Digital dash guys using FAST

[TurboDave]

Here's my question, and maybe puddin can answer this.... Why cut and splice into the injector harness (12v side)?? The original harness in the car has the wire going from the ECM to the injector harness (via a fuse I assume)(cant check, scot's got my books)
So if that wire's there and the FAST has an interface harness, and FAST should be applying power to various things similar to the stock ECM, why was there a new source of 12v run to the injector harness.
Didn't fast have that same provision supplying power to the already existing wire harness????

 

[Mike Licht]

Scot. If you are using a jumper harness to connect the fast to the stock harness you must make a connection from the signal lead of maf to the signal of the MAP to get the ifn to the ecm. The MAF signal wire is grey with a red tracer (middle wire) the MAP signal is also the middle wire and in the stock harness is green. If you have a digital dash car you will need to supply 5 volts to power the MAP but it sounds like you have that covered. Call me if you need some help 586 294 4404
Mike

 

[Mike Licht]

Here's my question, and maybe puddin can answer this.... Why cut and splice into the injector harness (12v side)?? The original harness in the car has the wire going from the ECM to the injector harness (via a fuse I assume)(cant check, scot's got my books)
So if that wire's there and the FAST has an interface harness, and FAST should be applying power to various things similar to the stock ECM, why was there a new source of 12v run to the injector harness.
Didn't fast have that same provision supplying power to the already existing wire harness????

The stock ECM harness does not power the MAP sensor, it is not connected to the ECM it just runs the stock boost gauge so the power comes from the dashboard. If you do not have an analog dash with a boost gauge (digital dash) you have no power going to the MAP harness
Mike

 

[puddinpower]

Here's my question, and maybe puddin can answer this.... Why cut and splice into the injector harness (12v side)?? The original harness in the car has the wire going from the ECM to the injector harness (via a fuse I assume)(cant check, scot's got my books)
So if that wire's there and the FAST has an interface harness, and FAST should be applying power to various things similar to the stock ECM, why was there a new source of 12v run to the injector harness.
Didn't fast have that same provision supplying power to the already existing wire harness????

Dave my understanding is that wire is a signal wire for the fast.

 

[Mike Licht]

Here's my question, and maybe puddin can answer this.... Why cut and splice into the injector harness (12v side)?? The original harness in the car has the wire going from the ECM to the injector harness (via a fuse I assume)(cant check, scot's got my books)
So if that wire's there and the FAST has an interface harness, and FAST should be applying power to various things similar to the stock ECM, why was there a new source of 12v run to the injector harness.
Didn't fast have that same provision supplying power to the already existing wire harness????

Dave I misread you question. When the PTE jumper harness was made for the FP/FAST it was thought that the factory power lead to the injectors was not good enough for LOW-Z injectors and the extra power they draw so they supply a new injector power lead that is bigger and goes right to the battery. We have used them both ways and not seen much difference.
MIke

 

[TurboDave]

Dave I misread you question. When the PTE jumper harness was made for the FP/FAST it was thought that the factory power lead to the injectors was not good enough for LOW-Z injectors and the extra power they draw so they supply a new injector power lead that is bigger and goes right to the battery. We have used them both ways and not seen much difference.
MIke

Ahhhh. thanks. makes sense. But I'd rather try the original with a minimum of cutting and splicing, then change only if needed.
Any time there's a cut or splice needed, there's room for errors.

Probably why I would always opt to pay the extra $$$ for plug-n-play adapters whenever possible.

 

[scot w.]

Dave I misread you question. When the PTE jumper harness was made for the FP/FAST it was thought that the factory power lead to the injectors was not good enough for LOW-Z injectors and the extra power they draw so they supply a new injector power lead that is bigger and goes right to the battery. We have used them both ways and not seen much difference.
MIke

This was the problem!! It's solved now!! WEWWW!!

I want to personally thank Everyone who was involved with helping me on this problem I really appreciate what you have done for me and can't say thanks enough.

Sincerly, Scot W.

 

[HighPSI]

No problem. have Puddin' call me again if you have any more questions. I will send out a start up program tonight.

 

[TurboDave]

Now we have to track down a new IAC angle boss. Seems the one Scot has must have taken a differnet IAC. The seat surface inside where the iac plunger should seat is HUGE. At least .100 larger in diameter than the pintle on the iac. We couldn't get the idle under control (stayed at about 1500) until replacing the angle boss with a stock piece.

Are there different angle bosses??

 

[SloGN]

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

YOU HIT THE NAIL ON THE HEAD MIKE.

i was having a tuning issue with my car and i used the 5 volt power supply in the dash and just unhooked the center map wire and spliced in the map reference wire.

what i noticed was at an idle the kpa would be like 43-45 then i turn the headlights on and it would jump up and be idling at 55-60 kpa.

this made tunning for me a pain cause at night i would cruise around and tune my part throttle tables and the next day it would be real lean and have to add fuel back into it.

so my fix was to pull power from the TPS like you recommended above

i have post info on this before
It would be my guess that since the power supply gets unstable that would be the reason for the tach/boost gauge to become goofy also

 

[TurboDave]

YOU HIT THE NAIL ON THE HEAD MIKE.

i was having a tuning issue with my car and i used the 5 volt power supply in the dash and just unhooked the center map wire and spliced in the map reference wire.

what i noticed was at an idle the kpa would be like 43-45 then i turn the headlights on and it would jump up and be idling at 55-60 kpa.

this made tunning for me a pain cause at night i would cruise around and tune my part throttle tables and the next day it would be real lean and have to add fuel back into it.

so my fix was to pull power from the TPS like you recommended above

i have post info on this before
It would be my guess that since the power supply gets unstable that would be the reason for the tach/boost gauge to become goofy also

YUP!!

As I have been learning the hard way over the years. I've learned that if I need a good (fairly stable) source (whether it be 12v or 5v), I go under the hood to find it, not in/under the dash.