Digital dash guys using FAST

[scot w.]

I need help with something please! I just installed FAST b2b and just turned the key to "on" today for the first time and noticed that when turned off and the key taken out of the ignition, the dash lights and the yellow turbo light stays on untill it's disconected from the batt. (Note) I have a optima red top batt and the reg car stuff runs off the top posts and the fast system runs off the side posts. please help!! Thank you! Scot w.

here is a pic of the unit...

 

[krom]

I remember that a 5 volt supply was missing and had to be found to make both of my digital dash cars work. The person who did the installs knew about the missing voltage while connecting the harness.

 

[scot w.]

Well i narrowed it down to the injector plug connector. The pink wire was cut and spliced correctly and ohms out fine! you plug the injector harness up turn the key to the "on" possition and turn it back off "the dash lights still stay on" after turning the key off.. I un-plug the injector harness and they go out.. this if Fricking killing me here!!!! ?????????????

 

[HighPSI]

PM sent

 

[scot w.]

still not fixed!!!

 

[LV GN]

i think it has something to do with the map sensor wiring. did you try unpluging it?

 

[puddinpower]

Cal you have a Pm

Puddin

 

[Mike Licht]

Easy place to pull power for the MAP sensor is from the TPS. Caspers has a harness for this that makes it all plug and play
Mike

 

[TurboDave]

I'll have to check the voltage/grounds on the plugs on my cars. I would think that both "map" connectors (the map 3 prong, and the 2 prong boost light) should have 12 volts and ground.
I could be wrong though, may the voltage ground are applied to the appropriate plug via the dash installed.

In other words, in a digital dash car, the 3 prong map plug is still out there under the hood, but does it have 12 v and ground applied?

 

[scot w.]

Easy place to pull power for the MAP sensor is from the TPS. Caspers has a harness for this that makes it all plug and play
Mike

i think the easyiest place would be right next to the map sensor, it's the existing two prong that went to the "old" style pressure switch type that ran the boost lights, that two prong plug has 12v on it with the key "On". I'm using a adapter harness from the FAST to the ECM wires, shouldn't that be like a plug and play?

 

[scot w.]

I'll have to check the voltage/grounds on the plugs on my cars. I would think that both "map" connectors (the map 3 prong, and the 2 prong boost light) should have 12 volts and ground.
I could be wrong though, may the voltage ground are applied to the appropriate plug via the dash installed.

In other words, in a digital dash car, the 3 prong map plug is still out there under the hood, but does it have 12 v and ground applied?

answer to the last question: "no" mine don't! with "key on" the grey wire has 5v and the other two don't have anything, and if i put one test lead on a ground and one on the other two prongs of the 3-bar plug "Nothing" no ground either!

 

[scot w.]

i think it has something to do with the map sensor wiring. did you try unpluging it?

YES!

 

[Mike Licht]

map sensors need 5 volts not 12, the 5 volts comes from the dashboard on an analog dash car. At this point in time we are seing more and more cars with unstable 5 volts from the dash which is causing tuning problems on Big Stuff, XFI, and T-Pro cars that use the dash for powering the MAP sensor.
Mike

 

[puddinpower]

You all tell me if i am wrong but, On the old systems, including gen6 DFI'S, didn't we run a wire from the 5volt wire and a ground wire from the maf plug to the map plug??( Back in the old days )
At least the car i have is wired that way and before the motor was pulled, it ran great. Mine is on the old gen 6 DfI. Doesn't the b2b fast get wired the same way. ( but now under the dash instead of under the hood )

Puddin

 

[Mike Licht]

The only wire we used to run from the MAF was the signal wire on the MAF to the signal wire on the MAP. That gets the signal to the ECM since there was not connection from the ECM to the MAP.
Mike

 

[puddinpower]

is the signal wire a 5 volt wire or a 12 volt wire??

 

[TurboDave]

You all tell me if i am wrong but, On the old systems, including gen6 DFI'S, didn't we run a wire from the 5volt wire and a ground wire from the maf plug to the map plug??( Back in the old days )
At least the car i have is wired that way and before the motor was pulled, it ran great. Mine is on the old gen 6 DfI. Doesn't the b2b fast get wired the same way. ( but now under the dash instead of under the hood )

Puddin

Puddin, I'm no expert on this subject, but.... My recommedation would be to get the 5volt reference and any needed grounds from a convenient point under the hood. It's closer, and if my assumptions are correct, it would be a more stable source since it would have fewer bulkhead connections to navigate.
Like I said, I'm just guessing.

 

[puddinpower]

Puddin, I'm no expert on this subject, but.... My recommedation would be to get the 5volt reference and any needed grounds from a convenient point under the hood. It's closer, and if my assumptions are correct, it would be a more stable source since it would have fewer bulkhead connections to navigate.
Like I said, I'm just guessing.

I was just wandering about the old way that it used to be done.There has to be a simple reason why his dash lights are doing this. I think that there is only about 3 or 4 things that can or could be happening. #1 a problem with the wire,circuit,or.... in the pink wire that goes to the injector harness #2 the wiring from the maf to the map is wrong and it is feeding some how a constant 12 volts to the map plug in which in return is giving him 12 volts to the dash when actavated and does not cut off when the key is turned off. #3 bad interface harness ( wiring in the harness is screwed up on this circuit )
#4 Scot and i are losing our minds and we are going to rely on beer to retain the little bit of sanity we have left !!!!!!!

Puddin

 

[scot w.]

map sensors need 5 volts not 12, the 5 volts comes from the dashboard on an analog dash car. At this point in time we are seing more and more cars with unstable 5 volts from the dash which is causing tuning problems on Big Stuff, XFI, and T-Pro cars that use the dash for powering the MAP sensor.
Mike

what is being done to solve this? Also: so if iv'e already got 5v to the grey wire on the 3-bar map sensor plug what do i need to do next?

My MAP sensor plug has: grey / red / black

the MAF sensor plug has: pnk/blk, wht/red, blk/wht

 

[scot w.]

I was just wandering about the old way that it used to be done.There has to be a simple reason why his dash lights are doing this. I think that there is only about 3 or 4 things that can or could be happening. #1 a problem with the wire,circuit,or.... in the pink wire that goes to the injector harness #2 the wiring from the maf to the map is wrong and it is feeding some how a constant 12 volts to the map plug in which in return is giving him 12 volts to the dash when actavated and does not cut off when the key is turned off. #3 bad interface harness ( wiring in the harness is screwed up on this circuit )
#4 Scot and i are losing our minds and we are going to rely on beer to retain the little bit of sanity we have left !!!!!!!

Puddin

Well on #1 it's more likely the pink wire (cause prior to hooking up the FAST wire, "it didn't do it!") #2 the wiring to from maf to map has been cut in two thus elliminating #2! #3 - very possible! #4 if problem not solved i'll just go back with the reg ECM and a chip. ALOT cheaper and less headachs