Ok, so I've used these two posts here: https://www.thirdgen.org/forums/v6/1...code-54-a.html

and here:
http://chevythunder.com/fuel_pump_code_54.htm

religiously trying to figure out why I'm getting a code 54, and my fuel pump won't prime.

The car has a brand new fuel pump relay, brand new oil pressure switch. I can manually make the fuel pump run by using the G terminal in the ADSL, so I know that's running. I'm thinking the only thing left to try is checking each wire for a short? When I've run the tests on the two pages I linked, my end result has always been either "no problem", "bad relay", or "bad oil pressure switch". It's none of those, and I don't know what to do. Any help would be appreciated.

Also, I've read the the wires leading to the fuel pump run along the underside of the car. I have a bundle of wires that runs along the floor (inside the car) and exits the hump in the back, right in front of where the pump is. Are those my wires?

 

I'd start by doing a resistence test between the componets in the diagram, like between the relay & the ecm, relay & pump, relay & fuse box,ect.

 

Have you confirmed 12V all the time ( key off ) at the OP switch and pump relay

 

Not yet. I will do that as soon as I dig in the car tomorrow. This was an existing problem when I bought the car, and I'm seeing probe marks in the wires, like near the ecm and such. It seems from what I saw today that it's an intermittent problem as well, because for one startup, there was no SES light.

 

You are wasting your time doing anything else until you have confirmed 12V pump power feed
available from the batt ( single feed wire supplies both relay and OP switch)

 

Just checked, and indeed i get 12v+ to relay and ops

 

This is a pic of a wire bundle that is behind myback seat, goes into the hump right about where my fuel tank is. Its a huge mess because the PO put dynamat over everything. Are these my fuel pump wires?

 

Yes there is a connector in front of your fuel tank that those three wires feed. They are ground, 12VDC pump power and fuel level send wire to your fuel gauge. I recently worked on removing ny tank and replacing fuel pump on 88 firebird. With your ignition on you should have 12 VDC at the connector.

 

I only have 5v to the pink wire in that harness. Which is probably why I'm getting the code 54. Does that wire run to the ecm? Is there any chance I have a bad ecm?

 

Did you LOOK at the pump circuit diagram I posted for you??????
The pump wire ALSO goes to the ECM so it can monitor pump voltage so the ECM is telling you that pump voltage is low because you only have 5V going to the pump

 

Yea, I LOOKED at the diagram, also looked at the one in my Chilton's, and my service manual. I have a PINK wire supplying 5v back to the pump. A color NOT in your diagram. I'm trying to figure out WHY I'm only getting 5v to that wire. I know next to nothing about cars, and come here for advice on what to do because I don't have the money to take it to a shop.

I need constructive replies, because everything I've found on my own hasn't led me to my problem, or how to fix it.

If that wire is going, per your diagram, to the fuse, OPS, relay, and ecm, and my OPS and relay are brand new and all getting 12v, then the only other component on there is the ecm. I've already asked if my problem could be caused by a bad ecm. Unless there is a break in the PINK wire of mine that is causing enough resistance to only see 5v? I don't know, hence why I'm asking you guys.

 

If you read 5VDC instead of the correct 12VDC at the connector with your black lead to the black wire and your red lead to the middle or pink
I would use the diagram provided by vetteoz above. You should see 12VDC on terminal E and ground at your fuel pump relay.

 

As I already said the ECM is only monitoring that wire to see what the voltage is ,
has no control over it

You know the wiring is OK from relay to pump because pump ran when you used ALDL terminal

 

How are you checking for voltage at that connector.

There is no power going to the pump except when engine is running
( or for the 2 second prime after the key turned on which you say doesn't work )

You originally said your problem was no pump prime;key on
you have not stated if fuel pump will run off the OP switch ( and engine fire up )
when the engine is cranked over ?

 

There were already probe holes in the wires @ the well, so I've been using those. I throw one probe in the ground wire, another in the pink. the wire reads 5v anytime the key is on. No difference between if it's been on for 1-2 secs, or 2 mins. Always 5v.

Should I try the readings with the car actually running as well? Or is my key-on test enough?

 

I am looking at my Chiltons Firebird 82-92 manual anf the error code list only goes as high as 48
Your car is a 1988 camaro V6 correct.
I saw a 95 OBD1 list on this site.TGO that shows a 54 low fuel pump voltage or digital EGR valve. Is this why you are checking the circuit since 1988 did not use a digital EGR?

By the way my 88 V6 firebird wires in the rear at the tank connector pump were black green and gray if I remember correctly. I think black was ground,
Since you said the ADSL pin g test primed the pump I would check the voltage again at the connector in rear If Black os ground I would check the third for 12VDC as it may be the one that goes to your pump.
I have tested my 94 chevy silverado truck with the key in the on position and did see 12VDC when it was not running before I replaced a pump years ago.

 

When i bought the car, the owner said that the check engine light was on because they thought there was a short to the fuel pump. Also, i have never heard the pump prime when i turn the key on. These are the reasons ive been going after the low voltage part of the code.

My wires at the back are black, which is ground, pink, which im getting 5v at, and tan/white, which carries no voltage when key off or on. Havent checked with motor running. The PO said the engine was rebuilt about 300 miles ago, but i decided to replace the ops and fuel pump relay anyway.

The relay pigtail looks horrendous, with bare wires near the connector, but they are wrapped for now until i get money for a new pigtail. However, a visual check didnt look like the wires had burned from a short at all.

Im wondering, per the earlier diagram, if the red wire that connect everything may be bad. But like vetteoz said, i can get the pump running per the test terminal.

Im really lost on this one.

 

The engine will start, unless the relay is unplugged. Does that answer your question? I still can drive the car around. When running it only feels like a timing problem, not a fuel one. But i could be wrong. Like i said before, i know next to nothing about cars. Have only gotten this far because im fairly mechanically enclined.

 

So you still have a problem because pump should still run with no relay.
As shown in diagram , the OP switch supplies power direct to pump

Wire you are seeing V on is most likely the gauge wire ; pump will be the tan /white which has no voltage unless engine is running

but your electrical skills need fixing.
You already know the pump works when jumpered @ALDL so the wiring from relay to pump is fine,
no point testing under seat.
Problem is with pump wiring up front
Why no power from OP switch to pump

 

The pink wire is to the fuel level sending unit. The voltage you see there is the fuel level signal, 5v would be about 1/2 tank. The power to the pump is the Tan wire.

 

Ok, I get power to the tan/white wire when I start the car. However, I'm NOT getting it when I turn the key to on. Might there be a problem between the ignition and the fuel pump relay?

I'm assuming since I can start the car, and the engine stays running that the pump is running off the OPS, am I correct in this? Since I don't see the ignition circuit in the above diagram, I'm guessing that it's on the other side of the ecm.

Maybe since everything is seeming to check out in the fuel circuit, that it's between the ignition and the ecm. One of the POs did a lot of detrimental damage to the wiring, (for example, my blower motor turns on when the key is on, and I don't think it's supposed to do that) he very well could have caused this problem.

Does it sound like my thinking here is sound?

 

If you have a long crank time when trying to start the engine first thing, or, after it has sat for a bit.... chances are good, that the ECM isn't controlling the relay. Verify that you get 12 volts across B and C at the relay when cranking, or, engine running.

If that checks out, verify that the ECM is actually grounding the black/white wire.

 

Ok, with the engine running, I have no power at B, and 0.08v at C. I checked B as well as the ground at the back, to a ground on the car, and got continuity. Both measuring around 0.5 ohms.

A friend said "I had to run a ground wire to thew computer case to the body". Is it possible my ecm isn't grounding properly?

 

Odds are that the transistor in the ECM popped. This is what supplies +12 volts to the relay coil to activate it. With the bad insulation on the wires at the relay it likely shorted and pop goes the transistor.

It is easy to replace the transistor (PN2907 works). Or swap the ECM and keep that one for a spare.

Whatever you do don't ground the ECM case. It is already tied to the engine block via the EFI harness. A local ground is bad news.

RBob.

 

Excellent. I will go take it out now, pop it open, and see what I found.

 

Ok. Now I'm really at a loss. I see multiple transistors in this thing. Could you point me to the one that might be blown? I've got a site here telling me how to test a pnp transistor, but there's a lot on there, you could save me a fair amount of time finding which one is bad if you know which would have popped.

Also, if I decide to just replace the ecm, what replacement should I be looking for? Here's my current one.

 

Also, if i have to replace the ecm, ive read that you can replace the chip from the old ecm to keep all the specs forthe car. I looked up my vin, and and it says my car was an automatic, which it isnt now. I dont know if the ecm was ever changed from stock. It having one that thinks it has an auto negatively affect me at all?

 

ECM has nothing to do with it.
What ever is programmed on the prom (chip ) determines what it is set up for
which is why you swap the old prom over to any new ECM you install.
You need to find out what " tune" you have on your prom

 

I imagine that will involve taking it do the dealership or getting the setup that people use to burn custom ones?

 

Dealership will be little use for such ancient technology.
Does engine run right?
If so I wouldn't worry about the tune because little difference between auto and stick tunes
except for TCC which you don't have on a stick car

Even if you had a " auto" tune and it was " trying" to lock the convertor;
there is nothing there for it to operate and nothing to tell ECM that the convertor is not there anyway

 

Ok, excellent. Thank you for all the help Vetteoz. So at this point in my issue, I'm either finding another ecm, or seeing if RBob comes in again and lets me know what transistor he's referring too.

Helluva lot better position than I was in even a few days ago. Been dealing with this problem for a couple months.

 

The transistor is Q6, in the upper left corner of your picture. It is the taller of the two there.

Note that HNL is a 2.8l 5-spd calibration (chip).

RBob.

 

Well, a little update. There was only one place in the area that carried those transistors. Went and picked up a few, and replaced the one RBob said to, and sure as ****, when I plugged the ecm back in and turned the key to on, I heard my fuel pump kick on. All this time banging my head on this problem, and it was fixed with a 50 cent part. Thank you so much man. Really. I took each one of the terminals out of the relay harness and threw heat shrink on them until I can replace the pigtail so hopefully I don't have another short. Now I can finally put this problem away and move onto another!