i'm going to use my existing high speed fuel pump relay, when you say "sent the fuel pump signal to a relay", do you let the PCM energize the high speed fuel pump relay? looks like I could energize the relay directly from the ignition switch in the run/start position but the pump would run all the time the switch is on and that may be ok, but with the PCM controlling the relay, I guess it would run the pump a few seconds when you turn the ignition on then stop if you don't go to start (i'm guessing at this). which way do you think would be best?Shouldn't be to difficult, been running mine for years with out it used a temp sensor in the block for the fan via a relay and sent the fuel pump signal to a relay for that as well. You just wont have the variable speed for either.
do you recall what circuit you used to fire the fuel pump relay? I tried circuit 926, pin 18, (fuel pump input) from the PCM but it didn't work. I thought I had previously measured 12vdc at this circuit but now I only measure <1vdc. I think the PCM is powered up ok, if I fire the fuel pump relay with +12vdc from the switch, it starts and runs fine.Yes, use the PCM signal to fire the relay. also i found a 190 temp switch (gm Part), I double checked for a placement I put that one in the cross over tube as well as the sensor for the PCM the gauge sending unit went in the block under the driver side header toward the rear.
sorry Patrick, I wrote down the wrong end of that circuit 926. it is pin 22, fuel pump enable. when I was troubleshooting to find out that the vcrm was bad, I thought I read +12vdc on it at the data link connector.Try fuel pump output enable pin 22. I'm at work right know when I get home I can look at my notes and let you know exactly. it's been six years so I would like to be sure.
sorry to revive a 6 year old thread but my 93 Mark VIII fried the VCRM and finding a replacement is impossible. Think you’d be able to go a little more in depth on how you bypassed the VCRM? Ac and fan control isn’t an issue.Getting it running is my goal. You can also email me @ [email protected]thanks Patrick, I hooked it up like you said and it works great. can't think you guys enough, without help from you guys a lot of these projects would be abandoned.