Is there any way to test to see if the fuel pump relay system is still working or do i have to just replace it?

 

Locate the relay and there will be a green/white, black, orange, and grey wire. Remove the relay and hook up a test light to the green/white wire and turn the key on, it should light up for a few secs. This will tell you if the computer is commanding the relay on. The black wire is a ground, check and make sure its a good ground. The orange is bat power and the grey is the fuel pump wire. Jump between the orange and grey and it the fuel pump works then the wiring there is fine. hope i was helpful

 

Hey, I did some searching and found this to try and fix my problem. I do not get power to the green/white wire as described in the first step. Does that mean I need a new computer? The car has a hypertech chip that was installed when I got it and also the fan comes on when it starts, which I read in another post could have damaged the computer. I had a mechanic work on this for a long time and I still crank until the oil pressure kicks in. I would love to get this resolved finally. Thanks!

 

The computer doesn't operate quite like that (Not far from). Get a digital volt meter, and check the orange and black wires on the fuel pump relay harness. Make sure that is getting 12V. If you green wire isn't getting voltage you may have a small problem like i'm experiencing. You will need to go to your passenger side and drop the ECM. Check terming A1 (green/white wire), turn the key on, if you get 12V, then there is a break between there and the fuel pump relay plug. The way the system works is that the computer sends 12V to the green/white wire, and being the relay is powered already by the orange wire, it will flip the switch and send a signal via the tan/white wire to the fuel pump and back to the ECU. When the ECU gets the 12V back to the ECM via the tan/white wire is when it will activate the 2 second activation ("prime"). So therefore if you test it with the relay out it should stay at 12V at the green/white. Check your green/white wire at terminal A1 at the ECU and if you have 12V, then you must replace the wire (what i'm doing right now for mine...so it does happen although it may be rare) all the way from the ECM to the fuel pump relay plug. Hope this helps.

 

There is power when I checked the orange and black wires. I took the relay out and checked A1 with the key on. There was no power to A1. (I checked with test light, does that matter?) Does this point to a ECU issue?

 

Did you mean terminal A1 of the four plugs going into the ECU (car's computer; under passenger side dash)??? If you don't have power there then you may have an issue.

 

I checked A1 right at the computer with the key turned to the on position. Does that mean an ECU issue or something else? What would I do next? Thanks for the help.

 

Should I try a different ECU? How much do they cost?

 

if you get them at like a pick-n-pull junk yard...anywhere from $20-50, and by me they have no questions warranty so you can return it if you wanted. Other junk yards will try and scam $100 for the labor of taking out 5 screws, 4 plugs, and 10 minutes of their lives, with the possibility of no warranty.

As far as not getting power there, i would assume issue with ECU, but i cannot be sure, i had power so i haven't had to diagnose any farther. Yet there is supposed to be a SES code for a bad ECU...but i thought about that...if the ECU is bad...hows it supposed to throw a code??, lol. My easiest suggestion for you is if you can find another ECU to just swap them to see if it works.

 

Do I need to be specific with the computer or do others in the GM line interchange? The last good yard I lived by was in Colorado.

 

i know every car has their own...past that i can't speak on interchangability. I suggest doing a search in the above tool bar. I would assume that it needs to be similar, have similar sensors and such, and at least be fuel injected. I can't speak specifics becuase i haven't faced it yet, hopefully someone will chime in soon.

 

I put in a new ECM with the stock chip. No dice. Code 54 again. I really want to figure this out....what can I try next?

 

I'm also having a relay code, and you(84redta) seem to have the best understanding of this system. I have 12V at the green/white wire when unplugged. But when i plug in to a relay there is no voltage at the green/white wire anymore (or very little). This is where im confused.

its a 5wire relay, with the power to the fuel pump on the A, B=ground, C=green/white, & D empty?, E=ignition power.

i may not be buying the right relay for an 85', not sure. but the one that used to work isnt working either.

i'm at a lost & I really need this running better by tomorrow.

 

So i have looked at this some more. This is the strange part, my multi-meter will measure 12V on the green, but it wont light up test light bulb, does this mean under a load something in the computer is fried?

I think the relay is good, because i soldered in a wire to the 4th spot, which was supposed to be the ALDL wire & hooked it up to a manual switch. it runs way better when the switch is on, then when its trying to run from the oil pressure switch only.

any suggestions? I have a spare computer, but i need to have moates solder in a new adapter, as i'm using flash chips.

 

sorry, i must have unsubscribed before you posted. If you are still having this problem then this may apply...i was having that problem. With no relay plugged in i was getting the full 12V off of terminal A1 on the ECU (dark green/white stripe wire). I would also get it on the other end at the fuel pump relay. As far as the wiring...i know it's supposed to be orange, black (white stripe maybe?), red, dark green/white stripe, and tan/white stripe. I'm not sure if this applies to 85 as it was the very first year of fuel injection in F-bodies to my knowledge. Don't know if this is firebird or camaro...but in the tech articles off of the home page...there is in the electrical section i believe the wiring schematics to an 85 or 86...this should guide you in the right direction.

Back to my story...i would plug in a brand new fuel pump relay (because i was ruling out the cheapest possibilities), and under "load", the ECU would drop that 12V to something like 600 mV (very tiny)...so i had a conversation with BigBabyLou (his user name) and between my testing and his brains we discovered that there was a good chance that the ECU was fried. I went to a JY and got lucky enough to find an 88 automatic TBI for my 88 manual TBI, so all i had to do was change the chip internally and everything worked. Actually was a remanufactured ECU provided by Delco, so at least it wasn't 20 years old. But that was my answer to that problem...i can't promise you that will be the miracle answer...but it worked for me. Any other electrical issues feel free to ask me as i've studied the schematics of our cars a little too much, lol, or contact BigBabyLou, he as well very good at the electronic issues of our cars and the fix for them.

Hope this helps.
Jon

 

Bill, you say you have a spare computer. The memcal should just easily come out and you should be able to put in the memcal from your current ECM. That way, you can test whether the ECM is the cause of your problem (which kinda sounds like it from your troubleshooting).

Lou

 

what happens when you are not getting any power from the ecu green / white wire to fuel pump relay...i am still not getting any power to fuel pump..

 

WHAT HAPPENS WHEN YOU CHECK THE VOLTS AT THE ECM ON THE GREEN/WHITE WIRE AND YOU ARE GETTING NO VOLTS ON THE WIRE TO RELAY....WHAT HAPPENS KNOW...WHAT DO YOU DO IS MY ECM OUT..

 

BILLDORN

WHAT HAPPENS IF YOU STILL ARE NOT GETTING ANY VOLTAGE FROM THE GREEN/WHITE WIRE FROM ECM AND RELAY.....

 

Might start a new post, that was from 13 years ago. Does the ECM actually send voltage to the relay coil, or does it switch ground.

 

to be honest i am not sure...is there a way i could find out....
everything is new , fuel pump, oil sending unit, ignition switch,
i am getting power to the ecm and everything else...i am evening getting power from the ignitoin switch to the ecm but nothing coming out of the ecm to the relay ....so it would prime