Code 54: Coming back to haunt me
Thread Starter
Pro
Joined: Apr 2001
Posts: 539
Likes: 4
From: Rochester, NY
Code 54: Coming back to haunt me
A month ago my 89 vette had difficulty starting when it was idle for over 6 hours (would have to crank the engine several times before it would start) and a couple of folks suggested replacing the Fuel Pump Relay which work for a couple of weeks. Now the car is back to not starting unless I crank the engine 3 - 4 times. Is it possible that the Fuel Pump Relay is defective or is there a larger issue ???
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Re: Code 54: Coming back to haunt me (csc67)
Put a pressure guage on the rail. Turn the key to the ON position. You should see the pressure rise to the 40# area. If not the pump is not coming ON by means of the ECM. Typical cause: bad relay. (I may be wrong, I forget the exact circuit.) Question now would be,. what is toasting your relay's? New one may have been a bad part, or the pump/pump electrical may have problems.
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Code 54: Coming back to haunt me (csc67)
Does 54 stil set? Do you get the code right away and does SES light stay on, or does SES light only come on sometimes while driving?
54 was made to find a bad fuel pump relay. The relay and the oil pressure switch get power from the same source, but both can run the fuel pump.
If the relay is new, and not defective - wrong part, etc., I would check the connections on the relay. Also could be a bad connection or bad driver from the ECM. Fuel pump relay is one of the few part that actually gets driven (+ voltage) from the ecm. The ecm connection is a Dark Green wire (465). You should check this connection at the ecm.
If replacing the relay solves the problem, but the problem returns (and correct relay is being used), could be the pump is drawing too much current. Not sure if I have ever heard of this before but certainly possible.
54 was made to find a bad fuel pump relay. The relay and the oil pressure switch get power from the same source, but both can run the fuel pump.
If the relay is new, and not defective - wrong part, etc., I would check the connections on the relay. Also could be a bad connection or bad driver from the ECM. Fuel pump relay is one of the few part that actually gets driven (+ voltage) from the ecm. The ecm connection is a Dark Green wire (465). You should check this connection at the ecm.
If replacing the relay solves the problem, but the problem returns (and correct relay is being used), could be the pump is drawing too much current. Not sure if I have ever heard of this before but certainly possible.
Thread Starter
Pro
Joined: Apr 2001
Posts: 539
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From: Rochester, NY
Re: Code 54: Coming back to haunt me (PeteL)
Pete L,
The SES light stays on unless I drive the car within a couple of hours of the original, then I think it doesn't appear (only when it hasn't been driven for a while). The code appears a couple of seconds after it "turns over" and stays until the car is shut down. I can only tell you that the part was new, unsure if it was defective. It ran great for several weeks after replacing the Fuel Filter relay. I may take this relay back to the store and see if they can detect if the relay is stilll "good". Any more thoughts would be great
The SES light stays on unless I drive the car within a couple of hours of the original, then I think it doesn't appear (only when it hasn't been driven for a while). The code appears a couple of seconds after it "turns over" and stays until the car is shut down. I can only tell you that the part was new, unsure if it was defective. It ran great for several weeks after replacing the Fuel Filter relay. I may take this relay back to the store and see if they can detect if the relay is stilll "good". Any more thoughts would be great
7th Gear
Joined: Sep 2001
Posts: 7
Likes: 0
From: essex ontario
Re: Code 54: Coming back to haunt me (csc67)
I went thru this same problem earlier this year. I replaced the ecm which solved the code 54 showing up. However it did not solve the hard starting problem I also had. It turned out I had a leaking injector. I replaced all of them with Accel 23# injectors and it starts like new.
Get a fuel pressure gauge and see if your pressure drops after you shut the engine off. If it drops (and it sounds like it will) I would bet that's your problem.
Bob
Get a fuel pressure gauge and see if your pressure drops after you shut the engine off. If it drops (and it sounds like it will) I would bet that's your problem.
Bob
Le Mans Master
Joined: Jul 2001
Posts: 5,297
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From: Stamford VT
Re: Code 54: Coming back to haunt me (Smash)
When I had code 54 and occasional hard start, it was my ECM taking a dump. :D
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Code 54: Coming back to haunt me (csc67)
Sure sounds like the relay is not working, for whatever reason.
Fuel pump relay connector looks like this:
_
C _ A
D E F
I know this won't come out on the forum.
D and F and the connections to the relay coil. ECM provides +12v at D (dark Green wire) and F (black / white wire) is the ground (to engine ground and ecm ground). Put a test light or vom between D and a good known ground like the battery - post. Test light should come on when you turn the ignition on, for at least 2 seconds. If it does then the ecm appears OK, at least for this test. If it does not then check for bad connections on the DK Green wire at the relay socket and at the ECM.
If you get +12V at terminal D and have +12V at terminal A and the fuel pump does not come on it is very likely that the relay is bad.
Just FYI:
Terminal A is the power feed from the battery and should be 12V all the time. This is the source voltage that is switched in the relay to run your pump. It is switched to terminal E - which is the fuel pump. Lack of +12v at terminal E is what set your code.
Terminal C is directly connected to the aldl connector under the dash.
Hope this helps.
Pete
Fuel pump relay connector looks like this:
_
C _ A
D E F
I know this won't come out on the forum.
D and F and the connections to the relay coil. ECM provides +12v at D (dark Green wire) and F (black / white wire) is the ground (to engine ground and ecm ground). Put a test light or vom between D and a good known ground like the battery - post. Test light should come on when you turn the ignition on, for at least 2 seconds. If it does then the ecm appears OK, at least for this test. If it does not then check for bad connections on the DK Green wire at the relay socket and at the ECM.
If you get +12V at terminal D and have +12V at terminal A and the fuel pump does not come on it is very likely that the relay is bad.
Just FYI:
Terminal A is the power feed from the battery and should be 12V all the time. This is the source voltage that is switched in the relay to run your pump. It is switched to terminal E - which is the fuel pump. Lack of +12v at terminal E is what set your code.
Terminal C is directly connected to the aldl connector under the dash.
Hope this helps.
Pete
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