Installed FAST/fuel pump stays on

[TMGN]

I just installed a FAST B2B system on my 86GN.I also installed a complete external pumped/sumped tank fuel system.Anyway,when I turn the key on and usually the pump primes for 2 seconds ,the pump turns on and stays on.I checked the wiring and it looks good.I beleive it has to do with the FAST system.Any suggestions???THanks,Tony

 

[EightSecV6]

how did you wire it? Sounds lie the 85 terminal on the relay is possibly shorted to ground.

 

[Dusty Bradford]

I just installed a FAST B2B system on my 86GN.I also installed a complete external pumped/sumped tank fuel system.Anyway,when I turn the key on and usually the pump primes for 2 seconds ,the pump turns on and stays on.I checked the wiring and it looks good.I beleive it has to do with the FAST system.Any suggestions???THanks,Tony

Are you using the stand alone harness or the factory harness with adapter?

 

[bobc455]

There is a setting in CalCom that allows up to 25 seconds (I think) of fuel pump "priming". Does it stay on for that long?

Also, "looks good" is a bit light of a description for checking the wiring. Are you sure that the output from the FAST grounds the relay "trigger"? Remember that you don't want any significant current going through the FAST.

-Bob C.

 

[TMGN]

Its the factory harness with the adapter harness.I went over the fuel pump wiring.I beleive its right.I am very new to FAST so I was looking around and didnt realize you can change the fuel pump priming time.I will try and see if this works.Thanks for all the help.Keep it coming.

 

[TMGN]

I went into the FAST priming section and it said 10 sec.So I adjusted it to 3.Thought I had it.But I turned the key and still running constantly.Let me know what you think?Fuel pump relay??

 

[Otto J]

If the fuel pump turns on with hte key it may just be a stcuk relay,
Check the factory relay and the hotwire relay if you have one,Just tap on them while the pump is running
That may work

 

[TMGN]

Well I changed the stock relay and put on a whole new hot wire kit that has a new relay also.I turned the key and it still runs constantly.I have it wired like this:87to the pump,86 ground,30 is power going to the alt,85 is the trigger going to the grey wire coming out of the stock harness.Is the 3 wires in the stock harness a ground/fuel guage wire/and the trigger wire?When I turn the key and I test the trigger (grey wire)it has a constant 12 volts.Any ideas ,I am running out of ideas and dont know what to do at this point.I stress that I'm very new to FAST .Thanks For your time,Tony

 

[EightSecV6]

Turn on the key, unplug the STOCK relay, does it stop?

 

[TMGN]

Sorry it took so long to get back,yes it does turn off when I pull the stock relay.

 

[TMGN]

ttttttttttttttttttttt

 

[HighPSI]

It sounds like the tigger wire is permanently grounded. If you want, give me a call and we'll double check a few things.

 

[TMGN]

Thanks Cal.Whens a good time to call?Thanks,Tony

 

[EightSecV6]

Pull the relay and test it with an ohm meter, it is probably stuck. You can also test it quickly by leaving the key on with the pump running, pull the factory relay to make it stop, plug it back in and listen/feel it to see if it clicks (closes). If it does click, more than likely it is in the wiring.I know you changed the relay once, we just got a bad one right from GM about 2 weeks ago.

 

[Buzzard]

Check the oil pressure switch connector, if the sending unit leaks the connector turns to mush and the wiring can touch causing the fuel pump to run whenever the key is turned on.

 

[HighPSI]

Thanks Cal.Whens a good time to call?Thanks,Tony

You can call me anytime at 321-863-2303. If you get my voicemail (likely) just leave a message.

 

[Buzzard]

Did you get this fixed yet, if so post your results please.

 

[TMGN]

No not fixed yet.Not sure what to do.I changed a bunch of things that I guess could of caused this.Besides installing FAST, I put an external fuel pump,battery in trunk with on/off swich.The trigger wire (grey) is always hot.Thanks Tony