code 54 and pressure drop?
Thread Starter
Heel & Toe
Joined: Mar 2005
Posts: 21
Likes: 0
code 54 and pressure drop?
My scan only pulls up code 54 for the fuel circuit. (oh yeah, Its an 85).
cranks, no start. Got spark, but when I put the fuel guage on it initially goes to 40 psi, but drops quickly to around 20, when I say quickly, definitely less than 2 minutes, when I crank the motor it pumps back up to around 40 psi while cranking.
I pulled the vacuum line of the pressure reg and it was all dry so I assume this is okay.
Right as I shut off the key, I will also here kind of a pop type noise up by what sounds like the passenger front side of the motor and that is when the pressure drops.
Is the check valve a part of the pump or seperate in the line somewhere?
Could an injector loose that much that quickly? Also, when I put a test light on the injector with the key on, they are lit up before even cranking the motor, when I crank the motor, the light goes from bright to dim, is this normal or should it go from completely off to on?
cranks, no start. Got spark, but when I put the fuel guage on it initially goes to 40 psi, but drops quickly to around 20, when I say quickly, definitely less than 2 minutes, when I crank the motor it pumps back up to around 40 psi while cranking.
I pulled the vacuum line of the pressure reg and it was all dry so I assume this is okay.
Right as I shut off the key, I will also here kind of a pop type noise up by what sounds like the passenger front side of the motor and that is when the pressure drops.
Is the check valve a part of the pump or seperate in the line somewhere?
Could an injector loose that much that quickly? Also, when I put a test light on the injector with the key on, they are lit up before even cranking the motor, when I crank the motor, the light goes from bright to dim, is this normal or should it go from completely off to on?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
wow... that's trouble.
Do you smell gas? I mean, under normal circumstances? I know it will smell of it now.
With the pressure dropping... that's odd... It sounds like the pump is failing. Is the pump loud? Can you really hear it? Is there gas in the tank? I know the gauge may say it's full, but are you SURE it's full... the senders on these things are notorious for failing.
There is a FP relay, that is apparently working, and once the engine is running, the oil pressure (fuel pump) switch will keep it going if the relay was to fail. That switch will keep (or fire up) the fuel pump as long as 4 PSI of oil pressure is seen. This is a fail safe from relay related failure. But, it is NOT a fail safe if the oil pressure was to crash!
I wonder if something is amiss with the fuel filter... again, you would smell it. Same with a big leak, you would see signs of gas leaking, and smell them.
Do you have the FSM?? There are some tests you can perform on the various fuel lines, but I don't remember the details right now.
Do you smell gas? I mean, under normal circumstances? I know it will smell of it now.
With the pressure dropping... that's odd... It sounds like the pump is failing. Is the pump loud? Can you really hear it? Is there gas in the tank? I know the gauge may say it's full, but are you SURE it's full... the senders on these things are notorious for failing.
There is a FP relay, that is apparently working, and once the engine is running, the oil pressure (fuel pump) switch will keep it going if the relay was to fail. That switch will keep (or fire up) the fuel pump as long as 4 PSI of oil pressure is seen. This is a fail safe from relay related failure. But, it is NOT a fail safe if the oil pressure was to crash!
I wonder if something is amiss with the fuel filter... again, you would smell it. Same with a big leak, you would see signs of gas leaking, and smell them.
Do you have the FSM?? There are some tests you can perform on the various fuel lines, but I don't remember the details right now.
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
First disconnect the battery for 30 seconds to clear codes. Then listen for the pump running for two seconds after the key is turned on. If the code shows back up back probe terminal B2 (red wire..fuel pump signal) on the ECM with a test light to ground. Ignition should be off for 10 seconds then note light on when the key is turned on for the first two seconds. If the light comes on, replace the ECM. If the light is off, repair the open in circuit B2 (red wire).
