Quote:
Originally Posted by GregWeld
Sounds to me you might have isolated the issue already.... unless I'm just all messed up. Which is usually the case.
The ECU pin out is NEGATIVE -- so it doesn't actually put out any "voltage" -- it just goes to ground - thus grounding the relay actuating it. The relay would have a big gauge wire ground - big gauge load positive - ignition 12V positive - and a ground. In this case the ground would go to the ECU...
correct me if I'm wrong -- so then the RELAY operates some kind of pump controller??? Or does the pump "controller" run the relay??
It's so hard to troubleshoot without a schematic to follow so I'm just picturing in my head - your particular set up and I'm unfamiliar with the Vaporworks (other than I know Carl and he and his stuff are GREAT!).
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Greg... I don't know all the details of how Carl's digital fuel pump controller works, but I'll try to explain it. One 12 volt + input wire with a 25 amp fuse goes from the battery to the digital controller. One 12 volt + input from the ECM "fuel system relay arming source" goes to the digital controller "signal conditioning module"... and one ground wire goes from the chassis to the digital controller.
When the key is on... the digital controller then puts out whatever voltage is required to run the fuel pump and maintain the desired preset fuel pressure. My pump runs in the range of about 7-12 volts to maintain a fuel system pressure of 58 psi..
You do have to be careful when wiring devices to the ECM. Some pin outputs are negative and some are positive. My fuel system relay arming source was positive. The best bet is to get a schematic like you said.
I was finally able to get the car running today after 2 days of trouble shooting!! The problem was a bad ground. There is main ground for the ECM that is grounded at the back of the engine block next to the head. The bolt securing the ground was tight.... but it turned out the bolt had bottomed out in the hole before the ground connection was completely tight. I cut 1/8" off the end of the bolt... and then re-tightened the connection and that solved the problem. The voltage output from the ECM to the "signal conditioning module" went from 9.8 to 12 volts!!
It was not obvious that the connection was loose... so I feel very lucky that I was able to solve the problem. It's great to be up and running again
