have replacement spark plugboots and injectors on the way. The fuel in the tank was super old and nasty looking; was a bit yellow. The thing that really bothers me is when I am using the Torque diagnostic app on my phone to read the o2's they both read 0v. The fuel trim is massively high. Like 42% constantly it dips down to 32% on occasion. I am at a loss of what to do. Once my new clean injectors and boots are installed I plan to drain the tank and fill with new fuel and then see if I can get the engine to run long enough to get to operating temp to run a compression test and leak down test, I am worried about cyl 4. No matter if spark or fuel is disconnected it doesn't change the idle. If the car is brought just above idle it will chug along and stay running. If it is left at idle it surges from such low rpm it knocks and clanks to jumping up to 1000 rpm and back down over and over.
Any advice would be appreciated. I am really running out of diagnostic ideas here. Is there any way to reliably do a cold engine leak down or compression test if I can't get it to run long enough? I really hate running the car this over fueled. It has to be causing engine damage.
Once I get it cleaned up and the ghetto chromed out 18's off it ill post some pictures
:
Last edited:
