I have a 89 5.7 tpi Camaro. I was driving home one day and noticed the temp rising. I got it home without completely overheating the car. A few days later I went out and restarted the car and watched the temp gauge. I noticed after a while that the guage wasn't moving. I shut the car down and noticed that I had a leak and the system had drained. I fixed the leak and tried restarting the car but had no success.

A few months later (its my project car) I looked into it again. The battery was bad so I hooked it up to my truck to jump it. I noticed that I wasn't getting fuel to the engine so I started trouble shooting the fuel pump. I noticed that the fuel pump relay wasn't getting power to it on the orange wire. I traced the issue back to the inline fuse located at the battery. I cut out the fuse housing as it seemed to be my issue as I had power on one side but not the other with a good fuse. I jumped the 2 leads together and eureka I had fuel to the engine. I was able to start the car and it ran for about 20 mins when I shut it down.

Its been about 3 weeks and yesterday I went out to move the car to my new house. I put in a new battery and the car started right away. I was letting it warm up as I checked the air pressure in the tires. When I was getting ready to get in and take off she just died.

Here is what I found so far. I am not getting voltage to the fuel pump relay (actually I am getting 1.0-1.5 vdc). I went back to the old fuse location where I jumped it out and tested the voltage again and getting the same reading 1-1.5 vdc. I disconnect the jumper and the voltage jumps to 12 volts. I am not sure what is going on. I am starting to think that the ECM is going bad is shorting out the voltage. This car has eaten through some batteries. I have put 4 batteries in the car in the past 5 years.

Has anyone else experienced this problem? Is there a way to test? Am I on the right track? any help would be appreciated as I need to get the car moved asap.

Thanks

 

This sounds like a bad wire connection upstream of your original fuse location and it is causing a voltage drop and yielding only your 1.5V that you measure at that point.
I would trace the red wire upstream (toward the battery) and see where it joins the main harness and check all those connections. The fault must be there or at the battery cable/ terminals.
A quick thing to check also would be to disconnect your temporary connection where the inline fuse used to be. Does it spark? That would point to a parasitic draw.

 

You realize the fuse was there for a reason?
To stop your car burning down should that wire short out

ECM has no connection to that power wire , all it does is close the pump relay so power passes from your wire to the pump.
If the ECM was grounding (operating ) the relay when it should not then your pump would be running fulltime

 

Check the fuel pump relay connector, make sure their isn't any corrosion or lose wires.

 

Thanks for the responses. I have taken the fuseable link completely out. When the red and orange wire is connected I have only 1.5 vdc. when I disconnect the orange and red wire I have 12.3 vdc on red wire and 0 vdc on orange. When I reconnect them it drops back down to 1.5 vdc.

I am reading 1.5 volts at the fuel pump relay also on the orange wire. I have cut this wire to isolate the relay and the pump and I am still getting the draw on the wire. I have since reconnected. I am getting a great connection at the relay.

I do understand why the fuse was there. I removed it for a temporary time to simply trouble shoot the problem It seemed as though it was the issue and I was losing power at that location. I don't leave the battery hooked up unless I am working on it. I will replace when I figure out the issue with a new inline fuse holder and fuse.

Looking at the following wire diagram it does go to the dcm and a few other locations.
http://www.austinthirdgen.org/index.php?pid=19

I am thinking that one of the other items is the issue. I just dont understand why she ran perfect for 20 min and then just shut down.

 

There's something wrong with that schematic (fig 43 1989 5.7 Engine) If you look at the Mass Air Flow Relay (the one that looks like a relay and not the empty rectangle below it), it clearly shows that when the relay activates it will short the Orange wire straight to Ground (BLK/WHT). That can't be right.

 

The ECM actually provides a 12 volt positive trigger to the fuel pimp relay.

The problem sounds like a corroded connection upstream of the fuse holder location. I have traced several similar voltage problems in 80's GM vehicles to corroded connections, both under the hood and inside. There is enough of a connection to provide full voltage with no load (disconnected from the relay) but not enough of a connection to provide sufficient current when connected to a load. I'm sure you'd find that 1.5v drop to 0 when you tried energizing thw fuel through that same wire, such as key on fuel pump prime.

You will likely need to trace farther upstream towards the battery, looking for a splice or a bulged part of the wire, this would be likely locations for corrosion. You may end up needing to replace the wire entirely.

 

I will try this. To test can I go straight from battery terminal to orange wire for the fuseable link. Thanks for the advice

 

my car will run only if i push on the gas, 12v to red wire on the relay, nothing on all the others, i tried jumping it under the dash and no fuel pump sound but i can hear it prime when i turn the key on though, and thoughts please

 

Most cars do that, but if you step on the other pedal it will stop. Lol jk what engine do you have?

 

350 tpi? Make sure your fuel pressure regulator is working properly, check fuel pressure, should be 35 40 psi , vacuum leaks, timing. Fuel pump relay. Worse case scenario fuel injectors going bad.